4coder/4ed_rendering.h

/*
 * Mr. 4th Dimention - Allen Webster
 *
 * 17.12.2014
 *
 * Rendering layer for project codename "4ed"
 *
 */

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#ifndef FRED_RENDERING_H
#define FRED_RENDERING_H

internal void*
part_alloc(int size, void *context){
    Partition *part = (Partition*)context;
    void *result = push_block(part, size);
    return(result);
}

internal void
part_free(void *ptr, void *context){
}

#define STBTT_malloc part_alloc
#define STBTT_free part_free

#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_truetype.h"

struct Glyph_Data{
    b32 exists;
};

struct Render_Font{
    char name_[24];
    String name;
    b32 loaded;
    
	Glyph_Data glyphs[256];
    stbtt_packedchar chardata[256];
    float advance_data[256];
	i32 height, ascent, descent, line_skip;
    i32 advance;
    u32 tex;
    i32 tex_width, tex_height;
};

struct Render_Target;

#define Draw_Push_Clip_Sig(name) void name(Render_Target *target, i32_Rect clip_box)
typedef Draw_Push_Clip_Sig(Draw_Push_Clip);

#define Draw_Pop_Clip_Sig(name) void name(Render_Target *target)
typedef Draw_Pop_Clip_Sig(Draw_Pop_Clip);

enum Render_Piece_Type{
    piece_type_rectangle,
    piece_type_outline,
    piece_type_gradient,
    piece_type_glyph,
    piece_type_mono_glyph,
    piece_type_mono_glyph_advance
};

struct Render_Piece_Header{
    i32 type;
};

struct Render_Piece_Rectangle{
    f32_Rect rect;
    u32 color;
};

struct Render_Piece_Gradient{
    f32_Rect rect;
    u32 left_color, right_color;
};

struct Render_Piece_Glyph{
    Vec2 pos;
    u32 color;
    i16 font_id;
    u8 character;
};

struct Render_Piece_Glyph_Advance{
    Vec2 pos;
    u32 color;
    f32 advance;
    i16 font_id;
    u8 character;
};

struct Render_Piece_Combined{
    Render_Piece_Header header;
    union{
        Render_Piece_Rectangle rectangle;
        Render_Piece_Gradient gradient;
        Render_Piece_Glyph glyph;
        Render_Piece_Glyph_Advance glyph_advance;
    };
};

#define Draw_Push_Piece_Sig(name) void name(Render_Target *target, Render_Piece_Combined piece)
typedef Draw_Push_Piece_Sig(Draw_Push_Piece);

#define Font_Load_Sig(name) i32 name(                                   \
        Render_Font *font_out,                                          \
        char *filename,                                                 \
        i32 pt_size,                                                    \
        i32 tab_width)
typedef Font_Load_Sig(Font_Load);

#define Font_Info_Load_Sig(name) i32 name(         \
        Partition *partition,                      \
        char *filename,                            \
        i32 pt_size,                               \
        i32 *height,                               \
        i32 *advance)
typedef Font_Info_Load_Sig(Font_Info_Load);

#define Release_Font_Sig(name) void name(Render_Font *font)
typedef Release_Font_Sig(Release_Font);

struct Font_Table_Entry{
    u32 hash;
    String name;
    i16 font_id;
};

struct Font_Info{
    Render_Font *font;
    String filename;
    String name;
    i32 height, advance;
    i32 pt_size;
};

struct Font_Slot{
    Font_Slot *next, *prev;
    i16 font_id;
    u8 padding[14];
};

struct Font_Set{
    Font_Info *info;
    Font_Table_Entry *entries;
    u32 count, max;

    void *font_block;
    Font_Slot free_slots;
    Font_Slot used_slots;

    Font_Info_Load *font_info_load;
    Font_Load *font_load;
    Release_Font *release_font;

    b8 *font_used_flags;
    i16 used_this_frame;
    i16 live_max;
};

struct Render_Target{
    void *handle;
    void *context;
    i32_Rect clip_boxes[5];
    i32 clip_top;
	i32 width, height;
    i32 bound_texture;
    u32 color;
    
    byte *push_buffer;
    i32 size, max;
    
    Font_Set font_set;
    Partition *partition;
    
    Draw_Push_Clip *push_clip;
    Draw_Pop_Clip *pop_clip;
    Draw_Push_Piece *push_piece;
};

inline i32_Rect
rect_from_target(Render_Target *target){
	return i32R(0, 0, target->width, target->height);
}

inline Font_Info*
get_font_info(Font_Set *set, i16 font_id){
    Font_Info *result = set->info + font_id - 1;
    return(result);
}

#endif

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