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#include <cmath>
#include <cstdlib>
#include <ctime>
#include "BulletInverseDynamics/IDConfig.hpp"
#include "BulletInverseDynamics/IDMath.hpp"
#include "IDRandomUtil.hpp"
namespace btInverseDynamics
{
// constants for random mass and inertia generation
// these are arbitrary positive values.
static const float mass_min = 0.001;
static const float mass_max = 1.0;
void randomInit() { srand(time(NULL)); }
void randomInit(unsigned seed) { srand(seed); }
int randomInt(int low, int high) { return rand() % (high + 1 - low) + low; }
float randomFloat(float low, float high)
{
return low + static_cast<float>(rand()) / RAND_MAX * (high - low);
}
float randomMass() { return randomFloat(mass_min, mass_max); }
vec3 randomInertiaPrincipal()
{
vec3 inertia;
do
{
inertia(0) = randomFloat(mass_min, mass_max);
inertia(1) = randomFloat(mass_min, mass_max);
inertia(2) = randomFloat(mass_min, mass_max);
} while (inertia(0) + inertia(1) < inertia(2) || inertia(0) + inertia(2) < inertia(1) ||
inertia(1) + inertia(2) < inertia(0));
return inertia;
}
mat33 randomInertiaMatrix()
{
// generate random valid inertia matrix by first getting valid components
// along major axes and then rotating by random amount
vec3 principal = randomInertiaPrincipal();
mat33 rot(transformX(randomFloat(-BT_ID_PI, BT_ID_PI)) * transformY(randomFloat(-BT_ID_PI, BT_ID_PI)) *
transformZ(randomFloat(-BT_ID_PI, BT_ID_PI)));
mat33 inertia;
inertia(0, 0) = principal(0);
inertia(0, 1) = 0;
inertia(0, 2) = 0;
inertia(1, 0) = 0;
inertia(1, 1) = principal(1);
inertia(1, 2) = 0;
inertia(2, 0) = 0;
inertia(2, 1) = 0;
inertia(2, 2) = principal(2);
return rot * inertia * rot.transpose();
}
vec3 randomAxis()
{
vec3 axis;
idScalar length;
do
{
axis(0) = randomFloat(-1.0, 1.0);
axis(1) = randomFloat(-1.0, 1.0);
axis(2) = randomFloat(-1.0, 1.0);
length = BT_ID_SQRT(BT_ID_POW(axis(0), 2) + BT_ID_POW(axis(1), 2) + BT_ID_POW(axis(2), 2));
} while (length < 0.01);
return axis / length;
}
} // namespace btInverseDynamics
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