Add GLEW 1.10.0 emulation

Includes library_glew.js that stubs the init functions, but also provides the
other functions.

GL/glew.h is now changed to work with GLEW_EXT_foo_bar constants,
some missing constants that are in GLEW 1.10.0 are also provided.

Otherwise it still uses SDL_opengl.h to provide function definitions and
other constants.

Linaro's GLEW (glew-oes) is also supported to some degree to make it
easier to get ES1 and ES2 software using it running.

What it lacks:
- Some constants and function declarations that are in GLEW 1.10.0
might be missing.
- The real glew-es fork also includes normal GL constants and
function pointers, this does not.

Tests ran:
- tests/runner.py browser

Real world example using this code (and upcomming glfw3 port) can be found here:
http://cloudef.eu/glhck
http://cloudef.eu/glhck/qb.html

2 files changed, 136 insertions, 1 deletions

diff --git a/src/library_glew.js b/src/library_glew.js
new file mode 100644
index 00000000..f7da5f82
--- /dev/null
+++ b/src/library_glew.js
@@ -0,0 +1,135 @@
+/*******************************************************************************
+ * EMSCRIPTEN GLEW 1.10.0 emulation
+ *
+ * What it does:
+ * - Stubs init function.
+ * - GL Extensions support.
+ *
+ * Optional:
+ * - isLinaroFork variable to enable glew-es specific error strings.
+ *   This is enabled by default, but should be disabled when upstream glew conflicts.
+ *
+ * Authors:
+ * - Jari Vetoniemi <mailroxas@gmail.com>
+ ******************************************************************************/
+
+var LibraryGLEW = {
+  $GLEW__deps: ['glGetString'],
+  $GLEW: {
+    isLinaroFork: 1,
+    extensions: null,
+
+    error: {
+      0:null, // GLEW_OK || GLEW_NO_ERROR
+      1:null, // GLEW_ERROR_NO_GL_VERSION
+      2:null, // GLEW_ERROR_GL_VERSION_10_ONLY
+      3:null, // GLEW_ERROR_GLX_VERSION_11_ONLY
+
+      4:null, // GLEW_ERROR_NOT_GLES_VERSION
+      5:null, // GLEW_ERROR_GLES_VERSION
+      6:null, // GLEW_ERROR_NO_EGL_VERSION
+      7:null, // GLEW_ERROR_EGL_VERSION_10_ONLY
+
+      8:null, // Unknown error
+    },
+
+    version: {
+      1:null, // GLEW_VERSION
+      2:null, // GLEW_VERSION_MAJOR
+      3:null, // GLEW_VERSION_MINOR
+      4:null, // GLEW_VERSION_MICRO
+    },
+
+    errorStringConstantFromCode: function(error) {
+      if (GLEW.isLinaroFork) {
+        switch (error) {
+          case 4:return "OpenGL ES lib expected, found OpenGL lib"; // GLEW_ERROR_NOT_GLES_VERSION
+          case 5:return "OpenGL lib expected, found OpenGL ES lib"; // GLEW_ERROR_GLES_VERSION
+          case 6:return "Missing EGL version"; // GLEW_ERROR_NO_EGL_VERSION
+          case 7:return "EGL 1.1 and up are supported"; // GLEW_ERROR_EGL_VERSION_10_ONLY
+          default:break;
+        }
+      }
+
+      switch (error) {
+        case 0:return "No error"; // GLEW_OK || GLEW_NO_ERROR
+        case 1:return "Missing GL version"; // GLEW_ERROR_NO_GL_VERSION
+        case 2:return "GL 1.1 and up are supported"; // GLEW_ERROR_GL_VERSION_10_ONLY
+        case 3:return "GLX 1.2 and up are supported"; // GLEW_ERROR_GLX_VERSION_11_ONLY
+        default:return null;
+      }
+    },
+
+    errorString: function(error) {
+      if (!GLEW.error[error]) {
+        var string = GLEW.errorStringConstantFromCode(error);
+        if (!string) {
+          string = "Unknown error";
+          error = 8; // prevent array from growing more than this
+        }
+        GLEW.error[error] = allocate(intArrayFromString(string), 'i8', ALLOC_NORMAL);
+      }
+      return GLEW.error[error];
+    },
+
+    versionStringConstantFromCode: function(name) {
+      switch (name) {
+        case 1:return "1.10.0"; // GLEW_VERSION
+        case 2:return "1"; // GLEW_VERSION_MAJOR
+        case 3:return "10"; // GLEW_VERSION_MINOR
+        case 4:return "0"; // GLEW_VERSION_MICRO
+        default:return null;
+      }
+    },
+
+    versionString: function(name) {
+      if (!GLEW.version[name]) {
+        var string = GLEW.versionStringConstantFromCode(name);
+        if (!string)
+          return 0;
+        GLEW.version[name] = allocate(intArrayFromString(string), 'i8', ALLOC_NORMAL);
+      }
+      return GLEW.version[name];
+    },
+
+    extensionIsSupported: function(name) {
+      if (!GLEW.extensions) {
+        GLEW.extensions = Pointer_stringify(_glGetString(0x1F03)).split(' ');
+      }
+
+      if (GLEW.extensions.indexOf(name) != -1)
+        return 1;
+
+      // extensions from GLEmulations do not come unprefixed
+      // so, try with prefix
+      return (GLEW.extensions.indexOf("GL_" + name) != -1);
+    },
+  },
+
+  glewInit: function() { return 0; },
+
+  glewIsSupported: function(name) {
+    var exts = Pointer_stringify(name).split(' ');
+    for (i in exts) {
+      if (!GLEW.extensionIsSupported(exts[i]))
+        return 0;
+    }
+    return 1;
+  },
+
+  glewGetExtension: function(name) {
+    return GLEW.extensionIsSupported(Pointer_stringify(name));
+  },
+
+  glewGetErrorString: function(error) {
+    return GLEW.errorString(error);
+  },
+
+  glewGetString: function(name) {
+    return GLEW.versionString(name);
+  },
+
+};
+
+autoAddDeps(LibraryGLEW, '$GLEW');
+mergeInto(LibraryManager.library, LibraryGLEW);
diff --git a/src/modules.js b/src/modules.js
index c0b98f6f..ad467ba7 100644
--- a/src/modules.js
+++ b/src/modules.js
@@ -424,7 +424,7 @@ var LibraryManager = {
   load: function() {
     if (this.library) return;
 
-    var libraries = ['library.js', 'library_path.js', 'library_fs.js', 'library_idbfs.js', 'library_memfs.js', 'library_nodefs.js', 'library_sockfs.js', 'library_tty.js', 'library_browser.js', 'library_sdl.js', 'library_gl.js', 'library_glut.js', 'library_xlib.js', 'library_egl.js', 'library_gc.js', 'library_jansson.js', 'library_openal.js', 'library_glfw.js', 'library_uuid.js'].concat(additionalLibraries);
+    var libraries = ['library.js', 'library_path.js', 'library_fs.js', 'library_idbfs.js', 'library_memfs.js', 'library_nodefs.js', 'library_sockfs.js', 'library_tty.js', 'library_browser.js', 'library_sdl.js', 'library_gl.js', 'library_glut.js', 'library_xlib.js', 'library_egl.js', 'library_gc.js', 'library_jansson.js', 'library_openal.js', 'library_glfw.js', 'library_uuid.js', 'library_glew.js'].concat(additionalLibraries);
     for (var i = 0; i < libraries.length; i++) {
       eval(processMacros(preprocess(read(libraries[i]))));
     }