I have been played with Geometry Shader for a while, and I know I can emit vertices from Geometry Shader. However, I’m not quite sure the typical applications of GS.
Can someone give me some examples where Geometry Shader gives you lots of benefits?
- Billboard expansion ( rain, fireworks, fire, explosions, blah blah )
- Basic terrain LOD + snow
- Patches/subdivision surfaces
- Procedural vegetation creation
- Laser beams
- Spaceship motor marks
- Shadow volume extrussion
- Fur and hair
- All that your imagination can create
However the current GS-capable hardware has three limitations:
- The GS speed is not exceptional
- The current HW can only emit maximum 1024 primitives per input.
- I’m not sure if all the HW supports texture fetching inside the GS. See the http://opengl.org/registry/specs/EXT/geometry_shader4.txt
Geometry shaders have the ability to do a lookup into a texture map, if
supported by the GL implementation. The maximum number of texture image
units available to a geometry shader is
MAX_GEOMETRY_TEXTURE_IMAGE_UNITS_EXT; a maximum number of zero indicates
that the GL implementation does not support texture accesses in geometry
so if returns zero then you cannot fetch.
hope it helps.
Thanks a lot. It really helps
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