Move towards geometry instancing for shadows

shader/positional/blank.frag

@@ -0,0 +1,6 @@
+#version 450 core
+out vec4 fColor;
+void main()
+{
+  fColor = vec4 (0,0,0,0);
+}

shader/positional/blank.vert

@@ -0,0 +1,6 @@
+#version 450 core
+layout (location = 0) in vec3 pos;
+layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
+void main() {
+  gl_Position = theMat * vec4(pos,1);
+}