basic fog support

3 files changed, 354 insertions, 11 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index 9dd29bb7..68716a39 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -906,7 +906,14 @@ var LibraryGL = {
 
   $GLEmulation__postset: 'GLEmulation.init();',
   $GLEmulation: {
+    // Fog support. Partial, we assume shaders are used that implement fog. We just pass them uniforms
+    fogStart: 0,
+    fogEnd: 1,
+    fogColor: null,
+
     init: function() {
+      GLEmulation.fogColor = new Float32Array(4);
+
       // Add some emulation workarounds
       Module.printErr('WARNING: using emscripten GL emulation. This is a collection of limited workarounds, do not expect it to work');
 
@@ -1071,16 +1078,16 @@ var LibraryGL = {
             source = 'varying vec4 v_color; \n' + source.replace(/gl_Color/g, 'v_color');
           }
           if (source.indexOf('gl_Fog.color') >= 0) {
-            source = 'uniform vec4 a_fogColor;   \n' +
-                     source.replace(/gl_Fog.color/g, 'a_fogColor');
+            source = 'uniform vec4 u_fogColor;   \n' +
+                     source.replace(/gl_Fog.color/g, 'u_fogColor');
           }
           if (source.indexOf('gl_Fog.end') >= 0) {
-            source = 'uniform float a_fogEnd;   \n' +
-                     source.replace(/gl_Fog.end/g, 'a_fogEnd');
+            source = 'uniform float u_fogEnd;   \n' +
+                     source.replace(/gl_Fog.end/g, 'u_fogEnd');
           }
           if (source.indexOf('gl_Fog.scale') >= 0) {
-            source = 'uniform float a_fogScale;   \n' +
-                     source.replace(/gl_Fog.scale/g, 'a_fogScale');
+            source = 'uniform float u_fogScale;   \n' +
+                     source.replace(/gl_Fog.scale/g, 'u_fogScale');
           }
           if (source.indexOf('gl_FogFragCoord') >= 0) {
             source = 'varying float v_fogFragCoord;   \n' +
@@ -1170,11 +1177,11 @@ var LibraryGL = {
         } else if (pname == 0x0BA8) { // GL_TEXTURE_MATRIX
           HEAPF32.set(GL.immediate.matrix['t' + GL.immediate.clientActiveTexture], params >> 2);
         } else if (pname == 0x0B66) { // GL_FOG_COLOR
-          {{{ makeSetValue('params', '0', '0', 'float') }}};
+          HEAPF32.set(GLEmulation.fogColor, params >> 2);
         } else if (pname == 0x0B63) { // GL_FOG_START
-          {{{ makeSetValue('params', '0', '0', 'float') }}};
+          {{{ makeSetValue('params', '0', 'GLEmulation.fogStart', 'float') }}};
         } else if (pname == 0x0B64) { // GL_FOG_END
-          {{{ makeSetValue('params', '0', '0', 'float') }}};
+          {{{ makeSetValue('params', '0', 'GLEmulation.fogEnd', 'float') }}};
         } else {
           glGetFloatv(pname, params);
         }
@@ -1580,6 +1587,11 @@ var LibraryGL = {
           this.hasNormal = normalSize > 0 && this.normalLocation >= 0;
 
           this.floatType = Module.ctx.FLOAT; // minor optimization
+
+          this.fogColorLocation = Module.ctx.getUniformLocation(this.program, 'u_fogColor');
+          this.fogEndLocation = Module.ctx.getUniformLocation(this.program, 'u_fogEnd');
+          this.fogScaleLocation = Module.ctx.getUniformLocation(this.program, 'u_fogScale');
+          this.hasFog = !!(this.fogColorLocation || this.fogEndLocation || this.fogScaleLocation);
         },
 
         prepare: function() {
@@ -1661,6 +1673,11 @@ var LibraryGL = {
             Module.ctx.bindTexture(Module.ctx.TEXTURE_2D, texture);
             Module.ctx.uniform1i(this.textureLocation, 0);
           }
+          if (this.hasFog) {
+            if (this.fogColorLocation) Module.ctx.uniform4fv(this.fogColorLocation, GLEmulation.fogColor);
+            if (this.fogEndLocation) Module.ctx.uniform1f(this.fogEndLocation, GLEmulation.fogEnd);
+            if (this.fogScaleLocation) Module.ctx.uniform1f(this.fogScaleLocation, 1/(GLEmulation.fogEnd - GLEmulation.fogStart));
+          }
         },
 
         cleanup: function() {
@@ -2018,10 +2035,26 @@ var LibraryGL = {
     _glColor4f({{{ makeGetValue('p', '0', 'float') }}}, {{{ makeGetValue('p', '4', 'float') }}}, {{{ makeGetValue('p', '8', 'float') }}}, {{{ makeGetValue('p', '12', 'float') }}});
   },
 
-  glFogf: function(){}, // TODO
+  glFogf: function(pname, param) { // partial support, TODO
+    switch(pname) {
+      case 0x0B63: // GL_FOG_START
+        GLEmulation.fogStart = param; break;
+      case 0x0B64: // GL_FOG_END
+        GLEmulation.fogEnd = param; break;
+    }
+  },
   glFogi: function(){}, // TODO
   glFogx: function(){}, // TODO
-  glFogfv: function(){}, // TODO
+  glFogfv: function(pname, param) { // partial support, TODO
+    switch(pname) {
+      case 0x0B66: // GL_FOG_COLOR
+        GLEmulation.fogColor[0] = {{{ makeGetValue('param', '0', 'float') }}};
+        GLEmulation.fogColor[1] = {{{ makeGetValue('param', '4', 'float') }}};
+        GLEmulation.fogColor[2] = {{{ makeGetValue('param', '8', 'float') }}};
+        GLEmulation.fogColor[3] = {{{ makeGetValue('param', '12', 'float') }}};
+        break;
+    }
+  },
 
   glPolygonMode: function(){}, // TODO
 
diff --git a/tests/cubegeom_fog.c b/tests/cubegeom_fog.c
new file mode 100644
index 00000000..9c04a55d
--- /dev/null
+++ b/tests/cubegeom_fog.c
@@ -0,0 +1,307 @@
+/*
+THIS WORK, INCLUDING THE SOURCE CODE, DOCUMENTATION
+AND RELATED MEDIA AND DATA, IS PLACED INTO THE PUBLIC DOMAIN.
+
+THE ORIGINAL AUTHOR IS KYLE FOLEY.
+
+THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY
+OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF
+MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE,
+ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE
+RESULTING FROM THE USE, MODIFICATION, OR
+REDISTRIBUTION OF THIS SOFTWARE.
+*/
+
+#if !EMSCRIPTEN
+#define USE_GLEW 1
+#endif
+
+#if USE_GLEW
+#include "GL/glew.h"
+#endif
+
+#include "SDL/SDL.h"
+#if !USE_GLEW
+#include "SDL/SDL_opengl.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+void verify() {
+  int width = 640, height = 480;
+  unsigned char *data = (unsigned char*)malloc(width*height*4);
+  glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);
+  int sum = 0;
+  for (int x = 0; x < width*height*4; x++) {
+    if (x % 4 != 3) sum += x * data[x];
+  }
+#if EMSCRIPTEN
+  int result = sum;
+  REPORT_RESULT();
+#endif
+}
+
+int main(int argc, char *argv[])
+{
+    SDL_Surface *screen;
+    if ( SDL_Init(SDL_INIT_VIDEO) != 0 ) {
+        printf("Unable to initialize SDL: %s\n", SDL_GetError());
+        return 1;
+    }
+
+    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
+    screen = SDL_SetVideoMode( 640, 480, 24, SDL_OPENGL );
+    if ( !screen ) {
+        printf("Unable to set video mode: %s\n", SDL_GetError());
+        return 1;
+    }
+    
+    glClearColor( 0, 0, 0, 0 );
+    glClear( GL_COLOR_BUFFER_BIT );
+
+    // Fog
+
+    glEnable(GL_FOG);
+    glFogf(GL_FOG_START, 100);
+    glFogf(GL_FOG_END, 2000);
+    glFogi(GL_FOG_MODE, GL_LINEAR);
+    GLfloat fogcolor[4] = { 0.9, 0.1, 0.35, 0 };
+    glFogfv(GL_FOG_COLOR, fogcolor);
+
+    // Create a texture
+
+    GLuint texture;
+    glGenTextures( 1, &texture );
+    glBindTexture( GL_TEXTURE_2D, texture );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+    GLubyte textureData[16*16*4];
+    for (int x = 0; x < 16; x++) {
+      for (int y = 0; y < 16; y++) {
+        *((int*)&textureData[(x*16 + y) * 4]) = x*16 + ((y*16) << 8);
+      }
+    }
+    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, 
+                  GL_RGBA, GL_UNSIGNED_BYTE, textureData );
+
+    // Create a second texture
+
+    GLuint texture2;
+    glGenTextures( 1, &texture2 );
+    glBindTexture( GL_TEXTURE_2D, texture2 );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+    GLubyte texture2Data[] = { 0xff,    0,    0, 0xff,
+                                  0, 0xff,    0, 0xaa,
+                                  0,    0, 0xff, 0x55,
+                               0x80, 0x90, 0x70,    0 };
+    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0,
+                  GL_RGBA, GL_UNSIGNED_BYTE, texture2Data );
+    
+    // BEGIN
+
+#if USE_GLEW
+    glewInit();
+#endif
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    // original: glFrustum(-0.6435469817188064, 0.6435469817188064 ,-0.48266022190470925, 0.48266022190470925 ,0.5400000214576721, 2048);
+    glFrustum(-0.6435469817188064, 0.1435469817188064 ,-0.48266022190470925, 0.88266022190470925 ,0.5400000214576721, 2048);
+    glRotatef(-30, 1, 1, 1);
+    //GLfloat pm[] = { 1.372136116027832, 0, 0, 0, 0, 0.7910231351852417, 0, 0, -0.6352481842041016, 0.29297152161598206, -1.0005275011062622, -1, 0, 0, -1.080284833908081, 0 };
+    //glLoadMatrixf(pm);
+
+    glMatrixMode(GL_MODELVIEW);
+    GLfloat matrixData[] = { -1, 0, 0, 0,
+                              0, 0,-1, 0,
+                              0, 1, 0, 0,
+                              0, 0, 0, 1 };
+    glLoadMatrixf(matrixData);
+    //glTranslated(-512,-512,-527); // XXX this should be uncommented, but if it is then nothing is shown
+
+    glEnable(GL_CULL_FACE);
+    glEnable(GL_DEPTH_TEST);
+
+    glClear(GL_DEPTH_BUFFER_BIT);
+
+    glEnableClientState(GL_NORMAL_ARRAY);
+    glEnableClientState(GL_COLOR_ARRAY);
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+
+    glActiveTexture(GL_TEXTURE0);
+
+    glEnableClientState(GL_VERTEX_ARRAY);
+
+    GLuint arrayBuffer, elementBuffer;
+    glGenBuffers(1, &arrayBuffer);
+    glGenBuffers(1, &elementBuffer);
+
+    GLubyte arrayData[] = {
+/*
+[0, 0,   0, 67] ==>  128 float
+[0, 0, 128, 67] ==>  256 float
+[0, 0,   0, 68] ==>  512 float
+[0, 0, 128, 68] ==> 1024 float
+
+[vertex x        ] [vertex y         ] [vertex z         ] [nr]                [texture u        ] [texture v        ] [lm u   ] [lm v   ] [color r,g,b,a    ] */
+  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  68,  11,   10,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128, //  0
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,  68,  23,   20,   0,   0,   0,   0,   0,  67,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128, //  1
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,  35,   30,   0,   0,   0,   0,   0,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  2
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,  68,  47,   40,   0,   0,   0,   0,   0,   0,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  3
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,  68,  51,   50,   0,   0,   0,   0,   0,  67,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128, //  4
+  0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,  68,  64,   60,   0,   0,   0,   0, 128,  67,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128, //  5
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,  68,  70,   70,   0,   0,   0,   0, 128,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  6
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,  89,   80,   0,   0,   0,   0,   0,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  7
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,  68,  94,   90,   0,   0,   0,   0,   0,   0,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  8
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,  20,   10,   0,   0,   0,   0,   0,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, //  9
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,  68,  31,   20,   0,   0,   0,   0,   0,  67,   0,   0, 128,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 10
+  0,   0,   0,   0,   0,   0, 128,  68,   0,   0,   0,  68,  42,   30,   0,   0,   0,   0,   0,   0,   0,   0, 128,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 11
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,  53,   40,   0,   0,   0,   0,   0,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 12
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,  68,  64,   50,   0,   0,   0,   0, 128,  67,   0,   0,   0,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 13
+  0,   0, 128,  68,   0,   0, 128,  68,   0,   0,   0,  68,  75,   60,   0,   0,   0,   0, 128,  67,   0,   0, 128,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 14
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,  68,  86,   70,   0,   0,   0,   0,   0,  67,   0,   0, 128,  67,   0,   0,   0,   0, 128, 128, 128, 128, // 15
+
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,   0,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,   0,   0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0,   0,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0, 128,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128,
+  0,   0, 128,  68,   0,   0, 128,  68,   0,   0,   0,  68,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 128, 128, 128, 128
+    };
+    assert(sizeof(arrayData) == 1408);
+    glBindBuffer(GL_ARRAY_BUFFER, arrayBuffer);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(arrayData), arrayData, GL_STATIC_DRAW);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+    GLushort elementData[] = { 1, 2, 0, 2, 3, 0, 5, 6, 4, 6, 7, 4, 9, 10, 8, 10, 11, 8, 13, 14, 12, 14, 15, 12 };
+    assert(sizeof(elementData) == 48);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elementBuffer);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elementData), elementData, GL_STATIC_DRAW);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+    glBindBuffer(GL_ARRAY_BUFFER, arrayBuffer);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elementBuffer);
+
+    // sauer vertex data is apparently 0-12: V3F, 12: N1B, 16-24: T2F, 24-28: T2S, 28-32: C4B
+    glVertexPointer(3, GL_FLOAT, 32, (void*)0); // all these apply to the ARRAY_BUFFER that is bound
+    glTexCoordPointer(2, GL_FLOAT, 32, (void*)16);
+    glClientActiveTexture(GL_TEXTURE1); // XXX seems to be ignored in native build
+    glTexCoordPointer(2, GL_SHORT, 32, (void*)24);
+    glClientActiveTexture(GL_TEXTURE0); // likely not needed, it is a cleanup
+    glNormalPointer(GL_BYTE, 32, (void*)12);
+    glColorPointer(4, GL_UNSIGNED_BYTE, 32, (void*)28);
+
+    glBindTexture(GL_TEXTURE_2D, texture); // diffuse?
+    glActiveTexture(GL_TEXTURE0);
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, texture2); // lightmap?
+    glActiveTexture(GL_TEXTURE0);
+
+    GLint ok;
+
+    const char *vertexShader = "uniform vec4 texgenscroll;\n"
+                               "void main(void)\n"
+                               "{\n"
+                               "    gl_Position = ftransform();\n"
+                               "    gl_TexCoord[0].xy = gl_MultiTexCoord0.xy/10000.0 + (0.001*texgenscroll.xy) + gl_Normal.xy;\n" // added /100 here
+                               "    gl_TexCoord[1].xy = gl_MultiTexCoord1.xy/100.0 * 3.051851e-05;\n"
+                               "    gl_FogFragCoord = gl_Position.z;\n"
+                               "}\n";
+    const char *fragmentShader = "uniform vec4 colorparams;\n"
+                                 "uniform sampler2D diffusemap, lightmap;\n"
+                                 "void main(void)\n"
+                                 "{\n"
+                                 "    vec4 diffuse = texture2D(diffusemap, gl_TexCoord[0].xy);\n"
+                                 "    vec4 lm = texture2D(lightmap, gl_TexCoord[1].xy);\n"
+                                 "    diffuse *= colorparams;\n"
+                                 "    vec4 color = diffuse * lm;\n"
+                                 "    gl_FragColor.rgb = mix((gl_Fog.color).rgb, color.rgb, clamp((gl_Fog.end - gl_FogFragCoord) * gl_Fog.scale, 0.0, 1.0));\n"
+                                 //"    gl_FragColor.rgb = 0.0001 * color.rgb + ((gl_Fog.color).rgb * (1.0-clamp((gl_FogFragCoord)* 1.0/1000.0, 0.0, 1.0)));\n"
+                                 "}\n";
+
+    GLuint vs = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vs, 1, &vertexShader, NULL);
+    glCompileShader(vs);
+    glGetShaderiv(vs, GL_COMPILE_STATUS, &ok);
+    assert(ok);
+
+    GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fs, 1, &fragmentShader, NULL);
+    glCompileShader(fs);
+    glGetShaderiv(fs, GL_COMPILE_STATUS, &ok);
+    assert(ok);
+
+    GLuint program = glCreateProgram();
+
+    glAttachShader(program, vs);
+    glAttachShader(program, fs);
+    glLinkProgram(program);
+    glGetProgramiv(program, GL_LINK_STATUS, &ok);
+    assert(ok);
+
+    glUseProgram(program);
+
+    GLint lightmapLocation = glGetUniformLocation(program, "lightmap");
+    assert(lightmapLocation >= 0);
+    glUniform1i(lightmapLocation, 1); // sampler2D? Is it the texture unit?
+
+    GLint diffusemapLocation = glGetUniformLocation(program, "diffusemap");
+    assert(diffusemapLocation >= 0);
+    glUniform1i(diffusemapLocation, 0);
+
+    GLint texgenscrollLocation = glGetUniformLocation(program, "texgenscroll");
+    assert(texgenscrollLocation >= 0);
+
+    GLint colorparamsLocation = glGetUniformLocation(program, "colorparams");
+    assert(colorparamsLocation >= 0);
+
+    GLfloat texgenscrollData[] = { 0, 0, 0, 0 };
+    glUniform4fv(texgenscrollLocation, 1, texgenscrollData);
+
+    GLfloat colorparamsData[] = { 2, 2, 2, 1 };
+    glUniform4fv(colorparamsLocation, 1, colorparamsData);
+
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*)12);
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*) 0);
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*)24);
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, (void*)36);
+
+    // END
+
+    SDL_GL_SwapBuffers();
+
+    verify();
+   
+#if !EMSCRIPTEN
+    SDL_Delay(1500);
+#endif
+
+    SDL_Quit();
+    
+    return 0;
+}
diff --git a/tests/runner.py b/tests/runner.py
index d0360e00..77b648ec 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -7741,6 +7741,9 @@ elif 'browser' in str(sys.argv):
     def test_cubegeom_texturematrix(self):
       self.btest('cubegeom_texturematrix.c', expected='1297500583')
 
+    def test_cubegeom_fog(self):
+      self.btest('cubegeom_fog.c', expected='1617140399')
+
     def test_cube_explosion(self):
       self.btest('cube_explosion.c', expected='667220544')