2008-09-25 22:39:08 +08:00
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char volume_frag[] = "uniform sampler3D baseTexture;\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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" 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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2008-09-30 02:30:17 +08:00
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" if (num_iterations<2.0) num_iterations = 2.0;\n"
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2008-09-25 22:39:08 +08:00
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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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" vec3 deltaTexCoord=(te-t0)/float(num_iterations-1.0);\n"
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" vec3 texcoord = t0;\n"
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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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" vec4 color = texture3D( baseTexture, texcoord);\n"
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" float r = color[3]*transparency;\n"
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" if (r>alphaCutOff)\n"
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" {\n"
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" fragColor.xyz = fragColor.xyz*(1.0-r)+color.xyz*r;\n"
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" fragColor.w += r;\n"
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" }\n"
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2008-09-30 02:30:17 +08:00
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"\n"
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" if (fragColor.w<color.w)\n"
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" {\n"
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" fragColor = color;\n"
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" }\n"
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2008-09-25 22:39:08 +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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2008-09-30 02:30:17 +08:00
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" fragColor.w *= transparency;\n"
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"\n"
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2008-09-25 22:39:08 +08:00
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" if (fragColor.w>1.0) fragColor.w = 1.0; \n"
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2008-09-30 02:30:17 +08:00
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" if (fragColor.w<alphaCutOff) discard;\n"
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" \n"
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2008-09-25 22:39:08 +08:00
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" gl_FragColor = fragColor;\n"
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"}\n"
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"\n";
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