load method
Writes the texel at (x, y) of the base level into rgba, as four
floats from nought to one, or four zeros outside the texture.
Implementation
@override
void load(int x, int y, Float32List out) {
if (x < 0 || y < 0 || x >= width || y >= height) {
out.fillRange(0, 4, 0);
return;
}
final at = (y * width + x) * 4;
for (var c = 0; c < 4; c++) {
out[c] = unormValue(rgba[at + c]);
}
}