Implement lambertian shading w/ directional light

frag.glsl

@@ -1,9 +1,15 @@
 #version 450
 
+float ambient = 0.05;
+vec3 light_dir = normalize(vec3(2, 1, -1));
+vec3 base_colour = vec3(1.0, 0.94, 0.8);
+
 layout(location = 0) in vec3 frag_normal;
 layout(location = 0) out vec4 out_colour;
 
 void main()
 {
-	out_colour = vec4(frag_normal, 1.0);
+	float lambertian = max(dot(frag_normal, light_dir), 0.0);
+	float intensity = min(lambertian + ambient, 1.0);
+	out_colour = vec4(intensity * base_colour, 1.0);
 }

vert.glsl

@@ -13,5 +13,5 @@ layout(push_constant) uniform MVP {
 
 void main() {
 	gl_Position = mvp.proj * mvp.view * mvp.model * vec4(position, 1.0);
-	frag_normal = normal;
+	frag_normal = mat3(mvp.model) * normal;
 }