compositor: Correctly calculate changed sub image rectangle
When calling glTexSubImage2D for sub image updates for SHM surfaces the
changed rectangle was being wrongly calculated. This resulted in interesting
redraw artefacts for clients using SHM.
diff --git a/src/compositor.c b/src/compositor.c
index bdcc2cd..677b5c8 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -1001,7 +1001,7 @@
glPixelStorei(GL_UNPACK_SKIP_ROWS, rectangles[i].y1);
glTexSubImage2D(GL_TEXTURE_2D, 0,
rectangles[i].x1, rectangles[i].y1,
- rectangles[i].x2 - rectangles[i].y1,
+ rectangles[i].x2 - rectangles[i].x1,
rectangles[i].y2 - rectangles[i].y1,
GL_BGRA_EXT, GL_UNSIGNED_BYTE, data);
}