notes:
- render a mesh using this shader program.
- cpu runs sequentially, gpu runs in parallel.
nice example to show cpu vs gpu
- no order in how things are run in over the gpu.
GLSL includes many variable types.
Scalars: float, int, bool Vectors: vec2, vec3, vec4 — groups of values. (2 for 2d: x, y) Matrices: mat3, mat4, mat3x4, … : a grid of values Samplers: sampler2D, samplerCube, … : for textures (images)
Variables can also have qualifiers. These determine where their values come from and what their intended use is (their scope).
uniform: Shared data between all instances of the program (all vertices). attribute: Vertex data that is specific to a single instance of the program (a vertex). comes in per instance from the cpu. varying: Data that is specific to a single instance and passed between different shaders in the pipeline.
vertex shader outputs a 4-d vector for position(x,y,z,1).
aPosition is a p5 variable that stores coordinates for each p5.shape being drawn.
glPosition accepts it in clip space (-1,1), and not canvas-space.
in frag:
precision is # of decimals in float.