flattexalphazcfog.h

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inline void LeRasterizer::fillFlatTexAlphaZCFog(int y, int x1, int x2, int w1, int w2, int u1, int u2, int v1, int v2)
{
    uint8_t * sc = (uint8_t *)&curTriangle->solidColor;
    uint8_t * fc = (uint8_t *)&curTrilist->fog.color;

    int d = x2 - x1;
    if (d == 0) return;

    int au = (u2 - u1) / d;
    int av = (v2 - v1) / d;
    int aw = (w2 - w1) / d;

    const float sw = 0x1p8;
    int32_t znear = (int32_t)(curTrilist->fog.near * sw);
    int32_t zfar = (int32_t)(curTrilist->fog.far * sw);
    int32_t zscale = (1 << 30) / (zfar - znear);

    if (++x2 > frame.tx) x2 = frame.tx;
    uint8_t * p = (uint8_t *)(x1 + y * frame.tx + pixels);

    for (int x = x1; x < x2; x++) {
        int32_t z = (1 << 30) / (w1 >> 8);
        uint32_t tu = (((int64_t)u1 * z) >> 24) & texMaskU;
        uint32_t tv = (((int64_t)v1 * z) >> 24) & texMaskV;
        uint8_t * t = (uint8_t *)&texDiffusePixels[tu + (tv << texSizeU)];

        int32_t ff = ((int64_t)(z - znear) * zscale) >> 15;
        ff = cmmax(0, ff);
        ff = cmmin((1 << 15), ff);
        int fb = (ff * ff) >> (14 + 8);
        
        int n = t[3];
        int a = 256 - n;

        int r = t[0] * sc[0];
        int g = t[1] * sc[1];
        int b = t[2] * sc[2];
        r = r + (((fc[0] * n - r) * fb) >> 8);
        g = g + (((fc[1] * n - g) * fb) >> 8);
        b = b + (((fc[2] * n - b) * fb) >> 8);

        p[0] = (p[0] * a + r) >> 8;
        p[1] = (p[1] * a + g) >> 8;
        p[2] = (p[2] * a + b) >> 8;
        p += 4;

        u1 += au;
        v1 += av;
        w1 += aw;
    }
}