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@srndpty
Last active Feb 19, 2018
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Get angle between 2 objects ignoring Y axis
#include <cmath>
struct vec3
{
float x, y, z;
};
float length(vec3 v)
{
return sqrt(v.x * v.x + v.y * v.y + v.z * v.z);
}
float dot(vec3 a, vec3 b)
{
return a.x * b.x + a.y * b.y + a.z * b.z;
}
float cross(vec3 a, vec3 b)
{
vec3 out;
out.x = a.y * b.z - b.y * a.z;
out.y = a.z * b.x - b.z * a.x;
out.z = a.x * b.y - b.x * a.y;
return out;
}
float getRelAngleBetweenXZ(vec3 a, vec3 b)
{
a.y = 0.0f;
b.y = 0.0f;
float cosTheta = dot(a, b) / length(a) * length(b);
float rad = acosf(cosTheta);
vec3 cp = cross(a, b);
if (cp.y > 0)
{
rad *= -1;
}
return rad;
}
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