Extra2D/include/graphics/opengl/gl_texture.h

#pragma once

#include <graphics/alpha_mask.h>
#include <graphics/texture.h>

#include <glad/glad.h>

#include <memory>
#include <string>

namespace extra2d {

// ============================================================================
// OpenGL 纹理实现
// ============================================================================
class GLTexture : public Texture {
public:
  GLTexture(int width, int height, const uint8_t *pixels, int channels);
  GLTexture(const std::string &filepath);
  ~GLTexture();

  // Texture 接口实现
  int width() const override { return width_; }
  int height() const override { return height_; }
  Size size() const override {
    return Size(static_cast<float>(width_), static_cast<float>(height_));
  }
  int getChannels() const override { return channels_; }
  PixelFormat getFormat() const override;
  void *getNativeHandle() const override {
    return reinterpret_cast<void *>(static_cast<uintptr_t>(textureID_));
  }
  bool isValid() const override { return textureID_ != 0; }
  void setFilter(bool linear) override;
  void setWrap(bool repeat) override;

  // 从参数创建纹理的工厂方法
  static Ptr<Texture> create(int width, int height, PixelFormat format);

  // 加载压缩纹理（KTX/DDS 格式）
  bool loadCompressed(const std::string &filepath);

  // OpenGL 特定
  GLuint getTextureID() const { return textureID_; }
  void bind(unsigned int slot = 0) const;
  void unbind() const;

  // 获取纹理数据大小（字节），用于 VRAM 跟踪
  size_t getDataSize() const { return dataSize_; }

  // Alpha 遮罩
  bool hasAlphaMask() const {
    return alphaMask_ != nullptr && alphaMask_->isValid();
  }
  const AlphaMask *getAlphaMask() const { return alphaMask_.get(); }
  void generateAlphaMask(); // 从当前纹理数据生成遮罩

private:
  GLuint textureID_;
  int width_;
  int height_;
  int channels_;
  PixelFormat format_;
  size_t dataSize_;

  // 原始像素数据（用于生成遮罩）
  std::vector<uint8_t> pixelData_;
  std::unique_ptr<AlphaMask> alphaMask_;

  void createTexture(const uint8_t *pixels);

  // KTX 文件加载
  bool loadKTX(const std::string &filepath);
  // DDS 文件加载
  bool loadDDS(const std::string &filepath);
};

} // namespace extra2d