[PATCH v3 0/2] MR188: vkd3d-shader/tpf: Add support for emitting sample_l instructions

[Ethan Lee (＠flibitijibibo)]

From what I can tell, the recent work on SampleBias/SampleLevel did all of the work for us, we just need to take the same framework and include the case for the `sample_l` instruction.

Tested with some shaders from the native Linux version of Little Racers STREET.

--
  v3: vkd3d-shader/tpf: Add support for emitting sample_l instructions
      tests: Add a test for SampleLevel() function.

https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/188

[PATCH v3 1/2] tests: Add a test for SampleLevel() function.

[Ethan Lee]

From: Ethan Lee

Currently marked TODO, since the SM4 emitter does not support sample_l yet.

Signed-off-by: Ethan Lee 
---
 tests/sampler.shader_test | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tests/sampler.shader_test b/tests/sampler.shader_test
index 2cb70a0b..89883029 100644
--- a/tests/sampler.shader_test
+++ b/tests/sampler.shader_test
@@ -33,6 +33,19 @@ float4 main() : sv_target
 draw quad
 probe all rgba (0.25, 0, 0.25, 0)

+[pixel shader todo]
+SamplerState s;
+Texture2D t;
+
+float4 main() : sv_target
+{
+    return t.SampleLevel(s, float2(0.5, 0.5), 0.0);
+}
+
+[test todo]
+draw quad
+probe all rgba (0.25, 0, 0.25, 0)
+
 [pixel shader]
 SamplerState s;
 Texture2D t;

[PATCH v3 2/2] vkd3d-shader/tpf: Add support for emitting sample_l instructions

[Ethan Lee]

From: Ethan Lee

This gets the SampleLevel() HLSL test to pass.

Signed-off-by: Ethan Lee 
---
 libs/vkd3d-shader/tpf.c   | 12 +++++++-----
 tests/sampler.shader_test |  4 ++--
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/libs/vkd3d-shader/tpf.c b/libs/vkd3d-shader/tpf.c
index 3debe952..5d194709 100644
--- a/libs/vkd3d-shader/tpf.c
+++ b/libs/vkd3d-shader/tpf.c
@@ -3717,6 +3717,10 @@ static void write_sm4_sample(struct hlsl_ctx *ctx, struct vkd3d_bytecode_buffer
             instr.opcode = VKD3D_SM4_OP_SAMPLE;
             break;

+        case HLSL_RESOURCE_SAMPLE_LOD:
+            instr.opcode = VKD3D_SM4_OP_SAMPLE_LOD;
+            break;
+
         case HLSL_RESOURCE_SAMPLE_LOD_BIAS:
             instr.opcode = VKD3D_SM4_OP_SAMPLE_B;
             break;
@@ -3743,7 +3747,8 @@ static void write_sm4_sample(struct hlsl_ctx *ctx, struct vkd3d_bytecode_buffer
     sm4_src_from_deref(ctx, &instr.srcs[2], sampler, sampler->var->data_type, VKD3DSP_WRITEMASK_ALL);
     instr.src_count = 3;

-    if (load->load_type == HLSL_RESOURCE_SAMPLE_LOD_BIAS)
+    if (load->load_type == HLSL_RESOURCE_SAMPLE_LOD
+           || load->load_type == HLSL_RESOURCE_SAMPLE_LOD_BIAS)
     {
         sm4_src_from_node(&instr.srcs[3], load->lod.node, VKD3DSP_WRITEMASK_ALL);
         ++instr.src_count;
@@ -4515,6 +4520,7 @@ static void write_sm4_resource_load(struct hlsl_ctx *ctx,
             break;

case HLSL_RESOURCE_SAMPLE:
+        case HLSL_RESOURCE_SAMPLE_LOD:
         case HLSL_RESOURCE_SAMPLE_LOD_BIAS:
             if (!load->sampler.var)
             {
@@ -4543,10 +4549,6 @@ static void write_sm4_resource_load(struct hlsl_ctx *ctx,
             write_sm4_gather(ctx, buffer, resource_type, &load->node, &load->resource,
                     &load->sampler, coords, HLSL_SWIZZLE(W, W, W, W), texel_offset);
             break;
-
-        case HLSL_RESOURCE_SAMPLE_LOD:
-            hlsl_fixme(ctx, &load->node.loc, "SM4 sample-LOD expression.");
-            break;
     }
 }

diff --git a/tests/sampler.shader_test b/tests/sampler.shader_test
index 89883029..62c71b39 100644
--- a/tests/sampler.shader_test
+++ b/tests/sampler.shader_test
@@ -33,7 +33,7 @@ float4 main() : sv_target
 draw quad
 probe all rgba (0.25, 0, 0.25, 0)

-[pixel shader todo]
+[pixel shader]
 SamplerState s;
 Texture2D t;

@@ -42,7 +42,7 @@ float4 main() : sv_target
     return t.SampleLevel(s, float2(0.5, 0.5), 0.0);
 }

-[test todo]
+[test]
 draw quad
 probe all rgba (0.25, 0, 0.25, 0)

[Ethan Lee (＠flibitijibibo)]

One last update before the weekend: While SampleLevel was supported by hlsl.y, the test did not exist yet, so that's been added as part of this fix.

[Francisco Casas (＠fcasas)]

Francisco Casas (@fcasas) commented about tests/sampler.shader_test:
> draw quad
>  probe all rgba (0.25, 0, 0.25, 0)
>
> +[pixel shader todo]
> +SamplerState s;
> +Texture2D t;
> -
>
> +float4 main() : sv_target
> +{
> - return t.SampleLevel(s, float2(0.5, 0.5), 0.0);
>
> +}
> -
>
> +[test todo]

Currently, there doesn't exist a `[test todo]` Section for the shader_runner. 
This only seems to work (in this incomplete stage) because the shader_runner is handling the section the same as the previous one, `[pixel shader todo]`.

The proper way to write this part is:
```
[test]
todo draw quad
todo probe all rgba (0.25, 0, 0.25, 0)
```

and remove the `todo`s in the next commit.