136 lines
3.3 KiB
Markdown
136 lines
3.3 KiB
Markdown
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# OpenGLBuffer
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OpenGL 缓冲区的实现，封装 OpenGL buffer object。
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## 头文件
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```cpp
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#include <XCEngine/RHI/OpenGL/OpenGLBuffer.h>
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```
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## 继承关系
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```
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RHIBuffer (interface)
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└── OpenGLBuffer (implementation)
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```
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## OpenGLBufferType 枚举
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| 值 | 描述 |
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|----|------|
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| `Vertex` | 顶点缓冲区 |
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| `Index` | 索引缓冲区 |
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| `Uniform` | Uniform 缓冲区 (UBO) |
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| `CopyRead` | 复制源缓冲区 |
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| `CopyWrite` | 复制目标缓冲区 |
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| `AtomicCounter` | 原子计数器缓冲区 |
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| `DispatchIndirect` | 间接计算调用缓冲区 |
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| `DrawIndirect` | 间接绘制缓冲区 |
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| `ShaderBindingTable` | 光线追踪 Shader 绑定表 |
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## 公共成员函数
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### 构造函数与析构函数
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#### `OpenGLBuffer()`
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#### `~OpenGLBuffer() override`
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### 初始化
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#### `bool Initialize(OpenGLBufferType type, size_t size, const void* data = nullptr, bool dynamic = false)`
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通用初始化。
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- `type`: 缓冲区类型
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- `size`: 大小（字节）
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- `data`: 初始数据（可选）
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- `dynamic`: 是否动态更新
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#### `bool InitializeVertexBuffer(const void* data, size_t size)`
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初始化顶点缓冲区。
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#### `bool InitializeIndexBuffer(const void* data, size_t size)`
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初始化索引缓冲区。
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#### `void Shutdown() override`
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### 绑定操作
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#### `void Bind() const`
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绑定缓冲区到当前 target。
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#### `void Unbind() const`
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解除绑定。
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#### `void BindBase(unsigned int target, unsigned int index) const`
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绑定到指定的 binding point（用于 UBO、SSBO 等）。
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### 数据操作
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#### `void* Map() override`
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映射缓冲区到 CPU。
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#### `void Unmap() override`
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解除映射。
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#### `void SetData(const void* data, size_t size, size_t offset = 0) override`
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更新缓冲区数据。
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### 属性
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#### `unsigned int GetID() const`
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获取 OpenGL buffer ID。
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#### `uint64_t GetSize() const override`
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获取缓冲区大小。
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#### `OpenGLBufferType GetType() const`
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获取缓冲区类型。
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#### `bool IsDynamic() const`
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是否动态缓冲区。
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#### `BufferType GetBufferType() const override / void SetBufferType(BufferType type) override`
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#### `uint32_t GetStride() const override / void SetStride(uint32_t stride) override`
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#### `void* GetNativeHandle() override`
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返回 `reinterpret_cast<void*>(static_cast<uintptr_t>(m_buffer))`
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#### `ResourceStates GetState() const override`
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返回 `ResourceStates::Common`（OpenGL 无显式状态）
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#### `const std::string& GetName() const override / void SetName(...) override`
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## 内部成员
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| 成员 | 类型 | 描述 |
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|------|------|------|
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| `m_buffer` | `unsigned int` | GL buffer ID |
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| `m_size` | `size_t` | 大小 |
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| `m_isIndexBuffer` | `bool` | 是否索引缓冲区 |
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| `m_dynamic` | `bool` | 是否动态 |
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| `m_type` | `OpenGLBufferType` | 缓冲区类型 |
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| `m_bufferType` | `BufferType` | RHI 缓冲区类型 |
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| `m_stride` | `uint32_t` | 顶点步长 |
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| `m_name` | `std::string` | 名称 |
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## 使用示例
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```cpp
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OpenGLBuffer vb;
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float vertices[] = { ... };
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vb.InitializeVertexBuffer(vertices, sizeof(vertices));
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vb.SetBufferType(BufferType::Vertex);
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vb.SetStride(sizeof(float) * 5);
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OpenGLBuffer ib;
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uint16_t indices[] = { 0, 1, 2, ... };
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ib.InitializeIndexBuffer(indices, sizeof(indices));
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// Bind and draw
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vb.Bind();
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ib.Bind();
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glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, 0);
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```
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