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
