diff --git a/src/rendering/twn_draw_c.h b/src/rendering/twn_draw_c.h
index 26264f9..9029341 100644
--- a/src/rendering/twn_draw_c.h
+++ b/src/rendering/twn_draw_c.h
@@ -37,6 +37,8 @@ enum {
     TWN_UNSIGNED_BYTE,
 };
 
+/* note: they're separate as on some targets they are not interchangeable like in opengl */
+/*       emscripten legacy gl emulation, for example, assumes first bind to be decisive in its future usage */
 
 typedef uint32_t VertexBuffer;
 typedef uint32_t IndexBuffer;
diff --git a/src/rendering/twn_gl_15_rendering.c b/src/rendering/twn_gl_15_rendering.c
index 79a70f4..ea80333 100644
--- a/src/rendering/twn_gl_15_rendering.c
+++ b/src/rendering/twn_gl_15_rendering.c
@@ -14,6 +14,10 @@
 #endif
 #include <stb_ds.h>
 
+/* note: care must be taken to always have interleaved VBOs with all data, */
+/*       as it is optimized in emscripten legacy gl emulation. */
+/*       constant color isn't supported there, so care must be given to provide alternative path with VBO as well. */
+
 
 static TextureMode texture_mode_last_used = TEXTURE_MODE_UNKNOWN;
 static Pipeline pipeline_last_used = PIPELINE_NO;