/*

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                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

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*/

#import <Appkit/AppKit.h>

#include <OpenGL/gl.h>

#include <OpenGL/glu.h>

#include <OpenGL/glext.h>

#import "GBuffer.h"

#import "CGText.h"

typedef struct _GlyphInfo

{

    CGRect bounds;

    float v_offset;

} GlyphInfo;

typedef struct _FontRecord

{

    char name[256];

    int size;

    GBuffer* image;

    NSFont* font;

    GlyphInfo glyph_infos[256];

    GLenum texture_id;

    CGSize inv_buffer_size;

} FontRecord;

/* the following 2 are temporaries, used when iterating through the glyphs of a font */

CGPoint image_offset;

float current_row_max_height;

@implementation CGText

/* ProcessGlyph will render a single glyph into the image bitmap */

void ProcessGlyph(unsigned char c, FontRecord* info, NSTextView* text_view)

{

    GlyphInfo* glyph_info = &info->glyph_infos[c];

    char c_str[2] = { c, '\0' };

    float font_height = [info->font ascender] - [info->font descender];

    [text_view setString:[NSString stringWithCString:c_str]];

    {

        NSGlyph char_glyph = [[text_view layoutManager] glyphAtIndex:0];

        if (char_glyph > [info->font numberOfGlyphs])

        {

            glyph_info->bounds = CGRectMake(0,0,0,0);

            return;

        }

        else

        {

            NSPoint nominal_glyph_size = [info->font positionOfGlyph: NSNullGlyph precededByGlyph: char_glyph isNominal: nil];

            if (image_offset.x + nominal_glyph_size.x > info->image->buffer_size.width)

            {

                image_offset.x = 0;

                image_offset.y += current_row_max_height;

                current_row_max_height = 0;

            }

            [info->image renderGlyph:(CGGlyph) char_glyph typeface:info->name size:info->size offset:image_offset];

            /* the 0.999's below are fudge factors */

            glyph_info->bounds = CGRectMake(image_offset.x+0.999, image_offset.y, nominal_glyph_size.x+0.999, font_height); 

            glyph_info->v_offset = [info->font descender];

            if (current_row_max_height < font_height)

                current_row_max_height = font_height;

            image_offset.x += nominal_glyph_size.x+4; //allow 4 slop columns between each character

        }

    }

}

/* SetFontImage will render all legal glyphs into the font's image bitmap */

void SetFontImage(FontRecord* info, BOOL debug)

{

    NSTextView* text_view = [[NSTextView alloc] initWithFrame:NSMakeRect(0.0f,0.0f,128.0f,128.0f)];

    info->font = [NSFont fontWithName:[NSString stringWithCString: info->name] size:info->size];

    [text_view setFont:info->font];

    [info->image clear: debug ? 1.0 : 0.0];

    image_offset = CGPointMake(0,- [info->font descender]);

    current_row_max_height = 0;

    {

        int i;

        for (i = 33; i < 256; i++)

            ProcessGlyph(i, info, text_view);

    }

    [text_view release];

    [info->font release];

    info->font = nil;

}

/* SetFontTexture will create an OpenGL texture from the font image */

void SetFontTexture(FontRecord* info)

{

    GBuffer* image = info->image;

    GLenum rgba_mode = GL_LUMINANCE_ALPHA;

    GLenum format = GL_BGRA_EXT;

    GLenum type = image->buffer_bitdepth == 32 ? GL_UNSIGNED_INT_8_8_8_8_REV : GL_UNSIGNED_SHORT_1_5_5_5_REV;

    glGenTextures(1, &info->texture_id);

    glBindTexture(GL_TEXTURE_2D, info->texture_id);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);

    glTexImage2D(GL_TEXTURE_2D, 0, rgba_mode, (GLint) image->buffer_size.width, (GLint) image->buffer_size.height, 0, format, type, image->buffer_ptr);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

    glBindTexture(GL_TEXTURE_2D, 0);

    info->inv_buffer_size = CGSizeMake(1/image->buffer_size.width, 1/image->buffer_size.height);

}

/* SetFont is called to bind the current font's OpenGL texture */

void SetFont(FontRecord* font)

{

    if (!font->texture_id)

        return;

    glBindTexture(GL_TEXTURE_2D, font->texture_id);

}

/* RenderFontText is called to render out the text. Note that an 2D projection is assumed */

void RenderFontText(FontRecord* font, const char* text, CGPoint dst)

{

    GLfloat coord_array[256*4][2];

    GLfloat vertex_array[256*4][2];

    SetFont(font);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    glEnableClientState(GL_VERTEX_ARRAY);

    glColor4f(1.0, 1.0, 1.0, 1.0);

    {

        const unsigned char* c;

        int num_quads = 0;

        GLfloat* current_coord = &coord_array[0][0];

        GLfloat* current_vertex = &vertex_array[0][0]; 

        glTexCoordPointer(2, GL_FLOAT, 0, coord_array);

        glVertexPointer(2, GL_FLOAT, 0, vertex_array);

        for (c = (const unsigned char*) text; *c; dst.x += (*c <= ' ' ? 8 : font->glyph_infos[*c].bounds.size.width), ++c)

        {

            if (*c > ' ')

            {

                typedef struct { GLfloat s,t; } TexCoord;

                typedef struct { GLfloat x,y; } VertexCoord;

                GlyphInfo* info = &font->glyph_infos[*c];

                TexCoord tc0 = { info->bounds.origin.x * font->inv_buffer_size.width, (info->bounds.origin.y + info->v_offset) * font->inv_buffer_size.height };

                TexCoord tc1 = { info->bounds.size.width * font->inv_buffer_size.width, info->bounds.size.height * font->inv_buffer_size.height };

                tc1.s += tc0.s, tc1.t += tc0.t;

                // the image we loaded was inverted, so invert texture coordinates t component here:

                tc0.t = 1 - tc0.t;

                tc1.t = 1 - tc1.t;

                // push coords into arrays:

                *current_coord++ = tc0.s;

                *current_coord++ = tc0.t;

                *current_vertex++ = dst.x;

                *current_vertex++ = dst.y;

                *current_coord++ = tc1.s;

                *current_coord++ = tc0.t;

                *current_vertex++ = dst.x+info->bounds.size.width;

                *current_vertex++ = dst.y;

                *current_coord++ = tc1.s;

                *current_coord++ = tc1.t;

                *current_vertex++ = dst.x+info->bounds.size.width;

                *current_vertex++ = dst.y+info->bounds.size.height;

                *current_coord++ = tc0.s;

                *current_coord++ = tc1.t;

                *current_vertex++ = dst.x;

                *current_vertex++ = dst.y+info->bounds.size.height;

                num_quads++;

            }

        }

        glDrawArrays(GL_QUADS, 0, num_quads*4);

        glDisableClientState(GL_TEXTURE_COORD_ARRAY);

        glDisableClientState(GL_VERTEX_ARRAY);

    }

}

FontRecord* font_info;  

+ (void) setFont:(const char*) typeface size:(int) size debug:(BOOL) debug

{

    if (!font_info)

    {

        font_info = malloc(sizeof(FontRecord));

        font_info->texture_id = 0;

    }

    else

    {

        glDeleteTextures(1, &font_info->texture_id);

        font_info->texture_id = 0;

    }

    strcpy(font_info->name, typeface);

    font_info->size = size;

    /* NOTE: the CG copyRect routine doesn't really support 8 or 16 bit images */

    /* Also the hardcoded 256x256 size won't be big enough for larger text sizes */

    font_info->image = [GBuffer create: CGSizeMake(256, 256) bitDepth:32];

    SetFontImage(font_info, debug);

    SetFontTexture(font_info);

    [font_info->image release];

    font_info->image = nil;

}

+ (void) displayText:(const char*) text at: (CGPoint) dst;

{

    if (font_info && text)

        RenderFontText(font_info, text, dst);

}

@end