Continue work on shadow rendering

shader/lighting/lineShadow.geom

@@ -1,71 +1,91 @@
 #version 450 core
-layout (lines_adjacency) in;
-layout (triangle_strip, max_vertices = 4) out;
-layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+layout(lines_adjacency) in;
+layout(triangle_strip, max_vertices = 4) out;
+layout(std140, binding = 0) uniform TheMat { mat4 theMat; };
 uniform vec3 lightPos;
 uniform float radiusUniform;
-//vec4 shift (vec4 p) { return (vec4 (p.xyz + (lumRad.a*normalize(p.xyz-lightPos)), 1));}
-vec4 shift (vec4 p) { return (vec4 (p.xyz + (100000*(p.xyz-lightPos)), 1));}
-vec4 shiftBy (float x,vec4 p) { return (vec4 (lightPos + (x*normalize(p.xyz-lightPos)), 1));}
-//vec4 shift (vec4 p) { return (vec4 (lightPos + (lumRad.a*normalize(p.xyz-lightPos)), 1));}
+// vec4 shift (vec4 p) { return (vec4 (p.xyz +
+// (lumRad.a*normalize(p.xyz-lightPos)), 1));}
+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{ if (x > 1) { return b; }
+      { return a + (x * (b- a));}
+  }
+}
+//vec3 closepoint = 
+vec4 shift(vec4 p) { return (vec4(p.xyz + (100000 * (p.xyz - lightPos)), 1)); }
+vec4 shiftBy(float x, vec4 p) {
+  return (vec4(lightPos + (x * normalize(p.xyz - lightPos)), 1));
+}
+// vec4 shift (vec4 p) { return (vec4 (lightPos +
+// (lumRad.a*normalize(p.xyz-lightPos)), 1));}
 // copied from lighting/cap.geom, should not be changed on its own
-vec4 projNear (vec4 pos)
-{
-    // note we project to a specific height
-    // this is quite brittle, not ideal
-    vec3 dir = pos.xyz - lightPos ;
-    float a = (140 - pos.z) / dir.z ;
-    vec2 xy = (pos.xyz + a * dir).xy ;
-    return vec4 ( xy, 140 , 1) ;
+vec4 projNear(vec4 pos) {
+  // note we project to a specific height
+  // this is quite brittle, not ideal
+  vec3 dir = pos.xyz - lightPos;
+  float a = (100 - pos.z) / dir.z;
+  vec2 xy = (pos.xyz + a * dir).xy;
+  return vec4(xy, 100, 1);
 }
-vec4 shiftNear (vec4 pos)
+vec4 shiftNear(vec4 pos)
 //{ vec4 sp = shiftBy(radiusUniform,pos);
-{ vec4 sp = shift(pos);
-    if (sp.z > 140)
-    { return projNear(pos) ; }
-    else
-    { return sp ; }
-}
-vec4 f (vec4 p) {return (theMat * p);}
-void main()
 {
-    float ru2 = radiusUniform * radiusUniform ;
-    vec4 p0 = gl_in[0].gl_Position;
-    vec4 p1 = gl_in[1].gl_Position;
-    vec4 mid = 0.5*(p0 + p1);
-    vec3 n0a = gl_in[2].gl_Position.xyz;
-    vec3 n1a = gl_in[3].gl_Position.xyz;
-    vec3 n0 = cross(p1.xyz - p0.xyz, n0a - p0.xyz) ;
-    vec3 n1 = cross(p0.xyz - p1.xyz, n1a - p1.xyz) ;
-    
-    //vec3 n2 = n0 + n1; // assumes the summands are normalized
-    vec3 lightDir = p0.xyz - lightPos.xyz;
-    vec3 lightDir2 = p1.xyz - lightPos.xyz;
-    // 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
-    // "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
-    {
-        vec4 p2 = shiftNear(p0);
-        vec4 p3 = shiftNear(p1);
-        if ( dot(n0 , lightDir) > 0)
-        {
-            gl_Position = f(p0); EmitVertex();
-            gl_Position = f(p1); EmitVertex();
-            gl_Position = f(p2); EmitVertex();
-            gl_Position = f(p3); EmitVertex();
-        }
-        else
-        {
-            gl_Position = f(p1); EmitVertex();
-            gl_Position = f(p0); EmitVertex();
-            gl_Position = f(p3); EmitVertex();
-            gl_Position = f(p2); EmitVertex();
-        }
-        EndPrimitive();
+  vec4 sp = shift(pos);
+  if (sp.z > 100) {
+    return projNear(pos);
+  } else {
+    return sp;
+  }
+}
+vec4 f(vec4 p) { return (theMat * p); }
+void main() {
+vec4 p0 = gl_in[0].gl_Position;
+vec4 p1 = gl_in[1].gl_Position;
+vec3 closepoint = closestPointOnSeg3(p0.xyz,p1.xyz,lightPos);
+  float ru2 = radiusUniform * radiusUniform;
+  vec4 mid = 0.5 * (p0 + p1);
+  vec3 n0a = gl_in[2].gl_Position.xyz;
+  vec3 n1a = gl_in[3].gl_Position.xyz;
+  vec3 n0 = cross(p1.xyz - p0.xyz, n0a - p0.xyz);
+  vec3 n1 = cross(p0.xyz - p1.xyz, n1a - p1.xyz);
+
+  // vec3 n2 = n0 + n1; // assumes the summands are normalized
+  vec3 lightDir = p0.xyz - lightPos.xyz;
+  vec3 lightDir2 = p1.xyz - lightPos.xyz;
+  // 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
+  // "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
+  {
+    //vec4 p2 = shiftNear(p0);
+    //vec4 p3 = shiftNear(p1);
+    vec4 p2 = shiftNear(p0);
+    vec4 p3 = shiftNear(p1);
+    gl_Position = f(p0);
+    EmitVertex();
+    if (dot(n0, lightDir) > 0) {
+      gl_Position = f(p2);
+      EmitVertex();
+      gl_Position = f(p1);
+      EmitVertex();
+    } else {
+      gl_Position = f(p1);
+      EmitVertex();
+      gl_Position = f(p2);
+      EmitVertex();
     }
-    else { }
+    gl_Position = f(p3);
+    EmitVertex();
+    EndPrimitive();
+  } else {
+  }
 }