Chipmunk2D Pro API Reference  7.0.1
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cpBB.h
1 /* Copyright (c) 2013 Scott Lembcke and Howling Moon Software
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21 
22 #ifndef CHIPMUNK_BB_H
23 #define CHIPMUNK_BB_H
24 
25 #include "chipmunk_types.h"
26 #include "cpVect.h"
27 
31 
33 typedef struct cpBB{
34  cpFloat l, b, r ,t;
35 } cpBB;
36 
38 static inline cpBB cpBBNew(const cpFloat l, const cpFloat b, const cpFloat r, const cpFloat t)
39 {
40  cpBB bb = {l, b, r, t};
41  return bb;
42 }
43 
45 static inline cpBB
46 cpBBNewForExtents(const cpVect c, const cpFloat hw, const cpFloat hh)
47 {
48  return cpBBNew(c.x - hw, c.y - hh, c.x + hw, c.y + hh);
49 }
50 
52 static inline cpBB cpBBNewForCircle(const cpVect p, const cpFloat r)
53 {
54  return cpBBNewForExtents(p, r, r);
55 }
56 
58 static inline cpBool cpBBIntersects(const cpBB a, const cpBB b)
59 {
60  return (a.l <= b.r && b.l <= a.r && a.b <= b.t && b.b <= a.t);
61 }
62 
64 static inline cpBool cpBBContainsBB(const cpBB bb, const cpBB other)
65 {
66  return (bb.l <= other.l && bb.r >= other.r && bb.b <= other.b && bb.t >= other.t);
67 }
68 
70 static inline cpBool cpBBContainsVect(const cpBB bb, const cpVect v)
71 {
72  return (bb.l <= v.x && bb.r >= v.x && bb.b <= v.y && bb.t >= v.y);
73 }
74 
76 static inline cpBB cpBBMerge(const cpBB a, const cpBB b){
77  return cpBBNew(
78  cpfmin(a.l, b.l),
79  cpfmin(a.b, b.b),
80  cpfmax(a.r, b.r),
81  cpfmax(a.t, b.t)
82  );
83 }
84 
86 static inline cpBB cpBBExpand(const cpBB bb, const cpVect v){
87  return cpBBNew(
88  cpfmin(bb.l, v.x),
89  cpfmin(bb.b, v.y),
90  cpfmax(bb.r, v.x),
91  cpfmax(bb.t, v.y)
92  );
93 }
94 
96 static inline cpVect
98 {
99  return cpvlerp(cpv(bb.l, bb.b), cpv(bb.r, bb.t), 0.5f);
100 }
101 
103 static inline cpFloat cpBBArea(cpBB bb)
104 {
105  return (bb.r - bb.l)*(bb.t - bb.b);
106 }
107 
109 static inline cpFloat cpBBMergedArea(cpBB a, cpBB b)
110 {
111  return (cpfmax(a.r, b.r) - cpfmin(a.l, b.l))*(cpfmax(a.t, b.t) - cpfmin(a.b, b.b));
112 }
113 
115 static inline cpFloat cpBBSegmentQuery(cpBB bb, cpVect a, cpVect b)
116 {
117  cpFloat idx = 1.0f/(b.x - a.x);
118 #ifdef _MSC_VER
119 #pragma warning(disable: 4056)
120 #endif
121  cpFloat tx1 = (bb.l == a.x ? -INFINITY : (bb.l - a.x)*idx);
122  cpFloat tx2 = (bb.r == a.x ? INFINITY : (bb.r - a.x)*idx);
123  cpFloat txmin = cpfmin(tx1, tx2);
124  cpFloat txmax = cpfmax(tx1, tx2);
125 
126  cpFloat idy = 1.0f/(b.y - a.y);
127  cpFloat ty1 = (bb.b == a.y ? -INFINITY : (bb.b - a.y)*idy);
128  cpFloat ty2 = (bb.t == a.y ? INFINITY : (bb.t - a.y)*idy);
129 #ifdef _MSC_VER
130 #pragma warning(default: 4056)
131 #endif
132  cpFloat tymin = cpfmin(ty1, ty2);
133  cpFloat tymax = cpfmax(ty1, ty2);
134 
135  if(tymin <= txmax && txmin <= tymax){
136  cpFloat min = cpfmax(txmin, tymin);
137  cpFloat max = cpfmin(txmax, tymax);
138 
139  if(0.0 <= max && min <= 1.0) return cpfmax(min, 0.0);
140  }
141 
142  return INFINITY;
143 }
144 
147 {
148  return (cpBBSegmentQuery(bb, a, b) != INFINITY);
149 }
150 
152 static inline cpVect
153 cpBBClampVect(const cpBB bb, const cpVect v)
154 {
155  return cpv(cpfclamp(v.x, bb.l, bb.r), cpfclamp(v.y, bb.b, bb.t));
156 }
157 
159 static inline cpVect
160 cpBBWrapVect(const cpBB bb, const cpVect v)
161 {
162  cpFloat dx = cpfabs(bb.r - bb.l);
163  cpFloat modx = cpfmod(v.x - bb.l, dx);
164  cpFloat x = (modx > 0.0f) ? modx : modx + dx;
165 
166  cpFloat dy = cpfabs(bb.t - bb.b);
167  cpFloat mody = cpfmod(v.y - bb.b, dy);
168  cpFloat y = (mody > 0.0f) ? mody : mody + dy;
169 
170  return cpv(x + bb.l, y + bb.b);
171 }
172 
174 static inline cpBB
175 cpBBOffset(const cpBB bb, const cpVect v)
176 {
177  return cpBBNew(
178  bb.l + v.x,
179  bb.b + v.y,
180  bb.r + v.x,
181  bb.t + v.y
182  );
183 }
184 
186 
187 #endif