GPU fragment shader color output channels are clamped to [0,1]; values exceeding 1 saturate and produce incorrect gradients

Color values returned from a fragment shader are clamped to the range [0, 1] per channel. If you pass raw cell coordinates (which range from 0 to grid size) directly as color components, all cells beyond the first row/column saturate at maximum brightness and appear identical. To produce a gradient across the whole grid, normalize by dividing by the grid size: cell / grid maps coordinates to [0, 1]. This clamping behavior is fundamental to RGBA color output and affects any attempt to use large numbers or negative values as colors.

Examples

// Wrong: clamps to 1 for all cells except the first row/column
return vec4f(cell, 0, 1);
// Correct: normalizes to [0,1] range across the full grid
return vec4f(cell / grid, 0, 1);

Assessment

A 32×32 grid passes cell coordinates (ranging 0–31) directly as color channels. What do cells (1,0) and (16,0) look like? How does dividing by grid fix the gradient?