213 lines
8.2 KiB
Plaintext
213 lines
8.2 KiB
Plaintext
////
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* Copyright (c) 2024, Huawei Technologies Co., Ltd.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 the "License";
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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////
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= Hello Triangle with Vulkan 1.3 Features
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ifdef::site-gen-antora[]
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TIP: The source for this sample can be found in the https://github.com/KhronosGroup/Vulkan-Samples/tree/main/samples/api/hello_triangle_1_3[Khronos Vulkan samples github repository].
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endif::[]
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This sample demonstrates how to render a simple triangle using Vulkan 1.3 core features. It modernizes the traditional "Hello Triangle" Vulkan sample by incorporating:
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- **Dynamic Rendering**
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- **Synchronization2**
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- **Extended Dynamic State**
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- **Vertex Buffers**
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## Overview
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The sample renders a colored triangle to the screen using Vulkan 1.3. It showcases how to:
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- Initialize Vulkan with Vulkan 1.3 features enabled.
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- Use dynamic rendering to simplify the rendering pipeline.
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- Employ the Synchronization2 API for improved synchronization.
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- Utilize extended dynamic states to reduce pipeline complexity.
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- Manage vertex data using vertex buffers instead of hard-coded vertices.
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## Key Features
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### 1. Dynamic Rendering
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**What is Dynamic Rendering?**
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Dynamic Rendering is a feature introduced in Vulkan 1.3 that allows rendering without pre-defined render passes and framebuffers. It simplifies the rendering process by enabling you to specify rendering states directly during command buffer recording.
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**How It's Used in the Sample:**
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- **No Render Passes or Framebuffers:** The sample does not create `VkRenderPass` or `VkFramebuffer` objects.
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- **`vkCmdBeginRendering()` and `vkCmdEndRendering()`:** These functions are used to begin and end rendering operations dynamically.
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- **Pipeline Creation:** Uses `VkPipelineRenderingCreateInfo` during pipeline creation to specify rendering details.
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**Benefits:**
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- Simplifies code by reducing boilerplate associated with render passes and framebuffers.
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- Increases flexibility by allowing rendering to different attachments without recreating render passes.
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### 2. Synchronization2
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**What is Synchronization2?**
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Synchronization2 is an improved synchronization API introduced in Vulkan 1.3. It provides more granular control over synchronization primitives and simplifies the synchronization process.
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**How It's Used in the Sample:**
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- **`vkCmdPipelineBarrier2()`:** Replaces the older `vkCmdPipelineBarrier()` for more detailed synchronization.
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- **`VkDependencyInfo` and `VkImageMemoryBarrier2`:** Used to specify precise memory dependencies and image layout transitions.
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**Example Usage:**
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```cpp
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VkImageMemoryBarrier2 image_barrier = {
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.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER_2,
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// ... other members ...
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};
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VkDependencyInfo dependency_info = {
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.sType = VK_STRUCTURE_TYPE_DEPENDENCY_INFO,
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.imageMemoryBarrierCount = 1,
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.pImageMemoryBarriers = &image_barrier,
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};
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vkCmdPipelineBarrier2(cmd, &dependency_info);
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```
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**Benefits:**
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- Provides more expressive and flexible synchronization.
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- Reduces the potential for synchronization errors.
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- Simplifies the specification of pipeline stages and access masks.
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### 3. Extended Dynamic State
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**What is Extended Dynamic State?**
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Extended Dynamic State allows more pipeline states to be set dynamically at command buffer recording time rather than during pipeline creation. This reduces the number of pipeline objects needed.
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**How It's Used in the Sample:**
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- **Dynamic States Enabled:** The sample enables dynamic states like `VK_DYNAMIC_STATE_CULL_MODE`, `VK_DYNAMIC_STATE_FRONT_FACE`, and `VK_DYNAMIC_STATE_PRIMITIVE_TOPOLOGY`.
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- **Dynamic State Commands:** Uses `vkCmdSetCullMode()`, `vkCmdSetFrontFace()`, and `vkCmdSetPrimitiveTopology()` to set these states dynamically.
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**Example Usage:**
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```cpp
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vkCmdSetCullMode(cmd, VK_CULL_MODE_NONE);
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vkCmdSetFrontFace(cmd, VK_FRONT_FACE_CLOCKWISE);
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vkCmdSetPrimitiveTopology(cmd, VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST);
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```
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**Benefits:**
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- Reduces the need to create multiple pipelines for different state configurations.
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- Enhances flexibility by allowing state changes without pipeline recreation.
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### 4. Vertex Buffers
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**What Changed?**
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Unlike the original sample, which used hard-coded vertices in the shader, this sample uses a vertex buffer to store vertex data.
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**How It's Used in the Sample:**
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- **Vertex Structure Defined:**
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```cpp
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struct Vertex {
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glm::vec2 position;
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glm::vec3 color;
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};
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```
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- **Vertex Data Stored in a Buffer:**
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```cpp
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std::vector<Vertex> vertices = {
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{{0.5f, -0.5f}, {1.0f, 0.0f, 0.0f}}, // Red Vertex
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// ... other vertices ...
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};
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```
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- **Buffer Creation and Memory Allocation:**
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```cpp
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VkBufferCreateInfo buffer_info = { /* ... */ };
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vkCreateBuffer(device, &buffer_info, nullptr, &vertex_buffer);
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VkMemoryAllocateInfo alloc_info = { /* ... */ };
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vkAllocateMemory(device, &alloc_info, nullptr, &vertex_buffer_memory);
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```
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- **Binding the Vertex Buffer:**
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```cpp
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vkCmdBindVertexBuffers(cmd, 0, 1, &vertex_buffer, &offset);
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```
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**Benefits:**
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- **Flexibility:** Easier to modify vertex data without changing shaders.
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- **Performance:** Potentially better performance due to efficient memory usage.
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- **Scalability:** Simplifies rendering more complex geometries.
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## How the Sample Works
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1. **Initialization:**
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- **Instance Creation:** Initializes a Vulkan instance with Vulkan 1.3 API version and required extensions.
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- **Device Selection:** Chooses a physical device that supports Vulkan 1.3 and required features.
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- **Logical Device Creation:** Creates a logical device with enabled Vulkan 1.3 features like dynamic rendering, synchronization2, and extended dynamic state.
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- **Surface and Swapchain Creation:** Sets up the window surface and initializes the swapchain for presenting images.
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2. **Vertex Buffer Setup:**
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- **Vertex Data Definition:** Defines vertices with positions and colors.
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- **Buffer Creation:** Creates a buffer to store vertex data.
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- **Memory Allocation:** Allocates memory for the buffer and maps the vertex data into it.
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3. **Pipeline Setup:**
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- **Shader Modules:** Loads and compiles vertex and fragment shaders.
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- **Pipeline Layout:** Creates a pipeline layout (empty in this case as no descriptors are used).
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- **Dynamic States Specification:** Specifies which states will be dynamic.
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- **Graphics Pipeline Creation:** Creates the graphics pipeline with dynamic rendering info and dynamic states enabled.
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4. **Rendering Loop:**
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- **Acquire Swapchain Image:** Gets the next available image from the swapchain.
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- **Command Buffer Recording:**
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- **Begin Rendering:** Uses `vkCmdBeginRendering()` with dynamic rendering info.
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- **Set Dynamic States:** Sets viewport, scissor, cull mode, front face, and primitive topology dynamically.
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- **Bind Pipeline and Vertex Buffer:** Binds the graphics pipeline and the vertex buffer.
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- **Draw Call:** Issues a draw call to render the triangle.
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- **End Rendering:** Uses `vkCmdEndRendering()` to finish rendering.
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- **Image Layout Transition:** Transitions the swapchain image layout for presentation using `vkCmdPipelineBarrier2()`.
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- **Queue Submission:** Submits the command buffer to the graphics queue.
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- **Present Image:** Presents the rendered image to the screen.
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5. **Cleanup:**
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- **Resource Destruction:** Cleans up Vulkan resources like pipelines, buffers, and swapchain images upon application exit.
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## Dependencies and Requirements
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- **Vulkan SDK 1.3 or Later:** Ensure you have the Vulkan SDK that supports Vulkan 1.3.
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- **Hardware Support:** A GPU that supports Vulkan 1.3 features, including dynamic rendering, synchronization2, and extended dynamic state.
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- **GLM Library:** Used for vector and matrix operations.
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- **Shader Compiler:** GLSL shaders are compiled at runtime using a GLSL compiler. |