56 lines
1.2 KiB
GLSL
56 lines
1.2 KiB
GLSL
#version 430 core
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layout (points) in;
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layout (triangle_strip, max_vertices = 12) out;
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in vec4 vBackPoss[];
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uniform vec2 lightPos;
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uniform mat4 worldMat;
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void emitLine (vec2 pa)
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{
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gl_Position = vec4 (pa, 0, 1);
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EmitVertex();
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gl_Position = vec4 (pa + (200 * (pa - lightPos)), 0 , 1);
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EmitVertex();
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}
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float isLHS (vec2 startV, vec2 testV)
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{
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return sign( -startV.x * testV.y + startV.y * testV.x);
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}
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void main()
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{
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vec4 frontL4 = worldMat * vec4(gl_in[0].gl_Position.xy, 0 ,1);
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vec4 frontR4 = worldMat * vec4(gl_in[0].gl_Position.zw, 0 ,1);
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vec2 frontL = frontL4.xy;
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vec2 frontR = frontR4.xy;
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vec4 backR4 = worldMat * vec4(vBackPoss[0].xy, 0 ,1);
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vec4 backL4 = worldMat * vec4(vBackPoss[0].zw, 0 ,1);
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vec2 backL = backL4.xy;
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vec2 backR = backR4.xy;
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// if (isLHS( lightPos - frontL, frontR - frontL) < 0)
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// // if (isLHS( lightPos - backL, backR - backL) < 0)
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// {
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// // emitLine (frontL);
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// // emitLine (backL);
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// // emitLine (frontL);
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// // emitLine (frontR);
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// // emitLine (backR);
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// // emitLine (frontR);
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//
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// emitLine (backR);
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// emitLine (backL);
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// }
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// else
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// {
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// emitLine (backR);
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// emitLine (backL);
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// }
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emitLine (frontR);
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emitLine (frontL);
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EndPrimitive();
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}
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