diff --git a/clutter/cogl/gl/cogl-texture.c b/clutter/cogl/gl/cogl-texture.c
index 5b7326c..1dac073 100644
--- a/clutter/cogl/gl/cogl-texture.c
+++ b/clutter/cogl/gl/cogl-texture.c
@@ -37,6 +37,7 @@
 
 #include <string.h>
 #include <stdlib.h>
+#include <math.h>
 
 /*
 #define COGL_DEBUG 1
@@ -555,7 +556,7 @@ _cogl_texture_upload_subregion_to_gl (CoglTexture *tex,
               guint wx, wy;
 
               src = source_bmp->data
-                  + (src_y +  (y_iter.intersect_start)
+                  + (src_y +  ((int)y_iter.intersect_start)
                      - dst_y)
                   * source_bmp->rowstride
                   + (src_x + x_span->start + x_span->size - x_span->waste
@@ -600,7 +601,7 @@ _cogl_texture_upload_subregion_to_gl (CoglTexture *tex,
               guint copy_width;
 
               src = source_bmp->data
-                  + (src_x +  (x_iter.intersect_start)
+                  + (src_x +  ((int)x_iter.intersect_start)
                      - dst_x)
                   * bpp
                   + (src_y + y_span->start + y_span->size - y_span->waste