ci: the offscreen example's shaders are looked for in the outDir resolution.json records

.github/tools/out_dir.sh prints the root package's outDir of the newest
build; the Linux, macOS and Windows graphics steps read the spirv headers
there instead of naming target/.build-mcpp/out.

Author: Sunrisepeak

.github/tools/out_dir.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+# Prints where `mcpp::out_dir()` pointed for the root package in the newest
+# build of the package in the current directory: its `outDir` in
+# resolution.json. Each configuration has its own output directory, so a check
+# reads it instead of naming target/.build-mcpp/out.
+r=$(ls -t target/*/*/resolution.json 2>/dev/null | head -1)
+[ -n "$r" ] || { echo "out_dir.sh: no resolution.json under target/" >&2; exit 1; }
+py=$(command -v python3 || command -v python)
+d=$("$py" -c 'import json, sys
+for p in json.load(open(sys.argv[1])).get("graph", {}).get("packages", []):
+    if p.get("root"):
+        print(p.get("outDir", ""))
+        break' "$r")
+[ -n "$d" ] || { echo "out_dir.sh: $r records no outDir for the root package" >&2; exit 1; }
+echo "$d"

.github/workflows/ci-linux.yml

@@ -349,8 +349,8 @@ jobs:
           # THE SHADERS ARE THE FIRST ASSERTION, and both of them: a rule that
           # compiled only the first source would leave the second header absent
           # and everything after this would still pass.
+          d="$(sh "$GITHUB_WORKSPACE/.github/tools/out_dir.sh")/spirv"
           for f in triangle_vert triangle_frag; do
-            d="target/.build-mcpp/out/spirv"
             test -f "$d/$f.h" || { echo "missing $d/$f.h"; exit 1; }
             # Either file: which of the two carries the words is a property of
             # the shader compiler the rule chose, not of the shader. See the

.github/workflows/ci-macos.yml

@@ -374,8 +374,8 @@ jobs:
           # a neighbouring step happened to select makes this step's subject
           # depend on step order, which is not a property anybody reads.
           "/tmp/mcpp-fresh" build --toolchain "llvm@${MCPP_LLVM_VER}"
+          d="$(sh "$GITHUB_WORKSPACE/.github/tools/out_dir.sh")/spirv"
           for f in triangle_vert triangle_frag; do
-            d="target/.build-mcpp/out/spirv"
             test -f "$d/$f.h" || { echo "missing $d/$f.h"; exit 1; }
             # THE MAGIC IS NOT ALWAYS IN THE HEADER, AND THAT IS THE POINT OF
             # THIS JOB. The rule chooses the shader compiler this platform

.github/workflows/ci-windows.yml

@@ -432,8 +432,8 @@ jobs:
           # a neighbouring step happened to select makes this step's subject
           # depend on step order, which is not a property anybody reads.
           "$MCPP_SELF" build --toolchain "llvm@23.1.3"
+          d="$(sh "$GITHUB_WORKSPACE/.github/tools/out_dir.sh")/spirv"
           for f in triangle_vert triangle_frag; do
-            d="target/.build-mcpp/out/spirv"
             test -f "$d/$f.h" || { echo "missing $d/$f.h"; exit 1; }
             # THE MAGIC IS NOT ALWAYS IN THE HEADER, AND THAT IS THE POINT OF
             # THIS JOB. The rule chooses the shader compiler this platform