ns/releases/3.1.4/source/util/Quat.cpp
2006-04-21 00:51:55 +00:00

210 lines
4.4 KiB
C++

#include "Quat.h"
#include "common/mathlib.h"
float WrapFloat(float, float, float);
void VectorsToAngles(const float forward[3], const float right[3], const float up[3], float angles[3]);
#include <math.h>
Quat::Quat()
{
}
Quat::Quat(float _x, float _y, float _z, float _w)
: x(_x), y(_y), z(_z), w(_w)
{
}
Quat::Quat(const float angles[3])
{
float xAxis[3];
float yAxis[3];
float zAxis[3];
AngleVectors(angles, yAxis, xAxis, zAxis);
*this = Quat(xAxis, yAxis, zAxis);
}
Quat::Quat(const float xAxis[3], const float yAxis[3], const float zAxis[3])
{
float t = xAxis[0] + yAxis[1] + zAxis[2];
if (t > 0) {
float s = sqrtf(t + 1);
x = (zAxis[1] - yAxis[2]) * (0.5f / s);
y = (xAxis[2] - zAxis[0]) * (0.5f / s);
z = (yAxis[0] - xAxis[1]) * (0.5f / s);
w = s * 0.5f;
} else {
if (xAxis[0] > yAxis[1] && xAxis[0] > zAxis[2]) {
float s = sqrtf(xAxis[0] - yAxis[1] - zAxis[2] + 1);
x = 0.5f * s;
y = (yAxis[0] + xAxis[1]) * (0.5f / s);
z = (zAxis[0] + xAxis[2]) * (0.5f / s);
w = (zAxis[1] - yAxis[2]) * (0.5f / s);
} else if (yAxis[1] > xAxis[0] && yAxis[1] > zAxis[2]) {
float s = sqrtf(yAxis[1] - xAxis[0] - zAxis[2] + 1);
x = (xAxis[1] + yAxis[0]) * (0.5f / s);
y = 0.5f * s;
z = (zAxis[1] + yAxis[2]) * (0.5f / s);
w = (xAxis[2] - zAxis[0]) * (0.5f / s);
} else {
float s = sqrtf(zAxis[2] - xAxis[0] - yAxis[1] + 1);
x = (xAxis[2] + zAxis[0]) * (0.5f / s);
y = (yAxis[2] + zAxis[1]) * (0.5f / s);
z = 0.5f * s;
w = (yAxis[0] - xAxis[1]) * (0.5f / s);
}
}
}
Quat::Quat(float angle, const float axis[3])
{
float sa = sinf(angle / 2);
float ca = cosf(angle / 2);
x = axis[0] * sa;
y = axis[1] * sa;
z = axis[2] * sa;
w = ca;
}
Quat Quat::Conjugate() const
{
return Quat(-x, -y, -z, w);
}
Quat Quat::Unit() const
{
float l = sqrtf(x * x + y * y + z * z + w * w);
return Quat(x / l, y / l, z / l, w / l);
}
void Quat::GetVectors(float xAxis[3], float yAxis[3], float zAxis[3]) const
{
float xx = x * x;
float xy = x * y;
float xz = x * z;
float xw = x * w;
float yy = y * y;
float yz = y * z;
float yw = y * w;
float zz = z * z;
float zw = z * w;
float ww = w * w;
xAxis[0] = 1 - 2 * (yy + zz);
xAxis[1] = 2 * (xy - zw);
xAxis[2] = 2 * (xz + yw);
yAxis[0] = 2 * (xy + zw);
yAxis[1] = 1 - 2 * (xx + zz);
yAxis[2] = 2 * (yz - xw);
zAxis[0] = 2 * (xz - yw);
zAxis[1] = 2 * (yz + xw);
zAxis[2] = 1 - 2 * (xx + yy);
}
Quat operator*(const Quat& q1, const Quat& q2)
{
return Quat(q1.w * q2.x + q1.x * q2.w + q1.y * q2.z - q1.z * q2.y,
q1.w * q2.y + q1.y * q2.w + q1.z * q2.x - q1.x * q2.z,
q1.w * q2.z + q1.z * q2.w + q1.x * q2.y - q1.y * q2.x,
q1.w * q2.w - q1.x * q2.x - q1.y * q2.y - q1.z * q2.z);
}
Quat ConstantRateLerp(const Quat& src, const Quat& dst, float amount)
{
Quat rot = (dst * src.Conjugate()).Unit();
// Compute the axis and angle we need to rotate about to go from src
// to dst.
float angle = acosf(rot.w) * 2;
float sinAngle = sqrtf(1.0f - rot.w * rot.w);
if (fabs(sinAngle) < 0.0005f)
{
sinAngle = 1;
}
vec3_t axis;
axis[0] = rot.x / sinAngle;
axis[1] = rot.y / sinAngle;
axis[2] = rot.z / sinAngle;
// Wrap the angle to the range -PI to PI
angle = WrapFloat(angle, (float)(-M_PI), (float)(M_PI));
// Amount to rotate this frame.
float frameAngle = amount;
if (fabs(angle) <= frameAngle)
{
// If we are very close, just jump to the goal orientation.
return dst;
}
else
{
Quat final;
if (angle < 0)
{
final = Quat(-frameAngle, axis) * src;
}
else
{
final = Quat(frameAngle, axis) * src;
}
return final;
}
}
void Quat::GetAngles(float outAngles[3]) const
{
vec3_t xAxis;
vec3_t yAxis;
vec3_t zAxis;
GetVectors(xAxis, yAxis, zAxis);
VectorsToAngles(yAxis, xAxis, zAxis, outAngles);
}