diff --git a/src/xrt/compositor/render/render_gfx.c b/src/xrt/compositor/render/render_gfx.c
index 3e4ccff19..b46ae55bb 100644
--- a/src/xrt/compositor/render/render_gfx.c
+++ b/src/xrt/compositor/render/render_gfx.c
@@ -651,7 +651,7 @@ render_gfx_end_target(struct render_gfx *rr)
 }
 
 void
-render_gfx_begin_view(struct render_gfx *rr, uint32_t view, struct render_viewport_data *viewport_data)
+render_gfx_begin_view(struct render_gfx *rr, uint32_t view, const struct render_viewport_data *viewport_data)
 {
 	struct vk_bundle *vk = vk_from_rr(rr);
 
diff --git a/src/xrt/compositor/render/render_interface.h b/src/xrt/compositor/render/render_interface.h
index 2d2db38ee..7f58c3d41 100644
--- a/src/xrt/compositor/render/render_interface.h
+++ b/src/xrt/compositor/render/render_interface.h
@@ -750,7 +750,7 @@ render_gfx_end_target(struct render_gfx *rr);
  * @public @memberof render_gfx
  */
 void
-render_gfx_begin_view(struct render_gfx *rr, uint32_t view, struct render_viewport_data *viewport_data);
+render_gfx_begin_view(struct render_gfx *rr, uint32_t view, const struct render_viewport_data *viewport_data);
 
 /*!
  * @public @memberof render_gfx