hackathon-dev #1
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@ -19,7 +19,9 @@ inline static BYTE line_clip_outcode(INT32 x, INT32 y, INT32 xmin, INT32 ymin, I
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return rc;
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}
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#define CPX 8 /* clipping precision in bits */
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#define CPX 4 /* clipping precision in bits */
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#define ONE (1 << CPX) /* constant for mathematics */
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/* these macros keep the number of bits straight when doing fixed-point multiply & divide */
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#define M(a, b) ((((a) * (b))) >> CPX)
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@ -74,16 +76,16 @@ static BOOL line_clip(PINT32 output, INT32 x1, INT32 y1, INT32 x2, INT32 y2, INT
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}
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else if (outcode1 & 0x4)
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{
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tmp = M(x2 - x1, D(ymax - y1, y2 - y1));
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tmp = M(x2 - x1, D(ymax - ONE - y1, y2 - y1));
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x1 += tmp;
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y1 = ymax;
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y1 = ymax - ONE;
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Log(LDEBUG, "clipped against bottom to point (%d, %d), dx=%d/%d", x1 >> CPX, y1 >> CPX, tmp >> CPX, tmp);
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}
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else if (outcode1 & 0x2)
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{
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tmp = M(y2 - y1, D(xmax - x1, x2 - x1));
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tmp = M(y2 - y1, D(xmax - ONE - x1, x2 - x1));
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y1 += tmp;
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x1 = xmax;
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x1 = xmax - ONE;
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Log(LDEBUG, "clipped against right to point (%d, %d), dy=%d/%d", x1 >> CPX, y1 >> CPX, tmp >> CPX, tmp);
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}
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else if (outcode1 & 0x1)
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