From 5bcd66fb6bd3b2543df74705f0d6cd557f74a80a Mon Sep 17 00:00:00 2001
From: Amber <amber@igalia.com>
Date: Wed, 26 Oct 2022 13:40:44 +0200
Subject: [PATCH] Use a staging buffer.

---
 src/main.c | 81 +++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 68 insertions(+), 13 deletions(-)

diff --git a/src/main.c b/src/main.c
index 83b463a..5745a1e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -910,38 +910,93 @@ uint32_t find_memory_type (ApplicationState* state, uint32_t type_filter, VkMemo
     exit(1);
 }
 
-void create_vertex_buffer(ApplicationState* state) {
+void create_buffer(ApplicationState* state, VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags properties,
+        VkBuffer* buffer, VkDeviceMemory* memory) {
     VkBufferCreateInfo buffer_info = {0};
     buffer_info.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
-    buffer_info.size = sizeof(Vertex) * ARRSIZE(vertices);
-    buffer_info.usage = VK_BUFFER_USAGE_VERTEX_BUFFER_BIT;
+    buffer_info.size = size;
+    buffer_info.usage = usage;
     buffer_info.sharingMode = VK_SHARING_MODE_EXCLUSIVE;
 
-    if (vkCreateBuffer(state->device, &buffer_info, NULL, &state->vertex_buffer) != VK_SUCCESS) {
-        printf("Failed to create vertex buffer\n");
+    if (vkCreateBuffer(state->device, &buffer_info, NULL, buffer) != VK_SUCCESS) {
+        printf("Failed to create buffer\n");
         exit(1);
     }
 
     VkMemoryRequirements mem_req;
-    vkGetBufferMemoryRequirements(state->device, state->vertex_buffer, &mem_req);
+    vkGetBufferMemoryRequirements(state->device, *buffer, &mem_req);
 
     VkMemoryAllocateInfo alloc_info = {0};
     alloc_info.sType = VK_STRUCTURE_TYPE_MEMORY_ALLOCATE_INFO;
     alloc_info.allocationSize = mem_req.size;
-    alloc_info.memoryTypeIndex = find_memory_type(state, mem_req.memoryTypeBits,
-            VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT);
+    alloc_info.memoryTypeIndex = find_memory_type(state, mem_req.memoryTypeBits, properties);
 
-    if (vkAllocateMemory(state->device, &alloc_info, NULL, &state->vertex_buffer_memory) != VK_SUCCESS) {
+    if (vkAllocateMemory(state->device, &alloc_info, NULL, memory) != VK_SUCCESS) {
         printf("failed to allocate memory for buffer\n");
         exit(1);
     }
 
-    vkBindBufferMemory(state->device, state->vertex_buffer, state->vertex_buffer_memory, 0);
+    vkBindBufferMemory(state->device, *buffer, *memory, 0);
+}
+
+void copy_buffer(ApplicationState* state, VkBuffer src, VkBuffer dst, VkDeviceSize size) {
+    VkCommandBufferAllocateInfo command_buf_allocate_info = {0};
+    command_buf_allocate_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
+    command_buf_allocate_info.commandPool = state->commandPool;
+    command_buf_allocate_info.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
+    command_buf_allocate_info.commandBufferCount = 1;
+
+    VkCommandBuffer buffer;
+
+    if (vkAllocateCommandBuffers(state->device, &command_buf_allocate_info, &buffer) != VK_SUCCESS) {
+        printf("failed to allocated command buffer for transfer\n");
+        exit(1);
+    }
+
+    VkCommandBufferBeginInfo begin_info = {0};
+    begin_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
+    begin_info.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+
+    vkBeginCommandBuffer(buffer, &begin_info);
+
+    VkBufferCopy copy = {0};
+    copy.size = size;
+    vkCmdCopyBuffer(buffer, src, dst, 1, &copy);
+
+    vkEndCommandBuffer(buffer);
+
+    VkSubmitInfo submit_info = {0};
+    submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+    submit_info.commandBufferCount = 1;
+    submit_info.pCommandBuffers = &buffer;
+
+    vkQueueSubmit(state->graphics_queue, 1, &submit_info, VK_NULL_HANDLE);
+    vkQueueWaitIdle(state->graphics_queue);
+
+    vkFreeCommandBuffers(state->device, state->commandPool, 1, &buffer);
+}
+
+void create_vertex_buffer(ApplicationState* state) {
+    VkDeviceSize buffer_size = sizeof(Vertex) * ARRSIZE(vertices);
+
+    //we use a staging buffer for transferring data in order to use a more efficient memory type for the vertex buffer
+    VkBuffer staging_buffer;
+    VkDeviceMemory staging_buffer_memory;
+    create_buffer(state, buffer_size, VK_BUFFER_USAGE_TRANSFER_SRC_BIT, VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT,
+            &staging_buffer, &staging_buffer_memory);
 
     void* data;
-    vkMapMemory(state->device, state->vertex_buffer_memory, 0, buffer_info.size, 0, &data);
-    memcpy(data, vertices, buffer_info.size);
-    vkUnmapMemory(state->device, state->vertex_buffer_memory);
+    vkMapMemory(state->device, staging_buffer_memory, 0, buffer_size, 0, &data);
+    memcpy(data, vertices, buffer_size);
+    vkUnmapMemory(state->device, staging_buffer_memory);
+
+    create_buffer(state, buffer_size, VK_BUFFER_USAGE_TRANSFER_DST_BIT | VK_BUFFER_USAGE_VERTEX_BUFFER_BIT, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT,
+            &state->vertex_buffer, &state->vertex_buffer_memory);
+
+    copy_buffer(state, staging_buffer, state->vertex_buffer, buffer_size);
+
+    vkDestroyBuffer(state->device, staging_buffer, NULL);
+    vkFreeMemory(state->device, staging_buffer_memory, NULL);
 }
 
 void create_command_buffer(ApplicationState* state) {