text_shader.h

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/*
 This file is part of the MinGfx Project.
 
 Copyright (c) 2017,2018 Regents of the University of Minnesota.
 All Rights Reserved.
 
 Original Author(s) of this File:
    Dan Keefe, 2018, University of Minnesota
    
 Author(s) of Significant Updates/Modifications to the File:
    ...
 */
 
#ifndef SRC_TEXT_SHADER_H_
#define SRC_TEXT_SHADER_H_
 
#include <string>
#include <map>
 
#include "matrix4.h"
#include "mesh.h"
#include "shader_program.h"
#include "texture2d.h"
 
// disable warnings for this 3rd party code
#pragma warning ( push, 0 )
#include <stb_truetype.h>
#pragma warning ( pop )
 
namespace mingfx {
    
 
 
class TextShader {
public:
    TextShader();
    virtual ~TextShader();
    
    bool Init(const std::string &font_file, int native_font_size);
    
    enum class HorizAlign {
        HORIZ_ALIGN_LEFT,
        HORIZ_ALIGN_CENTER,
        HORIZ_ALIGN_RIGHT
    };
 
    enum class VertAlign {
        VERT_ALIGN_TOP,
        VERT_ALIGN_CENTER,
        VERT_ALIGN_BASELINE,
        VERT_ALIGN_BOTTOM
    };
    
    class TextFormat {
    public:
        // constructor sets defaults
        TextFormat() :
            size(0.1f),
            color(1,1,1,1),
            h_align(HorizAlign::HORIZ_ALIGN_CENTER),
            v_align(VertAlign::VERT_ALIGN_BASELINE) {}
        
        float size;
        Color color;
        HorizAlign h_align;
        VertAlign v_align;
    };
    
 
    //void Draw2D(const Point2 &pos,
    //            const std::string &text, TextFormat format, bool cache=false);
 
    
    void Draw3D(const Matrix4 &model, const Matrix4 &view, const Matrix4 &projection,
                const std::string &text, TextFormat format, bool cache=false);
 
    
    Vector2 TextExtents(const std::string &text, TextFormat format, bool cache=false);
    
    float native_font_size();
    
private:
    Texture2D atlas_;
    float native_font_size_;
    
    stbtt_packedchar chardata_[128];
    
    struct MeshData {
        Mesh mesh;
        Point2 min;
        Point2 max;
    };
    
    void SetTextMesh(const std::string &text, MeshData *md);
 
    std::map<std::string, MeshData> cache_;
    MeshData tmp_md_;
 
    ShaderProgram shader_;
};
    
} // end namespace
 
#endif