Add "cap" shadow shader

shader/lighting/cap.frag

@@ -0,0 +1,6 @@
+#version 430 core
+out vec4 fColor;
+void main()
+{
+  fColor = vec4(0,1,0,1);
+}

shader/lighting/cap.geom

@@ -0,0 +1,19 @@
+#version 430 core
+layout (triangles) in;
+layout (triangle_strip, max_vertices = 3) out;
+layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+uniform vec3 lightPos;
+void main()
+{
+    vec4 p0 = gl_in[0].gl_Position ;
+    vec4 p1 = gl_in[1].gl_Position ;
+    vec4 p2 = gl_in[2].gl_Position ;
+    if ( dot( lightPos, cross( p0.xyz - p1.xyz, p1.xyz - p2.xyz)) < 0)
+    {
+        gl_Position = theMat * p0; EmitVertex();
+        gl_Position = theMat * p1; EmitVertex();
+        gl_Position = theMat * p2; EmitVertex();
+        EndPrimitive();
+    }
+    else {}
+}

shader/lighting/cap.vert

@@ -0,0 +1,11 @@
+#version 430 core
+layout (location = 0) in vec3 position;
+layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+uniform vec3 lightPos;
+uniform vec4 lumRad;
+out vec3 dField;
+out vec3 lum;
+void main()
+{
+    gl_Position = vec4(position,1);
+}

shader/lighting/surfaceCap.vert

@@ -0,0 +1,13 @@
+#version 430 core
+layout (location = 0) in vec3 position;
+layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+uniform vec3 lightPos;
+uniform vec4 lumRad;
+out vec3 dField;
+out vec3 lum;
+void main()
+{
+    dField = (position - lightPos) / lumRad.a;
+    lum = lumRad.rgb;
+    gl_Position = theMat * vec4(position,1);
+}