multitexture and GLSL samplers: bug or ignorance?

[casty]

Hi,

Yesterday I posted this in the Bugs report, but I'm maybe missing something, because no one else complains about that.
http://irrlicht.sourceforge.net/phpBB2/ ... hp?t=12651

I'm just trying to access two diferent textures in a pixel program, here is a copy of the post.
----------------------------
Ok here's a simpler version of my problem with irrlicht shaders example.

In main.cpp, test scene node1 initialization, change:

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node->setMaterialTexture(0,driver->getTexture("../../media/wall.bmp"));

by

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node->setMaterialTexture(0, driver->getTexture("../../media/water.jpg"));
node->setMaterialTexture(1, driver->getTexture("../../media/wall.bmp"));

So it shows the water texture by default.

In OnSetConstants, add:

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float a = 1;
services->setPixelShaderConstant("wall", &a, 1);

(y assume UseHighLevelShaders of course)
And finally, in the fragment program:

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uniform sampler2D myTexture;
uniform sampler2D wall;

...

vec4 e_col = texture2D(wall, vec2(gl_TexCoord[0]));

It keeps showing the /&%$ water!
-----------------------

Could I be missing anything ??

PS: irrlicht 1.1 + VS2005

[mandrav]

Try this:

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int a = 1;
services->setPixelShaderConstant("wall", (const float*)&a, 1);

Notice that "a" is an integer, not a float. That's because in the driver (at least the OpenGL that I know) there is an implicit cast to integer for the case of sampler2D uniforms.
You can imagine that casting a (float*) to (int*) won't give you what you would expect .

[casty]

It works!! Thanks!

I think they should use extGlUniform1iARB instead extGlUniform1ivARB, to avoid such a counterintuitive format.

[Cosmin]

Hello it seams that i have the same problem but i do not understand why if i use the dx shader works just fine(i use 3 textures: 2 texture to blend by vertex color values and 1 as normal map for the second texture)
And this is the only code i use for multitexture(no IShaderConstantSetCallBack)

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stringc shaderPath = curentPath + "\\shaders\\OGL\\OGLalphablend.txt";//DX\\alphablendPSH.txt";
		video::IGPUProgrammingServices* gpu = driver->getGPUProgrammingServices();
		s32 newMaterialType1 = 0;
		if(gpu)
		{
			newMaterialType1 = gpu->addHighLevelShaderMaterialFromFiles(vShaderPath,"",video::EVST_VS_1_1,shaderPath,"main",video::EPST_PS_2_0);
		}
		Model->setMaterialType((video::E_MATERIAL_TYPE)newMaterialType1);
........................

for(int i = 0;i<_IRR_MATERIAL_MAX_TEXTURES_;i++)
		{
			index = materialTextures.findFirstChar(";",1);
			int textureId = 0;
			if(index==-1)
				textureId = atoi(materialTextures.subString(0,materialTextures.size()).c_str());
			else
			{
				textureId = atoi(materialTextures.subString(0,index).c_str());
				materialTextures = materialTextures.subString(index+1,materialTextures.size());
			}
			stringc tex = curentPath + (stringc)"\\media\\textures\\" + getTexture(textureId).Name();
			Model->getMaterial(matNumber).setTexture(i,Device->getVideoDriver()->getTexture( tex.c_str() ));// applying the texture
			if(index==-1)// no more textures for this material
				break;
		}

[Luben]

I dont know about the dx issue, but..

glUniform1i and
glUniform1iv are the only two functions
that may be used to load uniform variables defined as sampler
types. Loading samplers with any other function will result in a
GL_INVALID_OPERATION error.

http://www.opengl.org/sdk/docs/man/xhtml/glUniform.xml

[Cosmin]

So from what you are saying i really need to implement a IShaderConstantSetCallBack or i am wrong?? If so... pls tell me what i need to do exactly

Tnx