Hi, I use a TextureRectangle to store instances transformations matrix :
- TextureRectangle because it's easier to read a specific coordinate - texure format is set on RGBA_32F to get full 32 bit floating point precision - RGBA => there are 4 values (R, G, B, A) per pixel So, a full transform matrix is 4x4 = 16 values => I use 4 pixels to store a full matrix this way : - Texture size is 4 x InstanceCount - on each row, there are 4 pixels => 16 values So, in the shader, to retrieve the full matrix, I can do this : (code from memory, no garanty this is exact) mat4 matrix; matrix[0] = Texture2DRectangle(myTexture, 0, gl_InstanceID); => read 4 values matrix[1] = Texture2DRectangle(myTexture, 1, gl_InstanceID); => read 4 values matrix[2] = Texture2DRectangle(myTexture, 2, gl_InstanceID); => read 4 values matrix[3] = Texture2DRectangle(myTexture, 3, gl_InstanceID); => read 4 values and I transform gl_Vertex with this matrix. It's a little heavy (4 texel fetch for each vertex) but it allow to send full matrix (position, attitude, scale...). If you need only the position, you can store it as a vec4 in a RGBA_32F TextureRectangle of 1 pixel width. Cheers, Aurelien ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=51309#51309 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
