1 files changed, 87 insertions, 0 deletions
diff --git a/indra/newview/llselectmgr.cpp b/indra/newview/llselectmgr.cpp
index 291e3c2ed3..be4b449e2a 100644
--- a/indra/newview/llselectmgr.cpp
+++ b/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;
         }