So I've done some testing. I've decided to go the shader route as it will give
the most flexibility. I've modified osgdistortion from the latest svn. At the
end is a short patch to show the changes.
The main problem I'm getting is that the FBO texture doesn't appear to be
passing to the shader properly. All I'm getting is a black screen. If I swap
the shader to color based on texture coordinates, the output is correct. I'm
sure that I'm probably missing something simple in the setup/texture binding,
and any help is appreciated.
Mark
34,36d33
< #include <osg/Program>
< #include <osg/Shader>
< #include <osg/Uniform>
58,80d54
< ///////////////////////////////////////////////////////////////////////////
< // in-line GLSL source code for the "microshader" example
<
< static const char *shaderVertSource = {
< "// passthru - Simple pass through vertex shader\n"
< "void main(void)\n"
< "{\n"
< " gl_TexCoord[0].xy = gl_MultiTexCoord0.xy;\n"
< " gl_Position = ftransform();\n"
< "}\n"
< };
<
< static const char *shaderFragSource = {
< "uniform sampler2DRect textureIn;\n"
< "void main(void)\n"
< "{\n"
< // " gl_FragColor = vec4( gl_TexCoord[0].s, gl_TexCoord[0].t, 0.0, 1.0
);\n"
< " gl_FragColor = texture2DRect( textureIn, gl_TexCoord[0].st );\n"
< "}\n"
< };
<
< ///////////////////////////////////////////////////////////////////////////
<
94,98d67
< osg::Program* program = new osg::Program;
< program->setName( "texture_shader" );
< program->addShader( new osg::Shader( osg::Shader::VERTEX,
shaderVertSource ) );
< program->addShader( new osg::Shader( osg::Shader::FRAGMENT,
shaderFragSource ) );
<
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< osg::Vec3 cursor = bottom;
< osg::Vec2 texcoord = bottom_texcoord;
198,201c165,166
< stateset->setTextureAttributeAndModes( 0, texture,
osg::StateAttribute::ON );
< stateset->addUniform( new osg::Uniform( "textureIn", 0 ) );
< stateset->setAttributeAndModes( program, osg::StateAttribute::ON );
< stateset->setMode(GL_LIGHTING,osg::StateAttribute::ON);
---
> stateset->setTextureAttributeAndModes(0,
> texture,osg::StateAttribute::ON);
> stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
391d355
< osg::Vec3 cursor = bottom;
393,394d356
<
<
705c667
< if (!loadedModel) loadedModel = osgDB::readNodeFile("cow.osg");
---
> if (!loadedModel) loadedModel = osgDB::readNodeFile("cow.osgt");
786d747
< viewer.setUpViewOnSingleScreen( 0 );
Mark A. Bolstad
Scientific Computing
Janelia Farm Research Campus
Howard Hughes Medical Institute
19700 Helix Drive, Ashburn, VA 20147
email: [email protected]
office: +1.571.209.4623
web: http://www.hhmi.org/janelia/
On Jul 14, 2011, at 10:45 AM, J.P. Delport wrote:
> Hi,
>
> On 14/07/2011 16:37, Jason Daly wrote:
>> On 07/14/2011 10:08 AM, Bolstad, Mark wrote:
>>> I like the idea of combining the passes into one, but if I had a blue
>>> object and had to mask it into the red channel, wouldn't it just be
>>> black?
>>
>> Yes, it would be black on the red and green passes, but it would show up
>> on the blue pass. When you combined the three passes of the image to an
>> RGB texture, you'd have your blue object. The flow would look something
>> like this:
>>
>> - set the camera to draw to an RGB texture
>> - set camera's color mask to red only
>> - draw the first object
>> - set camera's color mask to green only
>> - draw the second object
>> - set camera's color mask to blue only
>> - draw the third object
>> - fetch the texture from the camera and use it however you need it
>>
>> as J-S said, you save the combine pass and you don't even need any
>> special shader magic.
>>
>>
>>> I had talked to a professor who had suggested a one-line fragment
>>> shader to do RGB-> Luminance and use Color Masking to write into the
>>> appropriate channel. Would rendering straight into a Luminance texture
>>> with Color Masking work?
>>
>> Maybe I'm not understanding you correctly, but I don't think this would
>> work. You'd end up with a luminance image (effectively, a grayscale
>> image) at the end and not a color image.
>
> I think prof meant he must stick the calculated luminance value into all
> three channels.
>
> jp
>
>>
>>
>>> In reality, this is actually more complicated in that it's not three
>>> objects, but three separate frames of animation. So the main loop is:
>>>
>>> while(1)
>>> {
>>> advance sim
>>> frame(); // Render to red
>>> advance sim
>>> frame(); // Render to green
>>> advance sim
>>> frame(); // Render to blue
>>> Render RTT texture to display.
>>> }
>>
>> Maybe if you explained what you're trying to do at a higher level, we'd
>> be able to better help. What is the problem you're trying to solve?
>>
>> --"J"
>>
>> _______________________________________________
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>> [email protected]
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
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