Add descriptor for shadow map

default-frag.glsl

@@ -9,6 +9,8 @@ layout(location = 1) in vec4 light_pos;
 
 layout(location = 0) out vec4 out_colour;
 
+layout(binding = 2) uniform sampler2DShadow shadow_map;
+
 void main()
 {
 	float lambertian = max(dot(frag_normal, light_dir), 0.0);