1uniform half4 colorGreen, colorRed;
2
3inline bool shouldLoop(half4 value) {
4    return value != colorGreen;
5}
6
7half4 main(float2 coords) {
8    half4 result = colorRed;
9    do {
10        result = colorGreen;
11    } while (shouldLoop(result));
12    return result;
13}
14