docs: mention drawArrays gl_PointSize (mdn#35483)

* docs: mention drawArrays gl_PointSize This is a silent error that may cause headache - it's worth noting. * Move the note --------- Co-authored-by: Joshua Chen <[email protected]>
hamishwillee · Aug 27, 2024 · fc9c6e0 · fc9c6e0
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diff --git a/files/en-us/web/api/webglrenderingcontext/drawarrays/index.md b/files/en-us/web/api/webglrenderingcontext/drawarrays/index.md
@@ -32,6 +32,9 @@ drawArrays(mode, first, count)
     - [`gl.TRIANGLE_FAN`](https://en.wikipedia.org/wiki/Triangle_fan)
     - `gl.TRIANGLES`: Draws a triangle for a group of three vertices.
 
+    > [!NOTE]
+    > If `mode` is `POINTS`, [`gl_PointSize`](https://www.opengl.org/sdk/docs/man4/html/gl_PointSize.xhtml) may need to be set for `drawArrays` to render, as its value is unknown if not explicitly written. Only some GPUs set its default as `1.0`.
+
 - `first`
   - : A {{domxref("WebGL_API/Types", "GLint")}} specifying the starting index in the array of vector points.
 - `count`