[no bug] Additional Textures cause problems in shaders

Beroc · Post by **Beroc** » Mon Oct 12, 2009 9:46 pm

I got to testing this in 1.6 as I needed 6 textures in my Splat shader.

I changed IrrCompileConfig.h line 102 from this:

#define _IRR_MATERIAL_MAX_TEXTURES_ 4

to this:

#define _IRR_MATERIAL_MAX_TEXTURES_ 6

Here are my findings:

4: shaders appear normal
5: shaders did not appear
6: shaders did not appear
7: shaders did not appear
8: The engine crashes

I tested this on d3d9 and opengl.

Though the engine starts running, I believe that there are still things that need "fixing" in the area of more material textures

vitek · Post by **vitek** » Tue Oct 13, 2009 12:35 am

Did you rebuild the Irrlicht library after changing IrrCompileConfig.h?

Travis

Beroc · Post by **Beroc** » Tue Oct 13, 2009 5:08 am

This is in the includes folder, I checked the Irrlicht.dll in the source, and apart from errors when I try to build it, it never goes into the include folder to get anything. Unless... I am just missing what you are saying.

Nadro · Post by **Nadro** » Tue Oct 13, 2009 7:39 am

Vitek means that always, after add some important changes in Irrlicht headers (include), You have to rebuild engine from sources.

vitek · Post by **vitek** » Tue Oct 13, 2009 4:54 pm

Exactly. If you change the value of _IRR_MATERIAL_MAX_TEXTURES_, you must rebuild the Irrlicht library for the changes to take effect.

The reason is that there is code inside the Irrlicht library that makes use of _IRR_MATERIAL_MAX_TEXTURES_. If the library was compiled with _IRR_MATERIAL_MAX_TEXTURES_ = 4, but your executable is compiled with _IRR_MATERIAL_MAX_TEXTURES_ = 8, your application will think that there are 8 textures, but the Irrlicht library only reserves space for and uses the 4 textures. When you access any texture past 4, you're actually asking the Irrlicht library to access one or more of its internal arrays past the end, which will cause crashes.

Of course it is a bug if the library attempts to index any of its internal arrays out of bounds. A bug report should be filed, and the issue should be fixed, but that won't actually resolve the problem that you will continue to see. Without rebuilding the library, you won't be able to access texture stages beyond 4.

Travis