I'm trying to write a simple app to render a scene and drop out 3
buffers : Depth, Color (RGB), and Alpha. I've pasted the code below,
and there's an important DEFINE at the top: SHOW_ALPHA. If you set
SHOW_ALPHA to 0, that disables the COLOR_BUFFER1 (a GL_ALPHA texture
attachment to the main camera) and everything works perfectly. I set
that to 1, and then my visuals get all scrambled and I get the following
error messages:
RenderStage::runCameraSetUp(), FBO setup failed, FBO status= 0x8cdd
Warning: RenderStage::runCameraSetUp(State&) Pbuffer does not support
multiple color outputs.
Warning: RenderStage::runCameraSetUp(State&) Pbuffer does not support
multiple color outputs.
RenderStage::runCameraSetUp(), FBO setup failed, FBO status= 0x8cdd
Warning: RenderStage::runCameraSetUp(State&) Pbuffer does not support
multiple color outputs.
Warning: RenderStage::runCameraSetUp(State&) Pbuffer does not support
multiple color outputs.
Now, I think I can accomplish what I want using a single RGBA texture
and a fragment shader to pull out the A. Am I doing something wrong, or
is the fragment-shader route the "right" way to go?
Code below:
#include <osgViewer/Viewer>
#include <osg/BlendFunc>
#include <osg/Geode>
#include <osg/TexGen>
#include <osg/Texture2D>
#include <osg/MatrixTransform>
#include <osg/LightModel>
#include <osg/Material>
#include <osgGA/NodeTrackerManipulator>
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>
#define SHOW_ALPHA 0
#define SHOW_DEPTH 1
#define HEIGHT_OFFSET 24
int main(void) {
int width=512, height=256;
osg::ref_ptr<osg::Geode> screenQuad = new osg::Geode;
osg::ref_ptr<osg::Texture2D> __depthTexture = new osg::Texture2D();
osg::ref_ptr<osg::Texture2D> __maskTexture = new osg::Texture2D();
osg::ref_ptr<osg::Texture2D> __colorTexture = new osg::Texture2D();
osg::ref_ptr<osg::Node> model =
osgDB::readNodeFile("/Users/rhand/Documents/MagicLeap/data/MLOS-Logo.obj");
osgViewer::Viewer V;
osg::ref_ptr<osg::Group> group = new osg::Group();
//model->getOrCreateStateSet()->setMode(GL_,osg::StateAttribute::OFF);
model->getOrCreateStateSet()->setMode(GL_BLEND,osg::StateAttribute::ON);
model->getOrCreateStateSet()->setMode(GL_DEPTH_TEST,osg::StateAttribute::ON);
V.getCamera()->setClearMask(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
V.getCamera()->setClearDepth(1.0);
V.getCamera()->setClearColor(osg::Vec4(0,0,0,0));
group->addChild(model.get());
V.setSceneData(group.get());
// Establish the "base" Graphics Context
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new
osg::GraphicsContext::Traits;
traits->x = 0;
traits->y = HEIGHT_OFFSET;
traits->width = width;
traits->height = height;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = 0; // Doesn't inherit from anything
traits->vsync = true; // Disable VSync (for now)
traits->supportsResize = false;
traits->windowName = "Color";
osg::ref_ptr<osg::GraphicsContext> gc =
osg::GraphicsContext::createGraphicsContext(traits.get());
{
__depthTexture->setTextureSize(width,height);
__depthTexture->setInternalFormat(GL_DEPTH_COMPONENT);
__depthTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::NEAREST);
__depthTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::NEAREST);
__depthTexture->setDataVariance( osg::Object::DYNAMIC );
__depthTexture->setResizeNonPowerOfTwoHint( false );
__maskTexture->setTextureSize(width,height);
__maskTexture->setInternalFormat(GL_ALPHA);
__maskTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::NEAREST);
__maskTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::NEAREST);
__maskTexture->setDataVariance( osg::Object::DYNAMIC );
__maskTexture->setResizeNonPowerOfTwoHint( false );
__colorTexture->setTextureSize(width,height);
__colorTexture->setInternalFormat(GL_RGB);
__colorTexture->setFilter(osg::Texture2D::MIN_FILTER,osg::Texture2D::NEAREST);
__colorTexture->setFilter(osg::Texture2D::MAG_FILTER,osg::Texture2D::NEAREST);
__colorTexture->setDataVariance( osg::Object::DYNAMIC );
__colorTexture->setResizeNonPowerOfTwoHint( false );
osg::ref_ptr<osg::Camera> __camera = new osg::Camera();
__camera->setGraphicsContext(gc.get());
__camera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
__camera->setViewport(new osg::Viewport(0,0, traits->width,
traits->height));
__camera->setComputeNearFarMode(osg::Camera::DO_NOT_COMPUTE_NEAR_FAR);
__camera->setProjectionMatrixAsPerspective(70,(height/width),
1,200);
__camera->setClearDepth(1.0);
__camera->setViewMatrixAsLookAt( osg::Vec3(0,0,0),
osg::Vec3(0,100,0), osg::Vec3(0,0,1) );
__camera->setRenderOrder(osg::Camera::PRE_RENDER);
__camera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
__camera->attach(osg::Camera::COLOR_BUFFER0, __colorTexture);
#if SHOW_DEPTH
__camera->attach(osg::Camera::DEPTH_BUFFER, __depthTexture);
#endif
#if SHOW_ALPHA
__camera->attach(osg::Camera::COLOR_BUFFER1, __maskTexture);
#endif
V.addSlave(__camera.get(), osg::Matrixd(), osg::Matrixd());
}
{ // Make the re-usable Quad for displaying the textures
// Make the quad with a little 10px border around the edges, for
debugging
osg::ref_ptr<osg::Drawable> quad = osg::createTexturedQuadGeometry(
osg::Vec3(10,10.0,0),
osg::Vec3(width-20,0,0),osg::Vec3(0,height-20,0),
0, 0, 1, 1);
quad->setDataVariance( osg::Object::STATIC ); // This is
_always_ a screen-aligned quad
quad->setUseDisplayList( true );
osg::StateSet* ss = quad->getOrCreateStateSet();
ss->setTextureMode(0, GL_TEXTURE_2D, osg::StateAttribute::ON);
ss->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
ss->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
ss->setMode(GL_BLEND, osg::StateAttribute::ON);
ss->setAttribute(new osg::BlendFunc(GL_SRC_ALPHA,
GL_ONE_MINUS_SRC_ALPHA), osg::StateAttribute::ON);
// Put the quad in a Geometry Node (Geode) and configure it for
Texture coordinates
//osg::ref_ptr<osg::Geode> *geode = new osg::Geode;
screenQuad->addDrawable( quad.get() );
}
#if SHOW_DEPTH
{ // Display the Depth MAsk
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new
osg::GraphicsContext::Traits;
traits->x = 0;
traits->y = height + (HEIGHT_OFFSET*3);
traits->width = width;
traits->height = height;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = gc.get();
traits->vsync = true; // Disable VSync (for now)
traits->supportsResize = false;
traits->windowName = "Depth";
osg::ref_ptr<osg::GraphicsContext> this_gc =
osg::GraphicsContext::createGraphicsContext(traits.get());
// now create a camera
// It's an orthographic 2D camera (sized to pixel match)
// Load an identity view matrix, and set the only geometry here
to be the quad
osg::ref_ptr<osg::Camera> __camera = new osg::Camera();
__camera->setGraphicsContext(this_gc.get());
__camera->setViewport(new osg::Viewport(0,0, width, height));
__camera->setClearMask(GL_COLOR_BUFFER_BIT);
__camera->setClearDepth(1.0);
__camera->setClearColor(osg::Vec4(1,0,0,0)); // Red border
__camera->setRenderOrder(osg::Camera::POST_RENDER);
__camera->setProjectionMatrix(osg::Matrix::ortho2D(0,width,0,height));
__camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
__camera->setViewMatrix(osg::Matrix::identity());
__camera->addChild(screenQuad.get());
osg::StateSet *ss = __camera->getOrCreateStateSet();
ss->setTextureAttributeAndModes(0, __depthTexture,
osg::StateAttribute::ON);
V.addSlave(__camera.get(), osg::Matrixd(), osg::Matrixd(), false);
}
#endif
#if SHOW_ALPHA
{ // display the Alpha mask
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new
osg::GraphicsContext::Traits;
traits->x = 0;
traits->y = 2*height+ 4*HEIGHT_OFFSET;
traits->width = width;
traits->height = height;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = gc.get();
traits->vsync = true; // Disable VSync (for now)
traits->supportsResize = false;
traits->windowName = "alpha";
osg::ref_ptr<osg::GraphicsContext> this_gc =
osg::GraphicsContext::createGraphicsContext(traits.get());
// now create a camera
// It's an orthographic 2D camera (sized to pixel match)
// Load an identity view matrix, and set the only geometry here
to be the quad
osg::ref_ptr<osg::Camera> __camera = new osg::Camera();
__camera->setGraphicsContext(this_gc.get());
__camera->setViewport(new osg::Viewport(0,0, width, height));
__camera->setClearMask(GL_COLOR_BUFFER_BIT);
__camera->setClearDepth(1.0);
__camera->setClearColor(osg::Vec4(0,0,0,0));
__camera->setRenderOrder(osg::Camera::POST_RENDER);
__camera->setProjectionMatrix(osg::Matrix::ortho2D(0,width,0,height));
__camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
__camera->setViewMatrix(osg::Matrix::identity());
__camera->addChild(screenQuad.get());
osg::StateSet *ss = __camera->getOrCreateStateSet();
ss->setTextureAttributeAndModes(0, __maskTexture,
osg::StateAttribute::ON);
V.addSlave(__camera.get(), osg::Matrixd(), osg::Matrixd(), false);
}
#endif
{ // display the Color mask
// now create a camera
// It's an orthographic 2D camera (sized to pixel match)
// Load an identity view matrix, and set the only geometry here
to be the quad
osg::ref_ptr<osg::Camera> __camera = new osg::Camera();
__camera->setGraphicsContext(gc.get());
__camera->setViewport(new osg::Viewport(0,0, width, height));
__camera->setClearMask(GL_COLOR_BUFFER_BIT);
__camera->setClearDepth(1.0);
__camera->setClearColor(osg::Vec4(0,0,0,0));
__camera->setRenderOrder(osg::Camera::POST_RENDER);
__camera->setProjectionMatrix(osg::Matrix::ortho2D(0,width,0,height));
__camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
__camera->setViewMatrix(osg::Matrix::identity());
__camera->addChild(screenQuad.get());
osg::StateSet *ss = __camera->getOrCreateStateSet();
ss->setTextureAttributeAndModes(0, __colorTexture,
osg::StateAttribute::ON);
V.addSlave(__camera.get(), osg::Matrixd(), osg::Matrixd(), false);
}
V.run();
}
--
Randall Hand
http://www.yeraze.com
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