flattexzcfog.h

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

    float d = x2 - x1;
    if (d == 0.0f) return;

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

    float znear = curTrilist->fog.near;
    float zfar = curTrilist->fog.far;
    float zscale = -1.0f / (znear - zfar);

    int xb = (int)(x1);
    int xe = (int)(x2 + 1.9999f);
    if (xe > frame.tx) xe = frame.tx;

    uint8_t * p = (uint8_t *)(xb + y * frame.tx + pixels);

    for (int x = xb; x < xe; x++) {
        float z = 1.0f / w1;
        uint32_t tu = ((int32_t) (u1 * z)) & texMaskU;
        uint32_t tv = ((int32_t) (v1 * z)) & texMaskV;
        uint8_t * t = (uint8_t *) &texDiffusePixels[tu + (tv << texSizeU)];

        int r = (t[0] * sc[0]) >> 8;
        int g = (t[1] * sc[1]) >> 8;
        int b = (t[2] * sc[2]) >> 8;

        float ff = (z - znear) * zscale;
        ff = cmmax(0.0f, ff);
        ff = cmmin(1.0f, ff);
        ff = 256.0f * ff * ff;
        int fb = (int) ff;

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

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