mirror of
https://github.com/bulletphysics/bullet3
synced 2024-12-14 22:00:05 +00:00
71 lines
2.0 KiB
C++
71 lines
2.0 KiB
C++
#include <cmath>
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#include <cstdlib>
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#include <ctime>
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#include "BulletInverseDynamics/IDConfig.hpp"
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#include "BulletInverseDynamics/IDMath.hpp"
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#include "IDRandomUtil.hpp"
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namespace btInverseDynamics {
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// constants for random mass and inertia generation
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// these are arbitrary positive values.
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static const float mass_min = 0.001;
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static const float mass_max = 1.0;
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void randomInit() { srand(time(NULL)); }
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int randomInt(int low, int high) { return rand() % (high + 1 - low) + low; }
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float randomFloat(float low, float high) {
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return low + static_cast<float>(rand()) / RAND_MAX * (high - low);
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}
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float randomMass() { return randomFloat(mass_min, mass_max); }
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vec3 randomInertiaPrincipal() {
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vec3 inertia;
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do {
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inertia(0) = randomFloat(mass_min, mass_max);
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inertia(1) = randomFloat(mass_min, mass_max);
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inertia(2) = randomFloat(mass_min, mass_max);
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} while (inertia(0) + inertia(1) < inertia(2) || inertia(0) + inertia(2) < inertia(1) ||
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inertia(1) + inertia(2) < inertia(0));
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return inertia;
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}
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mat33 randomInertiaMatrix() {
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// generate random valid inertia matrix by first getting valid components
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// along major axes and then rotating by random amount
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vec3 principal = randomInertiaPrincipal();
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mat33 rot(transformX(randomFloat(-BT_ID_PI, BT_ID_PI)) * transformY(randomFloat(-BT_ID_PI, BT_ID_PI)) *
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transformZ(randomFloat(-BT_ID_PI, BT_ID_PI)));
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mat33 inertia;
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inertia(0, 0) = principal(0);
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inertia(0, 1) = 0;
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inertia(0, 2) = 0;
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inertia(1, 0) = 0;
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inertia(1, 1) = principal(1);
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inertia(1, 2) = 0;
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inertia(2, 0) = 0;
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inertia(2, 1) = 0;
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inertia(2, 2) = principal(2);
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return rot * inertia * rot.transpose();
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}
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vec3 randomAxis() {
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vec3 axis;
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idScalar length;
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do {
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axis(0) = randomFloat(-1.0, 1.0);
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axis(1) = randomFloat(-1.0, 1.0);
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axis(2) = randomFloat(-1.0, 1.0);
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length = std::sqrt(std::pow(axis(0), 2) + std::pow(axis(1), 2) + std::pow(axis(2), 2));
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} while (length < 0.01);
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return axis / length;
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}
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}
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