diff --git a/engine/joint/v4k.h b/engine/joint/v4k.h
index 34e82a4..a861df8 100644
--- a/engine/joint/v4k.h
+++ b/engine/joint/v4k.h
@@ -17350,8 +17350,8 @@ API shadowmap_t shadowmap(int vsm_texture_width, int pcf_texture_width); // = 51
 API void shadowmap_destroy(shadowmap_t *s);
 
 API void shadowmap_begin(shadowmap_t *s);
-API bool   shadowmap_step(shadowmap_t *s);
-API void   shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< can be called once per shadowmap_step
+API bool   shadowmap_step(shadowmap_t *s); //< roll over to the next light if it returns false
+API void     shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< must be called at most once per shadowmap_step
 API void shadowmap_end(shadowmap_t *s);
 
 // -----------------------------------------------------------------------------
diff --git a/engine/split/v4k_render.h b/engine/split/v4k_render.h
index 0a15f0c..095d344 100644
--- a/engine/split/v4k_render.h
+++ b/engine/split/v4k_render.h
@@ -382,8 +382,8 @@ API shadowmap_t shadowmap(int vsm_texture_width, int pcf_texture_width); // = 51
 API void shadowmap_destroy(shadowmap_t *s);
 
 API void shadowmap_begin(shadowmap_t *s);
-API bool   shadowmap_step(shadowmap_t *s);
-API void   shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< can be called once per shadowmap_step
+API bool   shadowmap_step(shadowmap_t *s); //< roll over to the next light if it returns false
+API void     shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< must be called at most once per shadowmap_step
 API void shadowmap_end(shadowmap_t *s);
 
 // -----------------------------------------------------------------------------
diff --git a/engine/v4k.h b/engine/v4k.h
index 17471e3..d3f32fa 100644
--- a/engine/v4k.h
+++ b/engine/v4k.h
@@ -3417,8 +3417,8 @@ API shadowmap_t shadowmap(int vsm_texture_width, int pcf_texture_width); // = 51
 API void shadowmap_destroy(shadowmap_t *s);
 
 API void shadowmap_begin(shadowmap_t *s);
-API bool   shadowmap_step(shadowmap_t *s);
-API void   shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< can be called once per shadowmap_step
+API bool   shadowmap_step(shadowmap_t *s); //< roll over to the next light if it returns false
+API void     shadowmap_light(shadowmap_t *s, light_t *l, mat44 cam_proj, mat44 cam_view); //< must be called at most once per shadowmap_step
 API void shadowmap_end(shadowmap_t *s);
 
 // -----------------------------------------------------------------------------