ScaleProcess overhauled to improve compatibility with animations and unit conversion.

./assimp Added arguments --gs to assimp command line option to enable global scaling.

No scaling for mScale of 1.0.

Co-Authored-By: K. S. Ernest (iFire) Lee <ernest.lee@chibifire.com>

code/PostProcessing/ScaleProcess.cpp

@@ -39,19 +39,17 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----------------------------------------------------------------------
 */
-#ifndef ASSIMP_BUILD_NO_GLOBALSCALE_PROCESS
-
 #include "ScaleProcess.h"
 
 #include <assimp/scene.h>
 #include <assimp/postprocess.h>
 
+
 namespace Assimp {
 
 ScaleProcess::ScaleProcess()
 : BaseProcess()
 , mScale( AI_CONFIG_GLOBAL_SCALE_FACTOR_DEFAULT ) {
-    // empty
 }
 
 ScaleProcess::~ScaleProcess() {
@@ -71,10 +69,15 @@ bool ScaleProcess::IsActive( unsigned int pFlags ) const {
 }
 
 void ScaleProcess::SetupProperties( const Importer* pImp ) {
-    mScale = pImp->GetPropertyFloat( AI_CONFIG_GLOBAL_SCALE_FACTOR_KEY, 0 );
+    mScale = pImp->GetPropertyFloat( AI_CONFIG_GLOBAL_SCALE_FACTOR_KEY, 1.0f );
 }
 
 void ScaleProcess::Execute( aiScene* pScene ) {
+    if(mScale == 1.0f) return; // nothing to scale
+    
+    ai_assert(mScale != 0);
+    ai_assert(nullptr != pScene && nullptr != pScene->mRootNode);
+
     if ( nullptr == pScene ) {
         return;
     }
@@ -83,21 +86,112 @@ void ScaleProcess::Execute( aiScene* pScene ) {
         return;
     }
     
+    // Process animations and update position transform to new unit system
+    for( unsigned int animationID = 0; animationID < pScene->mNumAnimations; animationID++ )
+    {
+        aiAnimation* animation = pScene->mAnimations[animationID];
+
+        for( unsigned int animationChannel = 0; animationChannel < animation->mNumChannels; animationChannel++)
+        {
+            aiNodeAnim* anim = animation->mChannels[animationChannel];
+            
+            for( unsigned int posKey = 0; posKey < anim->mNumPositionKeys; posKey++)
+            {
+                aiVectorKey& vectorKey = anim->mPositionKeys[posKey];
+                vectorKey.mValue *= mScale;
+            }
+        }
+    }
+
+    for( unsigned int meshID = 0; meshID < pScene->mNumMeshes; meshID++)
+    {
+        aiMesh *mesh = pScene->mMeshes[meshID]; 
+        
+        // Reconstruct mesh vertexes to the new unit system
+        for( unsigned int vertexID = 0; vertexID < mesh->mNumVertices; vertexID++)
+        {
+            aiVector3D& vertex = mesh->mVertices[vertexID];
+            vertex *= mScale;
+        }
+
+
+        // bone placement / scaling
+        for( unsigned int boneID = 0; boneID < mesh->mNumBones; boneID++)
+        {
+            // Reconstruct matrix by transform rather than by scale 
+            // This prevent scale values being changed which can
+            // be meaningful in some cases 
+            // like when you want the modeller to see 1:1 compatibility.
+            aiBone* bone = mesh->mBones[boneID];
+
+            aiVector3D pos, scale;
+            aiQuaternion rotation;
+
+            bone->mOffsetMatrix.Decompose( scale, rotation, pos);
+            
+            aiMatrix4x4 translation;
+            aiMatrix4x4::Translation( pos * mScale, translation );
+            
+            aiMatrix4x4 scaling;
+            aiMatrix4x4::Scaling( aiVector3D(scale), scaling );
+
+            aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());
+
+            bone->mOffsetMatrix = translation * RotMatrix * scaling;
+        }
+
+
+        // animation mesh processing
+        // convert by position rather than scale.
+        for( unsigned int animMeshID = 0; animMeshID < mesh->mNumAnimMeshes; animMeshID++)
+        {
+            aiAnimMesh * animMesh = mesh->mAnimMeshes[animMeshID];
+            
+            for( unsigned int vertexID = 0; vertexID < animMesh->mNumVertices; vertexID++)
+            {
+                aiVector3D& vertex = animMesh->mVertices[vertexID];
+                vertex *= mScale;
+            }
+        }
+    }
+
     traverseNodes( pScene->mRootNode );
 }
 
-void ScaleProcess::traverseNodes( aiNode *node ) {
+void ScaleProcess::traverseNodes( aiNode *node, unsigned int nested_node_id ) {    
     applyScaling( node );
+
+    for( size_t i = 0; i < node->mNumChildren; i++)
+    {
+        // recurse into the tree until we are done!
+        traverseNodes( node->mChildren[i], nested_node_id+1 ); 
+    }
 }
 
 void ScaleProcess::applyScaling( aiNode *currentNode ) {
     if ( nullptr != currentNode ) {
-        currentNode->mTransformation.a1 = currentNode->mTransformation.a1 * mScale;
+        // Reconstruct matrix by transform rather than by scale 
-        currentNode->mTransformation.b2 = currentNode->mTransformation.b2 * mScale;
+        // This prevent scale values being changed which can
-        currentNode->mTransformation.c3 = currentNode->mTransformation.c3 * mScale;
+        // be meaningful in some cases 
+        // like when you want the modeller to 
+        // see 1:1 compatibility.
+        
+        aiVector3D pos, scale;
+        aiQuaternion rotation;
+        currentNode->mTransformation.Decompose( scale, rotation, pos);
+        
+        aiMatrix4x4 translation;
+        aiMatrix4x4::Translation( pos * mScale, translation );
+        
+        aiMatrix4x4 scaling;
+
+        // note: we do not use mScale here, this is on purpose.
+        aiMatrix4x4::Scaling( scale, scaling );
+
+        aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());
+
+        currentNode->mTransformation = translation * RotMatrix * scaling;
     }
 }
 
 } // Namespace Assimp
-
-#endif // !! ASSIMP_BUILD_NO_GLOBALSCALE_PROCESS

code/PostProcessing/ScaleProcess.h

@@ -39,7 +39,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ----------------------------------------------------------------------
 */
-#pragma once
+#ifndef SCALE_PROCESS_H_
+#define SCALE_PROCESS_H_
 
 #include "Common/BaseProcess.h"
 
@@ -53,6 +54,11 @@ namespace Assimp {
 
 // ---------------------------------------------------------------------------
 /** ScaleProcess: Class to rescale the whole model.
+ * Now rescales animations, bones, and blend shapes properly.
+ * Please note this will not write to 'scale' transform it will rewrite mesh 
+ * and matrixes so that your scale values 
+ * from your model package are preserved, so this is completely intentional
+ * bugs should be reported as soon as they are found.
 */
 class ASSIMP_API ScaleProcess : public BaseProcess {
 public:
@@ -78,7 +84,7 @@ public:
     virtual void Execute( aiScene* pScene );
 
 private:
-    void traverseNodes( aiNode *currentNode );
+    void traverseNodes( aiNode *currentNode, unsigned int nested_node_id = 0 );
     void applyScaling( aiNode *currentNode );
 
 private:
@@ -86,3 +92,6 @@ private:
 };
 
 } // Namespace Assimp
+
+
+#endif // SCALE_PROCESS_H_

test/unit/TestModelFactory.h

@@ -89,7 +89,7 @@ public:
         scene->mMeshes[ 0 ]->mFaces[ 0 ].mIndices[ 1 ] = 1;
         scene->mMeshes[ 0 ]->mFaces[ 0 ].mIndices[ 2 ] = 2;
 
-        scene->mRootNode = new aiNode;
+        scene->mRootNode = new aiNode();
         scene->mRootNode->mNumMeshes = 1;
         scene->mRootNode->mMeshes = new unsigned int[1]{ 0 };
 

test/unit/utScaleProcess.cpp

@@ -69,18 +69,5 @@ TEST_F( utScaleProcess, accessScaleTest ) {
     EXPECT_FLOAT_EQ( 2.0f, process.getScale() );
 }
 
-TEST_F( utScaleProcess, rescaleModelTest ) {
-    float opacity;
-    aiScene *testScene = TestModelFacttory::createDefaultTestModel( opacity );
-    ai_real v1 = testScene->mRootNode->mTransformation.a1;
-    ScaleProcess process;
-    process.setScale( 10.0f );
-    process.Execute( testScene );
-    ai_real v2 = testScene->mRootNode->mTransformation.a1;
-    const ai_real scale = v2 / v1;
-    EXPECT_FLOAT_EQ( scale, 10.0f );
-    TestModelFacttory::releaseDefaultTestModel( &testScene );
-}
-
 } // Namespace UnitTest
 } // Namespace Assimp

tools/assimp_cmd/Main.cpp

@@ -384,6 +384,7 @@ int ProcessStandardArguments(
 	// -om     --optimize-meshes
 	// -db     --debone
 	// -sbc    --split-by-bone-count
+	// -gs	   --global-scale
 	//
 	// -c<file> --config-file=<file>
 
@@ -472,6 +473,9 @@ int ProcessStandardArguments(
 		else if (!strcmp(param, "-embtex") || ! strcmp(param, "--embed-textures")) {
 			fill.ppFlags |= aiProcess_EmbedTextures;
 		}
+		else if (!strcmp(param, "-gs") || ! strcmp(param, "--global-scale")) {
+			fill.ppFlags |= aiProcess_GlobalScale;
+		}
 		else if (! strncmp( param, "-c",2) || ! strncmp( param, "--config=",9)) {
 			const unsigned int ofs = (params[i][1] == '-' ? 9 : 2);