Add MVP projection passed through push constant

gpu.c

@@ -436,9 +436,15 @@ void gpu_init(gpu_ctx_t *ctx, const gpu_config_t *config)
 	};
 
 	// Create pipeline layout
+	const VkPushConstantRange mvp_range = {
+		.stageFlags = VK_SHADER_STAGE_VERTEX_BIT,
+		.offset = 0,
+		.size = sizeof(mvp_t),
+	};
 	const VkPipelineLayoutCreateInfo pipeline_layout_config = {
 		.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO,
-		.pushConstantRangeCount = 0,
+		.pushConstantRangeCount = 1,
+		.pPushConstantRanges = &mvp_range,
 	};
 	result = vkCreatePipelineLayout(
 	    ctx->dev, &pipeline_layout_config, nullptr, &ctx->pipeline_layout);
@@ -641,7 +647,7 @@ void gpu_cleanup(const gpu_ctx_t *ctx)
 	vkDestroyInstance(ctx->inst, nullptr);
 }
 
-void gpu_render(const gpu_ctx_t *ctx)
+void gpu_render(const gpu_ctx_t *ctx, const mvp_t *mvp)
 {
 	VkResult result;
 
@@ -679,6 +685,11 @@ void gpu_render(const gpu_ctx_t *ctx)
 	vkCmdBindPipeline(
 	    ctx->cmd_buf, VK_PIPELINE_BIND_POINT_GRAPHICS, ctx->pipeline);
 
+	// Push MVP
+	vkCmdPushConstants(
+	    ctx->cmd_buf, ctx->pipeline_layout, VK_SHADER_STAGE_VERTEX_BIT, 0,
+	    sizeof(mvp_t), mvp);
+
 	// Bind vertex and index buffers then draw
 	vkCmdBindVertexBuffers(
 	    ctx->cmd_buf, 0, 1, &ctx->vertex_buf, &(VkDeviceSize) { 0 });