123 lines
3.1 KiB
C++
123 lines
3.1 KiB
C++
/**************************************************************************
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* *
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* Copyright (C) 1992, Silicon Graphics, Inc. *
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* *
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* These coded instructions, statements, and computer programs contain *
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* unpublished proprietary information of Silicon Graphics, Inc., and *
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* are protected by Federal copyright law. They may not be disclosed *
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* to third parties or copied or duplicated in any form, in whole or *
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* in part, without the prior written consent of Silicon Graphics, Inc. *
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* *
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**************************************************************************/
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/*
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* varray.c++ - $Revision: 1.6 $
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* Derrick Burns - 1991
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*/
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#include "glimport.h"
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#include "myassert.h"
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#include "mystdio.h"
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#include "varray.h"
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#include "arc.h"
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#include "math.h" // fabs()
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#define TINY 0.0001
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inline long sgn( REAL x )
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{
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return (x < -TINY) ? -1 : ((x > TINY) ? 1 : 0 );
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}
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Varray::Varray( void )
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{
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varray = 0;
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size = 0;
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}
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Varray::~Varray( void )
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{
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if( varray ) delete[] varray;
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}
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inline void
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Varray::update( Arc_ptr arc, long dir[2], REAL val )
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{
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register long ds = sgn(arc->tail()[0] - arc->prev->tail()[0]);
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register long dt = sgn(arc->tail()[1] - arc->prev->tail()[1]);
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if( dir[0] != ds || dir[1] != dt ) {
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dir[0] = ds;
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dir[1] = dt;
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append( val );
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}
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}
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void
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Varray::grow( long guess )
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{
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if( size < guess ) {
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size = guess * 2;
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if( varray ) delete[] varray;
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varray = new REAL[size];
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assert( varray != 0 );
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}
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}
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long
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Varray::init( REAL delta, Arc_ptr toparc, Arc_ptr botarc )
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{
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Arc_ptr left = toparc->next;
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Arc_ptr right = toparc;
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long ldir[2], rdir[2];
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ldir[0] = sgn( left->tail()[0] - left->prev->tail()[0] );
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ldir[1] = sgn( left->tail()[1] - left->prev->tail()[1] );
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rdir[0] = sgn( right->tail()[0] - right->prev->tail()[0] );
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rdir[1] = sgn( right->tail()[1] - right->prev->tail()[1] );
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vval[0] = toparc->tail()[1];
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numquads = 0;
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while( 1 ) {
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switch( sgn( left->tail()[1] - right->prev->tail()[1] ) ) {
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case 1:
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left = left->next;
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update( left, ldir, left->prev->tail()[1] );
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break;
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case -1:
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right = right->prev;
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update( right, rdir, right->tail()[1] );
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break;
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case 0:
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if( fabs(left->tail()[1] - botarc->tail()[1]) < TINY) goto end;
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if( fabs(left->tail()[0]-right->prev->tail()[0]) < TINY &&
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fabs(left->tail()[1]-right->prev->tail()[1]) < TINY) goto end;
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left = left->next;
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break;
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}
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}
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end:
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append( botarc->tail()[1] );
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grow( ((long) ((vval[0] - vval[numquads])/delta)) + numquads + 2 );
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long index = 0;
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for( long i=0; i<numquads; i++ ) {
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voffset[i] = index;
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varray[index++] = vval[i];
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REAL dist = vval[i] - vval[i+1];
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if( dist > delta ) {
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long steps = ((long) (dist/delta)) +1;
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float deltav = - dist / (REAL) steps;
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for( long j=1; j<steps; j++ )
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varray[index++] = vval[i] + j * deltav;
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}
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}
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voffset[i] = index;
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varray[index] = vval[i];
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return index;
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}
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