gl_PointSize - OpenGL ES 3.2 Reference Pages

## Name

gl_PointSize — contains size of rasterized points, in pixels

## Declaration

`gl_PointSize` is a member of the `gl_PerVertex` named block:

        out gl_PerVertex {
            highp vec4 gl_Position;
            highp float gl_PointSize;
        };

## Description

In the vertex, tessellation evaluation and geometry languages, a single global instance of the `gl_PerVertex` named block is available and its `gl_PointSize` member is an output that receives the intended size of the point to be rasterized, in pixels. It may be written at any time during shader execution.

In the tessellation control language, the `gl_PerVertex` named block is used to construct an array, `gl_out[]`, whose members become available as inputs to the subsequent tessellation evaluation shader.

The value of `gl_PointSize` (or the `gl_PointSize` member of the `gl_out[]` array, in the case of the tessellation control shader) is undefined after the vertex, tessellation control, and tessellation evaluation shading stages if the corresponding shader executable does not write to gl_PointSize. It is also undefined after the geometry processing stage if the geometry shader executable calls EmitVertex without having written `gl_PointSize` since the last call to EmitVertex (or hasn't written it at all).

In the tessellation control, tessellation evaluation and geometry languages, the `gl_PerVertex` named block is used to construct an array, `gl_in[]` of per-vertex or per-control point inputs whose content represents the corresponding outputs written by the previous stage.

The variable `gl_PointSize` is intended for a vertex shader to write the size of the point to be rasterized. It is measured in pixels. If `gl_PointSize` is not written to, its value is undefined in subsequent pipeline stages. If the last active stage is not a vertex shader and does not statically assign a value to `gl_PointSize` , the point size is 1.0.

## Version Support

| OpenGL ES Shading Language Version
--- | ---
Variable Name | 1.00 | 3.00 | 3.10 | 3.20
gl_PointSize | ✔ | ✔ | ✔ | ✔
gl_PointSize (geometry shader) | - | - | - | ✔
gl_PointSize (tessellation evaluation shader) | - | - | - | ✔

## See Also

gl_Position

## Copyright

Copyright © 2011-2015 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.