llquantize.h

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#ifndef LL_LLQUANTIZE_H
#define LL_LLQUANTIZE_H

const U16 U16MAX = 65535;
const F32 OOU16MAX = 1.f/(F32)(U16MAX);

const U8 U8MAX = 255;
const F32 OOU8MAX = 1.f/(F32)(U8MAX);

const U8 FIRSTVALIDCHAR = 54;
const U8 MAXSTRINGVAL = U8MAX - FIRSTVALIDCHAR; //we don't allow newline or null 


inline U16 F32_to_U16_ROUND(F32 val, F32 lower, F32 upper)
{
        val = llclamp(val, lower, upper);
        // make sure that the value is positive and normalized to <0, 1>
        val -= lower;
        val /= (upper - lower);

        // round the value.   Sreturn the U16
        return (U16)(llround(val*U16MAX));
}


inline U16 F32_to_U16(F32 val, F32 lower, F32 upper)
{
        val = llclamp(val, lower, upper);
        // make sure that the value is positive and normalized to <0, 1>
        val -= lower;
        val /= (upper - lower);

        // return the U16
        return (U16)(llfloor(val*U16MAX));
}

inline F32 U16_to_F32(U16 ival, F32 lower, F32 upper)
{
        F32 val = ival*OOU16MAX;
        F32 delta = (upper - lower);
        val *= delta;
        val += lower;

        F32 max_error = delta*OOU16MAX;

        // make sure that zero's come through as zero
        if (fabsf(val) < max_error)
                val = 0.f;

        return val;
}


inline U8 F32_to_U8_ROUND(F32 val, F32 lower, F32 upper)
{
        val = llclamp(val, lower, upper);
        // make sure that the value is positive and normalized to <0, 1>
        val -= lower;
        val /= (upper - lower);

        // return the rounded U8
        return (U8)(llround(val*U8MAX));
}


inline U8 F32_to_U8(F32 val, F32 lower, F32 upper)
{
        val = llclamp(val, lower, upper);
        // make sure that the value is positive and normalized to <0, 1>
        val -= lower;
        val /= (upper - lower);

        // return the U8
        return (U8)(llfloor(val*U8MAX));
}

inline F32 U8_to_F32(U8 ival, F32 lower, F32 upper)
{
        F32 val = ival*OOU8MAX;
        F32 delta = (upper - lower);
        val *= delta;
        val += lower;

        F32 max_error = delta*OOU8MAX;

        // make sure that zero's come through as zero
        if (fabsf(val) < max_error)
                val = 0.f;

        return val;
}

inline U8 F32_TO_STRING(F32 val, F32 lower, F32 upper)
{
        val = llclamp(val, lower, upper); //[lower, upper]
        // make sure that the value is positive and normalized to <0, 1>
        val -= lower;                                   //[0, upper-lower]
        val /= (upper - lower);                 //[0,1]
        val = val * MAXSTRINGVAL;               //[0, MAXSTRINGVAL]
        val = floor(val + 0.5f);                //[0, MAXSTRINGVAL]

        U8 stringVal = (U8)(val) + FIRSTVALIDCHAR;                      //[FIRSTVALIDCHAR, MAXSTRINGVAL + FIRSTVALIDCHAR]
        return stringVal;
}

inline F32 STRING_TO_F32(U8 ival, F32 lower, F32 upper)
{
        // remove empty space left for NULL, newline, etc.
        ival -= FIRSTVALIDCHAR;                                                         //[0, MAXSTRINGVAL]

        F32 val = (F32)ival * (1.f / (F32)MAXSTRINGVAL);        //[0, 1]
        F32 delta = (upper - lower);
        val *= delta;                                                                           //[0, upper - lower]
        val += lower;                                                                           //[lower, upper]

        return val;
}

#endif

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