Original Post
ok now i''m really pissed off
i made a nice little 8bit bmp loading function for my terrain renderer. i need 2^n + 1 sized images. ok first i tried with a 256 x 256 img and it works.
next i tried it with a 257 x 257 img and weird stuff happes like: horizontal lines with 0 values on the heightfield. the function for getting the height works so i suspect that the data is not loaded corectly. ex:
height[0] = 32; //for my bitmap
height[257] = 0; //the pixel on the next row (it should be 35 - i checked with an editor)
if ur confused heres the code for loading:
and for getting the value at some coordinates
i''m really confused why fread doesnt load corectly.
other weird stuff
i tried to write the data to another bitmap like this
fwrite(&head, sizeof(head), 1, fi)
fwrite(&info, sizeof(info), 1, fi);
fwrite(emptybuf, head.bfOffbits - sizeof(head) - sizeof(info), 1, fi);
fwrite(HeightData, MapSize * MapSize, 1, fi);
and the output is not a greyscale image (wtf not??? coz i used the exact same headers)
the output is a 8bit palleted image . weird.
and can some one explain 2 me what is the difference between
fread(&head, sizeof(head), 1, fi)
and
fread(&head, 1, sizeof(head), fi) ?
thnx in advance
/*ilici*/
int CTerrain::LoadFromFile(char *fname)
{
FILE *fi = NULL;
BITMAPFILEHEADER head;
BITMAPINFOHEADER info;
fi = fopen(fname, "rb");
if (!fi)
{
lprintf("Cannot open file %s\n", fname);
return SYS_ERR;
}
fread(&head, sizeof(head), 1, fi);
fread(&info, sizeof(info), 1, fi);
if (info.biWidth != info.biHeight)
{
lprintf("Map must be square size\n");
return SYS_ERR;
}
if (info.biBitCount != 8)
{
lprintf("Only 8 bit bitmaps supported\n");
return SYS_ERR;
}
MapSize = info.biWidth;
HeightData = (unsigned char*) malloc(MapSize * MapSize);
if (!HeightData)
{
lprintf("Cannot allocate %d memory\n", MapSize * MapSize);
return SYS_ERR;
}
fseek(fi, head.bfOffBits, SEEK_SET);
fread(HeightData, MapSize, MapSize, fi);
fclose(fi);
MapLogSize = log(MapSize - 1) / log(2);
MaxTreeLevel = MapLogSize >> 1;
CreateTree();
return SYS_OK;
}
inline unsigned char CTerrain::GetHeight(int x, int y)
{
if (x < 0 || y < 0 || x >= MapSize || y >= MapSize) return 255;
return HeightData[x * MapSize + y];
}
