hackathon-dev #1
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@ -1,4 +1,5 @@
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#include <stdlib.h>
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#include "log.h"
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#include "fbinit.h"
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#include "devctxt.h"
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#include "dc_screen.h"
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@ -78,6 +79,15 @@ static BOOL screen_line(PVOID privdata, INT32 x1, INT32 y1, INT32 x2, INT32 y2,
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INT32 tmp;
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PUINT16 loc;
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ASSERT(x1 >= 0);
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ASSERT(x1 < Fb_Info->width);
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ASSERT(y1 >= 0);
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ASSERT(y1 < Fb_Info->height);
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ASSERT(x2 >= 0);
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ASSERT(x2 < Fb_Info->width);
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ASSERT(y2 >= 0);
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ASSERT(y2 < Fb_Info->height);
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if (ABS(dx) < ABS(dy))
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{
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if (y1 > y2)
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@ -1,5 +1,6 @@
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#include <string.h>
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#include <stdlib.h>
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#include "log.h"
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#include "gfxtype.h"
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#include "gfxobj.h"
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#include "devctxt.h"
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@ -23,17 +24,27 @@ static BOOL line_clip(PINT32 output, INT32 x1, INT32 y1, INT32 x2, INT32 y2, INT
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BYTE outcode1, outcode2, tmpb;
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INT32 tmp;
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Log(LDEBUG, "clipping line from (%d, %d) to (%d, %d) against bounding box (%d, %d, %d, %d)", x1 >> 16, y1 >> 16, x2 >> 16, y2 >> 16,
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xmin >> 16, ymin >> 16, xmax >> 16, ymax >> 16);
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/* Cohen-Sutherland line-clipping algorithm (see Foley & Van Dam, pp. 145-149) */
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for (;;)
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{
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outcode1 = line_clip_outcode(x1, y1, xmin, ymin, xmax, ymax);
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outcode2 = line_clip_outcode(x2, y2, xmin, ymin, xmax, ymax);
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if ((outcode1 & outcode2) != 0)
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{
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Log.debug("*REJECT*");
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return FALSE; /* trivial rejection */
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}
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else if ((outcode1 == 0) && (outcode2 == 0))
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{
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Log.debug("*ACCEPT*");
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break; /* trivial acceptance */
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}
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if (outcode1 == 0)
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{
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Log(LDEBUG, "exchange points")
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tmp = x1;
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x1 = x2;
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x2 = tmp;
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@ -48,23 +59,28 @@ static BOOL line_clip(PINT32 output, INT32 x1, INT32 y1, INT32 x2, INT32 y2, INT
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{
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x1 += (x2 - x1) * (ymin - y1) / (y2 - y1);
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y1 = ymin;
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Log.debug("clipped against top to point (%d, %d)", x1 >> 16, y1 >> 16);
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}
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else if (outcode1 & 0x4)
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{
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x1 += (x2 - x1) * (ymax - y1) / (y2 - y1);
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y1 = ymax;
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Log.debug("clipped against bottom to point (%d, %d)", x1 >> 16, y1 >> 16);
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}
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else if (outcode1 & 0x2)
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{
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y1 += (y2 - y1) * (xmax - x1) / (x2 - x1);
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x1 = xmax;
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Log.debug("clipped against right to point (%d, %d)", x1 >> 16, y1 >> 16);
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}
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else if (outcode1 & 0x1)
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{
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y1 += (y2 - y1) * (xmin - x1) / (x2 - x1);
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x1 = xmin;
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Log.debug("clipped against left to point (%d, %d)", x1 >> 16, y1 >> 16);
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}
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}
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Log(LDEBUG, "final line is from (%d, %d) to (%d, %d)", x1 >> 16, y1 >> 16, x2 >> 16, y2 >> 16);
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output[0] = x1;
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output[1] = y1;
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output[2] = x2;
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