material: fix depth variant leak

The default material does not cover all of the depth variants,
and so for the client material's depth variants (with no custom
depth shader), we need to check if the program is allocated for
the material or if it is actually part of the default material.

filament/src/details/Material.cpp

@@ -347,6 +347,12 @@ FMaterial::~FMaterial() noexcept = default;
 
 void FMaterial::invalidate(Variant::type_t variantMask, Variant::type_t variantValue) noexcept {
     DriverApi& driverApi = mEngine.getDriverApi();
+    FMaterial const* const pDefaultMaterial = mEngine.getDefaultMaterial();
+    auto hasDefaultDepthVariant = [pDefaultMaterial](Variant k) {
+        auto const& end = pDefaultMaterial->mDepthVariants.end();
+        return end != std::find(pDefaultMaterial->mDepthVariants.begin(), end, k);
+    };
+
     if (mMaterialDomain == MaterialDomain::SURFACE) {
         auto& cachedPrograms = mCachedPrograms;
         for (size_t k = 0, n = VARIANT_COUNT; k < n; ++k) {
@@ -355,8 +361,9 @@ void FMaterial::invalidate(Variant::type_t variantMask, Variant::type_t variantV
                 if (UTILS_LIKELY(!mIsDefaultMaterial)) {
                     // The depth variants may be shared with the default material, in which case
                     // we should not free it now.
-                    bool const isSharedVariant =
-                            Variant::isValidDepthVariant(variant) && !mHasCustomDepthShader;
+                    bool const isSharedVariant = Variant::isValidDepthVariant(variant) &&
+                                                 !mHasCustomDepthShader &&
+                                                 hasDefaultDepthVariant(variant);
                     if (isSharedVariant) {
                         // we don't own this variant, skip.
                         continue;
@@ -367,8 +374,7 @@ void FMaterial::invalidate(Variant::type_t variantMask, Variant::type_t variantV
             }
         }
 
-         if (UTILS_UNLIKELY(!mIsDefaultMaterial && !mHasCustomDepthShader)) {
-            FMaterial const* const pDefaultMaterial = mEngine.getDefaultMaterial();
+        if (UTILS_UNLIKELY(!mIsDefaultMaterial && !mHasCustomDepthShader)) {
             for (Variant const variant: pDefaultMaterial->mDepthVariants) {
                 pDefaultMaterial->prepareProgram(variant);
                 if (!cachedPrograms[variant.key]) {
@@ -626,6 +632,7 @@ Program FMaterial::getProgramWithVariants(
 }
 
 void FMaterial::createAndCacheProgram(Program&& p, Variant variant) const noexcept {
+    assert_invariant(!mCachedPrograms[variant.key]);
     auto program = mEngine.getDriverApi().createProgram(std::move(p));
     mEngine.getDriverApi().setDebugTag(program.getId(), mName);
     assert_invariant(program);
@@ -737,12 +744,19 @@ void FMaterial::onQueryCallback(void* userdata, VariantList* pVariants) {
 void FMaterial::destroyPrograms(FEngine& engine) {
     DriverApi& driverApi = engine.getDriverApi();
     auto& cachedPrograms = mCachedPrograms;
+
+    auto hasDefaultDepthVariant = [pDefaultMaterial = engine.getDefaultMaterial()](Variant k) {
+        auto const& end = pDefaultMaterial->mDepthVariants.end();
+        return end != std::find(pDefaultMaterial->mDepthVariants.begin(), end, k);
+    };
+
     for (size_t k = 0, n = VARIANT_COUNT; k < n; ++k) {
         const Variant variant(k);
         if (!mIsDefaultMaterial) {
             // The depth variants may be shared with the default material, in which case
             // we should not free it now.
-            bool const isSharedVariant = Variant::isValidDepthVariant(variant) && !mHasCustomDepthShader;
+            bool const isSharedVariant = Variant::isValidDepthVariant(variant) &&
+                                         !mHasCustomDepthShader && hasDefaultDepthVariant(variant);
             if (isSharedVariant) {
                 // we don't own this variant, skip.
                 continue;