diff --git a/libkwineffects/kwinglutils.h b/libkwineffects/kwinglutils.h
--- a/libkwineffects/kwinglutils.h
+++ b/libkwineffects/kwinglutils.h
@@ -511,6 +511,16 @@
         s_virtualScreenSize = s;
     }
 
+    /**
+     * Sets the virtual screen geometry to @p g.
+     * This is the geometry of the OpenGL window currently being rendered to
+     * in the virtual geometry space the rendering geometries use.
+     * @since 5.9
+     **/
+    static void setVirtualScreenGeometry(const QRect &g) {
+        s_virtualScreenGeometry = g;
+    }
+
 
 protected:
     void initFBO();
@@ -523,6 +533,7 @@
     static bool s_blitSupported;
     static QStack<GLRenderTarget*> s_renderTargets;
     static QSize s_virtualScreenSize;
+    static QRect s_virtualScreenGeometry;
 
     GLTexture mTexture;
     bool mValid;
diff --git a/libkwineffects/kwinglutils.cpp b/libkwineffects/kwinglutils.cpp
--- a/libkwineffects/kwinglutils.cpp
+++ b/libkwineffects/kwinglutils.cpp
@@ -1129,6 +1129,7 @@
 bool GLRenderTarget::s_blitSupported = false;
 QStack<GLRenderTarget*> GLRenderTarget::s_renderTargets = QStack<GLRenderTarget*>();
 QSize GLRenderTarget::s_virtualScreenSize;
+QRect GLRenderTarget::s_virtualScreenGeometry;
 
 void GLRenderTarget::initStatic()
 {
@@ -1327,10 +1328,11 @@
     GLRenderTarget::pushRenderTarget(this);
     glBindFramebuffer(GL_DRAW_FRAMEBUFFER, mFramebuffer);
     glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
-    const QRect s = source.isNull() ? QRect(0, 0, s_virtualScreenSize.width(), s_virtualScreenSize.height()) : source;
+    const QRect s = source.isNull() ? s_virtualScreenGeometry : source;
     const QRect d = destination.isNull() ? QRect(0, 0, mTexture.width(), mTexture.height()) : destination;
 
-    glBlitFramebuffer(s.x(), s_virtualScreenSize.height() - s.y() - s.height(), s.x() + s.width(), s_virtualScreenSize.height() - s.y(),
+    glBlitFramebuffer(s.x() - s_virtualScreenGeometry.x(), s_virtualScreenGeometry.height() - s_virtualScreenGeometry.y() - s.y() - s.height(),
+                      s.x() - s_virtualScreenGeometry.x() + s.width(), s_virtualScreenGeometry.height() - s_virtualScreenGeometry.y() - s.y(),
                       d.x(), mTexture.height() - d.y() - d.height(), d.x() + d.width(), mTexture.height() - d.y(),
                       GL_COLOR_BUFFER_BIT, filter);
     GLRenderTarget::popRenderTarget();
diff --git a/scene_opengl.cpp b/scene_opengl.cpp
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -700,6 +700,7 @@
             // prepare rendering makes context current on the output
             QRegion repaint = m_backend->prepareRenderingForScreen(i);
             GLVertexBuffer::setVirtualScreenGeometry(geo);
+            GLRenderTarget::setVirtualScreenGeometry(geo);
 
             const GLenum status = glGetGraphicsResetStatus();
             if (status != GL_NO_ERROR) {
@@ -727,6 +728,7 @@
             return 0;
         }
         GLVertexBuffer::setVirtualScreenGeometry(screens()->geometry());
+        GLRenderTarget::setVirtualScreenGeometry(screens()->geometry());
 
         int mask = 0;
         updateProjectionMatrix();