Hi, Shuiying Attach GL_RGBA renderbuffer to camera, and check if you have blending disabled.
Cheers, Sergey. 27.10.2011, 14:17, "wang shuiying" <[email protected]>: > Hi, Robert > > Thank you for your reply. > > Sorry that I don't think I expressed my problem clearly. > > I want to simulate radar using osg camera. The important codes are: > > osg::Program * program = new osg::Program(); > > program->addShader(osg::Shader::readShaderFile(osg::Shader::FRAGMENT, > fragmentShaderPath)); > > program->addShader(osg::Shader::readShaderFile(osg::Shader::VERTEX, > vertexShaderPath)); > > osg::Image * image = new osg::Image(); > image->allocateImage(xRes, yRes, 1, GL_RGBA, > GL_FLOAT); > > osg::ref_ptr<osg::CameraNode> camera(new > osg::CameraNode()); > > camera->setComputeNearFarMode(osg::Camera::DO_NOT_COMPUTE_NEAR_FAR); > camera->setViewport(0, 0, xRes, yRes); > camera->setClearColor(osg::Vec4(1000.0f, 1000.0f, > 1000.0f, 1000.0f)); > camera->setClearMask(GL_COLOR_BUFFER_BIT | > GL_DEPTH_BUFFER_BIT); > > camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF); > camera->setProjectionMatrixAsFrustum(-tan( > viewYaw), tan(viewYaw), -tan(viewPitch), tan(viewPitch), zNear,zFar); > > camera->setViewMatrix(osg::Matrix::lookAt(osg::Vec3d(0, 0, 1.0f), > osg::Vec3d(-10.0f, 0.0f, 0), osg::Vec3d(0, 0, 1))); > > camera->setRenderOrder(osg::CameraNode::PRE_RENDER); > > camera->setRenderTargetImplementation(renderTargetImplementation); > camera->attach(osg::CameraNode::COLOR_BUFFER, > image); > > camera->getOrCreateStateSet()->setAttribute(program, > osg::StateAttribute::ON); > > in Fragment shader, I write, e.g: > > gl_FragColor = vec4(0.1,0.2,0.3,0.5); > > when I get the four elements through image attached to the camera, the > first three elements are just as expected to be 0.1,0.2,0.3 > respectively, but the fourth element is 1. No matter what value I > assign to the fourth element, it keeps to be 1. > > I cannot figure out why this happens. > > So does it still have something do do with graphics context when it > comes to Pre-render camera? > > Thank you very much! > > Shuiying > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
