lightlut.c

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#include "internal.h"
 
void LightLut_FromArray(C3D_LightLut* lut, float* data)
{
    int i;
    for (i = 0; i < 256; i ++)
    {
        float in = data[i], diff = data[i+256];
 
        u32 val = 0;
        if (in > 0.0f)
        {
            in *= 0x1000;
            val = (in < 0x1000) ? (u32)in : 0xFFF;
        }
 
        u32 val2 = 0;
        if (diff != 0.0f)
        {
            if (diff < 0)
            {
                diff = -diff;
                val2 = 0x800;
            }
            diff *= 0x800;
            val2 |= (diff < 0x800) ? (u32)diff : 0x7FF;
        }
 
        lut->data[i] = val | (val2 << 12);
    }
}
 
void LightLut_FromFunc(C3D_LightLut* lut, C3D_LightLutFunc func, float param, bool negative)
{
    int i;
    float data[512];
    memset(data, 0, sizeof(data));
    int min = negative ? (-128) : 0;
    int max = negative ?   128  : 256;
    for (i = min; i <= max; i ++)
    {
        float x   = (float)i/max;
        float val = func(x, param);
        int   idx = negative ? (i & 0xFF) : i;
        if (i < max)
            data[idx] = val;
        if (i > min)
            data[idx+255] = val-data[idx-1];
    }
    LightLut_FromArray(lut, data);
}
 
void LightLutDA_Create(C3D_LightLutDA* lut, C3D_LightLutFuncDA func, float from, float to, float arg0, float arg1)
{
    int i;
    float data[512];
 
    float range = to-from;
    lut->scale = 1.0f / range;
    lut->bias = -from*lut->scale;
 
    for (i = 0; i <= 256; i ++)
    {
        float x   = from + range*i/256.0f;
        float val = func(x, arg0, arg1);
        if (i < 256)
            data[i] = val;
        if (i > 0)
            data[i+255] = val-data[i-1];
    }
 
    LightLut_FromArray(&lut->lut, data);
}