Hi Michael,
As a side note:
In order to get your matrices to your shaders simply use the osg_
equivalents to the gl_-Matrices and setup aliasing:
Viewer->getCamera()->getGraphicsContext()->getState()->setUseModelViewAndProjectionUniforms(true);
Viewer->getCamera()->getGraphicsContext()->getState()->setUseVertexAttributeAliasing(true);
In general you need to create the render-target textures and bind them
to the FBO of your RTT-Camera. Basically there is the
osgmultiplerendertargets example which shows you how to achieve this.
Once you have a working example rendering the gbuffer, you can simply
add more absolute cameras to the graph to do the screenspace calculations.
Also take a look at osgPPU, which might offer some insight.
Cheers
Sebastian
Hi all,
I am trying to figure out RTT in combination with shaders for
implementing a gbuffer but I can't get the different examples to work
together.
This is a working example for using my shaders, but without RTT and also
for setting the StateSet for the model and not the camera.
const char* vertSource =
"#version 400\n"
"uniform mat4 MV;\n"
"uniform mat4 N;\n"
"uniform mat4 P;\n"
"layout(location = 0) in vec4 Vertex;\n"
"layout(location = 1) in vec3 Normal;\n"
"smooth out vec3 p;\n"
"smooth out vec3 n;\n"
"void main(void) {\n"
"p = (MV * Vertex).xyz;\n"
"n = normalize(N * vec4(Normal, 0)).xyz;\n"
"gl_Position = P * vec4(p, 1);\n"
"}\n";
const char* fragSource =
"#version 400\n"
"in vec3 p;\n"
"in vec3 n;\n"
"layout(location = 0) out vec4 position;\n"
"layout(location = 1) out vec4 normal;\n"
"layout(location = 2) out float depth;\n"
"void main(void) {\n"
"position = vec4(p,1);\n"
"normal = vec4(n,0);\n"
"depth = gl_FragCoord.z;\n"
//"gl_FragColor = vec4(n,1);\n"
"}\n";
#define Test1
struct ProjectionMatrixCallback: public osg::Uniform::Callback {
ProjectionMatrixCallback(osg::Camera* camera) :
_camera(camera) {
}
virtual void operator()(osg::Uniform* uniform, osg::NodeVisitor* nv) {
uniform->set(_camera->getProjectionMatrix());
}
osg::Camera* _camera;
};
struct NormalMatrixCallback: public osg::Uniform::Callback {
NormalMatrixCallback(osg::Camera* camera) :
_camera(camera) {
}
virtual void operator()(osg::Uniform* uniform, osg::NodeVisitor* nv) {
osg::Matrixd viewMatrix = _camera->getViewMatrix();
osg::Matrixd normalMatrix = osg::Matrix::inverse(viewMatrix);
uniform->set(normalMatrix);
}
osg::Camera* _camera;
};
struct ModelViewMatrixCallback: public osg::Uniform::Callback {
ModelViewMatrixCallback(osg::Camera* camera) :
_camera(camera) {
}
virtual void operator()(osg::Uniform* uniform, osg::NodeVisitor* nv) {
osg::Matrixd viewMatrix = _camera->getViewMatrix();
osg::Matrixd modelMatrix =
osg::computeLocalToWorld(nv->getNodePath());
osg::Matrixd modelViewMatrix = modelMatrix * viewMatrix;
uniform->set(modelViewMatrix);
}
osg::Camera* _camera;
};
int main(int, char**) {
osgViewer::Viewer viewer;
osg::Node* model = osgDB::readNodeFile("cow.osgt");
osg::ref_ptr<osg::Group> root = new osg::Group();
//create camera
osg::Camera* camera = viewer.getCamera();
// create shader
osg::ref_ptr<osg::Program> program = new osg::Program;
program->setName("shader");
program->addShader(new osg::Shader(osg::Shader::VERTEX, vertSource));
program->addShader(new osg::Shader(osg::Shader::FRAGMENT, fragSource));
osg::StateSet* state = model->getOrCreateStateSet();
state->setAttributeAndModes(program.get(), osg::StateAttribute::ON);
// add uniforms
osg::Uniform* modelViewMatrix = new osg::Uniform(osg::Uniform::FLOAT_MAT4,
"MV");
modelViewMatrix->setUpdateCallback(new ModelViewMatrixCallback(camera));
state->addUniform(modelViewMatrix);
osg::Uniform* normalMatrix = new osg::Uniform(osg::Uniform::FLOAT_MAT4,
"N");
normalMatrix->setUpdateCallback(new NormalMatrixCallback(camera));
state->addUniform(normalMatrix);
osg::Uniform* projectionMatrix = new osg::Uniform(osg::Uniform::FLOAT_MAT4,
"P");
projectionMatrix->setUpdateCallback(new ProjectionMatrixCallback(camera));
state->addUniform(projectionMatrix);
// turn lights off
state->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
// scene state run
root->addChild(model);
viewer.setSceneData(root.get());
viewer.setUpViewOnSingleScreen(0);
return viewer.run();
}
Another working example with RTT camera but without shaders can be found
here:https://github.com/xarray/osgRecipes/blob/master/cookbook/chapter6/ch06_04/read_depth.cpp
Can somebody help me combine these two or give me a minimal working example
(which is documented :) ).
Thanks,
Michael
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