glsl-square-frame

Given a screen size, get values between -1 and +1 for the current pixel.

Useful for full-screen shaders: whereas gl_FragCoord.xy changes scale with the canvas and sending the [width, height] over yourself results in stretching unless you scale it properly – using this function lets you get consistent points regardless of aspect ratio.

See the code in example.frag for example usage.

Usage

vec2 squareFrame(vec2 size)

vec2 squareFrame(vec2 size, vec2 coord)

Returns a vec2 containing the scaled screen position, ranging between -1 and +1.

• size is a vec2 containing the [width, height] of your canvas.
• coord is the position of the current fragment, in pixels. Defaults to gl_FragCoord.xy.

License

MIT. See LICENSE.md for details.