1 /***************************************************************************
2 mathfuncs.c - description
3 -------------------
4 begin : Thu Sep 6 2001
5 copyright : (C) 2001 by Michael Speck
6 email : kulkanie@gmx.net
7 ***************************************************************************/
8
9 /***************************************************************************
10 * *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
15 * *
16 ***************************************************************************/
17
18 #include "../client/lbreakout.h"
19 #include "mathfuncs.h"
20
21 char circle_msg[256];
22
23 /*
24 ====================================================================
25 Return vector struct with the specified coordinates.
26 ====================================================================
27 */
vector_get(float x,float y)28 Vector vector_get( float x, float y )
29 {
30 Vector v = { x, y };
31 return v;
32 }
33 /*
34 ====================================================================
35 Give vector the normed length of 1.
36 ====================================================================
37 */
vector_norm(Vector * v)38 void vector_norm( Vector *v )
39 {
40 float length;
41 if ( v->x == 0 && v->y == 0 ) return; /* NULL vector may not be normed */
42 length = sqrt( v->x * v->x + v->y * v->y );
43 v->x /= length;
44 v->y /= length;
45 }
46 /*
47 ====================================================================
48 Return monotony of vector. If vertical return 0
49 ====================================================================
50 */
vector_monotony(Vector v)51 float vector_monotony( Vector v )
52 {
53 if ( v.x == 0 ) return 0;
54 return v.y / v.x;
55 }
56 /*
57 ====================================================================
58 Set length of a vector.
59 ====================================================================
60 */
vector_set_length(Vector * v,float length)61 void vector_set_length( Vector *v, float length )
62 {
63 vector_norm( v );
64 v->x *= length; v->y *= length;
65 }
66
67 /*
68 ====================================================================
69 Initiate a line struct.
70 ====================================================================
71 */
line_set(Line * line,float x,float y,float m)72 void line_set( Line *line, float x, float y, float m )
73 {
74 line->vertical = 0;
75 line->m = m;
76 line->n = y - m*x;
77 }
line_set_vert(Line * line,float x)78 void line_set_vert( Line *line, float x )
79 {
80 line->vertical = 1;
81 line->x = x;
82 }
line_set_hori(Line * line,float y)83 void line_set_hori( Line *line, float y )
84 {
85 line->vertical = 0;
86 line->m = 0;
87 line->n = y;
88 }
89 /*
90 ====================================================================
91 Intersect lines and set 'pos' to intersecting point.
92 Return Value: True if lines intersect.
93 ====================================================================
94 */
line_intersect(Line * line,Line * target,Coord * pos)95 int line_intersect( Line *line, Line *target, Coord *pos )
96 {
97 /* reset pos */
98 pos->x = pos->y = 0;
99 /* if lines are parallel return False */
100 if ( line->vertical && target->vertical ) return 0; /* vertical parallels */
101 if ( !line->vertical && !target->vertical && line->m == target->m ) return 0; /* non-vertical parallels */
102 /* right now only one thing is supported: line horizontal */
103 if ( line->m == 0 && line->vertical == 0 ) {
104 pos->y = line->n;
105 if ( target->vertical )
106 pos->x = target->x;
107 else
108 pos->x = ( pos->y - target->n ) / target->m;
109 return 1;
110 }
111 if ( line->vertical ) {
112 if ( target->vertical ) return 0;
113 pos->x = line->x;
114 pos->y = target->m * pos->x + target->n;
115 return 1;
116 }
117 if ( target->vertical ) {
118 printf( "line_intersect: line non-vertical and target vertical not supported yet\n" );
119 return 1;
120 }
121 /* compute if both lines are neither vertical nor horizontal */
122 pos->x = ( line->n - target->n ) / ( target->m - line->m );
123 pos->y = line->m * pos->x + line->n;
124 return 1;
125 }
126
127 /*
128 ====================================================================
129 Initiate a line struct.
130 ====================================================================
131 */
iline_set(ILine * line,int x,int y,int m_4096)132 void iline_set( ILine *line, int x, int y, int m_4096 )
133 {
134 line->vertical = 0;
135 line->m_4096 = m_4096;
136 line->n = y - ((m_4096*x)>>12);
137 }
iline_set_vert(ILine * line,int x)138 void iline_set_vert( ILine *line, int x )
139 {
140 line->vertical = 1;
141 line->x = x;
142 }
iline_set_hori(ILine * line,int y)143 void iline_set_hori( ILine *line, int y )
144 {
145 line->vertical = 0;
146 line->m_4096 = 0;
147 line->n = y;
148 }
149 /*
150 ====================================================================
151 Intersect lines and set 'pos' to intersecting point.
152 Return Value: True if lines intersect.
153 ====================================================================
154 */
iline_intersect(ILine * line,ILine * target,ICoord * pos)155 int iline_intersect( ILine *line, ILine *target, ICoord *pos )
156 {
157 /* reset pos */
158 pos->x = pos->y = 0;
159 /* if lines are parallel return False */
160 if ( line->vertical && target->vertical ) return 0; /* vertical parallels */
161 if ( !line->vertical && !target->vertical )
162 if ( line->m_4096 == target->m_4096 ) return 0; /* non-vertical parallels */
163 /* right now only one thing is supported: line horizontal */
164 if ( line->m_4096 == 0 && line->vertical == 0 ) {
165 pos->y = line->n;
166 if ( target->vertical )
167 pos->x = target->x;
168 else
169 pos->x = (( pos->y - target->n )<<12) / target->m_4096;
170 return 1;
171 }
172 if ( line->vertical ) {
173 if ( target->vertical ) return 0;
174 pos->x = line->x;
175 pos->y = ((target->m_4096 * pos->x)>>12) + target->n;
176 return 1;
177 }
178 if ( target->vertical ) {
179 printf( "line_intersect: line non-vertical and target vertical not supported yet\n" );
180 return 1;
181 }
182 /* compute if both lines are neither vertical nor horizontal */
183 pos->x = (( line->n - target->n )<<12) / ( target->m_4096 - line->m_4096 );
184 pos->y = ((line->m_4096 * pos->x)>>12) + line->n;
185 return 1;
186 }
187
188 /*
189 ====================================================================
190 Intersect line pos+t*v with circle (x+m)�=r�
191 Important length of v MUST be 1.
192 Return Value: True if intersecting, Intersecting points
193 ====================================================================
194 */
circle_intersect(Vector m,int r,Vector pos,Vector v,Vector * t1,Vector * t2)195 int circle_intersect( Vector m, int r, Vector pos, Vector v, Vector *t1, Vector *t2 )
196 {
197 Vector delta = { pos.x - m.x, pos.y - m.y };
198 float delta_v = delta.x * v.x + delta.y * v.y;
199 float dis = delta_v * delta_v + r * r - ( delta.x * delta.x + delta.y * delta.y );
200 float t;
201
202 if ( dis < 0 ) {
203 #ifdef WITH_BUG_REPORT
204 sprintf( circle_msg, "Diskriminante < 0" );
205 #endif
206 return 0;
207 }
208 dis = sqrt( dis );
209
210 t = -delta_v + dis;
211 t1->x = pos.x + t * v.x; t1->y = pos.y + t * v.y;
212 t = -delta_v - dis;
213 t2->x = pos.x + t * v.x; t2->y = pos.y + t * v.y;
214 #ifdef WITH_BUG_REPORT
215 sprintf( circle_msg, "Intersection points: (%4.2f,%4.2f), (%4.2f,%4.2f)", t1->x, t1->y, t2->x, t2->y );
216 #endif
217 return 1;
218 }
219
220 /* convert vector to angle/2 0-180 and vice versa */
221 static Vector impact_vectors[180]; /* clockwise impact vectors in 2 degree steps */
222
init_angles(void)223 void init_angles( void )
224 {
225 int i;
226
227 /* create vectors for all degrees in 2� steps */
228 for ( i = 0; i < 180; i++ ) {
229 impact_vectors[i].x = cos( 6.28 * i / 180 );
230 impact_vectors[i].y = sin( 6.28 * i / 180 );
231 }
232 }
233
vec2angle(Vector * vec)234 int vec2angle( Vector *vec )
235 {
236 int degrees = 0;
237
238 /* translate impact vector (src-center) into degrees
239 * (0�: horizontally right, clockwise going) */
240 if ( vec->x == 0 )
241 degrees = 90; /* basically impossible as we mask this out */
242 else
243 degrees = (int)(360 * atan( (double)(fabs(vec->y))/fabs(vec->x) ) / 6.28);
244 /* get the proper quartal */
245 if ( vec->x > 0 ) {
246 if ( vec->y < 0 )
247 degrees = 360 - degrees;
248 }
249 else {
250 if ( vec->y >= 0 )
251 degrees = 180 - degrees;
252 else
253 degrees = 180 + degrees;
254 }
255
256 return degrees/2;
257 }
258
angle2vec(int angle,Vector * vec)259 void angle2vec( int angle, Vector *vec )
260 {
261 vec->x = 0;
262 vec->y = 0;
263
264 if ( angle < 0 ) return;
265 if ( angle > 179 ) return;
266
267 *vec = impact_vectors[angle];
268 }
269
270
271