Hi Antiro,
Hi,
I am converting a project written in pure opengl to use OSG to improve
compatibility and reduce maintenance. The original project used a deferred
rendering pipeline with a pretty big set of custom shaders. I would like to
reuse these shaders with minimum adjustments.
In order to do this I want to use the same uniform names and the same layout
for the VAO. I figured out that I can add callbacks to set the ModelView /
Projection / etc matrices to uniforms with the same names as used in in the
shaders, so that is taken care of.
I do however not know how to specify the vertex attribute layout. My shaders
all start with the following:
#version 330 core //so can't use gl_Normal etc
layout(location = 0) in vec3 position
layout(location = 1) in vec3 normal
layout(location = 2) in vec2 texCoords
layout(location = ....
I'm currently just using osgDB::readNodeFile() to read in the geometry and I'm
assuming I need to do something more sophisticated to control how the vertex
attributes are organized, but have been unable to figure out what.
If anyone could point me in the right direction, that would be most helpful!
The easiest way is to convert the shaders to use the osg_ -prefix and to
turn on the vertex attribute aliasing (basically all OSG will provide
all gl_ inputs)
A list:
//OSG inputs
layout(location = 0) in vec4 osg_Vertex;
layout(location = 1) in vec3 osg_Normal;
layout(location = 2) in vec4 osg_Color;
layout(location = 3)in vec4 osg_MultiTexCoord0;
layout(location = 4)in vec4 osg_MultiTexCoord1;
layout(location = 5)in vec4 osg_MultiTexCoord2;
layout(location = 6)in vec4 osg_MultiTexCoord3;
layout(location = 7)in vec4 osg_MultiTexCoord4;
layout(location = 8)in vec4 osg_MultiTexCoord5;
layout(location = 9)in vec4 osg_MultiTexCoord6;
layout(location = 10)in vec4 osg_MultiTexCoord7;
In order to turn on aliasing:
viewer->getCamera()->getGraphicsContext()->getState()->setUseModelViewAndProjectionUniforms(true);
viewer->getCamera()->getGraphicsContext()->getState()->setUseVertexAttributeAliasing(true);
Note, that the first line will set up the gl_XYZMatrix aliases, so no
need for a custom callback for this (at least for the std-matrices)
So you get these:
uniform mat4 osg_ModelViewProjectionMatrix;
uniform mat4 osg_ModelViewMatrix;
uniform mat4 osg_ViewMatrixInverse;
uniform mat3 osg_NormalMatrix;
uniform mat4 osg_ViewMatrix;
etc.
Cheers
Sebastian
Thank you!
Cheers,
antiro
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=71584#71584
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