Fix #4195: Preserve transforms when switching PBR materials (#4725)

Fixes texture transforms being reset when switching from Blinn-Phong to PBR materials and between PBR. Previously, custom scale, offset, and rotation settings would be lost, making it tedious to switch between PBR materials.

Author: Aqil-Ahmad

indra/llprimitive/llgltfmaterial.cpp

@@ -923,3 +923,34 @@ void LLGLTFMaterial::updateTextureTracking()
     // setTEGLTFMaterialOverride is responsible for tracking
     // for material overrides editor will set it
 }
+
+void LLGLTFMaterial::convertTextureTransformToPBR(
+    F32 tex_scale_s,
+    F32 tex_scale_t,
+    F32 tex_offset_s,
+    F32 tex_offset_t,
+    F32 tex_rotation,
+    LLVector2& pbr_scale,
+    LLVector2& pbr_offset,
+    F32& pbr_rotation)
+{
+    pbr_scale.set(tex_scale_s, tex_scale_t);
+    pbr_rotation = -(tex_rotation) / 2.f;
+    const F32 adjusted_offset_s = tex_offset_s;
+    const F32 adjusted_offset_t = -tex_offset_t;
+    F32 center_adjust_s = 0.5f * (1.0f - tex_scale_s);
+    F32 center_adjust_t = 0.5f * (1.0f - tex_scale_t);
+
+    if (pbr_rotation != 0.0f)
+    {
+        const F32 c = cosf(pbr_rotation);
+        const F32 s = sinf(pbr_rotation);
+        const F32 tmp_s = center_adjust_s * c - center_adjust_t * s;
+        const F32 tmp_t = center_adjust_s * s + center_adjust_t * c;
+        center_adjust_s = tmp_s;
+        center_adjust_t = tmp_t;
+    }
+
+    pbr_offset.set(adjusted_offset_s + center_adjust_s,
+                   adjusted_offset_t + center_adjust_t);
+}

indra/llprimitive/llgltfmaterial.h

@@ -214,6 +214,14 @@ class LLGLTFMaterial : public LLRefCount
     bool hasLocalTextures() { return !mTrackingIdToLocalTexture.empty(); }
     virtual bool replaceLocalTexture(const LLUUID& tracking_id, const LLUUID &old_id, const LLUUID& new_id);
     virtual void updateTextureTracking();
+
+    // Convert legacy TE transform values to PBR transform values.
+    static void convertTextureTransformToPBR(F32 tex_scale_s, F32 tex_scale_t,
+                                             F32 tex_offset_s, F32 tex_offset_t,
+                                             F32 tex_rotation,
+                                             LLVector2& pbr_scale,
+                                             LLVector2& pbr_offset,
+                                             F32& pbr_rotation);
 protected:
     static LLVector2 vec2FromJson(const std::map<std::string, tinygltf::Value>& object, const char* key, const LLVector2& default_value);
     static F32 floatFromJson(const std::map<std::string, tinygltf::Value>& object, const char* key, const F32 default_value);

indra/newview/llgltfmateriallist.cpp

@@ -380,17 +380,6 @@ void LLGLTFMaterialList::queueApply(const LLViewerObject* obj, S32 side, const L
         LLGLTFMaterial* material = new LLGLTFMaterial(*material_override);
         sApplyQueue.push_back({ obj->getID(), side, asset_id, material });
     }
-
-    if (sUpdates.size() >= MAX_TASK_UPDATES)
-    {
-        LLCoros::instance().launch("modifyMaterialCoro",
-            std::bind(&LLGLTFMaterialList::modifyMaterialCoro,
-                gAgent.getRegionCapability("ModifyMaterialParams"),
-                sUpdates,
-                std::shared_ptr<CallbackHolder>(nullptr)));
-
-        sUpdates = LLSD::emptyArray();
-    }
 }
 
 void LLGLTFMaterialList::queueUpdate(const LLSD& data)

indra/newview/llselectmgr.cpp

@@ -1996,9 +1996,96 @@ bool LLSelectMgr::selectionSetGLTFMaterial(const LLUUID& mat_id)
                     asset_id = BLANK_MATERIAL_ASSET_ID;
                 }
             }
+
+            // If this face already has the target material ID, do nothing.
+            // This prevents re-sending the same ID on OK, which can cause the server
+            // to drop overrides when queueApply is invoked with the OLD id.
+            if (objectp->getRenderMaterialID(te) == asset_id)
+            {
+                return true;
+            }
+
+            // Preserve existing texture transforms when switching to PBR material
+            LLTextureEntry* tep = objectp->getTE(te);
+            bool should_preserve_transforms = false;
+            LLGLTFMaterial* preserved_override = nullptr;
+
+            if (tep && asset_id.notNull())
+            {
+                // Only preserve transforms from existing GLTF material override
+                // Do not fall back to texture entry transforms when switching between PBR materials
+                LLGLTFMaterial* existing_override = tep->getGLTFMaterialOverride();
+                if (existing_override)
+                {
+                    // Check if existing override has non-default transforms
+                    const LLGLTFMaterial::TextureTransform& existing_transform = existing_override->mTextureTransform[0];
+                    const LLGLTFMaterial::TextureTransform& default_transform = LLGLTFMaterial::TextureTransform();
+
+                    if (existing_transform.mScale != default_transform.mScale ||
+                        existing_transform.mOffset != default_transform.mOffset ||
+                        existing_transform.mRotation != default_transform.mRotation)
+                    {
+                        // Preserve non-default transforms from current PBR material
+                        preserved_override = new LLGLTFMaterial();
+                        for (U32 i = 0; i < LLGLTFMaterial::GLTF_TEXTURE_INFO_COUNT; ++i)
+                        {
+                            preserved_override->mTextureTransform[i].mScale = existing_transform.mScale;
+                            preserved_override->mTextureTransform[i].mOffset = existing_transform.mOffset;
+                            preserved_override->mTextureTransform[i].mRotation = existing_transform.mRotation;
+                        }
+                        should_preserve_transforms = true;
+                    }
+                    // If existing override has default transforms, don't preserve anything
+                }
+                else
+                {
+                    // No existing PBR material override - check texture entry transforms
+                    // This handles the case of switching from Blinn-Phong to PBR material
+                    F32 existing_scale_s, existing_scale_t, existing_offset_s, existing_offset_t, existing_rotation;
+                    tep->getScale(&existing_scale_s, &existing_scale_t);
+                    tep->getOffset(&existing_offset_s, &existing_offset_t);
+                    existing_rotation = tep->getRotation();
+
+                    const LLGLTFMaterial::TextureTransform& default_transform = LLGLTFMaterial::TextureTransform();
+                    if (existing_scale_s != default_transform.mScale.mV[0] || existing_scale_t != default_transform.mScale.mV[1] ||
+                        existing_offset_s != default_transform.mOffset.mV[0] || existing_offset_t != default_transform.mOffset.mV[1] ||
+                        existing_rotation != default_transform.mRotation)
+                    {
+                        // Preserve non-default transforms from texture entry
+                        preserved_override = new LLGLTFMaterial();
+                        for (U32 i = 0; i < LLGLTFMaterial::GLTF_TEXTURE_INFO_COUNT; ++i)
+                        {
+                            LLVector2 pbr_scale, pbr_offset;
+                            F32 pbr_rotation;
+                            LLGLTFMaterial::convertTextureTransformToPBR(
+                                existing_scale_s, existing_scale_t,
+                                existing_offset_s, existing_offset_t,
+                                existing_rotation,
+                                pbr_scale, pbr_offset, pbr_rotation);
+                            preserved_override->mTextureTransform[i].mScale = pbr_scale;
+                            preserved_override->mTextureTransform[i].mOffset = pbr_offset;
+                            preserved_override->mTextureTransform[i].mRotation = pbr_rotation;
+                        }
+                        should_preserve_transforms = true;
+                    }
+                }
+            }
+
             objectp->clearTEWaterExclusion(te);
             // Blank out most override data on the object and send to server
             objectp->setRenderMaterialID(te, asset_id);
+            if (should_preserve_transforms && preserved_override)
+            {
+                // Apply material with preserved transforms
+                LLGLTFMaterialList::queueApply(objectp, te, asset_id, preserved_override);
+                // Update local state
+                objectp->setRenderMaterialID(te, asset_id, false, true);
+                tep->setGLTFMaterialOverride(preserved_override);
+            }
+            else
+            {
+                objectp->setRenderMaterialID(te, asset_id);
+            }
 
             return true;
         }