render: Don't try to rebuild D3D11, D3D12, Metal shaders without spirv-cross

Signed-off-by: Simon McVittie <smcv@debian.org>

src/render/gpu/shaders/build-shaders.sh

@@ -6,12 +6,15 @@ set -e
 
 which fxc &>/dev/null && HAVE_FXC=1 || HAVE_FXC=0
 which dxc &>/dev/null && HAVE_DXC=1 || HAVE_DXC=0
+which spirv-cross &>/dev/null && HAVE_SPIRV_CROSS=1 || HAVE_SPIRV_CROSS=0
 
 [ "$HAVE_FXC" != 0 ] || echo "fxc not in PATH; D3D11 shaders will not be rebuilt"
 [ "$HAVE_DXC" != 0 ] || echo "dxc not in PATH; D3D12 shaders will not be rebuilt"
+[ "$HAVE_SPIRV_CROSS" != 0 ] || echo "spirv-cross not in PATH; D3D11, D3D12, Metal shaders will not be rebuilt"
 
 USE_FXC=${USE_FXC:-$HAVE_FXC}
 USE_DXC=${USE_DXC:-$HAVE_DXC}
+USE_SPIRV_CROSS=${USE_SPIRV_CROSS:-$HAVE_SPIRV_CROSS}
 
 spirv_bundle="spir-v.h"
 dxbc50_bundle="dxbc50.h"
@@ -19,9 +22,9 @@ dxil60_bundle="dxil60.h"
 metal_bundle="metal.h"
 
 rm -f "$spirv_bundle"
-rm -f "$metal_bundle"
-[ "$USE_FXC" != 0 ] && rm -f "$dxbc50_bundle"
-[ "$USE_DXC" != 0 ] && rm -f "$dxil60_bundle"
+[ "$USE_SPIRV_CROSS" != 0 ] && rm -f "$metal_bundle"
+[ "$USE_SPIRV_CROSS" != 0 ] && [ "$USE_FXC" != 0 ] && rm -f "$dxbc50_bundle"
+[ "$USE_SPIRV_CROSS" != 0 ] && [ "$USE_DXC" != 0 ] && rm -f "$dxil60_bundle"
 
 make-header() {
     xxd -i "$1" | sed -e 's/^unsigned /const unsigned /g' > "$1.h"
@@ -60,6 +63,10 @@ for i in *.vert *.frag; do
     make-header "$spv"
     echo "#include \"$spv.h\"" >> "$spirv_bundle"
 
+    if [ "$USE_SPIRV_CROSS" = "0" ]; then
+        continue
+    fi
+
     spirv-cross "$spv" --hlsl --shader-model 50 --hlsl-enable-compat --output "$hlsl50"
     spirv-cross "$spv" --hlsl --shader-model 60 --hlsl-enable-compat --output "$hlsl60"