[osg-users] Textuiring a simple quad

[Sebastian Messerschmidt]

Hi Jochen,

can you please provide a minimal compiling example, or at least the 
vertex shader you use.
The

Cheers
Sebastian
> Hi, all :)
> 
> I have so a simple quastion but I can solve the problem.
> 
> I want to draw a quad attach a simple Shader with a simple texture operation.
> But I only get a black quad. The shader works when a color each fragmnent with the color red, but wen I want to get texture-colors... its only got black.
> 
> Some Code:
> 
> Code:
> 
> osg::Vec2Array* textureCoordinates = new osg::Vec2Array;
> 	osg::Vec3Array* quadVertices = new osg::Vec3Array;
> 	osg::Geometry* quadGeometry = new osg::Geometry();
> 
> 	// *********** Vertices ***********
> 	quadVertices->push_back(osg::Vec3(x - rad, y - rad, 0.0));
> 	quadVertices->push_back(osg::Vec3(x + rad, y - rad, 0.0));
> 	quadVertices->push_back(osg::Vec3(x + rad, y + rad, 0.0));
> 	quadVertices->push_back(osg::Vec3(x - rad, y + rad, 0.0));
> 
> 	quadGeometry->setVertexArray(quadVertices);
> 	// *********** Vertices - Ende ***********
> 
> 	// *********** Texturkorrdinaten ***********
> 	textureCoordinates->push_back(osg::Vec2(0, 0));
> 	textureCoordinates->push_back(osg::Vec2(1, 0));
> 	textureCoordinates->push_back(osg::Vec2(1, 1));
> 	textureCoordinates->push_back(osg::Vec2(0, 1));
> 
> 	quadGeometry->setTexCoordArray(0, textureCoordinates, osg::Array::BIND_PER_VERTEX);
> 	// *********** Texturkorrdinaten-Ende ***********
> 
> 
> 	// *********** Faces-Idizes ***********
> 	osg::DrawElementsUInt* gridFace = new osg::DrawElementsUInt(osg::PrimitiveSet::QUADS, 0);
> 	gridFace->push_back(0);
> 	gridFace->push_back(1);
> 	gridFace->push_back(2);
> 	gridFace->push_back(3);
> 
> 	quadGeometry->addPrimitiveSet(gridFace);
> 	// *********** Faces-Idizes - Ende ***********
> 
> 	// **** Logo - Texture ****
> 	{
> 		std::string path("Grafik\\");
> 		std::string fileName = path + std::string("Skull.tga");
> 
> 		osg::Image *image = osgDB::readImageFile(fileName);
> 		if (!image)
> 		{
> 			exit;
> 		}
> 
> 		osg::TextureRectangle* texture = new osg::TextureRectangle(image);
> 
> 		osg::TexMat* texmat = new osg::TexMat;
> 		texmat->setScaleByTextureRectangleSize(true);
> 
> 		// setup state
> 		osg::StateSet* state = new osg::StateSet();
> 		state->addUniform(new osg::Uniform("skull_Texture", SKULL_TEXTURE));
> 		state->setTextureAttributeAndModes(SKULL_TEXTURE, texture, osg::StateAttribute::ON);
> 		state->setTextureAttributeAndModes(SKULL_TEXTURE, texmat, osg::StateAttribute::ON);
> 
> 		state->setMode(GL_BLEND, osg::StateAttribute::ON);
> 	
> 	
> 		quadGeometry->setStateSet(state);
> 	}
> 
> 
> 
> 
> Here I attech the shader
> 
> Code:
> 
> 	// Shader-Logo
> 	{
> 		osg::StateSet* stateSet = quadGeometry->getOrCreateStateSet();
> 
> 		mShaderProgramLogo = new osg::Program;
> 		mShaderProgramLogo->setName("ProgramLogo");
> 		mVertexShaderLogo = new osg::Shader(osg::Shader::VERTEX);
> 		mFragmentShaderLogo = new osg::Shader(osg::Shader::FRAGMENT);
> 
> 		mShaderProgramLogo->addShader(mFragmentShaderLogo);
> 		mShaderProgramLogo->addShader(mVertexShaderLogo);
> 
> 		mVertexShaderLogo->loadShaderSourceFromFile("Shader\\vertLogo.txt");
> 		mFragmentShaderLogo->loadShaderSourceFromFile("Shader\\fragmentLogo.txt");
> 		stateSet->setAttributeAndModes(mShaderProgramLogo, osg::StateAttribute::ON);
> 		
> 		quadGeometry->setStateSet(stateSet);
> 	}
> 
> 
> 
> 
> 
> and here the fragment-shader code:
> 
> Code:
> 
> #version 330
> 
> uniform sampler2D skull_Texture;
> 
> varying vec2 textCoord;
> 
> void main(void)
> {
>      vec4 colSkull = texture2D(skull_Texture, textCoord);
> 
> 	//gl_FragColor = vec4(1.0,0,0,1.0); // => this works fine
> 	gl_FragColor = colSkull;	// => every fragment is black!!!
> }
> 
> 
> 
> 
> Can anybody help my.
> OSG is such a nice library...but why it doesn't work? :(
> 
> Thank you!
> 
> Cheers,
> JoseMan[/code]
> 
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=72151#72151
> 
> 
> 
> 
> 
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