reactos/rosapps/tests/polytest/polytest.cpp

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// this is a little 'sandbox' application I put together that duplicates
// the 'guts' of the Polygon algorithm. It allows for quick turn-around
// in testing the algorithm to see what effect your changes have.
//
// Royce3
// the stuff immediately following is support so that the sandbox code
// is nearly identical to the real thing.
// search for the _tagFILL_EDGE struct to find the beginning of the
// real stuff.
#include <memory.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include <conio.h>
#include <assert.h>
#define FASTCALL
#define STDCALL
#define INT int
#define CLIPOBJ int
#define SURFOBJ int
#define PBRUSHOBJ int
#define MIX char
#define BOOL bool
#define TRUE true
#define FALSE false
#define CONST const
#define MmCopyFromCaller memmove
#define ALTERNATE 0
#define WINDING 1
#define ASSERT assert
typedef struct W
{
int polyFillMode;
} W;
typedef struct DC
{
CLIPOBJ CombinedClip;
W w;
} DC, *PDC;
typedef struct tagPOINT
{
long x, y;
} POINT, *PPOINT, *LPPOINT;
typedef struct RECTL
{
long left, top, right, bottom;
} RECTL, *PRECTL;
#define EngFreeMem free
#define FL_ZERO_MEMORY 1
#define DPRINT1 printf("%i:",__LINE__);printf
inline void DPRINT(...){}
#define SCREENX 25
#define SCREENY 15
char screen[SCREENY][SCREENX];
#define EDGE_CHAR '*'
#define FILL_CHAR 'o'
void* EngAllocMem ( int zero, unsigned long size, int tag=0 )
{
void* p = malloc ( size );
if ( zero )
memset ( p, 0, size );
return p;
}
template <class T>
inline T MIN ( T a, T b )
{
return a < b ? a : b;
}
template <class T>
inline T MAX ( T a, T b )
{
return a > b ? a : b;
}
template <class T>
inline T abs ( T t )
{
return t < 0 ? -t : t;
}
void putpixel ( int x, int y, char c )
{
ASSERT( x >= 0 && x < SCREENX && y >= 0 && y < SCREENY );
if ( screen[y][x] == c )
return;
if ( screen[y][x] == ' ' )
screen[y][x] = c;
else
screen[y][x] = '#';
}
void IntEngLineTo (
SURFOBJ*,
CLIPOBJ,
PBRUSHOBJ,
int x1, int y1, int x2, int y2,
RECTL*,
MIX mix )
{
int dx = x2 - x1;
int dy = y2 - y1;
int absdx = abs(dx);
int absdy = abs(dy);
int EMax = MAX(absdx,absdy);
int E = EMax/2;
int xinc = dx < 0 ? -1 : 1,
yinc = dy < 0 ? -1 : 1;
if ( !dy )
{
while ( x1 != x2 )
{
putpixel ( x1, y1, mix );
x1 += xinc;
}
return;
}
if ( !dx )
{
while ( y1 != y2 )
{
putpixel ( x1, y1, mix );
y1 += yinc;
}
return;
}
for ( int i = 0; i < EMax; i++ )
{
putpixel ( x1, y1, mix );
if ( absdy > absdx )
{
y1 += yinc;
E += absdx;
if ( E >= EMax )
{
E -= absdy;
x1 += xinc;
}
}
else
{
x1 += xinc;
E += absdy;
if ( E >= EMax )
{
E -= absdx;
y1 += yinc;
}
}
}
}
#define FILL_EDGE_ALLOC_TAG 0x45465044
/*
** This struct is used for book keeping during polygon filling routines.
*/
typedef struct _tagFILL_EDGE
{
/*Basic line information*/
int FromX;
int FromY;
int ToX;
int ToY;
int dx;
int dy;
int absdx, absdy;
int x, y;
int xmajor;
/*Active Edge List information*/
int XIntercept[2];
int Error;
int ErrorMax;
int XDirection, YDirection;
/* The next edge in the active Edge List*/
struct _tagFILL_EDGE * pNext;
} FILL_EDGE;
typedef struct _FILL_EDGE_LIST
{
int Count;
FILL_EDGE** Edges;
} FILL_EDGE_LIST;
#if 0
static
void
DEBUG_PRINT_ACTIVE_EDGELIST ( FILL_EDGE* list )
{
FILL_EDGE* pThis = list;
if (0 == list)
{
DPRINT1("List is NULL\n");
return;
}
while(0 != pThis)
{
//DPRINT1("EDGE: (%d, %d) to (%d, %d)\n", pThis->FromX, pThis->FromY, pThis->ToX, pThis->ToY);
DPRINT1("EDGE: [%d,%d]\n", pThis->XIntercept[0], pThis->XIntercept[1] );
pThis = pThis->pNext;
}
}
#else
#define DEBUG_PRINT_ACTIVE_EDGELIST(x)
#endif
/*
** Hide memory clean up.
*/
static
void
FASTCALL
POLYGONFILL_DestroyEdgeList(FILL_EDGE_LIST* list)
{
int i;
if ( list )
{
if ( list->Edges )
{
for ( i = 0; i < list->Count; i++ )
{
if ( list->Edges[i] )
EngFreeMem ( list->Edges[i] );
}
EngFreeMem ( list->Edges );
}
EngFreeMem ( list );
}
}
/*
** This makes and initiaizes an Edge struct for a line between two points.
*/
static
FILL_EDGE*
FASTCALL
POLYGONFILL_MakeEdge(POINT From, POINT To)
{
FILL_EDGE* rc = (FILL_EDGE*)EngAllocMem(FL_ZERO_MEMORY, sizeof(FILL_EDGE), FILL_EDGE_ALLOC_TAG);
if (0 == rc)
return NULL;
//DPRINT1("Making Edge: (%d, %d) to (%d, %d)\n", From.x, From.y, To.x, To.y);
//Now Fill the struct.
if ( To.y < From.y )
{
rc->FromX = To.x;
rc->FromY = To.y;
rc->ToX = From.x;
rc->ToY = From.y;
rc->YDirection = -1;
// lines that go up get walked backwards, so need to be offset
// by -1 in order to make the walk identically on a pixel-level
rc->Error = -1;
}
else
{
rc->FromX = From.x;
rc->FromY = From.y;
rc->ToX = To.x;
rc->ToY = To.y;
rc->YDirection = 1;
rc->Error = 0;
}
rc->x = rc->FromX;
rc->y = rc->FromY;
rc->dx = rc->ToX - rc->FromX;
rc->dy = rc->ToY - rc->FromY;
rc->absdx = abs(rc->dx);
rc->absdy = abs(rc->dy);
rc->xmajor = rc->absdx > rc->absdy;
rc->ErrorMax = MAX(rc->absdx,rc->absdy);
rc->Error += rc->ErrorMax / 2;
rc->XDirection = (rc->dx < 0)?(-1):(1);
rc->pNext = 0;
DPRINT("MakeEdge (%i,%i)->(%i,%i) d=(%i,%i) dir=(%i,%i) err=%i max=%i\n",
From.x, From.y, To.x, To.y, rc->dx, rc->dy, rc->XDirection, rc->YDirection, rc->Error, rc->ErrorMax );
return rc;
}
/*
** My Edge comparison routine.
** This is for scan converting polygon fill.
** First sort by MinY, then Minx, then slope.
**
** This comparison will help us determine which
** lines will become active first when scanning from
** top (min y) to bottom (max y).
**
** Return Value Meaning
** Negative integer element1 < element2
** Zero element1 = element2
** Positive integer element1 > element2
*/
static
INT
FASTCALL
FILL_EDGE_Compare(FILL_EDGE* Edge1, FILL_EDGE* Edge2)
{
int e1 = Edge1->XIntercept[0] + Edge1->XIntercept[1];
int e2 = Edge2->XIntercept[0] + Edge2->XIntercept[1];
return e1 - e2;
}
/*
** Insert an edge into a list keeping the list in order.
*/
static
void
FASTCALL
POLYGONFILL_ActiveListInsert(FILL_EDGE** activehead, FILL_EDGE* NewEdge )
{
FILL_EDGE *pPrev, *pThis;
//DPRINT1("In POLYGONFILL_ActiveListInsert()\n");
ASSERT ( activehead && NewEdge );
if ( !*activehead )
{
NewEdge->pNext = NULL;
*activehead = NewEdge;
return;
}
/*
** First lets check to see if we have a new smallest value.
*/
if (FILL_EDGE_Compare(NewEdge, *activehead) <= 0)
{
NewEdge->pNext = *activehead;
*activehead = NewEdge;
return;
}
/*
** Ok, now scan to the next spot to put this item.
*/
pThis = *activehead;
pPrev = NULL;
while ( pThis && FILL_EDGE_Compare(pThis, NewEdge) < 0 )
{
pPrev = pThis;
pThis = pThis->pNext;
}
ASSERT(pPrev);
NewEdge->pNext = pPrev->pNext;
pPrev->pNext = NewEdge;
//DEBUG_PRINT_ACTIVE_EDGELIST(*activehead);
}
/*
** Create a list of edges for a list of points.
*/
static
FILL_EDGE_LIST*
FASTCALL
POLYGONFILL_MakeEdgeList(PPOINT Points, int Count)
{
int CurPt = 0;
FILL_EDGE_LIST* list = 0;
FILL_EDGE* e = 0;
if ( 0 == Points || 2 > Count )
return 0;
list = (FILL_EDGE_LIST*)EngAllocMem(FL_ZERO_MEMORY, sizeof(FILL_EDGE_LIST), FILL_EDGE_ALLOC_TAG);
if ( 0 == list )
goto fail;
list->Count = 0;
list->Edges = (FILL_EDGE**)EngAllocMem(FL_ZERO_MEMORY, Count*sizeof(FILL_EDGE*), FILL_EDGE_ALLOC_TAG);
if ( !list->Edges )
goto fail;
memset ( list->Edges, 0, Count * sizeof(FILL_EDGE*) );
for ( CurPt = 1; CurPt < Count; ++CurPt )
{
e = POLYGONFILL_MakeEdge ( Points[CurPt-1], Points[CurPt] );
if ( !e )
goto fail;
// if a straight horizontal line - who cares?
if ( !e->absdy )
EngFreeMem ( e );
else
list->Edges[list->Count++] = e;
}
e = POLYGONFILL_MakeEdge ( Points[CurPt-1], Points[0] );
if ( !e )
goto fail;
if ( !e->absdy )
EngFreeMem ( e );
else
list->Edges[list->Count++] = e;
return list;
fail:
DPRINT1("Out Of MEMORY!!\n");
POLYGONFILL_DestroyEdgeList ( list );
return 0;
}
/*
** This slow routine uses the data stored in the edge list to
** calculate the x intercepts for each line in the edge list
** for scanline Scanline.
**TODO: Get rid of this floating point arithmetic
*/
static
void
FASTCALL
POLYGONFILL_UpdateScanline(FILL_EDGE* pEdge, int Scanline)
{
if ( 0 == pEdge->dy )
return;
ASSERT ( pEdge->FromY <= Scanline && pEdge->ToY > Scanline );
if ( pEdge->xmajor )
{
int steps;
ASSERT ( pEdge->y == Scanline );
// now shoot to end of scanline collision
steps = (pEdge->ErrorMax-pEdge->Error-1)/pEdge->absdy;
if ( steps )
{
// record first collision with scanline
int x1 = pEdge->x;
pEdge->x += steps * pEdge->XDirection;
pEdge->Error += steps * pEdge->absdy;
ASSERT ( pEdge->Error < pEdge->ErrorMax );
pEdge->XIntercept[0] = MIN(x1,pEdge->x);
pEdge->XIntercept[1] = MAX(x1,pEdge->x);
}
else
{
pEdge->XIntercept[0] = pEdge->x;
pEdge->XIntercept[1] = pEdge->x;
}
// we should require exactly 1 step to step onto next scanline...
ASSERT ( (pEdge->ErrorMax-pEdge->Error-1) / pEdge->absdy == 0 );
pEdge->x += pEdge->XDirection;
pEdge->Error += pEdge->absdy;
ASSERT ( pEdge->Error >= pEdge->ErrorMax );
// now step onto next scanline...
pEdge->Error -= pEdge->absdx;
pEdge->y++;
}
else // then this is a y-major line
{
pEdge->XIntercept[0] = pEdge->x;
pEdge->XIntercept[1] = pEdge->x;
pEdge->Error += pEdge->absdx;
pEdge->y++;
if ( pEdge->Error >= pEdge->ErrorMax )
{
pEdge->Error -= pEdge->ErrorMax;
pEdge->x += pEdge->XDirection;
ASSERT ( pEdge->Error < pEdge->ErrorMax );
}
}
DPRINT("Line (%d, %d) to (%d, %d) intersects scanline %d at (%d,%d)\n",
pEdge->FromX, pEdge->FromY, pEdge->ToX, pEdge->ToY, Scanline, pEdge->XIntercept[0], pEdge->XIntercept[1] );
}
/*
** This method updates the Active edge collection for the scanline Scanline.
*/
static
void
STDCALL
POLYGONFILL_BuildActiveList ( int Scanline, FILL_EDGE_LIST* list, FILL_EDGE** ActiveHead )
{
int i;
ASSERT ( list && ActiveHead );
*ActiveHead = 0;
for ( i = 0; i < list->Count; i++ )
{
FILL_EDGE* pEdge = list->Edges[i];
ASSERT(pEdge);
if ( pEdge->FromY <= Scanline && pEdge->ToY > Scanline )
{
POLYGONFILL_UpdateScanline ( pEdge, Scanline );
POLYGONFILL_ActiveListInsert ( ActiveHead, pEdge );
}
}
}
/*
** This method fills the portion of the polygon that intersects with the scanline
** Scanline.
*/
static
void
STDCALL
POLYGONFILL_FillScanLineAlternate(
PDC dc,
int ScanLine,
FILL_EDGE* ActiveHead,
SURFOBJ *SurfObj,
PBRUSHOBJ BrushObj,
MIX RopMode )
{
FILL_EDGE *pLeft, *pRight;
if ( !ActiveHead )
return;
pLeft = ActiveHead;
pRight = pLeft->pNext;
ASSERT(pRight);
while ( NULL != pRight )
{
int x1 = pLeft->XIntercept[0];
int x2 = pRight->XIntercept[1];
if ( x2 > x1 )
{
RECTL BoundRect;
BoundRect.top = ScanLine;
BoundRect.bottom = ScanLine + 1;
BoundRect.left = x1;
BoundRect.right = x2;
DPRINT("Fill Line (%d, %d) to (%d, %d)\n",x1, ScanLine, x2, ScanLine);
IntEngLineTo( SurfObj,
dc->CombinedClip,
BrushObj,
x1,
ScanLine,
x2,
ScanLine,
&BoundRect, // Bounding rectangle
RopMode); // MIX
}
pLeft = pRight->pNext;
pRight = pLeft ? pLeft->pNext : NULL;
}
}
static
void
STDCALL
POLYGONFILL_FillScanLineWinding(
PDC dc,
int ScanLine,
FILL_EDGE* ActiveHead,
SURFOBJ *SurfObj,
PBRUSHOBJ BrushObj,
MIX RopMode )
{
FILL_EDGE *pLeft, *pRight;
int x1, x2, winding = 0;
RECTL BoundRect;
if ( !ActiveHead )
return;
BoundRect.top = ScanLine;
BoundRect.bottom = ScanLine + 1;
pLeft = ActiveHead;
winding = pLeft->YDirection;
pRight = pLeft->pNext;
ASSERT(pRight);
// setup first line...
x1 = pLeft->XIntercept[0];
x2 = pRight->XIntercept[1];
pLeft = pRight;
pRight = pLeft->pNext;
winding += pLeft->YDirection;
while ( NULL != pRight )
{
int newx1 = pLeft->XIntercept[0];
int newx2 = pRight->XIntercept[1];
if ( winding )
{
// check and see if this new line touches the previous...
if ( (newx1 >= x1 && newx1 <= x2)
|| (newx2 >= x1 && newx2 <= x2)
|| (x1 >= newx1 && x1 <= newx2)
|| (x2 >= newx2 && x2 <= newx2)
)
{
// yup, just tack it on to our existing line
x1 = MIN(x1,newx1);
x2 = MAX(x2,newx2);
}
else
{
// nope - render the old line..
BoundRect.left = x1;
BoundRect.right = x2;
DPRINT("Fill Line (%d, %d) to (%d, %d)\n",x1, ScanLine, x2, ScanLine);
IntEngLineTo( SurfObj,
dc->CombinedClip,
BrushObj,
x1,
ScanLine,
x2,
ScanLine,
&BoundRect, // Bounding rectangle
RopMode); // MIX
x1 = newx1;
x2 = newx2;
}
}
pLeft = pRight;
pRight = pLeft->pNext;
winding += pLeft->YDirection;
}
// there will always be a line left-over, render it now...
BoundRect.left = x1;
BoundRect.right = x2;
DPRINT("Fill Line (%d, %d) to (%d, %d)\n",x1, ScanLine, x2, ScanLine);
IntEngLineTo( SurfObj,
dc->CombinedClip,
BrushObj,
x1,
ScanLine,
x2,
ScanLine,
&BoundRect, // Bounding rectangle
RopMode); // MIX
}
//When the fill mode is ALTERNATE, GDI fills the area between odd-numbered and
//even-numbered polygon sides on each scan line. That is, GDI fills the area between the
//first and second side, between the third and fourth side, and so on.
//WINDING Selects winding mode (fills any region with a nonzero winding value).
//When the fill mode is WINDING, GDI fills any region that has a nonzero winding value.
//This value is defined as the number of times a pen used to draw the polygon would go around the region.
//The direction of each edge of the polygon is important.
BOOL
STDCALL
FillPolygon(
PDC dc,
SURFOBJ *SurfObj,
PBRUSHOBJ BrushObj,
MIX RopMode,
CONST PPOINT Points,
int Count,
RECTL BoundRect )
{
FILL_EDGE_LIST *list = 0;
FILL_EDGE *ActiveHead = 0;
int ScanLine;
void
STDCALL
(*FillScanLine)(
PDC dc,
int ScanLine,
FILL_EDGE* ActiveHead,
SURFOBJ *SurfObj,
PBRUSHOBJ BrushObj,
MIX RopMode );
DPRINT("FillPolygon\n");
/* Create Edge List. */
list = POLYGONFILL_MakeEdgeList(Points, Count);
/* DEBUG_PRINT_EDGELIST(list); */
if (NULL == list)
return FALSE;
if ( WINDING == dc->w.polyFillMode )
FillScanLine = POLYGONFILL_FillScanLineWinding;
else /* default */
FillScanLine = POLYGONFILL_FillScanLineAlternate;
/* For each Scanline from BoundRect.bottom to BoundRect.top,
* determine line segments to draw
*/
for ( ScanLine = BoundRect.top; ScanLine < BoundRect.bottom; ++ScanLine )
{
POLYGONFILL_BuildActiveList(ScanLine, list, &ActiveHead);
//DEBUG_PRINT_ACTIVE_EDGELIST(ActiveHead);
FillScanLine ( dc, ScanLine, ActiveHead, SurfObj, BrushObj, RopMode );
}
/* Free Edge List. If any are left. */
POLYGONFILL_DestroyEdgeList(list);
return TRUE;
}
// this is highly hacked from W32kPolygon...
BOOL
Polygon ( CONST PPOINT UnsafePoints, int Count, int polyFillMode )
{
BOOL ret;
RECTL DestRect;
int CurrentPoint;
PPOINT Points;
SURFOBJ* SurfObj = 0;
DC dc;
PBRUSHOBJ OutBrushObj = 0;
dc.CombinedClip = 0;
dc.w.polyFillMode = polyFillMode;
DPRINT1("In W32kPolygon()\n");
if ( NULL == UnsafePoints || Count < 2)
{
DPRINT1("ERROR_INVALID_PARAMETER\n");
return FALSE;
}
/* Copy points from userspace to kernelspace */
Points = (PPOINT)EngAllocMem(0, Count * sizeof(POINT));
if (NULL == Points)
{
DPRINT1("ERROR_NOT_ENOUGH_MEMORY\n");
return FALSE;
}
MmCopyFromCaller(Points, UnsafePoints, Count * sizeof(POINT));
if ( memcmp ( Points, UnsafePoints, Count * sizeof(POINT) ) )
{
free(Points);
return FALSE;
}
DestRect.left = Points[0].x;
DestRect.right = Points[0].x;
DestRect.top = Points[0].y;
DestRect.bottom = Points[0].y;
for (CurrentPoint = 1; CurrentPoint < Count; ++CurrentPoint)
{
DestRect.left = MIN(DestRect.left, Points[CurrentPoint].x);
DestRect.right = MAX(DestRect.right, Points[CurrentPoint].x);
DestRect.top = MIN(DestRect.top, Points[CurrentPoint].y);
DestRect.bottom = MAX(DestRect.bottom, Points[CurrentPoint].y);
}
// Draw the Polygon Edges with the current pen
for (CurrentPoint = 0; CurrentPoint < Count; ++CurrentPoint)
{
POINT To, From; //, Next;
/* Let CurrentPoint be i
* if i+1 > Count, Draw a line from Points[i] to Points[0]
* Draw a line from Points[i] to Points[i+1]
*/
From = Points[CurrentPoint];
if ( CurrentPoint + 1 >= Count)
{
To = Points[0];
}
else
{
To = Points[CurrentPoint + 1];
}
DPRINT1("Polygon Making line from (%d,%d) to (%d,%d)\n", From.x, From.y, To.x, To.y );
IntEngLineTo(SurfObj,
dc.CombinedClip,
OutBrushObj,
From.x,
From.y,
To.x,
To.y,
&DestRect,
EDGE_CHAR); /* MIX */
}
/* determine the fill mode to fill the polygon. */
ret = FillPolygon(&dc, SurfObj, OutBrushObj, FILL_CHAR, Points, Count, DestRect );
free(Points);
return ret;
}
int main()
{
memset ( screen, ' ', sizeof(screen) );
POINT pts[] =
{
#if 0
{ 0, 0 },
{ 12, 4 },
{ 4, 8 },
#elif 0
{ 3, 0 },
{ 0, 3 },
{ 3, 6 },
#elif 0
{ 1, 1 },
{ 3, 1 },
{ 3, 3 },
{ 1, 3 }
#elif 0
{ 0, 0 },
{ 4, 0 },
{ 4, 4 },
{ 8, 4 },
{ 8, 8 },
{ 4, 8 },
{ 4, 4 },
{ 0, 4 },
#else
{ 4, 12 },
{ 12, 0 },
{ 18, 12 },
{ 4, 4 },
{ 20, 4 }
#endif
};
const int pts_count = sizeof(pts)/sizeof(pts[0]);
// use ALTERNATE or WINDING for 3rd param
Polygon ( pts, pts_count, ALTERNATE );
// print out our "screen"
for ( int y = 0; y < SCREENY; y++ )
{
for ( int x = 0; x < SCREENX; x++ )
{
printf("%c", screen[y][x] );
}
printf("\n");
}
DPRINT1("Done!\n");
(void)getch();
}
/* EOF */