Mixing
Instanced-based VR rendering in OpenGL
I'm trying to use instancing to do VR rendering in OpenGL with 1 draw call, 2 instances (one for left eye, one for right eye). The vertex shader then translates the vertices left for instanceID 0 and right for instanceID 1. The only thing I need more is per-instance viewport for automatic hardware culling/clipping. This is doable in directX but is it in OpenGL?
opengl virtual-reality geometry-instancing
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
|
show 1 more comment
I'm trying to use instancing to do VR rendering in OpenGL with 1 draw call, 2 instances (one for left eye, one for right eye). The vertex shader then translates the vertices left for instanceID 0 and right for instanceID 1. The only thing I need more is per-instance viewport for automatic hardware culling/clipping. This is doable in directX but is it in OpenGL?
opengl virtual-reality geometry-instancing
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
1
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the sectionLayer and Viewport Selectionof any OpenGL-4 specification.
– datenwolf
Apr 8 '15 at 12:44
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25
|
show 1 more comment
I'm trying to use instancing to do VR rendering in OpenGL with 1 draw call, 2 instances (one for left eye, one for right eye). The vertex shader then translates the vertices left for instanceID 0 and right for instanceID 1. The only thing I need more is per-instance viewport for automatic hardware culling/clipping. This is doable in directX but is it in OpenGL?
opengl virtual-reality geometry-instancing
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
I'm trying to use instancing to do VR rendering in OpenGL with 1 draw call, 2 instances (one for left eye, one for right eye). The vertex shader then translates the vertices left for instanceID 0 and right for instanceID 1. The only thing I need more is per-instance viewport for automatic hardware culling/clipping. This is doable in directX but is it in OpenGL?
opengl virtual-reality geometry-instancing
opengl virtual-reality geometry-instancing
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
asked Apr 8 '15 at 6:33
TuxerTuxer
4531519
4531519
I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
1
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the sectionLayer and Viewport Selectionof any OpenGL-4 specification.
– datenwolf
Apr 8 '15 at 12:44
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25
|
show 1 more comment
I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
1
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the sectionLayer and Viewport Selectionof any OpenGL-4 specification.
– datenwolf
Apr 8 '15 at 12:44
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25
I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
1
1
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the section
Layer and Viewport Selection of any OpenGL-4 specification.– datenwolf
Apr 8 '15 at 12:44
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the section
Layer and Viewport Selection of any OpenGL-4 specification.– datenwolf
Apr 8 '15 at 12:44
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25
|
show 1 more comment
1 Answer
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Recently I was actually implementing instanced stereo rendering for VR and had the same problem. I had the choice of using geometry shader for instanced viewports but I didn't want the overhead it'd introduce. So, in the end I ended up shifting the perspective for each view and using a clip plane.
So that's probably what you're looking for, a clip plane. It's really simple to implement in a vertex shader too, you just pass the 'x' coord into gl_ClipDistance.
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_ClipDistance.xhtml
Good luck
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
add a comment |
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Recently I was actually implementing instanced stereo rendering for VR and had the same problem. I had the choice of using geometry shader for instanced viewports but I didn't want the overhead it'd introduce. So, in the end I ended up shifting the perspective for each view and using a clip plane.
So that's probably what you're looking for, a clip plane. It's really simple to implement in a vertex shader too, you just pass the 'x' coord into gl_ClipDistance.
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_ClipDistance.xhtml
Good luck
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
add a comment |
Recently I was actually implementing instanced stereo rendering for VR and had the same problem. I had the choice of using geometry shader for instanced viewports but I didn't want the overhead it'd introduce. So, in the end I ended up shifting the perspective for each view and using a clip plane.
So that's probably what you're looking for, a clip plane. It's really simple to implement in a vertex shader too, you just pass the 'x' coord into gl_ClipDistance.
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_ClipDistance.xhtml
Good luck
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
add a comment |
Recently I was actually implementing instanced stereo rendering for VR and had the same problem. I had the choice of using geometry shader for instanced viewports but I didn't want the overhead it'd introduce. So, in the end I ended up shifting the perspective for each view and using a clip plane.
So that's probably what you're looking for, a clip plane. It's really simple to implement in a vertex shader too, you just pass the 'x' coord into gl_ClipDistance.
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_ClipDistance.xhtml
Good luck
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
Recently I was actually implementing instanced stereo rendering for VR and had the same problem. I had the choice of using geometry shader for instanced viewports but I didn't want the overhead it'd introduce. So, in the end I ended up shifting the perspective for each view and using a clip plane.
So that's probably what you're looking for, a clip plane. It's really simple to implement in a vertex shader too, you just pass the 'x' coord into gl_ClipDistance.
https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/gl_ClipDistance.xhtml
Good luck
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
edited Nov 20 '18 at 9:31
Moritz
57.6k19131184
57.6k19131184
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
answered Nov 20 '18 at 9:24
ImQ009ImQ009
120312
120312
add a comment |
add a comment |
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I don't think you can have a per instance viewport (although there are other ways of doing per instance clipping). Out of curiosity, what's your DirectX solution?
– Jerem
Apr 8 '15 at 6:48
1
@Jerem: As of OpenGL-4 you can. The geometry shader stage allows to specify the FBO layer or/and viewport toward which a primitive is sent for rasterization. See the section
Layer and Viewport Selectionof any OpenGL-4 specification.– datenwolf
Apr 8 '15 at 12:44
I saw that regarding the geometry stage, but it's probably gonna negatively impact my performance...
– Tuxer
Apr 8 '15 at 15:25
Well, the actual performance impact that will have in the OP's scenario is quite unclear. Currently, when doing this, there is no way around the geometry shader for stock GL. There is the GL_AMD_vertex_shader_viewport_index GL extension which would suit the OP's needs ideally. But it is a vendor-specific extension, currently. Maybe it will be added to core GL later on, but I wouldn't bet on it.
– derhass
Apr 8 '15 at 18:14
That would be perfect actually, if I wasn't running on an NVIDIA chip :-'
– Tuxer
Apr 10 '15 at 21:25