/usr/include/chipmunk/constraints/util.h is in chipmunk-dev 5.3.4-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | /* Copyright (c) 2007 Scott Lembcke
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#define CP_DefineClassGetter(t) const cpConstraintClass * t##GetClass(){return (cpConstraintClass *)&klass;}
void cpConstraintInit(cpConstraint *constraint, const cpConstraintClass *klass, cpBody *a, cpBody *b);
#define J_MAX(constraint, dt) (((cpConstraint *)constraint)->maxForce*(dt))
// Get valid body pointers and exit early if the bodies are idle
#define CONSTRAINT_BEGIN(constraint, a_var, b_var) \
cpBody *a_var, *b_var; { \
a_var = ((cpConstraint *)constraint)->a; \
b_var = ((cpConstraint *)constraint)->b; \
if( \
(cpBodyIsSleeping(a_var) || cpBodyIsStatic(a_var)) && \
(cpBodyIsSleeping(b_var) || cpBodyIsStatic(b_var)) \
) return; \
}
static inline cpVect
relative_velocity(cpBody *a, cpBody *b, cpVect r1, cpVect r2){
cpVect v1_sum = cpvadd(a->v, cpvmult(cpvperp(r1), a->w));
cpVect v2_sum = cpvadd(b->v, cpvmult(cpvperp(r2), b->w));
return cpvsub(v2_sum, v1_sum);
}
static inline cpFloat
normal_relative_velocity(cpBody *a, cpBody *b, cpVect r1, cpVect r2, cpVect n){
return cpvdot(relative_velocity(a, b, r1, r2), n);
}
static inline void
apply_impulses(cpBody *a , cpBody *b, cpVect r1, cpVect r2, cpVect j)
{
cpBodyApplyImpulse(a, cpvneg(j), r1);
cpBodyApplyImpulse(b, j, r2);
}
static inline void
apply_bias_impulse(cpBody *body, cpVect j, cpVect r)
{
body->v_bias = cpvadd(body->v_bias, cpvmult(j, body->m_inv));
body->w_bias += body->i_inv*cpvcross(r, j);
}
static inline void
apply_bias_impulses(cpBody *a , cpBody *b, cpVect r1, cpVect r2, cpVect j)
{
apply_bias_impulse(a, cpvneg(j), r1);
apply_bias_impulse(b, j, r2);
}
static inline cpVect
clamp_vect(cpVect v, cpFloat len)
{
return cpvclamp(v, len);
// return (cpvdot(v,v) > len*len) ? cpvmult(cpvnormalize(v), len) : v;
}
static inline cpFloat
k_scalar(cpBody *a, cpBody *b, cpVect r1, cpVect r2, cpVect n)
{
cpFloat mass_sum = a->m_inv + b->m_inv;
cpFloat r1cn = cpvcross(r1, n);
cpFloat r2cn = cpvcross(r2, n);
cpFloat value = mass_sum + a->i_inv*r1cn*r1cn + b->i_inv*r2cn*r2cn;
cpAssert(value != 0.0, "Unsolvable collision or constraint.");
return value;
}
static inline void
k_tensor(cpBody *a, cpBody *b, cpVect r1, cpVect r2, cpVect *k1, cpVect *k2)
{
// calculate mass matrix
// If I wasn't lazy and wrote a proper matrix class, this wouldn't be so gross...
cpFloat k11, k12, k21, k22;
cpFloat m_sum = a->m_inv + b->m_inv;
// start with I*m_sum
k11 = m_sum; k12 = 0.0f;
k21 = 0.0f; k22 = m_sum;
// add the influence from r1
cpFloat a_i_inv = a->i_inv;
cpFloat r1xsq = r1.x * r1.x * a_i_inv;
cpFloat r1ysq = r1.y * r1.y * a_i_inv;
cpFloat r1nxy = -r1.x * r1.y * a_i_inv;
k11 += r1ysq; k12 += r1nxy;
k21 += r1nxy; k22 += r1xsq;
// add the influnce from r2
cpFloat b_i_inv = b->i_inv;
cpFloat r2xsq = r2.x * r2.x * b_i_inv;
cpFloat r2ysq = r2.y * r2.y * b_i_inv;
cpFloat r2nxy = -r2.x * r2.y * b_i_inv;
k11 += r2ysq; k12 += r2nxy;
k21 += r2nxy; k22 += r2xsq;
// invert
cpFloat determinant = k11*k22 - k12*k21;
cpAssert(determinant != 0.0, "Unsolvable constraint.");
cpFloat det_inv = 1.0f/determinant;
*k1 = cpv( k22*det_inv, -k12*det_inv);
*k2 = cpv(-k21*det_inv, k11*det_inv);
}
static inline cpVect
mult_k(cpVect vr, cpVect k1, cpVect k2)
{
return cpv(cpvdot(vr, k1), cpvdot(vr, k2));
}
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