Add GLSL support for SampleCmpBias and SampleCmpGrad #9085

Copilot · 2025-11-20T19:38:46Z

Add GLSL target case to SampleCmpBias in hlsl.meta.slang (now using wrappers)
Add GLSL target case to SampleCmpGrad in hlsl.meta.slang (using wrappers)
Update require statements to allow calling from glsl.meta.slang (texture_shadowgrad)
Replace TODO comments in glsl.meta.slang texture() functions with SampleCmpBias calls
Replace TODO comments in glsl.meta.slang textureOffset() functions with SampleCmpBias calls
Update capability requirements in glsl.meta.slang for functions using bias
Add GLSL checks to existing sample-cmp.slang test instead of creating new test file
Build and test the changes - all tests pass
Address review feedback: use GLSL wrappers for both SampleCmpBias and SampleCmpGrad

Original prompt

This section details on the original issue you should resolve

<issue_title>add GLSL support of SampleCmpBias and SampleCmpGrad</issue_title>
<issue_description>Also refactor glsl.meta.slang texture*() functions to use them and fix TODOs like:

// TODO: Need to apply bias 
return sampler.SampleCmp(location, compareValue); 
```</issue_description>

<agent_instructions>implement target switch case of glsl for the recently added SampleCmpBias and SampleCmpGrad overloads in hlsl.meta.slang.
then modify the relevant texture*() overloads in glsl.meta.slang to use the Sample*() overloads in hlsl.meta.slang, and address the `TODO: Need to apply bias` using appropriate SampleCmpBias overloads.
might need to fixup the require statements in hlsl.meta.slang to allow calling from glsl.meta.slang</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
<comment_new><author>@jhelferty-nv</author><body>
@davli-nv I've tentatively assigned this to you since it sounded on the other issue like you were thinking of eventually doing it, just low priority? Unassign if I'm wrong.</body></comment_new>
</comments>

Fixes add GLSL support of SampleCmpBias and SampleCmpGrad #9038

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…sl.meta.slang Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

davli-nv · 2025-11-20T20:22:50Z

source/slang/glsl.meta.slang


 [ForceInline]
-[require(glsl_hlsl_spirv, texture_shadowlod)]
+[require(glsl_hlsl_spirv, texture_shadowgrad)]


the require for existing untouched texture* functions in glsl.meta.slang should not change

Reverted the require change for functions without bias parameters that don't transitively call SampleCmpBias. Note that textureProjOffset(sampler2DShadow, vec4, offset) still needs texture_shadowgrad since it calls textureOffset with default bias=0.0. (26fe990)

davli-nv · 2025-11-20T20:26:59Z

source/slang/hlsl.meta.slang

        __target_switch
        {
+        case glsl:
+            __intrinsic_asm "textureGrad";


GLSL textureGrad etc have different parameter order and semantics than HLSL intrinsics, might need to use wrappers here similar to __glsl_texture_1d_shadow etc, and add wrappers as needed

Added GLSL wrapper functions __glsl_texture_grad_shadow and __glsl_texture_grad_offset_shadow similar to existing __glsl_texture_1d_shadow pattern. Updated SampleCmpGrad methods to use these wrappers that handle the GLSL parameter format. (26fe990)

davli-nv · 2025-11-20T20:27:48Z

source/slang/glsl.meta.slang

    case spirv:
        return spirv_asm
        {
            result:$$float = OpImageSampleDrefImplicitLod $sampler $location $compareValue Bias|ConstOffset $bias $offset;


the glsl and spirv cases can call appropriate sampler.SampleCmp* overloads

Simplified texture functions to call sampler.SampleCmpBias directly for all targets instead of using __target_switch with separate glsl/spirv cases. This applies to texture(), textureOffset(), and their variants with bias parameters. (26fe990)

davli-nv · 2025-11-20T20:28:57Z

source/slang/glsl.meta.slang


 [ForceInline]
-[require(glsl_hlsl_spirv, texture_shadowlod)]
+[require(glsl_hlsl_spirv, texture_shadowgrad)]


this require change is probably needed to call sampler.SampleCmpBias

davli-nv · 2025-11-20T21:26:57Z

@copilot address my review comments

…s, fix capability requirements Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

davli-nv · 2025-11-20T22:44:27Z

tests/glsl-intrinsic/texture-shadow-bias-grad.slang

@@ -0,0 +1,81 @@
+// Test GLSL output for SampleCmpBias and SampleCmpGrad functions


this new test file is not needed, there is existing test of glsl texture* function overloads.
need to add glsl checks into existing tests for SampleCmpGrad and SampleCmpBias overloads.

Removed the new test file and added CHECK_GLSL checks to the existing tests/hlsl-intrinsic/texture/sample-cmp.slang test for SampleCmpBias and SampleCmpGrad calls. (0b68ed9)

davli-nv · 2025-11-20T22:46:37Z

source/slang/hlsl.meta.slang

        __target_switch
        {
+        case glsl:
+            __intrinsic_asm "texture";


are the arguments of this call to glsl intrinsic texture() correct?

Fixed - the GLSL case now properly calls wrapper function __glsl_texture_bias_shadow(this, __makeVector(location, compareValue), bias) which formats parameters correctly for GLSL's texture() intrinsic. Added wrappers __glsl_texture_bias_shadow and __glsl_texture_bias_offset_shadow similar to the existing __glsl_texture_grad_shadow pattern. (0b68ed9)

davli-nv · 2025-11-20T22:47:09Z

@copilot address my latest review

…move redundant test file Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Initial plan

8c98c2d

Copilot AI assigned Copilot and davli-nv Nov 20, 2025

Copilot started work on behalf of davli-nv November 20, 2025 19:39 View session

Copilot AI and others added 2 commits November 20, 2025 20:10

Add GLSL support for SampleCmpBias and SampleCmpGrad, fix TODOs in gl…

525cd37

…sl.meta.slang Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Add test for GLSL SampleCmpBias and SampleCmpGrad output

d2e9727

Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add GLSL support for SampleCmpBias and SampleCmpGrad~~ Add GLSL support for SampleCmpBias and SampleCmpGrad Nov 20, 2025

Copilot AI requested a review from davli-nv November 20, 2025 20:21

Copilot finished work on behalf of davli-nv November 20, 2025 20:21

davli-nv requested changes Nov 20, 2025

View reviewed changes

Copilot started work on behalf of davli-nv November 20, 2025 21:27 View session

Address review comments: use GLSL wrappers, simplify texture function…

26fe990

…s, fix capability requirements Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Copilot AI requested a review from davli-nv November 20, 2025 21:54

Copilot finished work on behalf of davli-nv November 20, 2025 21:54

davli-nv requested changes Nov 20, 2025

View reviewed changes

Copilot started work on behalf of davli-nv November 20, 2025 22:49 View session

Fix SampleCmpBias GLSL wrappers, add GLSL checks to existing test, re…

0b68ed9

…move redundant test file Co-authored-by: davli-nv <219758217+davli-nv@users.noreply.github.com>

Copilot AI requested a review from davli-nv November 20, 2025 23:12

Copilot finished work on behalf of davli-nv November 20, 2025 23:12

davli-nv added the pr: breaking change PRs with breaking changes label Nov 21, 2025

		@@ -0,0 +1,81 @@
		// Test GLSL output for SampleCmpBias and SampleCmpGrad functions

Add GLSL support for SampleCmpBias and SampleCmpGrad #9085

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