56 lines
1.5 KiB
GLSL
56 lines
1.5 KiB
GLSL
// -*-C++-*-
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#version 120
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#extension GL_EXT_geometry_shader4 : enable
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#define MAX_LAYERS 30
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#define MIN_LAYERS 8
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#define MAX_MINUS_MIN_LAYERS 22
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uniform float max_height;
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varying in vec3 v_normal[3];
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varying out vec2 g_rawpos;
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varying out float g_distance_to_eye;
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varying out float g_layer;
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float min3(in float a, in float b, in float c)
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{
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float m = a;
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if (m > b) m = b;
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if (m > c) m = c;
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return m;
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}
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void main()
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{
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float distances[3];
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distances[0] = -(gl_ModelViewMatrix * gl_PositionIn[0]).z;
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distances[1] = -(gl_ModelViewMatrix * gl_PositionIn[1]).z;
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distances[2] = -(gl_ModelViewMatrix * gl_PositionIn[2]).z;
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float minDistance = min3(distances[0], distances[1], distances[2]);
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//float avgDistance = (distances[0]+distances[1]+distances[2])*0.33;
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int numLayers = MIN_LAYERS + int(smoothstep(500.0, 50.0, minDistance) * float(MAX_MINUS_MIN_LAYERS));
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float deltaLayer = 1.0 / float(numLayers);
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float currDeltaLayer = deltaLayer * 0.5;
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for (int layer = 0; layer < numLayers; ++layer) {
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for (int i = 0; i < 3; ++i) {
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vec4 pos = gl_PositionIn[i] + vec4(v_normal[i] * currDeltaLayer * max_height, 0.0);
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g_rawpos = gl_PositionIn[i].xy;
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g_distance_to_eye = distances[i];
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g_layer = currDeltaLayer;
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gl_Position = gl_ModelViewProjectionMatrix * pos;
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gl_TexCoord[0] = gl_TexCoordIn[i][0];
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EmitVertex();
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}
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EndPrimitive();
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currDeltaLayer += deltaLayer;
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}
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}
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