SDL: gpu: Metal depth write should behave like Vulkan/D3D12

SDL Commits
1 
From 6cdde10edb9770555b104f6058d68ade90016085 Mon Sep 17 00:00:00 2001
From: Ethan Lee <[EMAIL REDACTED]>
Date: Thu, 9 Jan 2025 15:18:54 -0500
Subject: [PATCH] gpu: Metal depth write should behave like Vulkan/D3D12

---
 src/gpu/metal/SDL_gpu_metal.m | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/gpu/metal/SDL_gpu_metal.m b/src/gpu/metal/SDL_gpu_metal.m
index eaa4d848ce83b..415b38c5bde2c 100644
--- a/src/gpu/metal/SDL_gpu_metal.m
+++ b/src/gpu/metal/SDL_gpu_metal.m
@@ -1135,7 +1135,8 @@ static void METAL_ReleaseGraphicsPipeline(
 
             depthStencilDescriptor = [MTLDepthStencilDescriptor new];
             depthStencilDescriptor.depthCompareFunction = createinfo->depth_stencil_state.enable_depth_test ? SDLToMetal_CompareOp[createinfo->depth_stencil_state.compare_op] : MTLCompareFunctionAlways;
-            depthStencilDescriptor.depthWriteEnabled = createinfo->depth_stencil_state.enable_depth_write;
+            // Disable write when test is disabled, to match other APIs' behavior
+            depthStencilDescriptor.depthWriteEnabled = createinfo->depth_stencil_state.enable_depth_write && createinfo->depth_stencil_state.enable_depth_test;
             depthStencilDescriptor.frontFaceStencil = frontStencilDescriptor;
             depthStencilDescriptor.backFaceStencil = backStencilDescriptor;