diff --git a/src/cairo-gl-composite.c b/src/cairo-gl-composite.c
index 1b7f6bb37..42eacf69e 100644
--- a/src/cairo-gl-composite.c
+++ b/src/cairo-gl-composite.c
@@ -682,6 +682,7 @@ _cairo_gl_context_setup_operand (cairo_gl_context_t *ctx,
                                  unsigned int        vertex_offset)
 {
     memcpy (&ctx->operands[tex_unit], operand, sizeof (cairo_gl_operand_t));
+    ctx->operands[tex_unit].vertex_offset = vertex_offset;
 
     switch (operand->type) {
     default:
diff --git a/src/cairo-gl-private.h b/src/cairo-gl-private.h
index a6aea40b8..410165165 100644
--- a/src/cairo-gl-private.h
+++ b/src/cairo-gl-private.h
@@ -158,6 +158,7 @@ typedef struct cairo_gl_operand {
 	    float radius_1;
 	} radial;
     };
+    unsigned int vertex_offset;
 } cairo_gl_operand_t;
 
 typedef struct _cairo_gl_context {