Prevent drawing of shadow caps when turned off

shader/lighting/cap.vert

@@ -1,11 +1,11 @@
 #version 450 core
-layout (location = 0) in vec3 position;
+layout (location = 0) in vec4 position;
 layout (std140, binding = 0) uniform TheMat { mat4 theMat; } ;
 uniform vec3 lightPos;
 uniform vec4 lumRad;
-out vec3 dField;
-out vec3 lum;
+out float drawbit;
 void main()
 {
-    gl_Position = vec4(position,1);
+    gl_Position = vec4(position.xyz,1);
+    drawbit = position.w;
 }