271 lines
8.1 KiB
C
271 lines
8.1 KiB
C
/***************************************************************************
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mathfuncs.c - description
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-------------------
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begin : Thu Sep 6 2001
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copyright : (C) 2001 by Michael Speck
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email : kulkanie@gmx.net
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#include "../client/lbreakout.h"
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#include "mathfuncs.h"
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char circle_msg[256];
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/*
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====================================================================
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Return vector struct with the specified coordinates.
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====================================================================
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*/
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Vector vector_get( float x, float y )
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{
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Vector v = { x, y };
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return v;
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}
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/*
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====================================================================
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Give vector the normed length of 1.
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====================================================================
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*/
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void vector_norm( Vector *v )
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{
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float length;
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if ( v->x == 0 && v->y == 0 ) return; /* NULL vector may not be normed */
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length = sqrt( v->x * v->x + v->y * v->y );
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v->x /= length;
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v->y /= length;
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}
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/*
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====================================================================
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Return monotony of vector. If vertical return 0
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====================================================================
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*/
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float vector_monotony( Vector v )
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{
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if ( v.x == 0 ) return 0;
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return v.y / v.x;
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}
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/*
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====================================================================
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Set length of a vector.
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====================================================================
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*/
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void vector_set_length( Vector *v, float length )
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{
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vector_norm( v );
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v->x *= length; v->y *= length;
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}
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/*
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====================================================================
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Initiate a line struct.
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====================================================================
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*/
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void line_set( Line *line, float x, float y, float m )
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{
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line->vertical = 0;
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line->m = m;
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line->n = y - m*x;
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}
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void line_set_vert( Line *line, float x )
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{
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line->vertical = 1;
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line->x = x;
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}
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void line_set_hori( Line *line, float y )
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{
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line->vertical = 0;
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line->m = 0;
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line->n = y;
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}
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/*
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====================================================================
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Intersect lines and set 'pos' to intersecting point.
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Return Value: True if lines intersect.
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====================================================================
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*/
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int line_intersect( Line *line, Line *target, Coord *pos )
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{
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/* reset pos */
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pos->x = pos->y = 0;
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/* if lines are parallel return False */
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if ( line->vertical && target->vertical ) return 0; /* vertical parallels */
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if ( !line->vertical && !target->vertical && line->m == target->m ) return 0; /* non-vertical parallels */
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/* right now only one thing is supported: line horizontal */
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if ( line->m == 0 && line->vertical == 0 ) {
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pos->y = line->n;
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if ( target->vertical )
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pos->x = target->x;
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else
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pos->x = ( pos->y - target->n ) / target->m;
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return 1;
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}
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if ( line->vertical ) {
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if ( target->vertical ) return 0;
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pos->x = line->x;
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pos->y = target->m * pos->x + target->n;
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return 1;
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}
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if ( target->vertical ) {
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printf( "line_intersect: line non-vertical and target vertical not supported yet\n" );
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return 1;
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}
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/* compute if both lines are neither vertical nor horizontal */
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pos->x = ( line->n - target->n ) / ( target->m - line->m );
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pos->y = line->m * pos->x + line->n;
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return 1;
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}
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/*
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====================================================================
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Initiate a line struct.
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====================================================================
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*/
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void iline_set( ILine *line, int x, int y, int m_4096 )
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{
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line->vertical = 0;
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line->m_4096 = m_4096;
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line->n = y - ((m_4096*x)>>12);
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}
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void iline_set_vert( ILine *line, int x )
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{
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line->vertical = 1;
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line->x = x;
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}
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void iline_set_hori( ILine *line, int y )
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{
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line->vertical = 0;
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line->m_4096 = 0;
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line->n = y;
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}
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/*
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====================================================================
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Intersect lines and set 'pos' to intersecting point.
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Return Value: True if lines intersect.
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====================================================================
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*/
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int iline_intersect( ILine *line, ILine *target, ICoord *pos )
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{
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/* reset pos */
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pos->x = pos->y = 0;
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/* if lines are parallel return False */
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if ( line->vertical && target->vertical ) return 0; /* vertical parallels */
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if ( !line->vertical && !target->vertical )
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if ( line->m_4096 == target->m_4096 ) return 0; /* non-vertical parallels */
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/* right now only one thing is supported: line horizontal */
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if ( line->m_4096 == 0 && line->vertical == 0 ) {
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pos->y = line->n;
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if ( target->vertical )
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pos->x = target->x;
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else
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pos->x = (( pos->y - target->n )<<12) / target->m_4096;
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return 1;
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}
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if ( line->vertical ) {
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if ( target->vertical ) return 0;
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pos->x = line->x;
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pos->y = ((target->m_4096 * pos->x)>>12) + target->n;
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return 1;
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}
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if ( target->vertical ) {
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printf( "line_intersect: line non-vertical and target vertical not supported yet\n" );
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return 1;
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}
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/* compute if both lines are neither vertical nor horizontal */
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pos->x = (( line->n - target->n )<<12) / ( target->m_4096 - line->m_4096 );
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pos->y = ((line->m_4096 * pos->x)>>12) + line->n;
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return 1;
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}
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/*
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====================================================================
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Intersect line pos+t*v with circle (x+m)²=r²
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Important length of v MUST be 1.
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Return Value: True if intersecting, Intersecting points
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====================================================================
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*/
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int circle_intersect( Vector m, int r, Vector pos, Vector v, Vector *t1, Vector *t2 )
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{
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Vector delta = { pos.x - m.x, pos.y - m.y };
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float delta_v = delta.x * v.x + delta.y * v.y;
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float dis = delta_v * delta_v + r * r - ( delta.x * delta.x + delta.y * delta.y );
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float t;
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if ( dis < 0 ) {
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#ifdef WITH_BUG_REPORT
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sprintf( circle_msg, "Diskriminante < 0" );
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#endif
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return 0;
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}
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dis = sqrt( dis );
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t = -delta_v + dis;
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t1->x = pos.x + t * v.x; t1->y = pos.y + t * v.y;
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t = -delta_v - dis;
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t2->x = pos.x + t * v.x; t2->y = pos.y + t * v.y;
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#ifdef WITH_BUG_REPORT
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sprintf( circle_msg, "Intersection points: (%4.2f,%4.2f), (%4.2f,%4.2f)", t1->x, t1->y, t2->x, t2->y );
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#endif
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return 1;
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}
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/* convert vector to angle/2 0-180 and vice versa */
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static Vector impact_vectors[180]; /* clockwise impact vectors in 2 degree steps */
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void init_angles( void )
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{
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int i;
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/* create vectors for all degrees in 2° steps */
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for ( i = 0; i < 180; i++ ) {
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impact_vectors[i].x = cos( 6.28 * i / 180 );
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impact_vectors[i].y = sin( 6.28 * i / 180 );
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}
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}
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int vec2angle( Vector *vec )
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{
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int degrees = 0;
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/* translate impact vector (src-center) into degrees
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* (0°: horizontally right, clockwise going) */
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if ( vec->x == 0 )
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degrees = 90; /* basically impossible as we mask this out */
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else
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degrees = (int)(360 * atan( (double)(fabs(vec->y))/fabs(vec->x) ) / 6.28);
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/* get the proper quartal */
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if ( vec->x > 0 ) {
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if ( vec->y < 0 )
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degrees = 360 - degrees;
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}
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else {
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if ( vec->y >= 0 )
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degrees = 180 - degrees;
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else
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degrees = 180 + degrees;
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}
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return degrees/2;
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}
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void angle2vec( int angle, Vector *vec )
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{
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vec->x = 0;
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vec->y = 0;
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if ( angle < 0 ) return;
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if ( angle > 179 ) return;
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*vec = impact_vectors[angle];
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}
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