2008-09-28 23:16:13 +08:00
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char volume_tf_iso_frag[] = "uniform sampler3D baseTexture;\n"
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2008-09-26 19:29:00 +08:00
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"uniform sampler1D tfTexture;\n"
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"uniform float sampleDensity;\n"
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"uniform float transparency;\n"
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"uniform float alphaCutOff;\n"
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"\n"
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"varying vec4 cameraPos;\n"
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"varying vec4 vertexPos;\n"
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"varying mat4 texgen;\n"
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"\n"
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"void main(void)\n"
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"{ \n"
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" vec3 t0 = (texgen * vertexPos).xyz;\n"
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" vec3 te = (texgen * cameraPos).xyz;\n"
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"\n"
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2008-09-26 23:47:31 +08:00
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" vec3 eyeDirection = normalize(te-t0);\n"
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"\n"
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2008-09-26 19:29:00 +08:00
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" if (te.x>=0.0 && te.x<=1.0 &&\n"
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" te.y>=0.0 && te.y<=1.0 &&\n"
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" te.z>=0.0 && te.z<=1.0)\n"
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" {\n"
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" // do nothing... te inside volume\n"
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" }\n"
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" else\n"
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" {\n"
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" if (te.x<0.0)\n"
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" {\n"
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" float r = -te.x / (t0.x-te.x);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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"\n"
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" if (te.x>1.0)\n"
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" {\n"
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" float r = (1.0-te.x) / (t0.x-te.x);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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"\n"
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" if (te.y<0.0)\n"
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" {\n"
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" float r = -te.y / (t0.y-te.y);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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"\n"
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" if (te.y>1.0)\n"
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" {\n"
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" float r = (1.0-te.y) / (t0.y-te.y);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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"\n"
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" if (te.z<0.0)\n"
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" {\n"
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" float r = -te.z / (t0.z-te.z);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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"\n"
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" if (te.z>1.0)\n"
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" {\n"
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" float r = (1.0-te.z) / (t0.z-te.z);\n"
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" te = te + (t0-te)*r;\n"
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" }\n"
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" }\n"
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"\n"
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" const float max_iteratrions = 2048.0;\n"
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" float num_iterations = ceil(length(te-t0)/sampleDensity);\n"
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" if (num_iterations<2.0) num_iterations = 2.0;\n"
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" \n"
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" if (num_iterations>max_iteratrions) \n"
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" {\n"
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" num_iterations = max_iteratrions;\n"
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" }\n"
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"\n"
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2008-09-28 23:16:13 +08:00
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" vec3 deltaTexCoord=(t0-te)/float(num_iterations-1.0);\n"
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" vec3 texcoord = te;\n"
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" float previousV = texture3D( baseTexture, texcoord).a;\n"
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"\n"
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" float normalSampleDistance = 1.0/512.0;\n"
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" vec3 deltaX = vec3(normalSampleDistance, 0.0, 0.0);\n"
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" vec3 deltaY = vec3(0.0, normalSampleDistance, 0.0);\n"
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" vec3 deltaZ = vec3(0.0, 0.0, normalSampleDistance);\n"
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2008-09-26 19:29:00 +08:00
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"\n"
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" vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0); \n"
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" while(num_iterations>0.0)\n"
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" {\n"
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2008-09-26 23:47:31 +08:00
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"\n"
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2008-09-28 23:16:13 +08:00
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" float v = texture3D( baseTexture, texcoord).a;\n"
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"\n"
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" float m = (previousV-alphaCutOff) * (v-alphaCutOff);\n"
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" if (m <= 0.0)\n"
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2008-09-26 19:29:00 +08:00
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" {\n"
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2008-09-28 23:16:13 +08:00
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" float r = (alphaCutOff-v)/(previousV-v);\n"
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" texcoord = texcoord - r*deltaTexCoord;\n"
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"\n"
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" v = texture3D( baseTexture, texcoord).a;\n"
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" vec4 color = texture1D( tfTexture, v);\n"
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"\n"
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" float px = texture3D( baseTexture, texcoord + deltaX).a;\n"
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" float py = texture3D( baseTexture, texcoord + deltaY).a;\n"
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" float pz = texture3D( baseTexture, texcoord + deltaZ).a;\n"
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"\n"
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" float nx = texture3D( baseTexture, texcoord - deltaX).a;\n"
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" float ny = texture3D( baseTexture, texcoord - deltaY).a;\n"
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" float nz = texture3D( baseTexture, texcoord - deltaZ).a;\n"
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" \n"
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" vec3 grad = vec3(px-nx, py-ny, pz-nz);\n"
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" vec3 normal = normalize(grad);\n"
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"\n"
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" float lightScale = 0.1 + abs(dot(normal.xyz, eyeDirection));\n"
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" \n"
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" \n"
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"#if 0\n"
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" color.x *= lightScale;\n"
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" color.y *= lightScale;\n"
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" color.z *= lightScale;\n"
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"#else\n"
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" color.x = lightScale;\n"
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" color.y = lightScale;\n"
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" color.z = lightScale;\n"
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"#endif\n"
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"\n"
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2008-09-26 19:29:00 +08:00
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" fragColor = color;\n"
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2008-09-28 23:16:13 +08:00
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" \n"
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" break;\n"
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2008-09-26 19:29:00 +08:00
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" }\n"
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2008-09-28 23:16:13 +08:00
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" \n"
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" previousV = v;\n"
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" \n"
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2008-09-26 19:29:00 +08:00
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" texcoord += deltaTexCoord; \n"
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"\n"
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" --num_iterations;\n"
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" }\n"
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"\n"
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" if (fragColor.w>1.0) fragColor.w = 1.0; \n"
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" if (fragColor.w<alphaCutOff) discard;\n"
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" gl_FragColor = fragColor;\n"
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"}\n"
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"\n";
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