[fixed] Terrain heightmap bug in 1.5

Eigen · Post by **Eigen** » Fri Dec 19, 2008 5:13 pm

I ran into an issue with terrain heightmaps. I'm using the official 1.5 release. I have made no changes or even recompiled it. One edge of the terrain is always distorted. It doesn't matter what size the heightmap is. I tried 129, 128 and even the default heightmap that comes with Irrlicht (You can see an error in one of the corners). You can easily reproduce this error by making the heightmap a single solid color.

256x256

129x129

Hope this helps.

rogerborg · Post by **rogerborg** » Fri Dec 19, 2008 5:50 pm

I can't replicate this in the latest 1.5 branch source. Perhaps hybrid has already fixed it?

Dorth · Post by **Dorth** » Fri Dec 19, 2008 5:57 pm

Wasn't there a bug a while back that made the side of the map average between the height given on the previous indice and 0? I think it had something to do with maps that were too big or something similar. Might want to check there. If not, maybe finding that fix will give you a lead, as the deformation seems strangely similar to the one seen then.

Eigen · Post by **Eigen** » Sat Dec 20, 2008 11:16 am

I tried the latest 1.5 branch version (1980) but still the same error occurs.

With terrain smoothing set to 0 it looks like this. It seems that one row of vertices isn't read or set.

Dorth · Post by **Dorth** » Sat Dec 20, 2008 4:44 pm

Yeah, ok, this looks exactly like the old bug. Search in the bug section, you should find a topic about a near identical bug with similar pics.

Eigen · Post by **Eigen** » Sun Dec 21, 2008 7:32 pm

Yes, I'll do the search in a second, but why would this happen? I mean, it's all standard .. the 1.5 release, running the example without any changes. I tried the official 1.4.2 release with the same plain heightmap and it works fine. So it must be something between these releases .. it can't be just me, can it?

hybrid · Post by **hybrid** » Sun Dec 21, 2008 9:23 pm

The bug is almost invisible in the standard heightmap. And no one complained in the mean time.

Eigen · Post by **Eigen** » Mon Dec 22, 2008 1:36 pm

I found a fix to the problem.
In CTerrainSceneNode::loadHeightMap I had to replace

Code: Select all

vertex.Pos.Y = (f32) heightMap->getPixel(TerrainData.Size-x,z).getLuminance();

with

Code: Select all

vertex.Pos.Y = (f32) heightMap->getPixel((TerrainData.Size-1)-x,z).getLuminance();

Now all heightmaps work as they are supposed to. I makes sense because when using 129x129 heightmap eg., it would try to read a pixel 129 when x is 0 and since it doesn't exist, it reads it as 0.

rogerborg · Post by **rogerborg** » Sun Dec 28, 2008 8:59 pm

Super, thanks very much for looking into this. I'll give that a try. Tracking.

Damn, hybrid beat me to it! Curse my 12-year-old-single-malt addled reflexes.