Use higher level transformations in UVController

components/nifosg/controller.cpp

@@ -277,22 +277,18 @@ void UVController::apply(osg::StateSet* stateset, osg::NodeVisitor* nv)
     if (hasInput())
     {
         float value = getInputValue(nv);
-        float uTrans = mUTrans.interpKey(value);
-        float vTrans = mVTrans.interpKey(value);
-        float uScale = mUScale.interpKey(value);
-        float vScale = mVScale.interpKey(value);
-
-        // First scale the UV relative to (0,0),
-        // then offset the UV to change the scaling origin to its center.
-        osg::Matrixf mat = osg::Matrixf::scale(uScale, vScale, 1);
-        float uOffset = 0.5f * (1.f - uScale);
-        float vOffset = 0.5f * (1.f - vScale);
-        // Apply the original offsets:
-        // U offset is supposed to be subtracted regardless of the graphics library,
-        // while V offset is made negative to account for OpenGL's Y axis convention.
-        uOffset -= uTrans;
-        vOffset -= vTrans;
-        mat.setTrans(uOffset, vOffset, 0);
+
+        // First scale the UV relative to its center, then apply the offset.
+        // U offset is flipped regardless of the graphics library,
+        // while V offset is flipped to account for OpenGL Y axis convention.
+        osg::Vec3f uvOrigin(0.5f, 0.5f, 0.f);
+        osg::Vec3f uvScale(mUScale.interpKey(value), mVScale.interpKey(value), 1.f);
+        osg::Vec3f uvTrans(-mUTrans.interpKey(value), -mVTrans.interpKey(value), 0.f);
+
+        osg::Matrixf mat = osg::Matrixf::translate(uvOrigin);
+        mat.preMultScale(uvScale);
+        mat.preMultTranslate(-uvOrigin);
+        mat.setTrans(mat.getTrans() + uvTrans);
 
         // setting once is enough because all other texture units share the same TexMat (see setDefaults).
         if (!mTextureUnits.empty())