loadShader()

Loads vertex and fragment shaders to create a p5.Shader object.

Shaders are programs that run on the graphics processing unit (GPU). They can process many pixels at the same time, making them fast for many graphics tasks. They’re written in a language called GLSL and run along with the rest of the code in a sketch.

Once the p5.Shader object is created, it can be used with the shader() function, as in shader(myShader). A shader program consists of two files, a vertex shader and a fragment shader. The vertex shader affects where 3D geometry is drawn on the screen and the fragment shader affects color.

loadShader() loads the vertex and fragment shaders from their .vert and .frag files. For example, calling loadShader('/assets/shader.vert', '/assets/shader.frag') loads both required shaders and returns a p5.Shader object.

The third parameter, successCallback, is optional. If a function is passed, it will be called once the shader has loaded. The callback function can use the new p5.Shader object as its parameter.

The fourth parameter, failureCallback, is also optional. If a function is passed, it will be called if the shader fails to load. The callback function can use the event error as its parameter.

Shaders can take time to load. Calling loadShader() in preload() ensures shaders load before they're used in setup() or draw().

Note: Shaders can only be used in WebGL mode.