refactor: reorganize docs into plan/ and add skills/

docs/api/rhi/opengl/opengl-sampler.md

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+# OpenGLSampler
+
+OpenGL 采样器实现。
+
+## 头文件
+
+```cpp
+#include <XCEngine/RHI/OpenGL/OpenGLSampler.h>
+```
+
+## 继承关系
+
+```
+RHISampler (interface)
+└── OpenGLSampler (implementation)
+```
+
+## 枚举
+
+### SamplerWrapMode
+
+| 值 | OpenGL 常量 |
+|----|-------------|
+| `Repeat` | `GL_REPEAT` |
+| `MirroredRepeat` | `GL_MIRRORED_REPEAT` |
+| `ClampToEdge` | `GL_CLAMP_TO_EDGE` |
+| `ClampToBorder` | `GL_CLAMP_TO_BORDER` |
+
+### SamplerFilter
+
+| 值 | OpenGL 常量 |
+|----|-------------|
+| `Nearest` | `GL_NEAREST` |
+| `Linear` | `GL_LINEAR` |
+| `NearestMipmapNearest` | `GL_NEAREST_MIPMAP_NEAREST` |
+| `LinearMipmapNearest` | `GL_LINEAR_MIPMAP_NEAREST` |
+| `NearestMipmapLinear` | `GL_NEAREST_MIPMAP_LINEAR` |
+| `LinearMipmapLinear` | `GL_LINEAR_MIPMAP_LINEAR` |
+
+### SamplerCompareMode
+
+| 值 | OpenGL 常量 |
+|----|-------------|
+| `None` | `GL_NONE` |
+| `CompareToRef` | `GL_COMPARE_REF_TO_TEXTURE` |
+
+## OpenGLSamplerDesc
+
+```cpp
+struct OpenGLSamplerDesc {
+    SamplerFilter minFilter = SamplerFilter::LinearMipmapLinear;
+    SamplerFilter magFilter = SamplerFilter::Linear;
+    SamplerWrapMode wrapS = SamplerWrapMode::Repeat;
+    SamplerWrapMode wrapT = SamplerWrapMode::Repeat;
+    SamplerWrapMode wrapR = SamplerWrapMode::Repeat;
+    SamplerCompareMode compareMode = SamplerCompareMode::None;
+    int compareFunc = 0;
+    float maxAnisotropy = 1.0f;
+    float minLod = -1000.0f;
+    float maxLod = 1000.0f;
+};
+```
+
+## 公共成员函数
+
+#### `OpenGLSampler()`
+
+#### `~OpenGLSampler() override`
+
+#### `bool Initialize(const OpenGLSamplerDesc& desc)`
+
+#### `void Shutdown() override`
+
+#### `void Bind(unsigned int unit) override`
+
+#### `void Unbind(unsigned int unit) override`
+
+#### `unsigned int GetID() const`
+
+#### `void* GetNativeHandle() override`
+
+## 内部成员
+
+| 成员 | 类型 | 描述 |
+|------|------|------|
+| `m_sampler` | `unsigned int` | GL sampler ID |
+| `m_desc` | `OpenGLSamplerDesc` | 采样器描述 |
+
+## 使用示例
+
+```cpp
+OpenGLSampler sampler;
+OpenGLSamplerDesc desc;
+desc.minFilter = SamplerFilter::LinearMipmapLinear;
+desc.magFilter = SamplerFilter::Linear;
+desc.wrapS = desc.wrapT = SamplerWrapMode::Repeat;
+desc.maxAnisotropy = 16.0f;
+sampler.Initialize(desc);
+
+sampler.Bind(0);
+glBindTextureUnit(0, texture.GetID());
+```