Pre-multiply V and P matrices

floor-vert.glsl

@@ -3,8 +3,7 @@
 layout(location = 0) out vec3 frag_normal;
 
 layout(push_constant) uniform vp_t {
-	mat4 view;
-	mat4 proj;
+	mat4 transform;
 } vp;
 
 vec2 vertices[4] = vec2[](
@@ -16,6 +15,6 @@ vec2 vertices[4] = vec2[](
 
 void main() {
 	const vec2 pos = 3 * vertices[gl_VertexIndex];
-	gl_Position = vp.proj * vp.view * vec4(pos.x, 0, pos.y, 1); 
+	gl_Position = vp.transform * vec4(pos.x, 0, pos.y, 1);
 	frag_normal = vec3(0, 1, 0);
 }

gpu.c

@@ -496,7 +496,7 @@ void gpu_init(gpu_ctx_t *ctx, GLFWwindow *window, const char *name)
 	const VkPushConstantRange push_constant_range = {
 		.stageFlags = VK_SHADER_STAGE_VERTEX_BIT,
 		.offset = 0,
-		.size = sizeof(vp_t),
+		.size = sizeof(mat4_t),
 	};
 
 	// Load vertex and fragment shader modules
@@ -956,7 +956,7 @@ void gpu_model_cleanup(const gpu_ctx_t *ctx, const gpu_model_t *model)
 }
 
 void gpu_render(
-    const gpu_ctx_t *ctx, vp_t vp, size_t model_count,
+    const gpu_ctx_t *ctx, mat4_t vp, size_t model_count,
     const gpu_model_t *models, const mat4_t **bone_matrices,
     const mat4_t *model_transforms)
 {
@@ -1001,7 +1001,7 @@ void gpu_render(
 	    ctx->cmd_buf, VK_PIPELINE_BIND_POINT_GRAPHICS, ctx->floor_pipeline);
 	vkCmdPushConstants(
 	    ctx->cmd_buf, ctx->model_pipeline_layout, VK_SHADER_STAGE_VERTEX_BIT,
-	    0, sizeof(vp_t), &vp);
+	    0, sizeof(mat4_t), &vp);
 	vkCmdDraw(ctx->cmd_buf, 4, 1, 0, 0);
 
 	// Draw models
@@ -1009,7 +1009,7 @@ void gpu_render(
 	    ctx->cmd_buf, VK_PIPELINE_BIND_POINT_GRAPHICS, ctx->model_pipeline);
 	vkCmdPushConstants(
 	    ctx->cmd_buf, ctx->model_pipeline_layout, VK_SHADER_STAGE_VERTEX_BIT,
-	    0, sizeof(vp_t), &vp);
+	    0, sizeof(mat4_t), &vp);
 	for (unsigned i = 0; i < model_count; ++i) {
 		models[i].transform_ptr[curr_img] = model_transforms[i];
 		memcpy(

gpu.h

@@ -9,11 +9,6 @@
 
 #define MAX_FRAMES_IN_FLIGHT 4
 
-typedef struct {
-	mat4_t view;
-	mat4_t proj;
-} vp_t;
-
 typedef struct {
 	VkInstance inst;
 	VkSurfaceKHR surface;
@@ -73,7 +68,7 @@ void gpu_model_load(
 void gpu_model_cleanup(const gpu_ctx_t *ctx, const gpu_model_t *model);
 
 void gpu_render(
-    const gpu_ctx_t *ctx, vp_t vp, size_t model_count,
+    const gpu_ctx_t *ctx, mat4_t vp, size_t model_count,
     const gpu_model_t *models, const mat4_t **bone_matrices,
     const mat4_t *model_transforms);
 

main.c

@@ -12,7 +12,7 @@
 
 #define DT (1'000'000 / 60) // Assume 60 Hz for now
 
-#define LIL_GUY_COUNT 2
+#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
 
 static void
 key_callback(GLFWwindow *window, int key, int scancode, int action, int mods)
@@ -59,11 +59,10 @@ int main(int argc, char *argv[])
 
 	const vec3_t cam = { 0, 4, -8 };
 	const vec3_t tgt = { 0, 0, 0 };
-	const vp_t vp = {
-		.view = mat4_lookat(cam, tgt, (vec3_t) { 0, 1, 0 }),
-		.proj = mat4_perspective((float)W / H, PI / 8, 0.1, 100.0),
-	};
-	mat4_t transforms[] = {
+	const mat4_t view = mat4_lookat(cam, tgt, (vec3_t) { 0, 1, 0 });
+	const mat4_t proj = mat4_perspective((float)W / H, PI / 8, 0.1, 100.0);
+	const mat4_t vp = mat4_mul(proj, view);
+	mat4_t transforms[NELEMS(gpu_models)] = {
 		mat4_mul(
 		    MAT4_TRANSLATE(1, 0, 0),
 		    (mat4_t) {
@@ -96,9 +95,13 @@ int main(int argc, char *argv[])
 
 		animation_update(&anim, &model, DT);
 
-		const mat4_t *bone_matrices[]
-		    = { anim.bone_matrices, anim.bone_matrices };
-		gpu_render(&gpu, vp, 2, gpu_models, bone_matrices, transforms);
+		const mat4_t *bone_matrices[NELEMS(gpu_models)] = {
+			anim.bone_matrices,
+			anim.bone_matrices,
+		};
+		gpu_render(
+		    &gpu, vp, NELEMS(gpu_models), gpu_models, bone_matrices,
+		    transforms);
 	}
 
 	// Clean up

model-vert.glsl

@@ -8,8 +8,7 @@ layout(location = 3) in vec4 weights;
 layout(location = 0) out vec3 frag_normal;
 
 layout(push_constant) uniform vp_t {
-	mat4 view;
-	mat4 proj;
+	mat4 transform;
 } vp;
 
 layout(binding = 0) uniform transform_t {
@@ -26,7 +25,7 @@ void main() {
 		+ weights.y * bones.matrices[bone_indices.y]
 		+ weights.z * bones.matrices[bone_indices.z]
 		+ weights.w * bones.matrices[bone_indices.w];
-	gl_Position = vp.proj * vp.view * transform.model * skinning_matrix
+	gl_Position = vp.transform * transform.model * skinning_matrix
 		* vec4(position, 1.0);
 	frag_normal = transpose(
 		inverse(mat3(transform.model * skinning_matrix))) * normal;