flattexalphazcfog.h

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inline void LeRasterizer::fillFlatTexAlphaZCFog(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 + ((int)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)];

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

        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;
    }
}