What is the largest you can make your bitmaps in a GRP and still have them work in StarCraft?

I remember seeing "500x500 pixels" somewhere
But "255x255" or "250x250" also sounds familiar.

255x255 is the largest individual size you can have. 256x256 is unstable and anything above will asplode.

You can have 500x500 units if you comprise them of four separate blocks.

But don't forget if you want to center your buildings properly the width and height should be multiples of 32, and the building centered in it, meaning 224x224 would be the biggest they could be (note: its is sometimes possible to center them without using this rule, it just usually takes forever).

If you use the right converter (I.E. not RetroGRP), your bitmap can have dimensions larger than 255x255, but keep in mind that the upper left corner of the portion that you actually use must not pass the (255, 255) coordinate position. Also, the portion you actually use cannot exceed 255x255 in size, otherwise it cannot be included in the image data. The largest practical size for a GRP is probably pretty much 512x512. Since you can't actually fill up that area with a single frame, this is more useful just for a large unit that has most of it pivoting around the center of the frame (like if the back or front of a ship was near the middle of the image, for example).

My converter (SFGrpConv) is specifically designed to handle these sizes, but I can't vouch for anyone else's converter at the moment, as I haven't tested it in others (but I can say with certainty that neither the input nor output images will work at all in RetroGRP -- the author probably took the stance that Starcraft's limit would be the same as the largest built-in graphic).

I remember retrogrp screwing up the Xel`Naga temple because of the size... but that was literally 8-9 years ago so yeah.

But then you have to take into account that all that pixel data could compile to a size bigger then the offsets can reference. This happened to me when working on PyGRP, I tried compiling a 255x255 graphic (or maybe a few 255x255 images) with almost the whole image filled with non repleating colors, and no duplicate rows of pixels. I havn't tested this on other editors, but I made an appropriate error message in mine.

That is not typical, though. The maximum number of consecutive non-repeating pixels should be high enough for any real-world examples. IIRC on the format, then basically you can up to 251 or 252 rows of non-repeating pixels. There also needs to be no more than 4 duplicate rows to reach this limit (depending on the converter).

Okay so... Your converter can make .GRPs over the size of 255x255... But can they be used in StarCraft that way? I'm a little confused.

Im not exactly sure what you mean, but yeah it is not typical, but it can happen when using large graphics.

The area in which to place the image for each frame can be over 255x255, but the image data itself cannot go over that size. This means that the total size, image data of 255x255 + transparent pixels at the sides, top, and bottom, can go over 255x255. This is basically useful for if you need over 256x256 to get your image positioned exactly how you want it.

You can have a maximum of 255 transparent pixels at the top or left sides. The other two sides can practically have unlimited transparent pixels (technically up to something like either 32,000 or 65,000, but the limit on how far down or right limits the usefulness of having any more than 255 at the bottom or right).


I said not typical mainly because it will pretty much only happen if you make a 255x255 square of random stuff or very close to it. If it isn't a square, it still basically has to almost be a square.

Post has been edited 2 time(s), last time on Oct 6 2008, 9:57 pm by ShadowFlare.

Interesting. I get it now.