Fix D3D12 DSV creation for array/cube/cube-array depth textures

DSV creation was missing a TEXTURE2DARRAY branch for array, cube, and
cube-array depth textures. It fell through to TEXTURE2D, so
FirstArraySlice was never set and all layers' DSVs targeted layer 0.
This caused incorrect rendering when using depth textures with multiple
layers, such as cubemap shadow maps.

Author: jessechounard

src/gpu/d3d12/SDL_gpu_d3d12.c

@@ -3646,7 +3646,12 @@ static D3D12Texture *D3D12_INTERNAL_CreateTexture(
                 dsvDesc.Format = SDLToD3D12_DepthFormat[createinfo->format];
                 dsvDesc.Flags = (D3D12_DSV_FLAGS)0;
 
-                if (isMultisample) {
+                if (createinfo->type == SDL_GPU_TEXTURETYPE_2D_ARRAY || createinfo->type == SDL_GPU_TEXTURETYPE_CUBE || createinfo->type == SDL_GPU_TEXTURETYPE_CUBE_ARRAY) {
+                    dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2DARRAY;
+                    dsvDesc.Texture2DArray.MipSlice = levelIndex;
+                    dsvDesc.Texture2DArray.FirstArraySlice = layerIndex;
+                    dsvDesc.Texture2DArray.ArraySize = 1;
+                } else if (isMultisample) {
                     dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2DMS;
                 } else {
                     dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2D;