ShaderPad Docs

ShaderPad initializes the following built-in uniforms for every instance. Declare only the ones your GLSL actually uses; the rest will be ignored, so performance is unaffected.

Built-in Uniforms

Name	Type	Initial value	Update timing	Notes
`u_time`	`float`	`0.0`	Updated by `play()` and `step()` before each rendered frame	Elapsed time in seconds from the current start time. `draw()` does not advance it.
`u_frame`	`int`	`0`	Updated by `play()` and `step()` before each rendered frame	Current frame index. `draw()` does not advance it.
`u_resolution`	`vec2`	current drawing buffer size	Initialized during setup and updated whenever the drawing buffer changes size	Values are in pixels.
`u_cursor`	`vec2`	`[0.5, 0.5]`	Updated on mouse or touch movement on `canvas` or `cursorTarget`	Normalized from `0.0` to `1.0` from left to right and bottom to top.
`u_click`	`vec3`	`[0.5, 0.5, 0.0]`	Updated on mouse or touch press and release on `canvas` or `cursorTarget`	`xy` is the normalized press position and `z` is `1.0` while pressed, otherwise `0.0`.

Typical GLSL Declarations

uniform float u_time;
uniform int u_frame;
uniform vec2 u_resolution;
uniform vec2 u_cursor;
uniform vec3 u_click;

Note about u_resolution

If you use the helpers plugin, it injects the u_resolution declaration for you. Do not declare u_resolution manually in that case.