42 lines
1.3 KiB
GLSL
42 lines
1.3 KiB
GLSL
#version 430 core
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layout (triangles) in;
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layout (triangle_strip, max_vertices = 3) out;
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layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
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uniform vec3 lightPos;
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// this code is duplicated in lineShadow.geom, should not be changed on its own
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vec4 projNear (vec4 pos)
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{
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// note we project to a specific height
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// this is quite brittle, not ideal
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vec3 dir = pos.xyz - lightPos ;
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float a = (140 - pos.z) / dir.z ;
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vec2 xy = (pos.xyz + a * dir).xy ;
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return vec4 ( xy, 140 , 1) ;
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}
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void main()
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{
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vec4 p0 = gl_in[0].gl_Position ;
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vec4 p1 = gl_in[1].gl_Position ;
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vec4 p2 = gl_in[2].gl_Position ;
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if ( //dot( p0.xyz - vec3 (0,0,1), cross( p0.xyz - p1.xyz, p1.xyz - p2.xyz)) < 0
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// &&
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( p0.z - lightPos.z > 0 )
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&& ( p1.z - lightPos.z > 0 )
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&& ( p2.z - lightPos.z > 0 )
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)
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{
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// front cap
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vec4 v1 = vec4 (0,0,1,0) ;
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gl_Position = theMat * projNear(p0); EmitVertex();
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gl_Position = theMat * projNear(p1); EmitVertex();
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gl_Position = theMat * projNear(p2); EmitVertex();
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EndPrimitive();
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// if light points downwards onto surface, draw back cap too
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if (dot ( p0.xyz - lightPos, vec3 ( 0,0,1) ) > 0)
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{
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}
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else {}
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}
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else {}
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}
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