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++ // Copyright (C) 2023 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
++
++ VARYING vec2 uv1;
++
++ void MAIN()
++ {
++ uv1 = UV1;
++
++ // The source View3D applied a flip when running with OpenGL, just
++ // to get the on-screen lightmap identical with all graphics
++ // APIs. Now we apply the opposite. Normally this would not be
++ // necessary.
++ if (FRAMEBUFFER_Y_UP == 1.0)
++ uv1.y = 1.0 - uv1.y;
++
++ POSITION = MODELVIEWPROJECTION_MATRIX * vec4(VERTEX, 1.0);
++ }