51 lines
1.3 KiB
GLSL
51 lines
1.3 KiB
GLSL
#version 430 core
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layout (points) in;
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layout (triangle_strip, max_vertices = 4) out;
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layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
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uniform vec3 lightPos;
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uniform vec2 radLum;
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out vec3 dField;
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out float lum;
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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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vec4 shiftCloser (vec4 v)
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{ return vec4 (v.xy , v.z-0.0001 , v.w) ; }
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void main()
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{
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vec4 p1 = vec4 (gl_in[0].gl_Position.xy,0.1,1);
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vec4 p2 = vec4 (gl_in[0].gl_Position.zw,0.1,1);
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if (isLHS (p1.xy - lightPos.xy, p2.xy - lightPos.xy) < 0)
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{
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lum = radLum.y;
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float rad = radLum.x;
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vec4 p3 = vec4 (p1.xy,-0.3,1);
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vec4 p4 = vec4 (p2.xy,-0.3,1);
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vec2 d1 = p1.xy - lightPos.xy;
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vec2 d2 = p2.xy - lightPos.xy;
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vec4 a1 = shiftCloser( theMat * p1 );
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vec4 a2 = shiftCloser( theMat * p2 );
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vec4 a3 = shiftCloser( theMat * p3 );
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vec4 a4 = shiftCloser( theMat * p4 );
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dField = vec3( d1.x/rad, d1.y/rad, 100.0/rad);
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gl_Position = a1;
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EmitVertex();
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dField = vec3( d1.x/rad, d1.y/rad, -300.0/rad);
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gl_Position = a3;
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EmitVertex();
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dField = vec3( d2.x/rad, d2.y/rad, 100.0/rad);
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gl_Position = a2;
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EmitVertex();
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dField = vec3( d2.x/rad, d2.y/rad, -300.0/rad);
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gl_Position = a4;
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EmitVertex();
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EndPrimitive();
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} else {}
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}
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