newtree/source/tga.c

/*
	tga.c

	targa image handling

	Copyright (C) 1996-1997  Id Software, Inc.

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "quakefs.h"
#include "sys.h"
#include "tga.h"

typedef struct _TargaHeader {
	unsigned char id_length, colormap_type, image_type;
	unsigned short colormap_index, colormap_length;
	unsigned char colormap_size;
	unsigned short x_origin, y_origin, width, height;
	unsigned char pixel_size, attributes;
} TargaHeader;


static int
fgetLittleShort (QFile *f)
{
	byte        b1, b2;

	b1 = Qgetc (f);
	b2 = Qgetc (f);

	return (short) (b1 + b2 * 256);
}

/*
static int
fgetLittleLong (QFile *f)
{
	byte	b1, b2, b3, b4;

	b1 = Qgetc(f);
	b2 = Qgetc(f);
	b3 = Qgetc(f);
	b4 = Qgetc(f);

	return b1 + (b2<<8) + (b3<<16) + (b4<<24);
}
*/


/*
=============
LoadTGA
=============
*/
byte       *
LoadTGA (QFile *fin)
{
	int         columns, rows, numPixels;
	byte       *pixbuf;
	int         row, column;
	unsigned char red = 0, green = 0, blue = 0, alphabyte = 0;

	TargaHeader targa_header;
	byte       *targa_rgba;

	targa_header.id_length = Qgetc (fin);
	targa_header.colormap_type = Qgetc (fin);
	targa_header.image_type = Qgetc (fin);

	targa_header.colormap_index = fgetLittleShort (fin);
	targa_header.colormap_length = fgetLittleShort (fin);
	targa_header.colormap_size = Qgetc (fin);
	targa_header.x_origin = fgetLittleShort (fin);
	targa_header.y_origin = fgetLittleShort (fin);
	targa_header.width = fgetLittleShort (fin);
	targa_header.height = fgetLittleShort (fin);
	targa_header.pixel_size = Qgetc (fin);
	targa_header.attributes = Qgetc (fin);

	if (targa_header.image_type != 2 && targa_header.image_type != 10)
		Sys_Error ("LoadTGA: Only type 2 and 10 targa RGB images supported\n");

	if (targa_header.colormap_type != 0
		|| (targa_header.pixel_size != 32 && targa_header.pixel_size != 24))
		Sys_Error
			("Texture_LoadTGA: Only 32 or 24 bit images supported (no colormaps)\n");

	columns = targa_header.width;
	rows = targa_header.height;
	numPixels = columns * rows;

	targa_rgba = malloc (numPixels * 4);

	if (targa_header.id_length != 0)
		Qseek (fin, targa_header.id_length, SEEK_CUR);	// skip TARGA image
														// comment

	if (targa_header.image_type == 2) {	// Uncompressed, RGB images
		for (row = rows - 1; row >= 0; row--) {
			pixbuf = targa_rgba + row * columns * 4;
			for (column = 0; column < columns; column++) {
				switch (targa_header.pixel_size) {
					case 24:

						blue = Qgetc (fin);
						green = Qgetc (fin);
						red = Qgetc (fin);
						*pixbuf++ = red;
						*pixbuf++ = green;
						*pixbuf++ = blue;
						*pixbuf++ = 255;
						break;
					case 32:
						blue = Qgetc (fin);
						green = Qgetc (fin);
						red = Qgetc (fin);
						alphabyte = Qgetc (fin);
						*pixbuf++ = red;
						*pixbuf++ = green;
						*pixbuf++ = blue;
						*pixbuf++ = alphabyte;
						break;
				}
			}
		}
	} else if (targa_header.image_type == 10) {	// Runlength encoded RGB
												// images
		unsigned char packetHeader, packetSize, j;

		for (row = rows - 1; row >= 0; row--) {
			pixbuf = targa_rgba + row * columns * 4;
			for (column = 0; column < columns;) {
				packetHeader = Qgetc (fin);
				packetSize = 1 + (packetHeader & 0x7f);
				if (packetHeader & 0x80) {	// run-length packet
					switch (targa_header.pixel_size) {
						case 24:
							blue = Qgetc (fin);
							green = Qgetc (fin);
							red = Qgetc (fin);
							alphabyte = 255;
							break;
						case 32:
							blue = Qgetc (fin);
							green = Qgetc (fin);
							red = Qgetc (fin);
							alphabyte = Qgetc (fin);
							break;
					}

					for (j = 0; j < packetSize; j++) {
						*pixbuf++ = red;
						*pixbuf++ = green;
						*pixbuf++ = blue;
						*pixbuf++ = alphabyte;
						column++;
						if (column == columns) {	// run spans across rows
							column = 0;
							if (row > 0)
								row--;
							else
								goto breakOut;
							pixbuf = targa_rgba + row * columns * 4;
						}
					}
				} else {				// non run-length packet
					for (j = 0; j < packetSize; j++) {
						switch (targa_header.pixel_size) {
							case 24:
								blue = Qgetc (fin);
								green = Qgetc (fin);
								red = Qgetc (fin);
								*pixbuf++ = red;
								*pixbuf++ = green;
								*pixbuf++ = blue;
								*pixbuf++ = 255;
								break;
							case 32:
								blue = Qgetc (fin);
								green = Qgetc (fin);
								red = Qgetc (fin);
								alphabyte = Qgetc (fin);
								*pixbuf++ = red;
								*pixbuf++ = green;
								*pixbuf++ = blue;
								*pixbuf++ = alphabyte;
								break;
						}
						column++;
						if (column == columns) {	// pixel packet run spans 
													// across rows
							column = 0;
							if (row > 0)
								row--;
							else
								goto breakOut;
							pixbuf = targa_rgba + row * columns * 4;
						}
					}
				}
			}
		  breakOut:;
		}
	}

	Qclose (fin);
	return targa_rgba;
}