92 lines
2.8 KiB
GLSL
92 lines
2.8 KiB
GLSL
#version 450 core
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layout(lines_adjacency) 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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layout(location=0) uniform vec3 lightPos;
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layout(location=1) uniform float radiusUniform;
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// vec4 shift (vec4 p) { return (vec4 (p.xyz +
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// (lumRad.a*normalize(p.xyz-lightPos)), 1));}
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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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if (x < 0) {
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return a;
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} else{ if (x > 1) { return b; }
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{ return a + (x * (b- a));}
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}
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}
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//vec3 closepoint =
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vec4 shift(vec4 p) { return (vec4(p.xyz + (100000 * (p.xyz - lightPos)), 1)); }
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vec4 shiftBy(float x, vec4 p) {
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return (vec4(lightPos + (x * normalize(p.xyz - lightPos)), 1));
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}
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// vec4 shift (vec4 p) { return (vec4 (lightPos +
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// (lumRad.a*normalize(p.xyz-lightPos)), 1));}
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// copied from lighting/cap.geom, should not be changed on its own
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vec4 projNear(vec4 pos) {
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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 = (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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//{ vec4 sp = shiftBy(radiusUniform,pos);
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{
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vec4 sp = shift(pos);
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if (sp.z > 100) {
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return projNear(pos);
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} else {
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return sp;
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}
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}
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vec4 f(vec4 p) { return (theMat * p); }
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void main() {
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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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vec3 closepoint = closestPointOnSeg3(p0.xyz,p1.xyz,lightPos);
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float ru2 = radiusUniform * radiusUniform;
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vec4 mid = 0.5 * (p0 + p1);
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vec3 n0a = gl_in[2].gl_Position.xyz;
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vec3 n1a = gl_in[3].gl_Position.xyz;
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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 n2 = n0 + n1; // assumes the summands are normalized
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vec3 lightDir = p0.xyz - lightPos.xyz;
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vec3 lightDir2 = p1.xyz - lightPos.xyz;
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// first test if the edge is part of the silhouette
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// that is, if the normals of the faces connected by the edge point are in
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// "different directions" wrt the light direction
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if (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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vec4 p2 = shiftNear(p0);
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vec4 p3 = shiftNear(p1);
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gl_Position = f(p0);
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EmitVertex();
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if (dot(n0, lightDir) > 0) {
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gl_Position = f(p2);
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EmitVertex();
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gl_Position = f(p1);
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EmitVertex();
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} else {
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gl_Position = f(p1);
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EmitVertex();
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gl_Position = f(p2);
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EmitVertex();
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}
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gl_Position = f(p3);
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EmitVertex();
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EndPrimitive();
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} else {
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}
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}
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