fog.c

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#include "internal.h"
 
void FogLut_FromArray(C3D_FogLut* lut, const float data[256])
{
    int i;
    for (i = 0; i < 128; i ++)
    {
        float in = data[i], diff = data[i+128];
 
        u32 val = 0;
        if (in > 0.0f)
        {
            in *= 0x800;
            val = (in < 0x800) ? (u32)in : 0x7FF;
        }
 
        u32 val2 = 0;
        if (diff != 0.0f)
        {
            diff *= 0x800;
            if (diff < -0x1000) diff = -0x1000;
            else if (diff > 0xFFF) diff = 0xFFF;
            val2 = (s32)diff & 0x1FFF;
        }
 
        lut->data[i] = val2 | (val << 13);
    }
}
 
void FogLut_Exp(C3D_FogLut* lut, float density, float gradient, float near, float far)
{
    int i;
    float data[256];
    for (i = 0; i <= 128; i ++)
    {
        float x = FogLut_CalcZ(i/128.0f, near, far);
        float val = expf(-powf(density*x, gradient));
        if (i < 128)
            data[i] = val;
        if (i > 0)
            data[i+127] = val-data[i-1];
    }
    FogLut_FromArray(lut, data);
}
 
void C3D_FogGasMode(GPU_FOGMODE fogMode, GPU_GASMODE gasMode, bool zFlip)
{
    C3D_Context* ctx = C3Di_GetContext();
 
    if (!(ctx->flags & C3DiF_Active))
        return;
 
    ctx->flags |= C3DiF_TexEnvBuf;
    ctx->texEnvBuf &= ~0x100FF;
    ctx->texEnvBuf |= (fogMode&7) | ((gasMode&1)<<3) | (zFlip ? BIT(16) : 0);
}
 
void C3D_FogColor(u32 color)
{
    C3D_Context* ctx = C3Di_GetContext();
 
    if (!(ctx->flags & C3DiF_Active))
        return;
 
    ctx->flags |= C3DiF_TexEnvBuf;
    ctx->fogClr = color;
}
 
void C3D_FogLutBind(C3D_FogLut* lut)
{
    C3D_Context* ctx = C3Di_GetContext();
 
    if (!(ctx->flags & C3DiF_Active))
        return;
 
    if (lut)
    {
        ctx->flags |= C3DiF_FogLut;
        ctx->fogLut = lut;
    } else
        ctx->flags &= ~C3DiF_FogLut;
}