sync headless code from bb

3 files changed, 666 insertions, 657 deletions

diff --git a/src/headless.js b/src/headless.js
index 1c7b8945..e5458641 100644
--- a/src/headless.js
+++ b/src/headless.js
@@ -1,23 +1,12 @@
 
 //== HEADLESS ==//
 
-// TODO: sync from bananabread headless.js
+var headlessPrint = function(x) {
+  //print(x);
+}
 
 var window = {
-  eventListeners: {},
-  addEventListener: function(id, func) {
-    var listeners = this.eventListeners[id];
-    if (!listeners) {
-      listeners = this.eventListeners[id] = [];
-    }
-    listeners.push(func);
-  },
-  callEventListeners: function(id) {
-    var listeners = this.eventListeners[id];
-    if (listeners) {
-      listeners.forEach(function(listener) { listener() });
-    }
-  },
+  // adjustable parameters
   location: {
     toString: function() {
       return '%s';
@@ -25,31 +14,37 @@ var window = {
     search: '?%s',
     pathname: '%s',
   },
+  onIdle: function(){ headlessPrint('triggering click'); document.querySelector('.fullscreen-button.low-res').callEventListeners('click'); window.onIdle = null; },
+  dirsToDrop: 0, // go back to root dir if first_js is in a subdir
+  //
+
+  headless: true,
+
+  stopped: false,
   fakeNow: 0, // we don't use Date.now()
   rafs: [],
   timeouts: [],
   uid: 0,
   requestAnimationFrame: function(func) {
     func.uid = window.uid++;
-    print('adding raf ' + func.uid);
+    headlessPrint('adding raf ' + func.uid);
     window.rafs.push(func);
   },
   setTimeout: function(func, ms) {
     func.uid = window.uid++;
-    print('adding timeout ' + func.uid);
+    headlessPrint('adding timeout ' + func.uid);
     window.timeouts.push({
       func: func,
       when: window.fakeNow + (ms || 0)
     });
     window.timeouts.sort(function(x, y) { return y.when - x.when });
   },
-  onIdle: %s,
   runEventLoop: function() {
     // run forever until an exception stops this replay
     var iter = 0;
-    while (1) {
-      var start = Recorder.dnow();
-      print('event loop: ' + (iter++));
+    while (!this.stopped) {
+      var start = Date.realNow();
+      headlessPrint('event loop: ' + (iter++));
       if (window.rafs.length == 0 && window.timeouts.length == 0) {
         if (window.onIdle) {
           window.onIdle();
@@ -62,7 +57,7 @@ var window = {
       window.rafs = [];
       for (var i = 0; i < currRafs.length; i++) {
         var raf = currRafs[i];
-        print('calling raf: ' + raf.uid);// + ': ' + raf.toString().substring(0, 50));
+        headlessPrint('calling raf: ' + raf.uid);// + ': ' + raf.toString().substring(0, 50));
         raf();
       }
       // timeouts
@@ -71,24 +66,14 @@ var window = {
       window.timeouts = [];
       while (timeouts.length && timeouts[timeouts.length-1].when <= now) {
         var timeout = timeouts.pop();
-        print('calling timeout: ' + timeout.func.uid);// + ': ' + timeout.func.toString().substring(0, 50));
+        headlessPrint('calling timeout: ' + timeout.func.uid);// + ': ' + timeout.func.toString().substring(0, 50));
         timeout.func();
       }
       // increment 'time'
       window.fakeNow += 16.666;
-      print('main event loop iteration took ' + (Recorder.dnow() - start) + ' ms');
+      headlessPrint('main event loop iteration took ' + (Date.realNow() - start) + ' ms');
     }
   },
-  URL: {
-    createObjectURL: function(x) {
-      return x; // the blob itself is returned
-    },
-    revokeObjectURL: function(x) {},
-  },
-  encodeURIComponent: function(x) { return x },
-};
-var setTimeout = window.setTimeout;
-var document = {
   eventListeners: {},
   addEventListener: function(id, func) {
     var listeners = this.eventListeners[id];
@@ -103,619 +88,25 @@ var document = {
       listeners.forEach(function(listener) { listener() });
     }
   },
+  URL: {
+    createObjectURL: function(x) {
+      return x; // the blob itself is returned
+    },
+    revokeObjectURL: function(x) {},
+  },
+  encodeURIComponent: function(x) { return x },
+};
+var setTimeout = window.setTimeout;
+var document = {
+  headless: true,
+  eventListeners: {},
+  addEventListener: window.addEventListener,
+  callEventListeners: window.callEventListeners,
   getElementById: function(id) {
     switch(id) {
       case 'canvas': {
         if (this.canvas) return this.canvas;
-        return this.canvas = {
-          getContext: function(which) {
-            switch(which) {
-              case 'experimental-webgl': {
-                return {
-                  /* ClearBufferMask */
-                  DEPTH_BUFFER_BIT               : 0x00000100,
-                  STENCIL_BUFFER_BIT             : 0x00000400,
-                  COLOR_BUFFER_BIT               : 0x00004000,
-                  
-                  /* BeginMode */
-                  POINTS                         : 0x0000,
-                  LINES                          : 0x0001,
-                  LINE_LOOP                      : 0x0002,
-                  LINE_STRIP                     : 0x0003,
-                  TRIANGLES                      : 0x0004,
-                  TRIANGLE_STRIP                 : 0x0005,
-                  TRIANGLE_FAN                   : 0x0006,
-                  
-                  /* AlphaFunction (not supported in ES20) */
-                  /*      NEVER */
-                  /*      LESS */
-                  /*      EQUAL */
-                  /*      LEQUAL */
-                  /*      GREATER */
-                  /*      NOTEQUAL */
-                  /*      GEQUAL */
-                  /*      ALWAYS */
-                  
-                  /* BlendingFactorDest */
-                  ZERO                           : 0,
-                  ONE                            : 1,
-                  SRC_COLOR                      : 0x0300,
-                  ONE_MINUS_SRC_COLOR            : 0x0301,
-                  SRC_ALPHA                      : 0x0302,
-                  ONE_MINUS_SRC_ALPHA            : 0x0303,
-                  DST_ALPHA                      : 0x0304,
-                  ONE_MINUS_DST_ALPHA            : 0x0305,
-                  
-                  /* BlendingFactorSrc */
-                  /*      ZERO */
-                  /*      ONE */
-                  DST_COLOR                      : 0x0306,
-                  ONE_MINUS_DST_COLOR            : 0x0307,
-                  SRC_ALPHA_SATURATE             : 0x0308,
-                  /*      SRC_ALPHA */
-                  /*      ONE_MINUS_SRC_ALPHA */
-                  /*      DST_ALPHA */
-                  /*      ONE_MINUS_DST_ALPHA */
-                  
-                  /* BlendEquationSeparate */
-                  FUNC_ADD                       : 0x8006,
-                  BLEND_EQUATION                 : 0x8009,
-                  BLEND_EQUATION_RGB             : 0x8009,   /* same as BLEND_EQUATION */
-                  BLEND_EQUATION_ALPHA           : 0x883D,
-                  
-                  /* BlendSubtract */
-                  FUNC_SUBTRACT                  : 0x800A,
-                  FUNC_REVERSE_SUBTRACT          : 0x800B,
-                  
-                  /* Separate Blend Functions */
-                  BLEND_DST_RGB                  : 0x80C8,
-                  BLEND_SRC_RGB                  : 0x80C9,
-                  BLEND_DST_ALPHA                : 0x80CA,
-                  BLEND_SRC_ALPHA                : 0x80CB,
-                  CONSTANT_COLOR                 : 0x8001,
-                  ONE_MINUS_CONSTANT_COLOR       : 0x8002,
-                  CONSTANT_ALPHA                 : 0x8003,
-                  ONE_MINUS_CONSTANT_ALPHA       : 0x8004,
-                  BLEND_COLOR                    : 0x8005,
-                  
-                  /* Buffer Objects */
-                  ARRAY_BUFFER                   : 0x8892,
-                  ELEMENT_ARRAY_BUFFER           : 0x8893,
-                  ARRAY_BUFFER_BINDING           : 0x8894,
-                  ELEMENT_ARRAY_BUFFER_BINDING   : 0x8895,
-                  
-                  STREAM_DRAW                    : 0x88E0,
-                  STATIC_DRAW                    : 0x88E4,
-                  DYNAMIC_DRAW                   : 0x88E8,
-                  
-                  BUFFER_SIZE                    : 0x8764,
-                  BUFFER_USAGE                   : 0x8765,
-                  
-                  CURRENT_VERTEX_ATTRIB          : 0x8626,
-                  
-                  /* CullFaceMode */
-                  FRONT                          : 0x0404,
-                  BACK                           : 0x0405,
-                  FRONT_AND_BACK                 : 0x0408,
-                  
-                  /* DepthFunction */
-                  /*      NEVER */
-                  /*      LESS */
-                  /*      EQUAL */
-                  /*      LEQUAL */
-                  /*      GREATER */
-                  /*      NOTEQUAL */
-                  /*      GEQUAL */
-                  /*      ALWAYS */
-                  
-                  /* EnableCap */
-                  /* TEXTURE_2D */
-                  CULL_FACE                      : 0x0B44,
-                  BLEND                          : 0x0BE2,
-                  DITHER                         : 0x0BD0,
-                  STENCIL_TEST                   : 0x0B90,
-                  DEPTH_TEST                     : 0x0B71,
-                  SCISSOR_TEST                   : 0x0C11,
-                  POLYGON_OFFSET_FILL            : 0x8037,
-                  SAMPLE_ALPHA_TO_COVERAGE       : 0x809E,
-                  SAMPLE_COVERAGE                : 0x80A0,
-                  
-                  /* ErrorCode */
-                  NO_ERROR                       : 0,
-                  INVALID_ENUM                   : 0x0500,
-                  INVALID_VALUE                  : 0x0501,
-                  INVALID_OPERATION              : 0x0502,
-                  OUT_OF_MEMORY                  : 0x0505,
-                  
-                  /* FrontFaceDirection */
-                  CW                             : 0x0900,
-                  CCW                            : 0x0901,
-                  
-                  /* GetPName */
-                  LINE_WIDTH                     : 0x0B21,
-                  ALIASED_POINT_SIZE_RANGE       : 0x846D,
-                  ALIASED_LINE_WIDTH_RANGE       : 0x846E,
-                  CULL_FACE_MODE                 : 0x0B45,
-                  FRONT_FACE                     : 0x0B46,
-                  DEPTH_RANGE                    : 0x0B70,
-                  DEPTH_WRITEMASK                : 0x0B72,
-                  DEPTH_CLEAR_VALUE              : 0x0B73,
-                  DEPTH_FUNC                     : 0x0B74,
-                  STENCIL_CLEAR_VALUE            : 0x0B91,
-                  STENCIL_FUNC                   : 0x0B92,
-                  STENCIL_FAIL                   : 0x0B94,
-                  STENCIL_PASS_DEPTH_FAIL        : 0x0B95,
-                  STENCIL_PASS_DEPTH_PASS        : 0x0B96,
-                  STENCIL_REF                    : 0x0B97,
-                  STENCIL_VALUE_MASK             : 0x0B93,
-                  STENCIL_WRITEMASK              : 0x0B98,
-                  STENCIL_BACK_FUNC              : 0x8800,
-                  STENCIL_BACK_FAIL              : 0x8801,
-                  STENCIL_BACK_PASS_DEPTH_FAIL   : 0x8802,
-                  STENCIL_BACK_PASS_DEPTH_PASS   : 0x8803,
-                  STENCIL_BACK_REF               : 0x8CA3,
-                  STENCIL_BACK_VALUE_MASK        : 0x8CA4,
-                  STENCIL_BACK_WRITEMASK         : 0x8CA5,
-                  VIEWPORT                       : 0x0BA2,
-                  SCISSOR_BOX                    : 0x0C10,
-                  /*      SCISSOR_TEST */
-                  COLOR_CLEAR_VALUE              : 0x0C22,
-                  COLOR_WRITEMASK                : 0x0C23,
-                  UNPACK_ALIGNMENT               : 0x0CF5,
-                  PACK_ALIGNMENT                 : 0x0D05,
-                  MAX_TEXTURE_SIZE               : 0x0D33,
-                  MAX_VIEWPORT_DIMS              : 0x0D3A,
-                  SUBPIXEL_BITS                  : 0x0D50,
-                  RED_BITS                       : 0x0D52,
-                  GREEN_BITS                     : 0x0D53,
-                  BLUE_BITS                      : 0x0D54,
-                  ALPHA_BITS                     : 0x0D55,
-                  DEPTH_BITS                     : 0x0D56,
-                  STENCIL_BITS                   : 0x0D57,
-                  POLYGON_OFFSET_UNITS           : 0x2A00,
-                  /*      POLYGON_OFFSET_FILL */
-                  POLYGON_OFFSET_FACTOR          : 0x8038,
-                  TEXTURE_BINDING_2D             : 0x8069,
-                  SAMPLE_BUFFERS                 : 0x80A8,
-                  SAMPLES                        : 0x80A9,
-                  SAMPLE_COVERAGE_VALUE          : 0x80AA,
-                  SAMPLE_COVERAGE_INVERT         : 0x80AB,
-                  
-                  /* GetTextureParameter */
-                  /*      TEXTURE_MAG_FILTER */
-                  /*      TEXTURE_MIN_FILTER */
-                  /*      TEXTURE_WRAP_S */
-                  /*      TEXTURE_WRAP_T */
-                  
-                  COMPRESSED_TEXTURE_FORMATS     : 0x86A3,
-                  
-                  /* HintMode */
-                  DONT_CARE                      : 0x1100,
-                  FASTEST                        : 0x1101,
-                  NICEST                         : 0x1102,
-                  
-                  /* HintTarget */
-                  GENERATE_MIPMAP_HINT            : 0x8192,
-                  
-                  /* DataType */
-                  BYTE                           : 0x1400,
-                  UNSIGNED_BYTE                  : 0x1401,
-                  SHORT                          : 0x1402,
-                  UNSIGNED_SHORT                 : 0x1403,
-                  INT                            : 0x1404,
-                  UNSIGNED_INT                   : 0x1405,
-                  FLOAT                          : 0x1406,
-                  
-                  /* PixelFormat */
-                  DEPTH_COMPONENT                : 0x1902,
-                  ALPHA                          : 0x1906,
-                  RGB                            : 0x1907,
-                  RGBA                           : 0x1908,
-                  LUMINANCE                      : 0x1909,
-                  LUMINANCE_ALPHA                : 0x190A,
-                  
-                  /* PixelType */
-                  /*      UNSIGNED_BYTE */
-                  UNSIGNED_SHORT_4_4_4_4         : 0x8033,
-                  UNSIGNED_SHORT_5_5_5_1         : 0x8034,
-                  UNSIGNED_SHORT_5_6_5           : 0x8363,
-                  
-                  /* Shaders */
-                  FRAGMENT_SHADER                  : 0x8B30,
-                  VERTEX_SHADER                    : 0x8B31,
-                  MAX_VERTEX_ATTRIBS               : 0x8869,
-                  MAX_VERTEX_UNIFORM_VECTORS       : 0x8DFB,
-                  MAX_VARYING_VECTORS              : 0x8DFC,
-                  MAX_COMBINED_TEXTURE_IMAGE_UNITS : 0x8B4D,
-                  MAX_VERTEX_TEXTURE_IMAGE_UNITS   : 0x8B4C,
-                  MAX_TEXTURE_IMAGE_UNITS          : 0x8872,
-                  MAX_FRAGMENT_UNIFORM_VECTORS     : 0x8DFD,
-                  SHADER_TYPE                      : 0x8B4F,
-                  DELETE_STATUS                    : 0x8B80,
-                  LINK_STATUS                      : 0x8B82,
-                  VALIDATE_STATUS                  : 0x8B83,
-                  ATTACHED_SHADERS                 : 0x8B85,
-                  ACTIVE_UNIFORMS                  : 0x8B86,
-                  ACTIVE_ATTRIBUTES                : 0x8B89,
-                  SHADING_LANGUAGE_VERSION         : 0x8B8C,
-                  CURRENT_PROGRAM                  : 0x8B8D,
-                  
-                  /* StencilFunction */
-                  NEVER                          : 0x0200,
-                  LESS                           : 0x0201,
-                  EQUAL                          : 0x0202,
-                  LEQUAL                         : 0x0203,
-                  GREATER                        : 0x0204,
-                  NOTEQUAL                       : 0x0205,
-                  GEQUAL                         : 0x0206,
-                  ALWAYS                         : 0x0207,
-                  
-                  /* StencilOp */
-                  /*      ZERO */
-                  KEEP                           : 0x1E00,
-                  REPLACE                        : 0x1E01,
-                  INCR                           : 0x1E02,
-                  DECR                           : 0x1E03,
-                  INVERT                         : 0x150A,
-                  INCR_WRAP                      : 0x8507,
-                  DECR_WRAP                      : 0x8508,
-                  
-                  /* StringName */
-                  VENDOR                         : 0x1F00,
-                  RENDERER                       : 0x1F01,
-                  VERSION                        : 0x1F02,
-                  
-                  /* TextureMagFilter */
-                  NEAREST                        : 0x2600,
-                  LINEAR                         : 0x2601,
-                  
-                  /* TextureMinFilter */
-                  /*      NEAREST */
-                  /*      LINEAR */
-                  NEAREST_MIPMAP_NEAREST         : 0x2700,
-                  LINEAR_MIPMAP_NEAREST          : 0x2701,
-                  NEAREST_MIPMAP_LINEAR          : 0x2702,
-                  LINEAR_MIPMAP_LINEAR           : 0x2703,
-                  
-                  /* TextureParameterName */
-                  TEXTURE_MAG_FILTER             : 0x2800,
-                  TEXTURE_MIN_FILTER             : 0x2801,
-                  TEXTURE_WRAP_S                 : 0x2802,
-                  TEXTURE_WRAP_T                 : 0x2803,
-                  
-                  /* TextureTarget */
-                  TEXTURE_2D                     : 0x0DE1,
-                  TEXTURE                        : 0x1702,
-                  
-                  TEXTURE_CUBE_MAP               : 0x8513,
-                  TEXTURE_BINDING_CUBE_MAP       : 0x8514,
-                  TEXTURE_CUBE_MAP_POSITIVE_X    : 0x8515,
-                  TEXTURE_CUBE_MAP_NEGATIVE_X    : 0x8516,
-                  TEXTURE_CUBE_MAP_POSITIVE_Y    : 0x8517,
-                  TEXTURE_CUBE_MAP_NEGATIVE_Y    : 0x8518,
-                  TEXTURE_CUBE_MAP_POSITIVE_Z    : 0x8519,
-                  TEXTURE_CUBE_MAP_NEGATIVE_Z    : 0x851A,
-                  MAX_CUBE_MAP_TEXTURE_SIZE      : 0x851C,
-                  
-                  /* TextureUnit */
-                  TEXTURE0                       : 0x84C0,
-                  TEXTURE1                       : 0x84C1,
-                  TEXTURE2                       : 0x84C2,
-                  TEXTURE3                       : 0x84C3,
-                  TEXTURE4                       : 0x84C4,
-                  TEXTURE5                       : 0x84C5,
-                  TEXTURE6                       : 0x84C6,
-                  TEXTURE7                       : 0x84C7,
-                  TEXTURE8                       : 0x84C8,
-                  TEXTURE9                       : 0x84C9,
-                  TEXTURE10                      : 0x84CA,
-                  TEXTURE11                      : 0x84CB,
-                  TEXTURE12                      : 0x84CC,
-                  TEXTURE13                      : 0x84CD,
-                  TEXTURE14                      : 0x84CE,
-                  TEXTURE15                      : 0x84CF,
-                  TEXTURE16                      : 0x84D0,
-                  TEXTURE17                      : 0x84D1,
-                  TEXTURE18                      : 0x84D2,
-                  TEXTURE19                      : 0x84D3,
-                  TEXTURE20                      : 0x84D4,
-                  TEXTURE21                      : 0x84D5,
-                  TEXTURE22                      : 0x84D6,
-                  TEXTURE23                      : 0x84D7,
-                  TEXTURE24                      : 0x84D8,
-                  TEXTURE25                      : 0x84D9,
-                  TEXTURE26                      : 0x84DA,
-                  TEXTURE27                      : 0x84DB,
-                  TEXTURE28                      : 0x84DC,
-                  TEXTURE29                      : 0x84DD,
-                  TEXTURE30                      : 0x84DE,
-                  TEXTURE31                      : 0x84DF,
-                  ACTIVE_TEXTURE                 : 0x84E0,
-                  
-                  /* TextureWrapMode */
-                  REPEAT                         : 0x2901,
-                  CLAMP_TO_EDGE                  : 0x812F,
-                  MIRRORED_REPEAT                : 0x8370,
-                  
-                  /* Uniform Types */
-                  FLOAT_VEC2                     : 0x8B50,
-                  FLOAT_VEC3                     : 0x8B51,
-                  FLOAT_VEC4                     : 0x8B52,
-                  INT_VEC2                       : 0x8B53,
-                  INT_VEC3                       : 0x8B54,
-                  INT_VEC4                       : 0x8B55,
-                  BOOL                           : 0x8B56,
-                  BOOL_VEC2                      : 0x8B57,
-                  BOOL_VEC3                      : 0x8B58,
-                  BOOL_VEC4                      : 0x8B59,
-                  FLOAT_MAT2                     : 0x8B5A,
-                  FLOAT_MAT3                     : 0x8B5B,
-                  FLOAT_MAT4                     : 0x8B5C,
-                  SAMPLER_2D                     : 0x8B5E,
-                  SAMPLER_CUBE                   : 0x8B60,
-                  
-                  /* Vertex Arrays */
-                  VERTEX_ATTRIB_ARRAY_ENABLED        : 0x8622,
-                  VERTEX_ATTRIB_ARRAY_SIZE           : 0x8623,
-                  VERTEX_ATTRIB_ARRAY_STRIDE         : 0x8624,
-                  VERTEX_ATTRIB_ARRAY_TYPE           : 0x8625,
-                  VERTEX_ATTRIB_ARRAY_NORMALIZED     : 0x886A,
-                  VERTEX_ATTRIB_ARRAY_POINTER        : 0x8645,
-                  VERTEX_ATTRIB_ARRAY_BUFFER_BINDING : 0x889F,
-                  
-                  /* Shader Source */
-                  COMPILE_STATUS                 : 0x8B81,
-                  
-                  /* Shader Precision-Specified Types */
-                  LOW_FLOAT                      : 0x8DF0,
-                  MEDIUM_FLOAT                   : 0x8DF1,
-                  HIGH_FLOAT                     : 0x8DF2,
-                  LOW_INT                        : 0x8DF3,
-                  MEDIUM_INT                     : 0x8DF4,
-                  HIGH_INT                       : 0x8DF5,
-                  
-                  /* Framebuffer Object. */
-                  FRAMEBUFFER                    : 0x8D40,
-                  RENDERBUFFER                   : 0x8D41,
-                  
-                  RGBA4                          : 0x8056,
-                  RGB5_A1                        : 0x8057,
-                  RGB565                         : 0x8D62,
-                  DEPTH_COMPONENT16              : 0x81A5,
-                  STENCIL_INDEX                  : 0x1901,
-                  STENCIL_INDEX8                 : 0x8D48,
-                  DEPTH_STENCIL                  : 0x84F9,
-                  
-                  RENDERBUFFER_WIDTH             : 0x8D42,
-                  RENDERBUFFER_HEIGHT            : 0x8D43,
-                  RENDERBUFFER_INTERNAL_FORMAT   : 0x8D44,
-                  RENDERBUFFER_RED_SIZE          : 0x8D50,
-                  RENDERBUFFER_GREEN_SIZE        : 0x8D51,
-                  RENDERBUFFER_BLUE_SIZE         : 0x8D52,
-                  RENDERBUFFER_ALPHA_SIZE        : 0x8D53,
-                  RENDERBUFFER_DEPTH_SIZE        : 0x8D54,
-                  RENDERBUFFER_STENCIL_SIZE      : 0x8D55,
-                  
-                  FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE           : 0x8CD0,
-                  FRAMEBUFFER_ATTACHMENT_OBJECT_NAME           : 0x8CD1,
-                  FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL         : 0x8CD2,
-                  FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE : 0x8CD3,
-                  
-                  COLOR_ATTACHMENT0              : 0x8CE0,
-                  DEPTH_ATTACHMENT               : 0x8D00,
-                  STENCIL_ATTACHMENT             : 0x8D20,
-                  DEPTH_STENCIL_ATTACHMENT       : 0x821A,
-                  
-                  NONE                           : 0,
-                  
-                  FRAMEBUFFER_COMPLETE                      : 0x8CD5,
-                  FRAMEBUFFER_INCOMPLETE_ATTACHMENT         : 0x8CD6,
-                  FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT : 0x8CD7,
-                  FRAMEBUFFER_INCOMPLETE_DIMENSIONS         : 0x8CD9,
-                  FRAMEBUFFER_UNSUPPORTED                   : 0x8CDD,
-                  
-                  FRAMEBUFFER_BINDING            : 0x8CA6,
-                  RENDERBUFFER_BINDING           : 0x8CA7,
-                  MAX_RENDERBUFFER_SIZE          : 0x84E8,
-                  
-                  INVALID_FRAMEBUFFER_OPERATION  : 0x0506,
-                  
-                  /* WebGL-specific enums */
-                  UNPACK_FLIP_Y_WEBGL            : 0x9240,
-                  UNPACK_PREMULTIPLY_ALPHA_WEBGL : 0x9241,
-                  CONTEXT_LOST_WEBGL             : 0x9242,
-                  UNPACK_COLORSPACE_CONVERSION_WEBGL : 0x9243,
-                  BROWSER_DEFAULT_WEBGL          : 0x9244,
-
-                  items: {},
-                  id: 0,
-                  getExtension: function() { return 1 },
-                  createBuffer: function() {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'buffer',
-                    };
-                    return id;
-                  },
-                  deleteBuffer: function(){},
-                  bindBuffer: function(){},
-                  bufferData: function(){},
-                  getParameter: function(pname) {
-                    switch(pname) {
-                      case /* GL_VENDOR                           */ 0x1F00: return 'FakeShellGLVendor';
-                      case /* GL_RENDERER                         */ 0x1F01: return 'FakeShellGLRenderer';
-                      case /* GL_VERSION                          */ 0x1F02: return '0.0.1';
-                      case /* GL_MAX_TEXTURE_SIZE                 */ 0x0D33: return 16384;
-                      case /* GL_MAX_CUBE_MAP_TEXTURE_SIZE        */ 0x851C: return 16384;
-                      case /* GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT   */ 0x84FF: return 16;
-                      case /* GL_MAX_TEXTURE_IMAGE_UNITS_NV       */ 0x8872: return 16;
-                      case /* GL_MAX_VERTEX_UNIFORM_VECTORS       */ 0x8DFB: return 4096;
-                      case /* GL_MAX_FRAGMENT_UNIFORM_VECTORS     */ 0x8DFD: return 4096;
-                      case /* GL_MAX_VARYING_VECTORS              */ 0x8DFC: return 32;
-                      case /* GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS */ 0x8B4D: return 32;
-                      default: console.log('getParameter ' + pname + '?'); return 0;
-                    }
-                  },
-                  getSupportedExtensions: function() {
-                    return ["OES_texture_float", "OES_standard_derivatives", "EXT_texture_filter_anisotropic", "MOZ_EXT_texture_filter_anisotropic", "MOZ_WEBGL_lose_context", "MOZ_WEBGL_compressed_texture_s3tc", "MOZ_WEBGL_depth_texture"];
-                  },
-                  createShader: function(type) {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'shader',
-                      type: type,
-                    };
-                    return id;
-                  },
-                  getShaderParameter: function(shader, pname) {
-                    switch(pname) {
-                      case /* GL_SHADER_TYPE    */ 0x8B4F: return this.items[shader].type;
-                      case /* GL_COMPILE_STATUS */ 0x8B81: return true;
-                      default: throw 'getShaderParameter ' + pname;
-                    }
-                  },
-                  shaderSource: function(){},
-                  compileShader: function(){},
-                  createProgram: function() {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'program',
-                      shaders: [],
-                    };
-                    return id;
-                  },
-                  attachShader: function(program, shader) {
-                    this.items[program].shaders.push(shader);
-                  },
-                  bindAttribLocation: function(){},
-                  linkProgram: function(){},
-                  getProgramParameter: function(program, pname) {
-                    switch(pname) {
-                      case /* LINK_STATUS     */ 0x8B82: return true;
-                      case /* ACTIVE_UNIFORMS */ 0x8B86: return 4;
-                      default: throw 'getProgramParameter ' + pname;
-                    }
-                  },
-                  deleteShader: function(){},
-                  deleteProgram: function(){},
-                  viewport: function(){},
-                  clearColor: function(){},
-                  clearDepth: function(){},
-                  depthFunc: function(){},
-                  enable: function(){},
-                  disable: function(){},
-                  frontFace: function(){},
-                  cullFace: function(){},
-                  activeTexture: function(){},
-                  createTexture: function() {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'texture',
-                    };
-                    return id;
-                  },
-                  deleteTexture: function(){},
-                  boundTextures: {},
-                  bindTexture: function(target, texture) {
-                    this.boundTextures[target] = texture;
-                  },
-                  texParameteri: function(){},
-                  pixelStorei: function(){},
-                  texImage2D: function(){},
-                  compressedTexImage2D: function(){},
-                  useProgram: function(){},
-                  getUniformLocation: function() {
-                    return null;
-                  },
-                  getActiveUniform: function(program, index) {
-                    return {
-                      size: 1,
-                      type: /* INT_VEC3 */ 0x8B54,
-                      name: 'activeUniform' + index,
-                    };
-                  },
-                  clear: function(){},
-                  uniform4fv: function(){},
-                  uniform1i: function(){},
-                  getAttribLocation: function() { return 1 },
-                  vertexAttribPointer: function(){},
-                  enableVertexAttribArray: function(){},
-                  disableVertexAttribArray: function(){},
-                  drawElements: function(){},
-                  drawArrays: function(){},
-                  depthMask: function(){},
-                  depthRange: function(){},
-                  bufferSubData: function(){},
-                  blendFunc: function(){},
-                  createFramebuffer: function() {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'framebuffer',
-                      shaders: [],
-                    };
-                    return id;
-                  },
-                  bindFramebuffer: function(){},
-                  framebufferTexture2D: function(){},
-                  checkFramebufferStatus: function() {
-                    return /* FRAMEBUFFER_COMPLETE */ 0x8CD5;
-                  },
-                  createRenderbuffer: function() {
-                    var id = this.id++;
-                    this.items[id] = {
-                      which: 'renderbuffer',
-                      shaders: [],
-                    };
-                    return id;
-                  },
-                  bindRenderbuffer: function(){},
-                  renderbufferStorage: function(){},
-                  framebufferRenderbuffer: function(){},
-                  scissor: function(){},
-                  colorMask: function(){},
-                  lineWidth: function(){},
-                };
-              }
-              case '2d': {
-                return {
-                  drawImage: function(){},
-                  getImageData: function(x, y, w, h) {
-                    return {
-                      width: w,
-                      height: h,
-                      data: new Uint8ClampedArray(w*h),
-                    };
-                  },
-                  save: function(){},
-                  restore: function(){},
-                  fillRect: function(){},
-                  measureText: function() { return 10 },
-                  fillText: function(){},
-                };
-              }
-              default: throw 'canvas.getContext: ' + which;
-            }
-          },
-          requestPointerLock: function() {
-            document.pointerLockElement = document.getElementById('canvas');
-            window.setTimeout(function() {
-              document.callEventListeners('pointerlockchange');
-            });
-          },
-          exitPointerLock: function(){},
-          style: {},
-          eventListeners: {},
-          addEventListener: document.addEventListener,
-          callEventListeners: document.callEventListeners,
-          requestFullScreen: function() {
-            document.fullscreenElement = document.getElementById('canvas');
-            window.setTimeout(function() {
-              document.callEventListeners('fullscreenchange');
-            });
-          },
-          offsetTop: 0,
-          offsetLeft: 0,
-        };
+        return this.canvas = headlessCanvas();
       }
       case 'status-text': case 'progress': {
         return {};
@@ -729,9 +120,9 @@ var document = {
       case 'script': {
         var ret = {};
         window.setTimeout(function() {
-          print('loading script: ' + ret.src);
+          headlessPrint('loading script: ' + ret.src);
           load(ret.src);
-          print('   script loaded.');
+          headlessPrint('   script loaded.');
           if (ret.onload) {
             window.setTimeout(function() {
               ret.onload(); // yeah yeah this might vanish
@@ -771,16 +162,14 @@ var document = {
 var alert = function(x) {
   print(x);
 };
-var originalDateNow = Date.now;
 var performance = {
   now: function() {
-    return originalDateNow.call(Date);
+    return Date.now();
   },
 };
 function fixPath(path) {
   if (path[0] == '/') path = path.substring(1);
-  var dirsToDrop = %d; // go back to root dir if first_js is in a subdir
-  for (var i = 0; i < dirsToDrop; i++) {
+  for (var i = 0; i < window.dirsToDrop; i++) {
     path = '../' + path;
   }
   return path
@@ -835,11 +224,11 @@ var Worker = function(workerPath) {
   workerPath = fixPath(workerPath);
   var workerCode = read(workerPath);
   workerCode = workerCode.replace(/Module/g, 'zzModuleyy' + (Worker.id++)). // prevent collision with the global Module object. Note that this becomes global, so we need unique ids
-                          replace(/Date.now/g, 'Recorder.dnow'). // recorded values are just for the "main thread" - workers were not recorded, and should not consume
-                          replace(/performance.now/g, 'Recorder.pnow').
-                          replace(/Math.random/g, 'Recorder.random').
+                          //replace(/Date.now/g, 'Recorder.dnow'). // recorded values are just for the "main thread" - workers were not recorded, and should not consume
+                          //replace(/performance.now/g, 'Recorder.pnow').
+                          //replace(/Math.random/g, 'Recorder.random').
                           replace(/\nonmessage = /, '\nvar onmessage = '); // workers commonly do "onmessage = ", we need to varify that to sandbox
-  print('loading worker ' + workerPath + ' : ' + workerCode.substring(0, 50));
+  headlessPrint('loading worker ' + workerPath + ' : ' + workerCode.substring(0, 50));
   eval(workerCode); // will implement onmessage()
 
   function duplicateJSON(json) {
@@ -854,18 +243,18 @@ var Worker = function(workerPath) {
   this.terminate = function(){};
   this.postMessage = function(msg) {
     msg.messageId = Worker.messageId++;
-    print('main thread sending message ' + msg.messageId + ' to worker ' + workerPath);
+    headlessPrint('main thread sending message ' + msg.messageId + ' to worker ' + workerPath);
     window.setTimeout(function() {
-      print('worker ' + workerPath + ' receiving message ' + msg.messageId);
+      headlessPrint('worker ' + workerPath + ' receiving message ' + msg.messageId);
       onmessage({ data: duplicateJSON(msg) });
     });
   };
   var thisWorker = this;
   var postMessage = function(msg) {
     msg.messageId = Worker.messageId++;
-    print('worker ' + workerPath + ' sending message ' + msg.messageId);
+    headlessPrint('worker ' + workerPath + ' sending message ' + msg.messageId);
     window.setTimeout(function() {
-      print('main thread receiving message ' + msg.messageId + ' from ' + workerPath);
+      headlessPrint('main thread receiving message ' + msg.messageId + ' from ' + workerPath);
       thisWorker.onmessage({ data: duplicateJSON(msg) });
     });
   };
diff --git a/src/headlessCanvas.js b/src/headlessCanvas.js
new file mode 100644
index 00000000..4951aed8
--- /dev/null
+++ b/src/headlessCanvas.js
@@ -0,0 +1,618 @@
+function headlessCanvas() {
+  return {
+    headless: true,
+    getContext: function(which) {
+      switch(which) {
+        case 'experimental-webgl': {
+          return {
+            /* ClearBufferMask */
+            DEPTH_BUFFER_BIT               : 0x00000100,
+            STENCIL_BUFFER_BIT             : 0x00000400,
+            COLOR_BUFFER_BIT               : 0x00004000,
+            
+            /* BeginMode */
+            POINTS                         : 0x0000,
+            LINES                          : 0x0001,
+            LINE_LOOP                      : 0x0002,
+            LINE_STRIP                     : 0x0003,
+            TRIANGLES                      : 0x0004,
+            TRIANGLE_STRIP                 : 0x0005,
+            TRIANGLE_FAN                   : 0x0006,
+            
+            /* AlphaFunction (not supported in ES20) */
+            /*      NEVER */
+            /*      LESS */
+            /*      EQUAL */
+            /*      LEQUAL */
+            /*      GREATER */
+            /*      NOTEQUAL */
+            /*      GEQUAL */
+            /*      ALWAYS */
+            
+            /* BlendingFactorDest */
+            ZERO                           : 0,
+            ONE                            : 1,
+            SRC_COLOR                      : 0x0300,
+            ONE_MINUS_SRC_COLOR            : 0x0301,
+            SRC_ALPHA                      : 0x0302,
+            ONE_MINUS_SRC_ALPHA            : 0x0303,
+            DST_ALPHA                      : 0x0304,
+            ONE_MINUS_DST_ALPHA            : 0x0305,
+            
+            /* BlendingFactorSrc */
+            /*      ZERO */
+            /*      ONE */
+            DST_COLOR                      : 0x0306,
+            ONE_MINUS_DST_COLOR            : 0x0307,
+            SRC_ALPHA_SATURATE             : 0x0308,
+            /*      SRC_ALPHA */
+            /*      ONE_MINUS_SRC_ALPHA */
+            /*      DST_ALPHA */
+            /*      ONE_MINUS_DST_ALPHA */
+            
+            /* BlendEquationSeparate */
+            FUNC_ADD                       : 0x8006,
+            BLEND_EQUATION                 : 0x8009,
+            BLEND_EQUATION_RGB             : 0x8009,   /* same as BLEND_EQUATION */
+            BLEND_EQUATION_ALPHA           : 0x883D,
+            
+            /* BlendSubtract */
+            FUNC_SUBTRACT                  : 0x800A,
+            FUNC_REVERSE_SUBTRACT          : 0x800B,
+            
+            /* Separate Blend Functions */
+            BLEND_DST_RGB                  : 0x80C8,
+            BLEND_SRC_RGB                  : 0x80C9,
+            BLEND_DST_ALPHA                : 0x80CA,
+            BLEND_SRC_ALPHA                : 0x80CB,
+            CONSTANT_COLOR                 : 0x8001,
+            ONE_MINUS_CONSTANT_COLOR       : 0x8002,
+            CONSTANT_ALPHA                 : 0x8003,
+            ONE_MINUS_CONSTANT_ALPHA       : 0x8004,
+            BLEND_COLOR                    : 0x8005,
+            
+            /* Buffer Objects */
+            ARRAY_BUFFER                   : 0x8892,
+            ELEMENT_ARRAY_BUFFER           : 0x8893,
+            ARRAY_BUFFER_BINDING           : 0x8894,
+            ELEMENT_ARRAY_BUFFER_BINDING   : 0x8895,
+            
+            STREAM_DRAW                    : 0x88E0,
+            STATIC_DRAW                    : 0x88E4,
+            DYNAMIC_DRAW                   : 0x88E8,
+            
+            BUFFER_SIZE                    : 0x8764,
+            BUFFER_USAGE                   : 0x8765,
+            
+            CURRENT_VERTEX_ATTRIB          : 0x8626,
+            
+            /* CullFaceMode */
+            FRONT                          : 0x0404,
+            BACK                           : 0x0405,
+            FRONT_AND_BACK                 : 0x0408,
+            
+            /* DepthFunction */
+            /*      NEVER */
+            /*      LESS */
+            /*      EQUAL */
+            /*      LEQUAL */
+            /*      GREATER */
+            /*      NOTEQUAL */
+            /*      GEQUAL */
+            /*      ALWAYS */
+            
+            /* EnableCap */
+            /* TEXTURE_2D */
+            CULL_FACE                      : 0x0B44,
+            BLEND                          : 0x0BE2,
+            DITHER                         : 0x0BD0,
+            STENCIL_TEST                   : 0x0B90,
+            DEPTH_TEST                     : 0x0B71,
+            SCISSOR_TEST                   : 0x0C11,
+            POLYGON_OFFSET_FILL            : 0x8037,
+            SAMPLE_ALPHA_TO_COVERAGE       : 0x809E,
+            SAMPLE_COVERAGE                : 0x80A0,
+            
+            /* ErrorCode */
+            NO_ERROR                       : 0,
+            INVALID_ENUM                   : 0x0500,
+            INVALID_VALUE                  : 0x0501,
+            INVALID_OPERATION              : 0x0502,
+            OUT_OF_MEMORY                  : 0x0505,
+            
+            /* FrontFaceDirection */
+            CW                             : 0x0900,
+            CCW                            : 0x0901,
+            
+            /* GetPName */
+            LINE_WIDTH                     : 0x0B21,
+            ALIASED_POINT_SIZE_RANGE       : 0x846D,
+            ALIASED_LINE_WIDTH_RANGE       : 0x846E,
+            CULL_FACE_MODE                 : 0x0B45,
+            FRONT_FACE                     : 0x0B46,
+            DEPTH_RANGE                    : 0x0B70,
+            DEPTH_WRITEMASK                : 0x0B72,
+            DEPTH_CLEAR_VALUE              : 0x0B73,
+            DEPTH_FUNC                     : 0x0B74,
+            STENCIL_CLEAR_VALUE            : 0x0B91,
+            STENCIL_FUNC                   : 0x0B92,
+            STENCIL_FAIL                   : 0x0B94,
+            STENCIL_PASS_DEPTH_FAIL        : 0x0B95,
+            STENCIL_PASS_DEPTH_PASS        : 0x0B96,
+            STENCIL_REF                    : 0x0B97,
+            STENCIL_VALUE_MASK             : 0x0B93,
+            STENCIL_WRITEMASK              : 0x0B98,
+            STENCIL_BACK_FUNC              : 0x8800,
+            STENCIL_BACK_FAIL              : 0x8801,
+            STENCIL_BACK_PASS_DEPTH_FAIL   : 0x8802,
+            STENCIL_BACK_PASS_DEPTH_PASS   : 0x8803,
+            STENCIL_BACK_REF               : 0x8CA3,
+            STENCIL_BACK_VALUE_MASK        : 0x8CA4,
+            STENCIL_BACK_WRITEMASK         : 0x8CA5,
+            VIEWPORT                       : 0x0BA2,
+            SCISSOR_BOX                    : 0x0C10,
+            /*      SCISSOR_TEST */
+            COLOR_CLEAR_VALUE              : 0x0C22,
+            COLOR_WRITEMASK                : 0x0C23,
+            UNPACK_ALIGNMENT               : 0x0CF5,
+            PACK_ALIGNMENT                 : 0x0D05,
+            MAX_TEXTURE_SIZE               : 0x0D33,
+            MAX_VIEWPORT_DIMS              : 0x0D3A,
+            SUBPIXEL_BITS                  : 0x0D50,
+            RED_BITS                       : 0x0D52,
+            GREEN_BITS                     : 0x0D53,
+            BLUE_BITS                      : 0x0D54,
+            ALPHA_BITS                     : 0x0D55,
+            DEPTH_BITS                     : 0x0D56,
+            STENCIL_BITS                   : 0x0D57,
+            POLYGON_OFFSET_UNITS           : 0x2A00,
+            /*      POLYGON_OFFSET_FILL */
+            POLYGON_OFFSET_FACTOR          : 0x8038,
+            TEXTURE_BINDING_2D             : 0x8069,
+            SAMPLE_BUFFERS                 : 0x80A8,
+            SAMPLES                        : 0x80A9,
+            SAMPLE_COVERAGE_VALUE          : 0x80AA,
+            SAMPLE_COVERAGE_INVERT         : 0x80AB,
+            
+            /* GetTextureParameter */
+            /*      TEXTURE_MAG_FILTER */
+            /*      TEXTURE_MIN_FILTER */
+            /*      TEXTURE_WRAP_S */
+            /*      TEXTURE_WRAP_T */
+            
+            COMPRESSED_TEXTURE_FORMATS     : 0x86A3,
+            
+            /* HintMode */
+            DONT_CARE                      : 0x1100,
+            FASTEST                        : 0x1101,
+            NICEST                         : 0x1102,
+            
+            /* HintTarget */
+            GENERATE_MIPMAP_HINT            : 0x8192,
+            
+            /* DataType */
+            BYTE                           : 0x1400,
+            UNSIGNED_BYTE                  : 0x1401,
+            SHORT                          : 0x1402,
+            UNSIGNED_SHORT                 : 0x1403,
+            INT                            : 0x1404,
+            UNSIGNED_INT                   : 0x1405,
+            FLOAT                          : 0x1406,
+            
+            /* PixelFormat */
+            DEPTH_COMPONENT                : 0x1902,
+            ALPHA                          : 0x1906,
+            RGB                            : 0x1907,
+            RGBA                           : 0x1908,
+            LUMINANCE                      : 0x1909,
+            LUMINANCE_ALPHA                : 0x190A,
+            
+            /* PixelType */
+            /*      UNSIGNED_BYTE */
+            UNSIGNED_SHORT_4_4_4_4         : 0x8033,
+            UNSIGNED_SHORT_5_5_5_1         : 0x8034,
+            UNSIGNED_SHORT_5_6_5           : 0x8363,
+            
+            /* Shaders */
+            FRAGMENT_SHADER                  : 0x8B30,
+            VERTEX_SHADER                    : 0x8B31,
+            MAX_VERTEX_ATTRIBS               : 0x8869,
+            MAX_VERTEX_UNIFORM_VECTORS       : 0x8DFB,
+            MAX_VARYING_VECTORS              : 0x8DFC,
+            MAX_COMBINED_TEXTURE_IMAGE_UNITS : 0x8B4D,
+            MAX_VERTEX_TEXTURE_IMAGE_UNITS   : 0x8B4C,
+            MAX_TEXTURE_IMAGE_UNITS          : 0x8872,
+            MAX_FRAGMENT_UNIFORM_VECTORS     : 0x8DFD,
+            SHADER_TYPE                      : 0x8B4F,
+            DELETE_STATUS                    : 0x8B80,
+            LINK_STATUS                      : 0x8B82,
+            VALIDATE_STATUS                  : 0x8B83,
+            ATTACHED_SHADERS                 : 0x8B85,
+            ACTIVE_UNIFORMS                  : 0x8B86,
+            ACTIVE_ATTRIBUTES                : 0x8B89,
+            SHADING_LANGUAGE_VERSION         : 0x8B8C,
+            CURRENT_PROGRAM                  : 0x8B8D,
+            
+            /* StencilFunction */
+            NEVER                          : 0x0200,
+            LESS                           : 0x0201,
+            EQUAL                          : 0x0202,
+            LEQUAL                         : 0x0203,
+            GREATER                        : 0x0204,
+            NOTEQUAL                       : 0x0205,
+            GEQUAL                         : 0x0206,
+            ALWAYS                         : 0x0207,
+            
+            /* StencilOp */
+            /*      ZERO */
+            KEEP                           : 0x1E00,
+            REPLACE                        : 0x1E01,
+            INCR                           : 0x1E02,
+            DECR                           : 0x1E03,
+            INVERT                         : 0x150A,
+            INCR_WRAP                      : 0x8507,
+            DECR_WRAP                      : 0x8508,
+            
+            /* StringName */
+            VENDOR                         : 0x1F00,
+            RENDERER                       : 0x1F01,
+            VERSION                        : 0x1F02,
+            
+            /* TextureMagFilter */
+            NEAREST                        : 0x2600,
+            LINEAR                         : 0x2601,
+            
+            /* TextureMinFilter */
+            /*      NEAREST */
+            /*      LINEAR */
+            NEAREST_MIPMAP_NEAREST         : 0x2700,
+            LINEAR_MIPMAP_NEAREST          : 0x2701,
+            NEAREST_MIPMAP_LINEAR          : 0x2702,
+            LINEAR_MIPMAP_LINEAR           : 0x2703,
+            
+            /* TextureParameterName */
+            TEXTURE_MAG_FILTER             : 0x2800,
+            TEXTURE_MIN_FILTER             : 0x2801,
+            TEXTURE_WRAP_S                 : 0x2802,
+            TEXTURE_WRAP_T                 : 0x2803,
+            
+            /* TextureTarget */
+            TEXTURE_2D                     : 0x0DE1,
+            TEXTURE                        : 0x1702,
+            
+            TEXTURE_CUBE_MAP               : 0x8513,
+            TEXTURE_BINDING_CUBE_MAP       : 0x8514,
+            TEXTURE_CUBE_MAP_POSITIVE_X    : 0x8515,
+            TEXTURE_CUBE_MAP_NEGATIVE_X    : 0x8516,
+            TEXTURE_CUBE_MAP_POSITIVE_Y    : 0x8517,
+            TEXTURE_CUBE_MAP_NEGATIVE_Y    : 0x8518,
+            TEXTURE_CUBE_MAP_POSITIVE_Z    : 0x8519,
+            TEXTURE_CUBE_MAP_NEGATIVE_Z    : 0x851A,
+            MAX_CUBE_MAP_TEXTURE_SIZE      : 0x851C,
+            
+            /* TextureUnit */
+            TEXTURE0                       : 0x84C0,
+            TEXTURE1                       : 0x84C1,
+            TEXTURE2                       : 0x84C2,
+            TEXTURE3                       : 0x84C3,
+            TEXTURE4                       : 0x84C4,
+            TEXTURE5                       : 0x84C5,
+            TEXTURE6                       : 0x84C6,
+            TEXTURE7                       : 0x84C7,
+            TEXTURE8                       : 0x84C8,
+            TEXTURE9                       : 0x84C9,
+            TEXTURE10                      : 0x84CA,
+            TEXTURE11                      : 0x84CB,
+            TEXTURE12                      : 0x84CC,
+            TEXTURE13                      : 0x84CD,
+            TEXTURE14                      : 0x84CE,
+            TEXTURE15                      : 0x84CF,
+            TEXTURE16                      : 0x84D0,
+            TEXTURE17                      : 0x84D1,
+            TEXTURE18                      : 0x84D2,
+            TEXTURE19                      : 0x84D3,
+            TEXTURE20                      : 0x84D4,
+            TEXTURE21                      : 0x84D5,
+            TEXTURE22                      : 0x84D6,
+            TEXTURE23                      : 0x84D7,
+            TEXTURE24                      : 0x84D8,
+            TEXTURE25                      : 0x84D9,
+            TEXTURE26                      : 0x84DA,
+            TEXTURE27                      : 0x84DB,
+            TEXTURE28                      : 0x84DC,
+            TEXTURE29                      : 0x84DD,
+            TEXTURE30                      : 0x84DE,
+            TEXTURE31                      : 0x84DF,
+            ACTIVE_TEXTURE                 : 0x84E0,
+            
+            /* TextureWrapMode */
+            REPEAT                         : 0x2901,
+            CLAMP_TO_EDGE                  : 0x812F,
+            MIRRORED_REPEAT                : 0x8370,
+            
+            /* Uniform Types */
+            FLOAT_VEC2                     : 0x8B50,
+            FLOAT_VEC3                     : 0x8B51,
+            FLOAT_VEC4                     : 0x8B52,
+            INT_VEC2                       : 0x8B53,
+            INT_VEC3                       : 0x8B54,
+            INT_VEC4                       : 0x8B55,
+            BOOL                           : 0x8B56,
+            BOOL_VEC2                      : 0x8B57,
+            BOOL_VEC3                      : 0x8B58,
+            BOOL_VEC4                      : 0x8B59,
+            FLOAT_MAT2                     : 0x8B5A,
+            FLOAT_MAT3                     : 0x8B5B,
+            FLOAT_MAT4                     : 0x8B5C,
+            SAMPLER_2D                     : 0x8B5E,
+            SAMPLER_CUBE                   : 0x8B60,
+            
+            /* Vertex Arrays */
+            VERTEX_ATTRIB_ARRAY_ENABLED        : 0x8622,
+            VERTEX_ATTRIB_ARRAY_SIZE           : 0x8623,
+            VERTEX_ATTRIB_ARRAY_STRIDE         : 0x8624,
+            VERTEX_ATTRIB_ARRAY_TYPE           : 0x8625,
+            VERTEX_ATTRIB_ARRAY_NORMALIZED     : 0x886A,
+            VERTEX_ATTRIB_ARRAY_POINTER        : 0x8645,
+            VERTEX_ATTRIB_ARRAY_BUFFER_BINDING : 0x889F,
+            
+            /* Shader Source */
+            COMPILE_STATUS                 : 0x8B81,
+            
+            /* Shader Precision-Specified Types */
+            LOW_FLOAT                      : 0x8DF0,
+            MEDIUM_FLOAT                   : 0x8DF1,
+            HIGH_FLOAT                     : 0x8DF2,
+            LOW_INT                        : 0x8DF3,
+            MEDIUM_INT                     : 0x8DF4,
+            HIGH_INT                       : 0x8DF5,
+            
+            /* Framebuffer Object. */
+            FRAMEBUFFER                    : 0x8D40,
+            RENDERBUFFER                   : 0x8D41,
+            
+            RGBA4                          : 0x8056,
+            RGB5_A1                        : 0x8057,
+            RGB565                         : 0x8D62,
+            DEPTH_COMPONENT16              : 0x81A5,
+            STENCIL_INDEX                  : 0x1901,
+            STENCIL_INDEX8                 : 0x8D48,
+            DEPTH_STENCIL                  : 0x84F9,
+            
+            RENDERBUFFER_WIDTH             : 0x8D42,
+            RENDERBUFFER_HEIGHT            : 0x8D43,
+            RENDERBUFFER_INTERNAL_FORMAT   : 0x8D44,
+            RENDERBUFFER_RED_SIZE          : 0x8D50,
+            RENDERBUFFER_GREEN_SIZE        : 0x8D51,
+            RENDERBUFFER_BLUE_SIZE         : 0x8D52,
+            RENDERBUFFER_ALPHA_SIZE        : 0x8D53,
+            RENDERBUFFER_DEPTH_SIZE        : 0x8D54,
+            RENDERBUFFER_STENCIL_SIZE      : 0x8D55,
+            
+            FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE           : 0x8CD0,
+            FRAMEBUFFER_ATTACHMENT_OBJECT_NAME           : 0x8CD1,
+            FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL         : 0x8CD2,
+            FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE : 0x8CD3,
+            
+            COLOR_ATTACHMENT0              : 0x8CE0,
+            DEPTH_ATTACHMENT               : 0x8D00,
+            STENCIL_ATTACHMENT             : 0x8D20,
+            DEPTH_STENCIL_ATTACHMENT       : 0x821A,
+            
+            NONE                           : 0,
+            
+            FRAMEBUFFER_COMPLETE                      : 0x8CD5,
+            FRAMEBUFFER_INCOMPLETE_ATTACHMENT         : 0x8CD6,
+            FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT : 0x8CD7,
+            FRAMEBUFFER_INCOMPLETE_DIMENSIONS         : 0x8CD9,
+            FRAMEBUFFER_UNSUPPORTED                   : 0x8CDD,
+            
+            FRAMEBUFFER_BINDING            : 0x8CA6,
+            RENDERBUFFER_BINDING           : 0x8CA7,
+            MAX_RENDERBUFFER_SIZE          : 0x84E8,
+            
+            INVALID_FRAMEBUFFER_OPERATION  : 0x0506,
+            
+            /* WebGL-specific enums */
+            UNPACK_FLIP_Y_WEBGL            : 0x9240,
+            UNPACK_PREMULTIPLY_ALPHA_WEBGL : 0x9241,
+            CONTEXT_LOST_WEBGL             : 0x9242,
+            UNPACK_COLORSPACE_CONVERSION_WEBGL : 0x9243,
+            BROWSER_DEFAULT_WEBGL          : 0x9244,
+
+            items: {},
+            id: 0,
+            getExtension: function() { return 1 },
+            createBuffer: function() {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'buffer',
+              };
+              return id;
+            },
+            deleteBuffer: function(){},
+            bindBuffer: function(){},
+            bufferData: function(){},
+            getParameter: function(pname) {
+              switch(pname) {
+                case /* GL_VENDOR                           */ 0x1F00: return 'FakeShellGLVendor';
+                case /* GL_RENDERER                         */ 0x1F01: return 'FakeShellGLRenderer';
+                case /* GL_VERSION                          */ 0x1F02: return '0.0.1';
+                case /* GL_MAX_TEXTURE_SIZE                 */ 0x0D33: return 16384;
+                case /* GL_MAX_CUBE_MAP_TEXTURE_SIZE        */ 0x851C: return 16384;
+                case /* GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT   */ 0x84FF: return 16;
+                case /* GL_MAX_TEXTURE_IMAGE_UNITS_NV       */ 0x8872: return 16;
+                case /* GL_MAX_VERTEX_UNIFORM_VECTORS       */ 0x8DFB: return 4096;
+                case /* GL_MAX_FRAGMENT_UNIFORM_VECTORS     */ 0x8DFD: return 4096;
+                case /* GL_MAX_VARYING_VECTORS              */ 0x8DFC: return 32;
+                case /* GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS */ 0x8B4D: return 32;
+                default: console.log('getParameter ' + pname + '?'); return 0;
+              }
+            },
+            getSupportedExtensions: function() {
+              return ["OES_texture_float", "OES_standard_derivatives", "EXT_texture_filter_anisotropic", "MOZ_EXT_texture_filter_anisotropic", "MOZ_WEBGL_lose_context", "MOZ_WEBGL_compressed_texture_s3tc", "MOZ_WEBGL_depth_texture"];
+            },
+            createShader: function(type) {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'shader',
+                type: type,
+              };
+              return id;
+            },
+            getShaderParameter: function(shader, pname) {
+              switch(pname) {
+                case /* GL_SHADER_TYPE    */ 0x8B4F: return this.items[shader].type;
+                case /* GL_COMPILE_STATUS */ 0x8B81: return true;
+                default: throw 'getShaderParameter ' + pname;
+              }
+            },
+            shaderSource: function(){},
+            compileShader: function(){},
+            createProgram: function() {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'program',
+                shaders: [],
+              };
+              return id;
+            },
+            attachShader: function(program, shader) {
+              this.items[program].shaders.push(shader);
+            },
+            bindAttribLocation: function(){},
+            linkProgram: function(){},
+            getProgramParameter: function(program, pname) {
+              switch(pname) {
+                case /* LINK_STATUS     */ 0x8B82: return true;
+                case /* ACTIVE_UNIFORMS */ 0x8B86: return 4;
+                default: throw 'getProgramParameter ' + pname;
+              }
+            },
+            deleteShader: function(){},
+            deleteProgram: function(){},
+            viewport: function(){},
+            clearColor: function(){},
+            clearDepth: function(){},
+            depthFunc: function(){},
+            enable: function(){},
+            disable: function(){},
+            frontFace: function(){},
+            cullFace: function(){},
+            activeTexture: function(){},
+            createTexture: function() {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'texture',
+              };
+              return id;
+            },
+            deleteTexture: function(){},
+            boundTextures: {},
+            bindTexture: function(target, texture) {
+              this.boundTextures[target] = texture;
+            },
+            texParameteri: function(){},
+            pixelStorei: function(){},
+            texImage2D: function(){},
+            compressedTexImage2D: function(){},
+            useProgram: function(){},
+            getUniformLocation: function() {
+              return null;
+            },
+            getActiveUniform: function(program, index) {
+              return {
+                size: 1,
+                type: /* INT_VEC3 */ 0x8B54,
+                name: 'activeUniform' + index,
+              };
+            },
+            clear: function(){},
+            uniform4fv: function(){},
+            uniform1i: function(){},
+            getAttribLocation: function() { return 1 },
+            vertexAttribPointer: function(){},
+            enableVertexAttribArray: function(){},
+            disableVertexAttribArray: function(){},
+            drawElements: function(){},
+            drawArrays: function(){},
+            depthMask: function(){},
+            depthRange: function(){},
+            bufferSubData: function(){},
+            blendFunc: function(){},
+            createFramebuffer: function() {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'framebuffer',
+                shaders: [],
+              };
+              return id;
+            },
+            bindFramebuffer: function(){},
+            framebufferTexture2D: function(){},
+            checkFramebufferStatus: function() {
+              return /* FRAMEBUFFER_COMPLETE */ 0x8CD5;
+            },
+            createRenderbuffer: function() {
+              var id = this.id++;
+              this.items[id] = {
+                which: 'renderbuffer',
+                shaders: [],
+              };
+              return id;
+            },
+            bindRenderbuffer: function(){},
+            renderbufferStorage: function(){},
+            framebufferRenderbuffer: function(){},
+            scissor: function(){},
+            colorMask: function(){},
+            lineWidth: function(){},
+            vertexAttrib4fv: function(){},
+          };
+        }
+        case '2d': {
+          return {
+            drawImage: function(){},
+            getImageData: function(x, y, w, h) {
+              return {
+                width: w,
+                height: h,
+                data: new Uint8ClampedArray(w*h),
+              };
+            },
+            save: function(){},
+            restore: function(){},
+            fillRect: function(){},
+            measureText: function() { return 10 },
+            fillText: function(){},
+          };
+        }
+        default: throw 'canvas.getContext: ' + which;
+      }
+    },
+    requestPointerLock: function() {
+      document.pointerLockElement = document.getElementById('canvas');
+      window.setTimeout(function() {
+        document.callEventListeners('pointerlockchange');
+      });
+    },
+    exitPointerLock: function(){},
+    style: {},
+    eventListeners: {},
+    addEventListener: function(){},
+    requestFullScreen: function() {
+      document.fullscreenElement = document.getElementById('canvas');
+      window.setTimeout(function() {
+        document.callEventListeners('fullscreenchange');
+      });
+    },
+    offsetTop: 0,
+    offsetLeft: 0,
+    // generics
+    classList: {
+      add: function(){},
+      remove: function(){},
+    },
+  };
+}
+
diff --git a/src/jsifier.js b/src/jsifier.js
index c7742288..683b1874 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -1806,6 +1806,8 @@ function JSify(data, functionsOnly, givenFunctions) {
     }
     if (HEADLESS) {
       print('if (!ENVIRONMENT_IS_WEB) {');
+      print(read('headlessCanvas.js'));
+      print('\n');
       print(read('headless.js').replace("'%s'", "'http://emscripten.org'").replace("'?%s'", "''").replace("'?%s'", "'/'").replace('%s,', 'null,').replace('%d', '0'));
       print('}');
     }