Explain the following GLSL keywords or function name. You must also explain the parameters and output if applicable. Provide examples. Do not write more than 500 words in total.
uniform
sampler2D
smoothstep
mix
When rendering multiple objects, do you use one single pair of vertex and fragment shaders, or do you use multiple shaders? Clearly state your reasons and arguments. Do not write more than 500 words in total.