+ if (texImage->TexObject->Target == GL_TEXTURE_1D_ARRAY) {
+ depth = height;
+ height = 1;
+ }
+
+ if (texImage->_BaseFormat == GL_LUMINANCE ||
+ texImage->_BaseFormat == GL_INTENSITY ||
+ texImage->_BaseFormat == GL_LUMINANCE_ALPHA) {
+ /* If a luminance (or intensity) texture is read back as RGB(A), the
+ * returned value should be (L,0,0,1), not (L,L,L,1). Set rebaseFormat
+ * here to get G=B=0.
+ */
+ rebaseFormat = texImage->_BaseFormat;
+ }
+ else if ((texImage->_BaseFormat == GL_RGBA ||
+ texImage->_BaseFormat == GL_RGB) &&
+ (destBaseFormat == GL_LUMINANCE ||
+ destBaseFormat == GL_LUMINANCE_ALPHA ||
+ destBaseFormat == GL_LUMINANCE_INTEGER_EXT ||
+ destBaseFormat == GL_LUMINANCE_ALPHA_INTEGER_EXT)) {
+ /* If we're reading back an RGB(A) texture as luminance then we need
+ * to return L=tex(R). Note, that's different from glReadPixels which
+ * returns L=R+G+B.
+ */
+ rebaseFormat = GL_LUMINANCE_ALPHA; /* this covers GL_LUMINANCE too */
+ }
+
+ for (img = 0; img < depth; img++) {
+ GLubyte *srcMap;
+ GLint rowstride;
+
+ /* map src texture buffer */
+ ctx->Driver.MapTextureImage(ctx, texImage, img,
+ 0, 0, width, height, GL_MAP_READ_BIT,
+ &srcMap, &rowstride);
+ if (srcMap) {