Support Geometry Shaders written in GLSL.

[csyonghe]

This include support for geometry shader specific builtin input/outputs, and related intrinsics like EmitVertex.

[ArielG-NV]

Section 8.13. Geometry Shader Functions void EmitStreamVertex(int stream) void EndStreamPrimitive(int stream) void EmitVertex() void EndPrimitive()

[ArielG-NV]

the associated code (was already written, but removed since scope of original task changed)

/// Section 8.13. Geometry Shader Functions

__glsl_version(430) [require(glsl)]
__spirv_version(1.0) [require(spirv)]
[ForceInline]
public void EmitStreamVertex(int stream)
{
    __target_switch
    {
    case glsl: __intrinsic_asm "EmitStreamVertex($0)";
    case spirv:
    {
        spirv_asm
        {
            OpCapability GeometryStreams;
            OpEmitStreamVertex $stream
        };
    }
    }
}
__glsl_version(430) [require(glsl)]
__spirv_version(1.0) [require(spirv)]
[ForceInline]
public void EndStreamPrimitive(int stream)
{
    __target_switch
    {
    case glsl: __intrinsic_asm "EndStreamPrimitive($0)";
    case spirv:
    {
        spirv_asm
        {
            OpCapability GeometryStreams;
            OpEndStreamPrimitive $stream
        };
    }
    }
}
__glsl_version(430) [require(glsl)]
__spirv_version(1.0) [require(spirv)]
[ForceInline]
public void EmitVertex()
{
    __target_switch
    {
    case glsl: __intrinsic_asm "EmitVertex($0)";
    case spirv:
    {
        spirv_asm
        {
            OpCapability Geometry;
            OpEmitVertex
        };
    }
    }
}
__glsl_version(430) [require(glsl)]
__spirv_version(1.0) [require(spirv)]
[ForceInline]
public void EndPrimitive()
{
    __target_switch
    {
    case glsl: __intrinsic_asm "EndPrimitive($0)";
    case spirv:
    {
        spirv_asm
        {
            OpCapability Geometry;
            OpEndPrimitive
        };
    }
    }
}

[csyonghe]

The intrinsics is half of the work, the other half is making sure stores to the builtin variables like gl_Position does indeed take effect. If there is not much work other than include them in the stdlib to get geometry shaders to work, let's do it. If it is more involved and takes time, then let's deprioritize.

[csyonghe]

I don’t see any issues of us committing these changes.

---

From: ArielG-NV @.> Sent: Tuesday, March 19, 2024 4:44:35 PM To: shader-slang/slang @.> Cc: Yong He @.>; Author @.> Subject: Re: [shader-slang/slang] Support Geometry Shaders written in GLSL. (Issue #3363)

the associated code (was already written, but removed since scope of original task changed)

/// Section 8.13. Geometry Shader Functions

glsl_version(430) [require(glsl)] __spirv_version(1.0) [require(spirv)] [ForceInline] public void EmitStreamVertex(int stream) { target_switch { case glsl: intrinsic_asm "EmitStreamVertex($0)"; case spirv: { spirv_asm { OpCapability GeometryStreams; OpEmitStreamVertex $stream }; } } } glsl_version(430) [require(glsl)] spirv_version(1.0) [require(spirv)] [ForceInline] public void EndStreamPrimitive(int stream) { __target_switch { case glsl: intrinsic_asm "EndStreamPrimitive($0)"; case spirv: { spirv_asm { OpCapability GeometryStreams; OpEndStreamPrimitive $stream }; } } } glsl_version(430) [require(glsl)] __spirv_version(1.0) [require(spirv)] [ForceInline] public void EmitVertex() { target_switch { case glsl: intrinsic_asm "EmitVertex($0)"; case spirv: { spirv_asm { OpCapability Geometry; OpEmitVertex }; } } } glsl_version(430) [require(glsl)] spirv_version(1.0) [require(spirv)] [ForceInline] public void EndPrimitive() { __target_switch { case glsl: intrinsic_asm "EndPrimitive($0)"; case spirv: { spirv_asm { OpCapability Geometry; OpEndPrimitive }; } } }

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