Extra2D/Easy2D/include/easy2d/graphics/opengl/gl_font_atlas.h

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#pragma once
#include <easy2d/core/types.h>
#include <easy2d/core/color.h>
#include <easy2d/core/math_types.h>
#include <easy2d/graphics/font.h>
#include <easy2d/graphics/texture.h>
#include <easy2d/graphics/opengl/gl_texture.h>
#include <stb/stb_truetype.h>
#include <stb/stb_rect_pack.h>
#include <unordered_map>
#include <vector>
#include <memory>
namespace easy2d {
// ============================================================================
// OpenGL 字体图集实现 - 使用 stb_rect_pack 进行矩形打包
// ============================================================================
class GLFontAtlas : public FontAtlas {
public:
GLFontAtlas(const std::string& filepath, int fontSize, bool useSDF = false);
~GLFontAtlas();
// FontAtlas 接口实现
const Glyph* getGlyph(char32_t codepoint) const override;
Texture* getTexture() const override { return texture_.get(); }
int getFontSize() const override { return fontSize_; }
float getAscent() const override { return ascent_; }
float getDescent() const override { return descent_; }
float getLineGap() const override { return lineGap_; }
float getLineHeight() const override { return ascent_ - descent_ + lineGap_; }
Vec2 measureText(const String& text) override;
bool isSDF() const override { return useSDF_; }
private:
// 图集配置
static constexpr int ATLAS_WIDTH = 512;
static constexpr int ATLAS_HEIGHT = 512;
static constexpr int PADDING = 2; // 字形之间的间距
int fontSize_;
bool useSDF_;
mutable std::unique_ptr<GLTexture> texture_;
mutable std::unordered_map<char32_t, Glyph> glyphs_;
// stb_rect_pack 上下文
mutable stbrp_context packContext_;
mutable std::vector<stbrp_node> packNodes_;
mutable int currentY_;
std::vector<unsigned char> fontData_;
stbtt_fontinfo fontInfo_;
float scale_;
float ascent_;
float descent_;
float lineGap_;
void createAtlas();
void cacheGlyph(char32_t codepoint) const;
};
} // namespace easy2d