Add alternate shadow volume rendering pathway (layered geo)

shader/shadow/light.vert

@@ -1,9 +1,4 @@
 #version 450 core
-layout (location = 0) in vec2 pos;
-layout (location = 1) in vec2 texPos;
-out vec2 vTexPos;
 void main()
 {
-  gl_Position = vec4(pos,0,1);
-  vTexPos = texPos;
 }