diff --git a/src/libkwineffects/kwineffects.cpp b/src/libkwineffects/kwineffects.cpp
index cfc01e5134..d010955bfa 100644
--- a/src/libkwineffects/kwineffects.cpp
+++ b/src/libkwineffects/kwineffects.cpp
@@ -1087,7 +1087,7 @@ void WindowQuadList::makeInterleavedArrays(unsigned int type, GLVertex2D *vertic
             for (int j = 0; j < 4; j++) {
                 const WindowVertex &wv = quad[j];
 
-                auto vertexPos = QVector2D(wv.x(), wv.y()) * scale;
+                auto vertexPos = roundVector(QVector2D(wv.x(), wv.y()) * scale);
                 GLVertex2D v;
                 v.position = vertexPos;
                 v.texcoord = QVector2D(wv.u(), wv.v()) * coeff + offset;
@@ -1104,7 +1104,7 @@ void WindowQuadList::makeInterleavedArrays(unsigned int type, GLVertex2D *vertic
             for (int j = 0; j < 4; j++) {
                 const WindowVertex &wv = quad[j];
 
-                auto vertexPos = QVector2D(wv.x(), wv.y()) * scale;
+                auto vertexPos = roundVector(QVector2D(wv.x(), wv.y()) * scale);
                 v[j].position = vertexPos;
                 v[j].texcoord = QVector2D(wv.u(), wv.v()) * coeff + offset;
             }
diff --git a/src/scenes/opengl/scene_opengl.cpp b/src/scenes/opengl/scene_opengl.cpp
index c117329fef..306efd98db 100644
--- a/src/scenes/opengl/scene_opengl.cpp
+++ b/src/scenes/opengl/scene_opengl.cpp
@@ -326,9 +326,9 @@ void SceneOpenGL::createRenderNode(Item *item, RenderContext *context)
     const QList<Item *> sortedChildItems = item->sortedChildItems();
 
     QMatrix4x4 matrix;
-    const auto logicalPosition = QVector3D(item->position().x(), item->position().y(), 0.0);
+    const auto logicalPosition = QVector2D(item->position().x(), item->position().y());
     const auto scale = context->renderTargetScale;
-    matrix.translate(logicalPosition * scale);
+    matrix.translate(roundVector(logicalPosition * scale).toVector3D());
     matrix *= item->transform();
     context->transformStack.push(context->transformStack.top() * matrix);