uniform half4 colorGreen, colorRed;

float sumArray(float a[5]) {
    float sum = 0;
    for (int i = 0; i < 5; ++i) {
        sum += a[i];
    }
    return sum;
}

float sumArrayMutating(float a[5]) {
    for (int i = 1; i < 5; ++i) {
        a[0] += a[i];
    }
    return a[0];
}

half4 main(float2 coords) {
    float data[5];
    data[0] = 1;
    data[1] = 2;
    data[2] = 3;
    data[3] = 4;
    data[4] = 5;
    return sumArray(data) == sumArrayMutating(data) ? colorGreen : colorRed;
}