Hi,
I am now working on a project of augmented reality. To make it work, I have to
make osg drawing on a transparent background . (The view below osg is camera
capture.)
I use setClearColor as follows, this code really works on the older version of
osg 3.1.4 with opengles 1.1. But when I change to osg 3.2.1 with opengles 2.0,
it does not make a transparent background but a black one.
Code:
- (void)setupCamera
{
//set the clear color of the camera to be semitransparent
_viewer->getCamera()->setClearColor(osg::Vec4(0.0f, 0.0f, 0.0f, 0.0f));
//set the clear mask for the camera
_viewer->getCamera()->setClearMask(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
_viewer->getCamera()->setRenderOrder(osg::Camera::POST_RENDER);
_viewer->getCamera()->setComputeNearFarMode(osgUtil::CullVisitor::DO_NOT_COMPUTE_NEAR_FAR);
}
Also my shaders is as follows :
[code] static const char gVertexShader1[] =
"varying vec2 v_texCoord; \n"
"void main() { \n"
" gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; \n"
" v_texCoord = gl_MultiTexCoord0.xy;
\n"
"} \n";
static const char gFragmentShader1[] =
"varying mediump vec2 v_texCoord;
\n"
"uniform sampler2D sam;
\n"
"void main() {
\n"
"gl_FragColor = texture2D(sam, v_texCoord);
\n"
"} \n";
osg::Shader* vShader = new osg::Shader( osg::Shader::VERTEX, gVertexShader1
);
osg::Shader* fShader = new osg::Shader( osg::Shader::FRAGMENT,
gFragmentShader1 );
osg::Program* program = new osg::Program;
program->addShader( vShader );
program->addShader( fShader );
stateSet->setAttribute( program );[/color]
And the other code of drawing osg file:
[code] // Init the Windata Variable that holds the handle for the Window to
display OSG in.
osg::ref_ptr<osgViewer::GraphicsWindowIOS::WindowData> windowData = new
osgViewer::GraphicsWindowIOS::WindowData(self->osgView,
osgViewer::GraphicsWindowIOS::WindowData::IGNORE_ORIENTATION, windowFactor);
// Init the Windata Variable that holds the handle for the Window to
display OSG in.
osg::ref_ptr<osg::Referenced> windata = windowData;
// Setup the traits parameters
traits->x = 0;
traits->y = 0;
traits->width = m_glview.frame.size.width*windowFactor;
traits->height = m_glview.frame.size.height*windowFactor;
traits->depth = 16; //keep memory down, default is currently 24
traits->alpha = 1;
//traits->stencil = 8;
traits->windowDecoration = false;
traits->doubleBuffer = true;
traits->sharedContext = 0;
traits->setInheritedWindowPixelFormat = true;
//traits->windowName = "osgViewer";
traits->inheritedWindowData = windata;
// Create the Graphics Context
osg::ref_ptr<osg::GraphicsContext> graphicsContext =
osg::GraphicsContext::createGraphicsContext(traits.get());
//create the viewer
_viewer = new osgViewer::Viewer();
//if the context was created then attach to our viewer
if(graphicsContext)
{
_viewer->getCamera()->setGraphicsContext(graphicsContext);
_viewer->getCamera()->setViewport(new osg::Viewport(0, 0,
traits->width, traits->height));
}
[/code]
Does anybody know how to solve this problem ?
Thank you!
Cheers,
Liu
------------------
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http://forum.openscenegraph.org/viewtopic.php?p=61565#61565
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