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@@ -23,11 +23,109 @@
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return mat3(tangent * invmax, binormal * invmax, normal);
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}
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- vec3 perturbNormal(vec3 viewDir)
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+ vec3 perturbNormal(vec3 viewDir, mat3 cotangentFrame, vec2 uv)
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{
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- vec3 map = texture2D(bumpSampler, vBumpUV).xyz;
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+ vec3 map = texture2D(bumpSampler, uv).xyz;
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map = map * 255. / 127. - 128. / 127.;
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- mat3 TBN = cotangent_frame(vNormalW * vBumpInfos.y, -viewDir, vBumpUV);
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- return normalize(TBN * map);
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+ return normalize(cotangentFrame * map);
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}
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+
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+#ifdef PARALLAX
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+ uniform float vParallaxScaleBias;
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+
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+ const float minSamples = 4.;
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+ const float maxSamples = 15.;
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+ const int iMaxSamples = 15;
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+
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+ // http://www.gamedev.net/page/resources/_/technical/graphics-programming-and-theory/a-closer-look-at-parallax-occlusion-mapping-r3262
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+ vec2 parallaxOcclusion(vec3 vViewDirCoT, vec3 vNormalCoT, vec2 texCoord, float parallaxScale) {
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+
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+ // Calculate the parallax offset vector max length.
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+ // This is equivalent to the tangent of the angle between the
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+ // viewer position and the fragment location.
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+ float parallaxLimit = length(vViewDirCoT.xy) / vViewDirCoT.z;
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+
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+ // Scale the parallax limit according to heightmap scale.
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+ parallaxLimit *= parallaxScale;
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+
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+ // Calculate the parallax offset vector direction and maximum offset.
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+ vec2 vOffsetDir = normalize(vViewDirCoT.xy);
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+ vec2 vMaxOffset = vOffsetDir * parallaxLimit;
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+
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+ // Calculate how many samples should be taken along the view ray
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+ // to find the surface intersection. This is based on the angle
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+ // between the surface normal and the view vector.
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+ float numSamples = maxSamples + (dot(vViewDirCoT, vNormalCoT) * (minSamples - maxSamples));
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+
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+ // Specify the view ray step size. Each sample will shift the current
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+ // view ray by this amount.
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+ float stepSize = 1.0 / numSamples;
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+
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+ // Calculate the texture coordinate partial derivatives in screen
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+ // space for the tex2Dgrad texture sampling instruction.
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+ //vec2 dx = dFdx(vBumpUV); // Uncomment whevener GL_EXT_shader_texture_lod with texture2DGradEXT will work
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+ //vec2 dy = dFdy(vBumpUV);
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+
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+ // Initialize the starting view ray height and the texture offsets.
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+ float currRayHeight = 1.0;
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+ vec2 vCurrOffset = vec2(0, 0);
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+ vec2 vLastOffset = vec2(0, 0);
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+
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+ float lastSampledHeight = 1.0;
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+ float currSampledHeight = 1.0;
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+
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+ for (int i = 0; i < iMaxSamples; i++)
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+ {
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+ // Sample the heightmap at the current texcoord offset. The heightmap
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+ // is stored in the alpha channel of the height/normal map.
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+ currSampledHeight = texture2D(bumpSampler, vBumpUV + vCurrOffset).w;
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+
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+ // Uncomment whevener GL_EXT_shader_texture_lod with texture2DGradEXT will work
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+ //currSampledHeight = texture2DGradEXT(bumpSampler, vBumpUV + vCurrOffset, dx, dy).w;
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+
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+ // Test if the view ray has intersected the surface.
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+ if (currSampledHeight > currRayHeight)
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+ {
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+ // Find the relative height delta before and after the intersection.
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+ // This provides a measure of how close the intersection is to
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+ // the final sample location.
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+ float delta1 = currSampledHeight - currRayHeight;
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+ float delta2 = (currRayHeight + stepSize) - lastSampledHeight;
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+ float ratio = delta1 / (delta1 + delta2);
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+
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+ // Interpolate between the final two segments to
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+ // find the true intersection point offset.
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+ vCurrOffset = (ratio)* vLastOffset + (1.0 - ratio) * vCurrOffset;
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+
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+ // Force the exit of the loop
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+ break;
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+ }
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+ else
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+ {
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+ // take the next view ray height step,
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+ currRayHeight -= stepSize;
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+
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+ // save the current texture coordinate offset and increment
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+ // to the next sample location,
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+ vLastOffset = vCurrOffset;
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+ vCurrOffset += stepSize * vMaxOffset;
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+
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+ // and finally save the current heightmap height.
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+ lastSampledHeight = currSampledHeight;
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+ }
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+ }
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+
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+ return vCurrOffset;
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+ }
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+
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+ vec2 parallaxOffset(vec3 viewDir, float heightScale)
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+ {
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+ // calculate amount of offset for Parallax Mapping With Offset Limiting
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+ float height = texture2D(bumpSampler, vBumpUV).w;
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+ vec2 texCoordOffset = heightScale * viewDir.xy * height;
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+ return -texCoordOffset;
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+ }
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+
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+#endif
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+
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#endif
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nockawa