Cleanup shadows

shader/lighting/lineShadow.vert

@@ -1,28 +1,29 @@
 #version 450 core
 struct PosColNorm { vec4 pos; vec4 dummy; };
 layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+layout (std140, binding = 1) uniform TheLight { vec4 lightPos; vec4 colrad; };
 layout (std430, binding = 3) readonly buffer Data { PosColNorm data[]; };
 layout (std430, binding = 5) readonly buffer Indices { uint indices[]; };
-layout(location=0)uniform vec3 lightPos;
-layout(location=1)uniform float radiusUniform;
 float closestPointOnLineParam3 (vec3 a, vec3 b, vec3 p) {
   return dot(p - a,b-a) / dot(b-a,b-a);
 }
 vec3 closestPointOnSeg3 (vec3 a,vec3 b, vec3 p) {
   float x = closestPointOnLineParam3(a,b,p);
-  if (x < 0) {
-      return a;
-  } else{ return (x > 1 ? b: a + (x * (b- a))); }
+  return (x < 0
+        ? a
+        : (x > 1 
+            ? b
+            : a + (x * (b- a)))) ; 
 }
-vec4 shift(vec4 p) { return (vec4(p.xyz + (10000 * (p.xyz - lightPos)), 1)); }
+vec4 shift(vec4 p) { return (vec4(p.xyz + (10000 * (p.xyz - lightPos.xyz)), 1)); }
 vec4 shiftBy(float x, vec4 p) {
-  return (vec4(lightPos + (x * normalize(p.xyz - lightPos)), 1));
+  return (vec4(lightPos.xyz + (x * normalize(p.xyz - lightPos.xyz)), 1));
 }
 vec4 projNear (vec4 pos)
 {
     // note we project to a specific height
     // this is quite brittle, not ideal
-    vec3 dir = pos.xyz - lightPos ;
+    vec3 dir = pos.xyz - lightPos.xyz ;
     float a = (100 - pos.z) / dir.z ;
     vec2 xy = (pos.xyz + a * dir).xy ;
     return vec4 ( xy, 100 , 1) ;
@@ -31,11 +32,13 @@ vec4 shiftNear(vec4 pos)
 {
   vec4 sp = shift(pos);
   return (sp.z > 100 ? projNear(pos) : sp);
-}
-int ks[6] =
-    {0,1,2      //  2--3
-    ,2,1,3      //  |  |
-    };          //  0--1
+}               
+// Output 6 vertices for 4 data inputs
+int ks[6] = //        Inputdata:  n1a   Shadow:
+    {0,1,2  //  2--3              /       p2--p3
+    ,2,1,3  //  |  |       p0---p1        /    |
+    };      //  0--1      /              /     |
+            //          n0a             p0----p1
 void main()
 {
     int k = ks[gl_VertexID % 6]; 
@@ -44,8 +47,8 @@ void main()
     vec4 p1 = data[indices[i0+1]].pos;
     vec3 n0a = data[indices[i0+2]].pos.xyz;
     vec3 n1a = data[indices[i0+3]].pos.xyz;
-    vec3 closepoint = closestPointOnSeg3(p0.xyz,p1.xyz,lightPos);
-    float ru2 = radiusUniform * radiusUniform;
+    vec3 closepoint = closestPointOnSeg3(p0.xyz,p1.xyz,lightPos.xyz);
+    float ru2 = colrad.w * colrad.w;
     vec4 mid = 0.5 * (p0 + p1);
     vec3 n0 = cross(p1.xyz - p0.xyz, n0a - p0.xyz);
     vec3 n1 = cross(p0.xyz - p1.xyz, n1a - p1.xyz);
@@ -53,15 +56,15 @@ void main()
     vec3 lightDir2 = p1.xyz - lightPos.xyz;
     vec4 p2 = shiftNear(p0);
     vec4 p3 = shiftNear(p1);
-  // first test if the edge is part of the silhouette
-  // that is, if the normals of the faces connected by the edge point are in
+  // test if the edge is part of the silhouette
+  // that is, if the slopes of the faces connected to the edge are in
   // "different directions" wrt the light direction
   if (dot(n0, lightDir) * dot(n1, lightDir) <= 0 &&
       (dot(lightDir, lightDir) < ru2 || dot(lightDir2, lightDir2) < ru2))
   // using <= rather than < seems to get rid of overlapping shadow
   // artefacts
   { 
-    if (dot(n0, lightDir) > 0) 
+    if (dot(n0, lightDir) < 0) 
         {
             vec4 sp[4] = {p1,p0,p3,p2};
             gl_Position = theMat * sp[k];}