59 lines
1.0 KiB
GLSL
59 lines
1.0 KiB
GLSL
#version 440 core
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layout(points) in;
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layout(triangle_strip, max_vertices=4) out;
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layout(std430, binding=1) buffer Positions {
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vec4 verts[];
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};
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layout(std140, binding=1) uniform Matrices {
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mat4 model;
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vec4 offset;
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mat4 view;
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mat4 proj;
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};
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in ivec4 inds[];
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out vec4 pos;
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void emit(vec4 v) {
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pos = v;
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gl_Position = proj * view * vec4(v.xyz, 1);
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EmitVertex();
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}
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void main() {
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vec4 pos4[4];
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for(int i = 0; i < 4; ++i) pos4[i] = offset + model * verts[inds[0][i]];
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int lo[4], L = 0;
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int hi[4], H = 0;
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for(int i = 0; i < 4; ++i) {
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if (pos4[i].w < 0) {
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lo[L++] = i;
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} else {
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hi[H++] = i;
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}
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}
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vec4 sect[4]; int S = 0;
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for (int l = 0; l < L; ++l) {
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for (int h = 0; h < H; ++h) {
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vec4 a = pos4[lo[l]];
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vec4 b = pos4[hi[h]];
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sect[S++] = (0 - a.w) / (b.w - a.w) * (b-a) + a;
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}
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}
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for(int s = 0; s < S; ++s) {
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emit(sect[s]);
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}
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EndPrimitive();
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}
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