[Mesa-dev] [PATCH 00/18] Multi-stream support for geometry shaders

[Ilia Mirkin]

On Wed, Jun 11, 2014 at 12:31 PM, Jordan Justen <jljusten at gmail.com> wrote:
> On Wed, Jun 11, 2014 at 2:49 AM, Iago Toral <itoral at igalia.com> wrote:
>> Hi Chris,
>>
>> thanks for the quick review!
>>
>> On Wed, 2014-06-11 at 21:45 +1200, Chris Forbes wrote:
>>> I sent comments on patches 1, 3, 5, 9, 11, 16, 18
>>
>> We will look into these.
>>
>>> Patches 2, 4, 6-8, 10, 12-15, 17 are:
>>>
>>> Reviewed-by: Chris Forbes <chrisf at ijw.co.nz>
>>>
>>> You should also include a patch to docs/GL3.txt marking off this
>>> subfeature for i965 :)
>>>
>>>
>>> Do you have a bunch of piglits which exercise all the tricky corners
>>> of this? I see a few tests
>>> which require the existence of the stream layout qualifier, but not
>>> covering all the behavior.
>>
>> No, so far we have been testing this with a standalone program. We will
>> check what already exists in piglit and add missing test cases.
>
> This is the only piglit test that I know about:
> http://patchwork.freedesktop.org/patch/19224/
>
> Note that it passed on nvidia, but failed on catalyst.

I just ran that test against this code (+ a few changes to add support
in gallium) and I got:

$ MESA_EXTENSION_OVERRIDE=GL_ARB_gpu_shader5
bin/arb_gpu_shader5-xfb-streams -fbo -auto
Failed to compile geometry shader: 0:3(1): error: invalid input layout
qualifiers used

source:
#version 150
#extension GL_ARB_gpu_shader5 : enable
layout(points, invocations = 32) in;
layout(points, max_vertices = 4) out;
out float stream0_0_out;
layout(stream = 1) out vec2 stream1_0_out;
layout(stream = 2) out float stream2_0_out;
layout(stream = 3) out vec3 stream3_0_out;
layout(stream = 1) out vec3 stream1_1_out;
layout(stream = 2) out vec4 stream2_1_out;
void main() {
  gl_Position = gl_in[0].gl_Position;
  stream0_0_out = 1.0 + gl_InvocationID;
  EmitVertex();
  EndPrimitive();
  stream3_0_out = vec3(12.0 + gl_InvocationID, 13.0 + gl_InvocationID,
                       14.0 + gl_InvocationID);
  EmitStreamVertex(3);
  EndStreamPrimitive(3);
  stream2_0_out = 7.0 + gl_InvocationID;
  stream2_1_out = vec4(8.0 + gl_InvocationID, 9.0 + gl_InvocationID,
                       10.0 + gl_InvocationID, 11.0 + gl_InvocationID);
  EmitStreamVertex(2);
  EndStreamPrimitive(2);
  stream1_0_out = vec2(2.0 + gl_InvocationID, 3.0 + gl_InvocationID);
  stream1_1_out = vec3(4.0 + gl_InvocationID, 5.0 + gl_InvocationID,
                       6.0 + gl_InvocationID);
  EmitStreamVertex(1);
  EndStreamPrimitive(1);
}PIGLIT: {'result': 'fail' }

I guess it doesn't like

"layout(points, invocations=32) in"? Not sure. I could also have
messed something up... doing a bisect over your patches blames

"glsl: Add parsing support for multi-stream output in geometry shaders."

Before that, it goes until the first stream=1 layout and fails there
(which is expected).

  -ilia