glx@9627: /* $Id$ */
glx@9627: 
glx@9627: /** @file grf.cpp */
glx@9627: 
glx@9626: #include "../stdafx.h"
glx@9626: #include "../gfx.h"
glx@9626: #include "../fileio.h"
glx@9626: #include "../debug.h"
glx@9626: #include "grf.hpp"
glx@9626: 
rubidium@9628: bool SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, const char *filename, uint32 file_pos)
glx@9626: {
glx@9626: 	/* Open the right file and go to the correct position */
glx@9626: 	FioSeekToFile(file_pos);
glx@9626: 
glx@9626: 	/* Read the size and type */
glx@9626: 	int num = FioReadWord();
glx@9626: 	byte type = FioReadByte();
glx@9626: 
glx@9626: 	/* Type 0xFF indicates either a colormap or some other non-sprite info; we do not handle them here */
glx@9626: 	if (type == 0xFF) return false;
glx@9626: 
glx@9626: 	sprite->height = FioReadByte();
glx@9626: 	sprite->width  = FioReadWord();
glx@9626: 	sprite->x_offs = FioReadWord();
glx@9626: 	sprite->y_offs = FioReadWord();
glx@9626: 
glx@9626: 	/* 0x02 indicates it is a compressed sprite, so we can't rely on 'num' to be valid.
glx@9626: 	 *  In case it is uncompressed, the size is 'num' - 8 (header-size). */
glx@9626: 	num = (type & 0x02) ? sprite->width * sprite->height : num - 8;
glx@9626: 
glx@9626: 	/* XXX -- We should use a pre-located memory segment for this, malloc/free is pretty expensive */
glx@9626: 	byte *dest_orig = MallocT<byte>(num);
glx@9626: 	byte *dest = dest_orig;
glx@9626: 
glx@9626: 	/* Read the file, which has some kind of compression */
glx@9626: 	while (num > 0) {
glx@9626: 		int8 code = FioReadByte();
glx@9626: 
glx@9626: 		if (code >= 0) {
glx@9626: 			/* Plain bytes to read */
glx@9626: 			int size = (code == 0) ? 0x80 : code;
glx@9626: 			num -= size;
glx@9626: 			for (; size > 0; size--) {
glx@9626: 				*dest = FioReadByte();
glx@9626: 				dest++;
glx@9626: 			}
glx@9626: 		} else {
glx@9626: 			/* Copy bytes from earlier in the sprite */
glx@9626: 			const uint data_offset = ((code & 7) << 8) | FioReadByte();
glx@9626: 			int size = -(code >> 3);
glx@9626: 			num -= size;
glx@9626: 			for (; size > 0; size--) {
glx@9626: 				*dest = *(dest - data_offset);
glx@9626: 				dest++;
glx@9626: 			}
glx@9626: 		}
glx@9626: 	}
glx@9626: 
glx@9626: 	assert(num == 0);
glx@9626: 
glx@9626: 	sprite->data = CallocT<SpriteLoader::CommonPixel>(sprite->width * sprite->height);
glx@9626: 
glx@9626: 	/* When there are transparency pixels, this format has an other trick.. decode it */
glx@9626: 	if (type & 0x08) {
glx@9626: 		for (int y = 0; y < sprite->height; y++) {
glx@9626: 			bool last_item = false;
glx@9626: 			/* Look up in the header-table where the real data is stored for this row */
glx@9626: 			int offset = (dest_orig[y * 2 + 1] << 8) | dest_orig[y * 2];
glx@9626: 			/* Go to that row */
glx@9626: 			dest = &dest_orig[offset];
glx@9626: 
glx@9626: 			do {
glx@9626: 				SpriteLoader::CommonPixel *data;
glx@9626: 				/* Read the header:
glx@9626: 				 *  0 .. 14  - length
glx@9626: 				 *  15       - last_item
glx@9626: 				 *  16 .. 31 - transparency bytes */
glx@9626: 				last_item  = ((*dest) & 0x80) != 0;
glx@9626: 				int length =  (*dest++) & 0x7F;
glx@9626: 				int skip   =   *dest++;
glx@9626: 
glx@9626: 				data = &sprite->data[y * sprite->width + skip];
glx@9626: 
glx@9626: 				for (int x = 0; x < length; x++) {
glx@9626: 					data->m = *dest;
glx@9626: 					dest++;
glx@9626: 					data++;
glx@9626: 				}
glx@9626: 			} while (!last_item);
glx@9626: 		}
glx@9626: 	} else {
glx@9626: 		dest = dest_orig;
glx@9626: 		for (int i = 0; i < sprite->width * sprite->height; i++)
glx@9626: 			sprite->data[i].m = dest[i];
glx@9626: 	}
glx@9626: 
rubidium@9628: 	/* Make sure to mark all transparent pixels transparent on the alpha channel too */
rubidium@9628: 	for (int i = 0; i < sprite->width * sprite->height; i++)
rubidium@9628: 		if (sprite->data[i].m != 0) sprite->data[i].a = 0xFF;
rubidium@9628: 
glx@9626: 	free(dest_orig);
glx@9626: 	return true;
glx@9626: }