83 lines
2.8 KiB
GLSL
83 lines
2.8 KiB
GLSL
#version 450 core
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struct PosColNorm { vec4 pos; vec4 dummy; };
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layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
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layout (std140, binding = 1) uniform TheLight { vec4 lightPos; vec4 colrad; };
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layout (std430, binding = 3) readonly buffer Data { PosColNorm data[]; };
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layout (std430, binding = 5) readonly buffer Indices { uint indices[]; };
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float closestPointOnLineParam3 (vec3 a, vec3 b, vec3 p) {
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return dot(p - a,b-a) / dot(b-a,b-a);
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}
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vec3 closestPointOnSeg3 (vec3 a,vec3 b, vec3 p) {
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float x = closestPointOnLineParam3(a,b,p);
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return (x < 0
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? a
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: (x > 1
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? b
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: a + (x * (b- a)))) ;
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}
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vec4 shift(vec4 p) { return (vec4(p.xyz + (10000 * (p.xyz - lightPos.xyz)), 1)); }
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vec4 shiftBy(float x, vec4 p) {
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return (vec4(lightPos.xyz + (x * normalize(p.xyz - lightPos.xyz)), 1));
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}
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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.xyz ;
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float a = (100 - pos.z) / dir.z ;
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vec2 xy = (pos.xyz + a * dir).xy ;
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return vec4 ( xy, 100 , 1) ;
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}
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vec4 shiftNear(vec4 pos)
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{
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vec4 sp = shift(pos);
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return (sp.z > 100 ? projNear(pos) : sp);
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}
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// Output 6 vertices for 4 data inputs
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int ks[6] = // Inputdata: n1a Shadow:
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{0,1,2 // 2--3 / p2--p3
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,2,1,3 // | | p0---p1 / |
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}; // 0--1 / / |
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// n0a p0----p1
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void main()
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{
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int k = ks[gl_VertexID % 6];
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int i0 = 4*(gl_VertexID / 6);
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vec4 p0 = data[indices[i0]].pos;
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vec4 p1 = data[indices[i0+1]].pos;
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vec3 n0a = data[indices[i0+2]].pos.xyz;
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vec3 n1a = data[indices[i0+3]].pos.xyz;
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vec3 closepoint = closestPointOnSeg3(p0.xyz,p1.xyz,lightPos.xyz);
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float ru2 = colrad.w * colrad.w;
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vec4 mid = 0.5 * (p0 + p1);
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vec3 n0 = cross(p1.xyz - p0.xyz, n0a - p0.xyz);
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vec3 n1 = cross(p0.xyz - p1.xyz, n1a - p1.xyz);
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vec3 lightDir = p0.xyz - lightPos.xyz;
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vec3 lightDir2 = p1.xyz - lightPos.xyz;
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// test if the edge is part of the silhouette
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// that is, if the normals of the faces connected to the edge are in
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// "different directions" wrt the light direction
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// (first test the "drawbit")
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if (p0.w==1 && dot(n0, lightDir) * dot(n1, lightDir) <= 0 &&
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(dot(lightDir, lightDir) < ru2 || dot(lightDir2, lightDir2) < ru2))
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// using <= rather than < seems to get rid of overlapping shadow
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// artefacts
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{
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vec4 p2 = shiftNear(p0);
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vec4 p3 = shiftNear(p1);
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if (dot(n0, lightDir) < 0)
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{
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vec4 sp[4] = {p1,p0,p3,p2};
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gl_Position = theMat * sp[k];}
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else {
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vec4 ps[4] = {p0,p1,p2,p3};
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gl_Position = theMat * ps[k]; }
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}
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else {gl_Position = vec4(1,1,1,0);}
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}
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//layout (location = 0) in vec3 pos;
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//void main()
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//{
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// gl_Position = vec4(pos,1);
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//}
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