// Copyright (c) Mark J. Kilgard, 1997. 
// This program is freely distributable without licensing fees and is
// provided without guarantee or warrantee expressed or implied. 
// This program is -not- in the public domain. 

#if defined(_WIN32)
#pragma warning (disable:4244)          // disable bogus conversion warnings
#endif

#include <assert.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#ifdef _WIN32
#include <windows.h>
#endif

#ifdef _WIN32
#include <GL/gl.h>
#endif

#ifdef __APPLE_CC__
#include <OpenGL/gl.h>
#endif


#include "texfont.h"

const char *font_names [] = 
{
	"Helvetica.txf",                   // 0. This is the default 
	"Helvetica-Bold.txf",		       // 1
	"Helvetica-Oblique.txf",	       // 2
	"Helvetica-BoldOblique.txf",       // 3
	"AvantGarde-Book.txf",             // 4
	"AvantGarde-BookOblique.txf",      // 5
	"AvantGarde-Demi.txf",		       // 6
	"AvantGarde-DemiOblique.txf",      // 7
	"Bookman-Light.txf",		       // 8
	"Bookman-LightItalic.txf",	       // 9
	"Bookman-Demi.txf",			       // 10
	"Bookman-DemiItalic.txf",	       // 11
	"Courier.txf",				       // 12
	"Courier-Bold.txf",			       // 13
	"Courier-Oblique.txf",		       // 14
	"Courier-BoldOblique.txf",	       // 15
	"NewCenturySchlbk-Roman.txf",      // 16
	"NewCenturySchlbk-Italic.txf",	   // 17
	"NewCenturySchlbk-Bold.txf",       // 18
	"NewCenturySchlbk-BoldItalic.txf", // 19
	"Palatino-Roman.txf",		       // 20
	"Palatino-Italic.txf",		       // 21
	"Palatino-Bold.txf",		       // 22
	"Palatino-BoldItalic.txf",	       // 23
	"Times-Roman.txf",			       // 24
	"Times-Italic.txf",			       // 25
	"Times-Bold.txf",			       // 26
	"Times-BoldItalic.txf",		       // 27
	"ZapfChancery-MediumItalic.txf",   // 28
	 NULL
} ;


#if 1
// Uncomment to debug various scenarios. 
#undef GL_VERSION_1_1
#undef GL_EXT_texture_object
#undef GL_EXT_texture
#endif

#ifndef GL_VERSION_1_1

#  if defined(GL_EXT_texture_object)
#    define glGenTextures glGenTexturesEXT
#    define glBindTexture glBindTextureEXT
#  else
     // Without OpenGL 1.1 or the texture object extension, use display lists.
#    define USE_DISPLAY_LISTS
#  endif

#  if defined(GL_EXT_texture)
#    define GL_INTENSITY4 GL_INTENSITY4_EXT
     int useLuminanceAlpha = 0;
#  else
     // Intensity texture format not in OpenGL 1.0; added by the EXT_texture
     // extension and now part of OpenGL 1.1. 
     int useLuminanceAlpha = 1;
#  endif

#else
   // OpenGL 1.1 case. 
   int useLuminanceAlpha = 0;
#endif

// byte swap a 32-bit value 
#define SWAPL(x, n) { \
                 n = ((char *) (x))[0];\
                 ((char *) (x))[0] = ((char *) (x))[3];\
                 ((char *) (x))[3] = n;\
                 n = ((char *) (x))[1];\
                 ((char *) (x))[1] = ((char *) (x))[2];\
                 ((char *) (x))[2] = n; }

// byte swap a short 
#define SWAPS(x, n) { \
                 n = ((char *) (x))[0];\
                 ((char *) (x))[0] = ((char *) (x))[1];\
                 ((char *) (x))[1] = n; }


static TexGlyphVertexInfo * getTCVI(TexFont * txf, int c){
	TexGlyphVertexInfo *tgvi;
	// Automatically substitute uppercase letters with lowercase if not
	// uppercase available (and vice versa). 
	if ((c >= txf->min_glyph) && (c < txf->min_glyph + txf->range)) {
		tgvi = txf->lut[c - txf->min_glyph];
		if (tgvi) {
			return tgvi;
		}
		if (islower(c)) {
			c = toupper(c);
			if ((c >= txf->min_glyph) && (c < txf->min_glyph + txf->range)) {
				return txf->lut[c - txf->min_glyph];
			}
		}
		if (isupper(c)) {
			c = tolower(c);
			if ((c >= txf->min_glyph) && (c < txf->min_glyph + txf->range)) {
				return txf->lut[c - txf->min_glyph];
			}
		}
	}
	fprintf(stderr, "texfont: tried to access unavailable font character \"%c\" (%d)\n",isprint(c) ? c : ' ', c);
	abort();
	// NOT REACHED 
	return NULL;
}


static char *lastError;


char * txfErrorString(void) {
	return lastError;
}


TexFont * txfLoadFont(const char *filename) {
	TexFont *txf;
	FILE *file;
	GLfloat w, h, xstep, ystep;
	char fileid[4], tmp;
	unsigned char *texbitmap;
	int min_glyph, max_glyph;
	int endianness, swap, format, stride, width, height;
	int i, j;
	unsigned long got;
	txf = NULL;
	file = fopen(filename, "rb");
	if (file == NULL) {
		lastError = "file open failed.";
		goto error;
	}
	txf = (TexFont *) malloc(sizeof(TexFont));
	if (txf == NULL) {
		lastError = "out of memory.";
		goto error;
	}
	// For easy cleanup in error case. 
	txf->tgi = NULL;
	txf->tgvi = NULL;
	txf->lut = NULL;
	txf->teximage = NULL;
	got = (unsigned long)fread(fileid, 1, 4, file);
	if (got != 4 || strncmp(fileid, "\377txf", 4)) {
		lastError = "not a texture font file.";
		goto error;
	}
	// CONSTANT CONDITION
	assert(sizeof(int) == 4);  // Ensure external file format size. 
	got = (unsigned long)fread(&endianness, sizeof(int), 1, file);
	if (got == 1 && endianness == 0x12345678) {
		swap = 0;
	} else if (got == 1 && endianness == 0x78563412) {
		swap = 1;
	} else {
		lastError = "not a texture font file.";
		goto error;
	}
#define EXPECT(n) if (got != (unsigned long) n) { lastError = "premature end of file."; goto error; }
	got = (unsigned long)fread(&format, sizeof(int), 1, file);
	EXPECT(1);
	got = (unsigned long)fread(&txf->tex_width, sizeof(int),  1, file);
	EXPECT(1);
	got = (unsigned long)fread(&txf->tex_height, sizeof(int), 1, file);
	EXPECT(1);
	got = (unsigned long)fread(&txf->max_ascent, sizeof(int), 1, file);
	EXPECT(1);
	got = (unsigned long)fread(&txf->max_descent, sizeof(int),1, file);
	EXPECT(1);
	got = (unsigned long)fread(&txf->num_glyphs, sizeof(int), 1, file);
	EXPECT(1);

	if (swap) {
		SWAPL(&format, tmp);
		SWAPL(&txf->tex_width, tmp);
		SWAPL(&txf->tex_height, tmp);
		SWAPL(&txf->max_ascent, tmp);
		SWAPL(&txf->max_descent,tmp);
		SWAPL(&txf->num_glyphs, tmp);
	}
	txf->tgi = (TexGlyphInfo *) malloc(txf->num_glyphs * sizeof(TexGlyphInfo));
	if (txf->tgi == NULL) {
		lastError = "out of memory.";
		goto error;
	}
	// CONSTANT CONDITION
	assert(sizeof(TexGlyphInfo) == 12);  // Ensure external file format size.
	got = (unsigned long)fread(txf->tgi, sizeof(TexGlyphInfo), txf->num_glyphs, file);
	EXPECT(txf->num_glyphs);

	if (swap) {
		for (i = 0; i < txf->num_glyphs; i++) {
			SWAPS(&txf->tgi[i].c, tmp);
			SWAPS(&txf->tgi[i].x, tmp);
			SWAPS(&txf->tgi[i].y, tmp);
		}
	}
	txf->tgvi = (TexGlyphVertexInfo *)
    malloc(txf->num_glyphs * sizeof(TexGlyphVertexInfo));
	if (txf->tgvi == NULL) {
		lastError = "out of memory.";
		goto error;
	}
	w = txf->tex_width;
	h = txf->tex_height;
	xstep = 0.5 / w;
	ystep = 0.5 / h;
	for (i = 0; i < txf->num_glyphs; i++) {
		TexGlyphInfo *tgi;
		tgi = &txf->tgi[i];
		txf->tgvi[i].t0[0] = tgi->x / w + xstep;
		txf->tgvi[i].t0[1] = tgi->y / h + ystep;
		txf->tgvi[i].v0[0] = tgi->xoffset;
		txf->tgvi[i].v0[1] = tgi->yoffset;
		txf->tgvi[i].t1[0] = (tgi->x + tgi->width) / w + xstep;
		txf->tgvi[i].t1[1] = tgi->y / h + ystep;
		txf->tgvi[i].v1[0] = tgi->xoffset + tgi->width;
		txf->tgvi[i].v1[1] = tgi->yoffset;
		txf->tgvi[i].t2[0] = (tgi->x + tgi->width) / w + xstep;
		txf->tgvi[i].t2[1] = (tgi->y + tgi->height) / h + ystep;
		txf->tgvi[i].v2[0] = tgi->xoffset + tgi->width;
		txf->tgvi[i].v2[1] = tgi->yoffset + tgi->height;
		txf->tgvi[i].t3[0] = tgi->x / w + xstep;
		txf->tgvi[i].t3[1] = (tgi->y + tgi->height) / h + ystep;
		txf->tgvi[i].v3[0] = tgi->xoffset;
		txf->tgvi[i].v3[1] = tgi->yoffset + tgi->height;
		txf->tgvi[i].advance = tgi->advance;
	}

	min_glyph = txf->tgi[0].c;
	max_glyph = txf->tgi[0].c;
	for (i = 1; i < txf->num_glyphs; i++) {
		if (txf->tgi[i].c < min_glyph) {
			min_glyph = txf->tgi[i].c;
		}
		if (txf->tgi[i].c > max_glyph) {
			max_glyph = txf->tgi[i].c;
		}
	}
	txf->min_glyph = min_glyph;
	txf->range = max_glyph - min_glyph + 1;

	txf->lut = (TexGlyphVertexInfo **)
    calloc(txf->range, sizeof(TexGlyphVertexInfo *));
	if (txf->lut == NULL) {
		lastError = "out of memory.";
		goto error;
	}
	for (i = 0; i < txf->num_glyphs; i++) {
		txf->lut[txf->tgi[i].c - txf->min_glyph] = &txf->tgvi[i];
	}

	switch (format) {
	case TXF_FORMAT_BYTE:
	if (useLuminanceAlpha) {
		unsigned char *orig;
		orig = (unsigned char *) malloc(txf->tex_width * txf->tex_height);
		if (orig == NULL) {
			lastError = "out of memory.";
			goto error;
		}
		got = (unsigned long)fread(orig, 1, txf->tex_width * txf->tex_height, file);
		EXPECT(txf->tex_width * txf->tex_height);
		txf->teximage = (unsigned char *)
        malloc(2 * txf->tex_width * txf->tex_height);
		if (txf->teximage == NULL) {
			lastError = "out of memory.";
			goto error;
		}
		for (i = 0; i < txf->tex_width * txf->tex_height; i++) {
			txf->teximage[i * 2] = orig[i];
			txf->teximage[i * 2 + 1] = orig[i];
		}
		free(orig);
	} 
	else {
		txf->teximage = (unsigned char *)
        malloc(txf->tex_width * txf->tex_height);
		if (txf->teximage == NULL) {
			lastError = "out of memory.";
        goto error;
      }
      got = (unsigned long)fread(txf->teximage, 1, txf->tex_width * txf->tex_height, file);
      EXPECT(txf->tex_width * txf->tex_height);
    }
    break;
	case TXF_FORMAT_BITMAP:
    width = txf->tex_width;
    height = txf->tex_height;
    stride = (width + 7) >> 3;
    texbitmap = (unsigned char *) malloc(stride * height);
    if (texbitmap == NULL) {
		lastError = "out of memory.";
		goto error;
    }
    got = (unsigned long)fread(texbitmap, 1, stride * height, file);
    EXPECT(stride * height);
    if (useLuminanceAlpha) {
		txf->teximage = (unsigned char *) calloc(width * height * 2, 1);
		if (txf->teximage == NULL) {
			lastError = "out of memory.";
			goto error;
		}
		for (i = 0; i < height; i++) {
			for (j = 0; j < width; j++) {
				if (texbitmap[i * stride + (j >> 3)] & (1 << (j & 7))) {
					txf->teximage[(i * width + j) * 2] = 255;
					txf->teximage[(i * width + j) * 2 + 1] = 255;
				}
			}
		}
	} 
	else {
		txf->teximage = (unsigned char *) calloc(width * height, 1);
		if (txf->teximage == NULL) {
			lastError = "out of memory.";
			goto error;
		}
		for (i = 0; i < height; i++) {
			for (j = 0; j < width; j++) {
				if (texbitmap[i * stride + (j >> 3)] & (1 << (j & 7))) {
					txf->teximage[i * width + j] = 255;
				}
			}
		}
	}
    free(texbitmap);
    break;
	}
	fclose(file);
	return txf;
error:
	if (txf) {
		if (txf->tgi) free(txf->tgi);
		if (txf->tgvi)free(txf->tgvi);
		if (txf->lut) free(txf->lut);
		if (txf->teximage) free(txf->teximage);
		free(txf);
	}
	if (file) fclose(file);
	return NULL;
}


GLuint CreateTexFont(TexFont * txf,GLuint texobj, GLboolean setupMipmaps){
	glGenTextures(1, &txf->texobj);
	glBindTexture(GL_TEXTURE_2D, txf->texobj);
#if 1
	// XXX Indigo2 IMPACT in IRIX 5.3 and 6.2 does not support the GL_INTENSITY
    // internal texture format. Sigh. Win32 non-GLX users should disable this code. 
	if (useLuminanceAlpha == 0) {
		char *vendor, *renderer, *version;
		renderer = (char *) glGetString(GL_RENDERER);
		vendor = (char *) glGetString(GL_VENDOR);
		if (!strcmp(vendor, "SGI") && !strncmp(renderer, "IMPACT", 6)) {
			version = (char *) glGetString(GL_VERSION);
			if (!strcmp(version, "1.0 Irix 6.2") || !strcmp(version, "1.0 Irix 5.3")) {
				unsigned char *latex;
				int width = txf->tex_width;
				int height = txf->tex_height;
				int i;
				useLuminanceAlpha = 1;
				latex = (unsigned char *) calloc(width * height * 2, 1);
				// XXX unprotected alloc. 
				for (i = 0; i < height * width; i++) {
					latex[i * 2] = txf->teximage[i];
					latex[i * 2 + 1] = txf->teximage[i];
				}
				free(txf->teximage);
				txf->teximage = latex;
			}
		}
	}
#endif
	if (useLuminanceAlpha) {
		if (setupMipmaps) {
			gluBuild2DMipmaps(GL_TEXTURE_2D, GL_LUMINANCE_ALPHA,
			txf->tex_width, txf->tex_height,
			GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, txf->teximage);
		} 
		else {
			glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA,
			txf->tex_width, txf->tex_height, 0,
			GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, txf->teximage);
		}
	} 
	else {
#if defined(GL_VERSION_1_1) || defined(GL_EXT_texture)
		// Use GL_INTENSITY4 as internal texture format since we want to use as
		// little texture memory as possible. 
		if (setupMipmaps) {
			gluBuild2DMipmaps(GL_TEXTURE_2D, GL_INTENSITY4,
			txf->tex_width, txf->tex_height,
			GL_LUMINANCE, GL_UNSIGNED_BYTE, txf->teximage);
		} 
		else {
			glTexImage2D(GL_TEXTURE_2D, 0, GL_INTENSITY4,
			txf->tex_width, txf->tex_height, 0,
			GL_LUMINANCE, GL_UNSIGNED_BYTE, txf->teximage);
		}
#endif
	}
	return txf->texobj;
}


void txfUnloadFont(TexFont * txf){
	if (txf->teximage) {
		free(txf->teximage);
	}
	free(txf->tgi);
	free(txf->tgvi);
	free(txf->lut);
	free(txf);
}


void txfGetStringMetrics(
	TexFont * txf,
	char *string,
	int len,
	int *width,
	int *max_ascent,
	int *max_descent){
	TexGlyphVertexInfo *tgvi;
	int w, i;
	w = 0;
	for (i = 0; i < len; i++) {
		if (string[i] == 27) {
			switch (string[i + 1]) {
			case 'M': i += 4; break;
			case 'T': i += 7; break;
			case 'L': i += 7; break;
			case 'F': i += 13;break;
			}
		} 
		else {
			tgvi = getTCVI(txf, string[i]);
			w += (int)tgvi->advance;
		}
	}
	*width = w;
	*max_ascent  = txf->max_ascent;
	*max_descent = txf->max_descent;
}


void txfRenderGlyph(TexFont * txf, int c){
	TexGlyphVertexInfo *tgvi;
	tgvi = getTCVI(txf, c);
	glBegin(GL_QUADS);
	glTexCoord2fv(tgvi->t0);
	glVertex2sv(tgvi->v0);
	glTexCoord2fv(tgvi->t1);
	glVertex2sv(tgvi->v1);
	glTexCoord2fv(tgvi->t2);
	glVertex2sv(tgvi->v2);
	glTexCoord2fv(tgvi->t3);
	glVertex2sv(tgvi->v3);
	glEnd();
	glTranslatef(tgvi->advance, 0.0, 0.0);
}


void txfRenderString(TexFont * txf, char *string, int len){
	int i;
	for (i = 0; i < len; i++) {
		txfRenderGlyph(txf, string[i]);
	}
}


enum {
	MONO, TOP_BOTTOM, LEFT_RIGHT, FOUR
};


void txfRenderFancyString( TexFont * txf, char *string, int len){
	TexGlyphVertexInfo *tgvi;
	GLubyte c[4][3];
	int mode = MONO;
	int i;
	for (i = 0; i < len; i++) {
		if (string[i] == 27) {
			switch (string[i + 1]) {
			case 'M':
			mode = MONO;
			glColor3ubv((GLubyte *) & string[i + 2]);
			i += 4;
			break;
			case 'T':
			mode = TOP_BOTTOM;
			memcpy(c, &string[i + 2], 6);
			i += 7;
			break;
			case 'L':
			mode = LEFT_RIGHT;
			memcpy(c, &string[i + 2], 6);
			i += 7;
			break;
			case 'F':
			mode = FOUR;
			memcpy(c, &string[i + 2], 12);
			i += 13;
			break;
			}
		} 
		else {
			switch (mode) {
			case MONO:
			txfRenderGlyph(txf, string[i]);
			break;
			case TOP_BOTTOM:
			tgvi = getTCVI(txf, string[i]);
			glBegin(GL_QUADS);
			glColor3ubv(c[0]);
			glTexCoord2fv(tgvi->t0);
			glVertex2sv(tgvi->v0);
			glTexCoord2fv(tgvi->t1);
			glVertex2sv(tgvi->v1);
			glColor3ubv(c[1]);
			glTexCoord2fv(tgvi->t2);
			glVertex2sv(tgvi->v2);
			glTexCoord2fv(tgvi->t3);
			glVertex2sv(tgvi->v3);
			glEnd();
			glTranslatef(tgvi->advance, 0.0, 0.0);
			break;
			case LEFT_RIGHT:
			tgvi = getTCVI(txf, string[i]);
			glBegin(GL_QUADS);
			glColor3ubv(c[0]);
			glTexCoord2fv(tgvi->t0);
			glVertex2sv(tgvi->v0);
			glColor3ubv(c[1]);
			glTexCoord2fv(tgvi->t1);
			glVertex2sv(tgvi->v1);
			glColor3ubv(c[1]);
			glTexCoord2fv(tgvi->t2);
			glVertex2sv(tgvi->v2);
			glColor3ubv(c[0]);
			glTexCoord2fv(tgvi->t3);
			glVertex2sv(tgvi->v3);
			glEnd();
			glTranslatef(tgvi->advance, 0.0, 0.0);
			break;
			case FOUR:
			tgvi = getTCVI(txf, string[i]);
			glBegin(GL_QUADS);
			glColor3ubv(c[0]);
			glTexCoord2fv(tgvi->t0);
			glVertex2sv(tgvi->v0);
			glColor3ubv(c[1]);
			glTexCoord2fv(tgvi->t1);
			glVertex2sv(tgvi->v1);
			glColor3ubv(c[2]);
			glTexCoord2fv(tgvi->t2);
			glVertex2sv(tgvi->v2);
			glColor3ubv(c[3]);
			glTexCoord2fv(tgvi->t3);
			glVertex2sv(tgvi->v3);
			glEnd();
			glTranslatef(tgvi->advance, 0.0, 0.0);
			break;
			}
		}
	}
}


int txfInFont(TexFont * txf, int c) {
	// NOTE: No uppercase/lowercase substituion. 
	if ((c >= txf->min_glyph) && (c < txf->min_glyph + txf->range)) {
		if (txf->lut[c - txf->min_glyph]) {
			return 1;
		}
	}
	return 0;
}