From f12a9bf4417a3d17ca0a37159a0c859c7d8ec692 Mon Sep 17 00:00:00 2001
From: Benjamin Kraft <benjamin.kraft@online.de>
Date: Thu, 5 Sep 2024 08:38:49 +0200
Subject: [PATCH] index buffer

---
 src/vulkan/application.cpp | 23 ++++++++++++++++++-----
 src/vulkan/application.hpp |  2 +-
 src/vulkan/buffer.cpp      | 22 +++++++++++++++-------
 src/vulkan/buffer.hpp      | 15 ++++++++++++++-
 4 files changed, 48 insertions(+), 14 deletions(-)

diff --git a/src/vulkan/application.cpp b/src/vulkan/application.cpp
index 1564711..25e92cf 100644
--- a/src/vulkan/application.cpp
+++ b/src/vulkan/application.cpp
@@ -9,12 +9,23 @@ Application::Application() {
 	instance = new Instance;
 	swapchain = new Swapchain(instance);
 	pipeline = new Pipeline(instance, swapchain->renderPass);
-	stagingBuffer = Buffer::createStagingBuffer(instance);
-	vertexBuffer = new Buffer(instance, stagingBuffer->size,
+	auto stagedVertexBuffer = Buffer::createStagedVertexBuffer(instance);
+	vertexBuffer = new Buffer(instance, stagedVertexBuffer->size,
 							  VK_BUFFER_USAGE_TRANSFER_DST_BIT | VK_BUFFER_USAGE_VERTEX_BUFFER_BIT,
 							  VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+
+	auto stagedIndexBuffer = Buffer::createStagedIndexBuffer(instance);
+	indexBuffer = new Buffer(instance, stagedIndexBuffer->size,
+							 VK_BUFFER_USAGE_TRANSFER_DST_BIT | VK_BUFFER_USAGE_INDEX_BUFFER_BIT,
+							 VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+
 	commandPool = new CommandPool(instance);
-	stagingBuffer->copyTo(vertexBuffer, commandPool);
+
+	stagedVertexBuffer->copyTo(vertexBuffer, commandPool);
+	stagedIndexBuffer->copyTo(indexBuffer, commandPool);
+
+	delete stagedVertexBuffer;
+	delete stagedIndexBuffer;
 
 	createSyncObjects();
 
@@ -137,7 +148,9 @@ void Application::recordCommandBuffer(VkCommandBuffer commandBuffer, uint32_t im
 	VkDeviceSize offsets[] = {0};
 	vkCmdBindVertexBuffers(commandBuffer, 0, 1, buffers, offsets);
 
-	vkCmdDraw(commandBuffer, 3, 1, 0, 0);
+	vkCmdBindIndexBuffer(commandBuffer, indexBuffer->handle, 0, VK_INDEX_TYPE_UINT32);
+
+	vkCmdDrawIndexed(commandBuffer, indices.size(), 1, 0, 0, 0);
 
 	vkCmdEndRenderPass(commandBuffer);
 	vkEndCommandBuffer(commandBuffer);
@@ -151,8 +164,8 @@ Application::~Application() {
 		vkDestroyFence(instance->device, inFlightFences[i], nullptr);
 	}
 	delete commandPool;
-	delete stagingBuffer;
 	delete vertexBuffer;
+	delete indexBuffer;
 	delete pipeline;
 	delete instance;
 }
diff --git a/src/vulkan/application.hpp b/src/vulkan/application.hpp
index 1168a2d..603bf58 100644
--- a/src/vulkan/application.hpp
+++ b/src/vulkan/application.hpp
@@ -45,8 +45,8 @@ private:
 	Instance* instance = nullptr;
 	Swapchain* swapchain = nullptr;
 	Pipeline* pipeline = nullptr;
-	Buffer* stagingBuffer = nullptr;
 	Buffer* vertexBuffer = nullptr;
+	Buffer* indexBuffer = nullptr;
 	CommandPool* commandPool = nullptr;
 
 	void recordCommandBuffer(VkCommandBuffer commandBuffer, uint32_t imageIndex);
diff --git a/src/vulkan/buffer.cpp b/src/vulkan/buffer.cpp
index 12a8023..87c77ef 100644
--- a/src/vulkan/buffer.cpp
+++ b/src/vulkan/buffer.cpp
@@ -5,12 +5,6 @@
 #include "instance.hpp"
 #include "command_pool.hpp"
 
-const std::vector<Vertex> vertices = {
-		{{0.0, -0.5}, {1, 0, 0}},
-		{{0.5, 0.5}, {0, 1, 0}},
-		{{-0.5, 0.5}, {0, 0, 1}}
-};
-
 Buffer::Buffer(Instance* instance, VkDeviceSize size, VkBufferUsageFlags usage, VkMemoryPropertyFlags properties) : instance(instance), size(size){
 	VkBufferCreateInfo bufferInfo{};
 	bufferInfo.sType = VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO;
@@ -51,7 +45,7 @@ Buffer::~Buffer() {
 	vkDestroyBuffer(instance->device, handle, nullptr);
 }
 
-Buffer* Buffer::createStagingBuffer(Instance* instance) {
+Buffer* Buffer::createStagedVertexBuffer(Instance* instance) {
 	VkDeviceSize size = vertices.size() * sizeof(Vertex);
 	VkBufferUsageFlags usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;
 	VkMemoryPropertyFlags properties = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
@@ -66,6 +60,20 @@ Buffer* Buffer::createStagingBuffer(Instance* instance) {
 	return stagingBuffer;
 }
 
+Buffer *Buffer::createStagedIndexBuffer(Instance *instance) {
+	VkDeviceSize size = indices.size() * sizeof(uint32_t);
+	VkBufferUsageFlags usage = VK_BUFFER_USAGE_TRANSFER_SRC_BIT;
+	VkMemoryPropertyFlags properties = VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
+	auto stagingBuffer = new Buffer(instance, size, usage, properties);
+
+	uint32_t *data;
+	vkMapMemory(instance->device, stagingBuffer->memory, 0, size, 0, reinterpret_cast<void**>(&data));
+	memcpy(data, indices.data(), sizeof(uint32_t) * indices.size());
+	vkUnmapMemory(instance->device, stagingBuffer->memory);
+
+	return stagingBuffer;
+}
+
 void Buffer::copyTo(Buffer *dst, CommandPool* commandPool) {
 	VkCommandBufferAllocateInfo allocateInfo {};
 	allocateInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
diff --git a/src/vulkan/buffer.hpp b/src/vulkan/buffer.hpp
index b176e8b..d45226b 100644
--- a/src/vulkan/buffer.hpp
+++ b/src/vulkan/buffer.hpp
@@ -2,6 +2,18 @@
 
 #include <vulkan/vulkan_core.h>
 #include <stdexcept>
+#include "vertex.hpp"
+
+const std::vector<Vertex> vertices = {
+		{{0.0, -0.5}, {1, 0, 0}},
+		{{0.5, 0.5}, {0, 1, 0}},
+		{{-0.5, 0.5}, {0, 0, 1}},
+		{{0.8, -0.5}, {1, 1, 1}}
+};
+
+const std::vector<uint32_t> indices = {
+		0, 1, 2, 0, 3, 1
+};
 
 class Instance;
 class CommandPool;
@@ -14,7 +26,8 @@ public:
 	VkDeviceMemory memory = VK_NULL_HANDLE;
 	VkDeviceSize size;
 
-	static Buffer* createStagingBuffer(Instance* instance);
+	static Buffer* createStagedVertexBuffer(Instance* instance);
+	static Buffer* createStagedIndexBuffer(Instance* instance);
 
 	void copyTo(Buffer* dst, CommandPool* commandPool);