SDL: GPU D3D12: Fix depth format sample count support check

SDL Commits
1 
From b54c7178b9b7bffc7ba81709a2935ff3f62c2d14 Mon Sep 17 00:00:00 2001
From: Evan Hemsley <[EMAIL REDACTED]>
Date: Tue, 1 Sep 2026 15:47:10 -0700
Subject: [PATCH] GPU D3D12: Fix depth format sample count support check

---
 src/gpu/d3d12/SDL_gpu_d3d12.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/gpu/d3d12/SDL_gpu_d3d12.c b/src/gpu/d3d12/SDL_gpu_d3d12.c
index b69307a8066ee..2a7af23367d86 100644
--- a/src/gpu/d3d12/SDL_gpu_d3d12.c
+++ b/src/gpu/d3d12/SDL_gpu_d3d12.c
@@ -8335,6 +8335,13 @@ static bool D3D12_SupportsSampleCount(
     featureData.Flags = (D3D12_MULTISAMPLE_QUALITY_LEVEL_FLAGS)0;
 #endif
     featureData.Format = SDLToD3D12_TextureFormat[format];
+
+    if (IsDepthFormat(format)) {
+        featureData.Format = SDLToD3D12_DepthFormat[format];
+    } else {
+        featureData.Format = SDLToD3D12_TextureFormat[format];
+    }
+
     featureData.SampleCount = SDLToD3D12_SampleCount[sampleCount];
     res = ID3D12Device_CheckFeatureSupport(
         renderer->device,