Extra2D/Extra2D/include/extra2d/graphics/backends/opengl/gl_font_atlas.h

78 lines
2.2 KiB
C++

#pragma once
#include <extra2d/graphics/backends/opengl/gl_texture.h>
#include <extra2d/graphics/texture/font.h>
#include <stb/stb_truetype.h>
#include <stb/stb_rect_pack.h>
#include <unordered_map>
#include <vector>
namespace extra2d {
// ============================================================================
// OpenGL 字体图集实现 (使用 STB 库)
// ============================================================================
class GLFontAtlas : public FontAtlas {
public:
GLFontAtlas(const std::string& filepath, int fontSize, bool useSDF = false);
~GLFontAtlas() override;
// 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 lineHeight_; }
bool isSDF() const override { return useSDF_; }
Vec2 measureText(const std::string& text) override;
private:
struct GlyphData {
float width;
float height;
float bearingX;
float bearingY;
float advance;
float u0, v0, u1, v1;
};
struct PackedCharData {
stbtt_packedchar packedChar;
bool valid;
};
bool useSDF_;
int fontSize_;
Ptr<GLTexture> texture_;
std::unordered_map<char32_t, GlyphData> glyphs_;
std::unordered_map<char32_t, PackedCharData> packedChars_;
float lineHeight_;
float ascent_;
float descent_;
float lineGap_;
// 字体数据
std::vector<unsigned char> fontData_;
stbtt_fontinfo fontInfo_;
float scale_;
// 图集打包参数
static constexpr int ATLAS_WIDTH = 512;
static constexpr int ATLAS_HEIGHT = 512;
// 初始化字体
bool initFont(const std::string& filepath);
// 渲染字形到图集
bool renderGlyph(char32_t codepoint);
// 更新图集纹理
void updateAtlas(int x, int y, int width, int height,
const std::vector<uint8_t>& data);
};
} // namespace extra2d