85 lines
2.6 KiB
C++
85 lines
2.6 KiB
C++
#pragma once
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#include <extra2d/graphics/backends/opengl/gl_texture.h>
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#include <extra2d/graphics/texture/font.h>
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#include <stb/stb_truetype.h>
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#include <stb/stb_rect_pack.h>
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#include <unordered_map>
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#include <vector>
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namespace extra2d {
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// ============================================================================
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// OpenGL 字体图集实现 (使用 STB 库)
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// 使用 stb_rect_pack 进行动态矩形打包，支持动态缓存字形
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// ============================================================================
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class GLFontAtlas : public FontAtlas {
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public:
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GLFontAtlas(const std::string& filepath, int fontSize, bool useSDF = false);
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~GLFontAtlas() override;
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// FontAtlas 接口实现
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const Glyph* getGlyph(char32_t codepoint) const override;
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Texture* getTexture() const override { return texture_.get(); }
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int getFontSize() const override { return fontSize_; }
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float getAscent() const override { return ascent_; }
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float getDescent() const override { return descent_; }
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float getLineGap() const override { return lineGap_; }
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float getLineHeight() const override { return lineHeight_; }
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bool isSDF() const override { return useSDF_; }
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Vec2 measureText(const std::string& text) override;
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private:
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// 字形数据内部结构
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struct GlyphData {
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float width;
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float height;
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float bearingX;
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float bearingY;
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float advance;
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float u0, v0, u1, v1;
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};
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// 图集配置 - 增大尺寸以支持更多字符
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static constexpr int ATLAS_WIDTH = 1024;
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static constexpr int ATLAS_HEIGHT = 1024;
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static constexpr int PADDING = 2; // 字形之间的间距
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bool useSDF_;
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int fontSize_;
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Ptr<GLTexture> texture_;
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std::unordered_map<char32_t, GlyphData> glyphs_;
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float lineHeight_;
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float ascent_;
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float descent_;
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float lineGap_;
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// 字体数据
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std::vector<unsigned char> fontData_;
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stbtt_fontinfo fontInfo_;
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float scale_;
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// stb_rect_pack 上下文 - 持久化以支持增量打包
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mutable stbrp_context packContext_;
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mutable std::vector<stbrp_node> packNodes_;
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// 预分配缓冲区，避免每次动态分配
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mutable std::vector<uint8_t> glyphBitmapCache_;
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mutable std::vector<uint8_t> glyphRgbaCache_;
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// 初始化字体
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bool initFont(const std::string& filepath);
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// 创建空白图集纹理
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void createAtlas();
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// 缓存字形到图集
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void cacheGlyph(char32_t codepoint);
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// 更新图集纹理区域
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void updateAtlas(int x, int y, int width, int height,
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const std::vector<uint8_t>& data);
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};
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} // namespace extra2d
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