Search notes:

Graphic Library Shader Language

Built in types

For example:

For example

Four types of variables:

uniforms: »constants« or global variables (for the duration of a scence?), used in both fragment and vertex shaders.
buffers/attributes: Only used in vertex shaders. A buffer is an array of data that is passed from JavaScript to the GPU. The attribute specifies how the data is extracted. Not random access!
textures: read/write arrays used in shaders. Often used for images, hence the name.
varyings: declared in vertex shader and shared with (or passed to) fragment shader.

Referring to the elements of a vec4 VEC:

The components can be concatenated to create a new vector. The following creates a four element vector whose first three elements are equal:

new_vec = VEC.rrra;