grad8() [3/3]

static int8_t grad8 ( uint8_t hash, int8_t x, int8_t y, int8_t z )

inlinestatic

Definition at line 209 of file noise.cpp.

                                                                                                       {
#if 0
    switch(hash & 0xF) {
        case  0: return (( x) + ( y))>>1;
        case  1: return ((-x) + ( y))>>1;
        case  2: return (( x) + (-y))>>1;
        case  3: return ((-x) + (-y))>>1;
        case  4: return (( x) + ( z))>>1;
        case  5: return ((-x) + ( z))>>1;
        case  6: return (( x) + (-z))>>1;
        case  7: return ((-x) + (-z))>>1;
        case  8: return (( y) + ( z))>>1;
        case  9: return ((-y) + ( z))>>1;
        case 10: return (( y) + (-z))>>1;
        case 11: return ((-y) + (-z))>>1;
        case 12: return (( y) + ( x))>>1;
        case 13: return ((-y) + ( z))>>1;
        case 14: return (( y) + (-x))>>1;
        case 15: return ((-y) + (-z))>>1;
    }
#else
 
    hash &= 0xF;
 
    int8_t u, v;
    //u = (hash&8)?y:x;
    u = selectBasedOnHashBit( hash, 3, y, x);
 
#if 1
    v = hash<4?y:hash==12||hash==14?x:z;
#else
    // Verbose version for analysis; generates idenitical code.
    if( hash < 4) { // 00 01 02 03
        v = y;
    } else {
        if( hash==12 || hash==14) { // 0C 0E
            v = x;
        } else {
            v = z; // 04 05 06 07   08 09 0A 0B   0D  0F
        }
    }
#endif
 
    if(hash&1) { u = -u; }
    if(hash&2) { v = -v; }
 
    return avg7(u,v);
#endif
}

References avg7(), selectBasedOnHashBit(), x, y, and z.

Referenced by inoise8_raw(), inoise8_raw(), and inoise8_raw().

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