peter1138@6872: /* $Id$ */
peter1138@6872: 
rubidium@9111: /** @file grf.cpp Reading graphics data from (New)GRF files. */
peter1138@6872: 
truelight@6852: #include "../stdafx.h"
rubidium@8123: #include "../gfx_func.h"
truelight@6852: #include "../fileio.h"
truelight@6852: #include "../debug.h"
rubidium@8130: #include "../core/alloc_func.hpp"
truelight@6852: #include "grf.hpp"
truelight@6852: 
rubidium@9390: bool SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos)
truelight@6852: {
truelight@6852: 	/* Open the right file and go to the correct position */
truelight@7570: 	FioSeekToFile(file_slot, file_pos);
truelight@6852: 
truelight@6852: 	/* Read the size and type */
truelight@6852: 	int num = FioReadWord();
truelight@6852: 	byte type = FioReadByte();
truelight@6852: 
truelight@6852: 	/* Type 0xFF indicates either a colormap or some other non-sprite info; we do not handle them here */
truelight@6852: 	if (type == 0xFF) return false;
truelight@6852: 
truelight@6852: 	sprite->height = FioReadByte();
truelight@6852: 	sprite->width  = FioReadWord();
truelight@6852: 	sprite->x_offs = FioReadWord();
truelight@6852: 	sprite->y_offs = FioReadWord();
truelight@6852: 
truelight@6852: 	/* 0x02 indicates it is a compressed sprite, so we can't rely on 'num' to be valid.
truelight@6852: 	 *  In case it is uncompressed, the size is 'num' - 8 (header-size). */
truelight@6852: 	num = (type & 0x02) ? sprite->width * sprite->height : num - 8;
truelight@6852: 
truelight@6852: 	/* XXX -- We should use a pre-located memory segment for this, malloc/free is pretty expensive */
truelight@6852: 	byte *dest_orig = MallocT<byte>(num);
truelight@6852: 	byte *dest = dest_orig;
truelight@6852: 
truelight@6852: 	/* Read the file, which has some kind of compression */
truelight@6852: 	while (num > 0) {
truelight@6852: 		int8 code = FioReadByte();
truelight@6852: 
truelight@6852: 		if (code >= 0) {
truelight@6852: 			/* Plain bytes to read */
truelight@6852: 			int size = (code == 0) ? 0x80 : code;
truelight@6852: 			num -= size;
truelight@6852: 			for (; size > 0; size--) {
truelight@6852: 				*dest = FioReadByte();
truelight@6852: 				dest++;
truelight@6852: 			}
truelight@6852: 		} else {
truelight@6852: 			/* Copy bytes from earlier in the sprite */
truelight@6852: 			const uint data_offset = ((code & 7) << 8) | FioReadByte();
truelight@6852: 			int size = -(code >> 3);
truelight@6852: 			num -= size;
truelight@6852: 			for (; size > 0; size--) {
truelight@6852: 				*dest = *(dest - data_offset);
truelight@6852: 				dest++;
truelight@6852: 			}
truelight@6852: 		}
truelight@6852: 	}
truelight@6852: 
truelight@6852: 	assert(num == 0);
truelight@6852: 
truelight@6852: 	sprite->data = CallocT<SpriteLoader::CommonPixel>(sprite->width * sprite->height);
truelight@6852: 
truelight@6852: 	/* When there are transparency pixels, this format has an other trick.. decode it */
truelight@6852: 	if (type & 0x08) {
truelight@6852: 		for (int y = 0; y < sprite->height; y++) {
truelight@6852: 			bool last_item = false;
truelight@6852: 			/* Look up in the header-table where the real data is stored for this row */
truelight@6852: 			int offset = (dest_orig[y * 2 + 1] << 8) | dest_orig[y * 2];
truelight@6852: 			/* Go to that row */
truelight@6852: 			dest = &dest_orig[offset];
truelight@6852: 
truelight@6852: 			do {
truelight@6852: 				SpriteLoader::CommonPixel *data;
truelight@6852: 				/* Read the header:
truelight@6852: 				 *  0 .. 14  - length
truelight@6852: 				 *  15       - last_item
truelight@6852: 				 *  16 .. 31 - transparency bytes */
truelight@6852: 				last_item  = ((*dest) & 0x80) != 0;
truelight@6852: 				int length =  (*dest++) & 0x7F;
truelight@6852: 				int skip   =   *dest++;
truelight@6852: 
truelight@6852: 				data = &sprite->data[y * sprite->width + skip];
truelight@6852: 
truelight@6852: 				for (int x = 0; x < length; x++) {
truelight@6852: 					data->m = *dest;
truelight@6852: 					dest++;
truelight@6852: 					data++;
truelight@6852: 				}
truelight@6852: 			} while (!last_item);
truelight@6852: 		}
truelight@6852: 	} else {
truelight@6852: 		dest = dest_orig;
truelight@6852: 		for (int i = 0; i < sprite->width * sprite->height; i++)
truelight@6852: 			sprite->data[i].m = dest[i];
truelight@6852: 	}
truelight@6852: 
truelight@6889: 	/* Make sure to mark all transparent pixels transparent on the alpha channel too */
truelight@6889: 	for (int i = 0; i < sprite->width * sprite->height; i++)
truelight@6889: 		if (sprite->data[i].m != 0) sprite->data[i].a = 0xFF;
truelight@6889: 
truelight@6852: 	free(dest_orig);
truelight@6852: 	return true;
truelight@6852: }