matdbg: Fix material collision

filament/src/details/Material.cpp

@@ -611,13 +611,10 @@ void FMaterial::createAndCacheProgram(Program&& p, Variant variant) const noexce
     FEngine const& engine = mEngine;
     DriverApi& driverApi = mEngine.getDriverApi();
 
-    bool const isSharedVariant =
-            (mMaterialDomain == MaterialDomain::SURFACE) &&
-            !mIsDefaultMaterial && !mHasCustomDepthShader &&
-            Variant::isValidDepthVariant(variant);
+    bool const isShared = isSharedVariant(variant);
 
     // Check if the default material has this program cached
-    if (isSharedVariant) {
+    if (isShared) {
         FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
         if (pDefaultMaterial) {
             auto program = pDefaultMaterial->mCachedPrograms[variant.key];
@@ -636,7 +633,7 @@ void FMaterial::createAndCacheProgram(Program&& p, Variant variant) const noexce
     // If the default material doesn't already have this program cached, and all caching conditions
     // are met (Surface Domain and no custom depth shader), cache it now.
     // New Materials will inherit these program automatically.
-    if (isSharedVariant) {
+    if (isShared) {
         FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
         if (pDefaultMaterial && !pDefaultMaterial->mCachedPrograms[variant.key]) {
             // set the tag to the default material name

filament/src/details/Material.h

@@ -156,6 +156,13 @@ class FMaterial : public Material {
         std::unique_lock<utils::Mutex> lock(mActiveProgramsLock);
         mActivePrograms.set(variant.key);
         lock.unlock();
+
+        if (isSharedVariant(variant)) {
+            FMaterial const* const pDefaultMaterial = mEngine.getDefaultMaterial();
+            if (pDefaultMaterial && pDefaultMaterial->mCachedPrograms[variant.key]) {
+                return pDefaultMaterial->getProgram(variant);
+            }
+        }
 #endif
         assert_invariant(mCachedPrograms[variant.key]);
         return mCachedPrograms[variant.key];
@@ -290,6 +297,11 @@ class FMaterial : public Material {
 
     void createAndCacheProgram(backend::Program&& p, Variant variant) const noexcept;
 
+    inline bool isSharedVariant(Variant variant) const {
+        return (mMaterialDomain == MaterialDomain::SURFACE) && !mIsDefaultMaterial &&
+               !mHasCustomDepthShader && Variant::isValidDepthVariant(variant);
+    }
+
     // try to order by frequency of use
     mutable std::array<backend::Handle<backend::HwProgram>, VARIANT_COUNT> mCachedPrograms;
     DescriptorSetLayout mPerViewDescriptorSetLayout;

libs/matdbg/src/DebugServer.cpp

@@ -193,8 +193,12 @@ DebugServer::addMaterial(const CString& name, const void* data, size_t size, voi
         return {};
     }
 
-    const uint32_t seed = 42;
-    const MaterialKey key = utils::hash::murmurSlow((const uint8_t*) data, size, seed);
+    // Note that it's possible to have two materials with the exact same content (however wasteful),
+    // but they refer to different instantiation of FMaterial. Hence we hash on userdata and the
+    // material data.
+    constexpr uint32_t seed = 42;
+    uint64_t dataSpace[2] = {(uint64_t) data, (uint64_t) userdata};
+    uint32_t const key = utils::hash::murmur3((const uint32_t*) dataSpace, sizeof(dataSpace), seed);
 
     // Retain a copy of the package to permit queries after the client application has
     // freed up the original material package.

libs/matdbg/web/app.js

@@ -662,8 +662,8 @@ class MaterialSidePanel extends LitElement {
                 let name = material.name || kUntitledPlaceholder;
                 if (name in duplicatedLabels) {
                     const index = duplicatedLabels[name];
-                    name = `${name} (${index})`;
                     duplicatedLabels[name] = index + 1;
+                    name = `${name} (${index})`;
                 }
                 return {
                     matid: matid,