Run shadow render pass and compute light position in vertex shaders

main.c

@@ -59,9 +59,12 @@ int main(int argc, char *argv[])
 
 	const vec3_t cam = { 0, 4, -8 };
 	const vec3_t tgt = { 0, 0, 0 };
-	const mat4_t view = mat4_lookat(cam, tgt, (vec3_t) { 0, 1, 0 });
+	const vec3_t up = { 0, 1, 0 };
+	const vec3_t light = { 2, 2, -1 };
+	const mat4_t view = mat4_lookat(cam, tgt, up);
 	const mat4_t proj = mat4_perspective((float)W / H, PI / 8, 0.1, 100.0);
 	const mat4_t vp = mat4_mul(proj, view);
+	const mat4_t light_vp = mat4_lookat(light, tgt, up);
 	mat4_t transforms[NELEMS(gpu_models)] = {
 		mat4_mul(
 		    MAT4_TRANSLATE(1, 0, 0),
@@ -100,8 +103,8 @@ int main(int argc, char *argv[])
 			anim.bone_matrices,
 		};
 		gpu_render(
-		    &gpu, vp, NELEMS(gpu_models), gpu_models, bone_matrices,
-		    transforms);
+		    &gpu, vp, light_vp, NELEMS(gpu_models), gpu_models,
+		    bone_matrices, transforms);
 	}
 
 	// Clean up