Add standard-deriv based normal mapping, update ammo.js

- Implemented standard derivatives based normal mapping from
http://www.thetenthplanet.de/archives/1180 to replace existing
screen-space normal map hack where supported.
- Upgraded ammo.js version
- Removed outdated octree tests.
- Added basic loading of available extensions to GLCore.extensions.

CubicVR.js

@@ -269,7 +269,9 @@ usage:
         resize_active: false,
         emptyLight: null,
         resizeList: [],
-        canvasSizeFactor:1
+        canvasSizeFactor:1,
+        extensions: {
+        }
     };
 
     function addFullscreenSupport() {
@@ -318,6 +320,19 @@ usage:
         }
 
         GLCore.gl = gl;
+        var available_extensions = gl.getSupportedExtensions();
+
+        GLCore.extensions.texture_filter_anisotropic = gl.getExtension("EXT_texture_filter_anisotropic");
+        GLCore.extensions.element_index_uint = gl.getExtension("OES_element_index_uint");
+        GLCore.extensions.standard_derivatives = gl.getExtension("OES_standard_derivatives");
+        GLCore.extensions.texture_float = gl.getExtension("OES_texture_float");
+        GLCore.extensions.texture_float_linear = gl.getExtension("OES_texture_float_linear");
+        GLCore.extensions.compressed_texture_s3tc = gl.getExtension("WEBGL_compressed_texture_s3tc");
+        //GLCore.extensions.lose_context = WEBGL_lose_context
+
+        // MOZ_WEBGL_lose_context
+        // MOZ_WEBGL_compressed_texture_s3tc
+
 
         if (GLCore.fixed_size !== null) {
           GLCore.width = GLCore.fixed_size[0];
@@ -733,7 +748,7 @@ usage:
 
 }(window, window.document, Math, function(){}));
 
-window.CubicVRShader = {};	// for embedding shaders and keeping context happy
+window.CubicVRShader = {};  // for embedding shaders and keeping context happy
 
 /* CubicVR:Makefile-cut */
 /* --- SNIP FOR MINIFICATION --- */

CubicVR_Core.fs

@@ -210,14 +210,70 @@ vec2 cubicvr_texCoord() {
   #endif
 }
 
+#if TEXTURE_NORMAL && OES_STANDARD_DERIVATIVES
+
+#extension GL_OES_standard_derivatives : enable
+
+// Normal Mapping Without Precomputed Tangents: http://www.thetenthplanet.de/archives/1180
+
+mat3 cotangent_frame( vec3 N, vec3 p, vec2 uv ) {
+    // get edge vectors of the pixel triangle
+    vec3 dp1 = dFdx( p );
+    vec3 dp2 = dFdy( p );
+    vec2 duv1 = dFdx( uv );
+    vec2 duv2 = dFdy( uv );
+
+    // solve the linear system
+    vec3 dp2perp = cross( dp2, N );
+    vec3 dp1perp = cross( N, dp1 );
+    vec3 T = dp2perp * duv1.x + dp1perp * duv2.x;
+    vec3 B = dp2perp * duv1.y + dp1perp * duv2.y;
+
+    // construct a scale-invariant frame 
+    float invmax = inversesqrt( max( dot(T,T), dot(B,B) ) );
+    return mat3( T * invmax, B * invmax, N );
+}
+
+#define WITH_NORMALMAP_UNSIGNED 1
+//#define WITH_NORMALMAP_GREEN_UP 1
+//#define WITH_NORMAL_2CHANNEL 1
+
+vec3 perturb_normal( vec3 N, vec3 V, vec2 texCoord ) {
+    // assume N, the interpolated vertex normal and 
+    // V, the view vector (vertex to eye)
+    vec3 map = texture2D( textureNormal, texCoord ).xyz;
+#ifdef WITH_NORMALMAP_UNSIGNED
+    map = map * 255./127. - 128./127.;
+#endif
+#ifdef WITH_NORMALMAP_2CHANNEL
+    map.z = sqrt( 1. - dot( map.xy, map.xy ) );
+#endif
+#ifdef WITH_NORMALMAP_GREEN_UP
+    map.y = -map.y;
+#endif
+    mat3 TBN = cotangent_frame( N, -V, texCoord );
+    return normalize( TBN * map );
+}
+
+#endif
+
+
 vec3 cubicvr_normal(vec2 texCoord) {
 #if TEXTURE_NORMAL && !LIGHT_DEPTH_PASS
+
+    // use standard derivatives version if available
+#if OES_STANDARD_DERIVATIVES 
+    return perturb_normal(vertexNormalOut, vertexPositionOut.xyz, texCoord);
+#else
+    // fake it otherwise, doesn't play well with rotation
     vec3 bumpNorm = vec3(texture2D(textureNormal, texCoord));
 
     vec3 n = (vec4(normalize(vertexNormalOut),1.0)).xyz;
     bumpNorm = (bumpNorm-0.5)*2.0;
     bumpNorm.y = -bumpNorm.y;
     return normalize((n+bumpNorm)/2.0);
+#endif
+
 #else
     return normalize(vertexNormalOut);
 #endif