问HLSL: Unitys Vector3.RotateTowards(...)

EN

float3 slerp(float3 current, float3 target, float maxAngle)
{
    // Dot product - the cosine of the angle between 2 vectors.
    float dot = dot(current, target);     

    // Clamp it to be in the range of Acos()
    // This may be unnecessary, but floating point
    // precision can be a fickle mistress.
    dot = clamp(dot, -1, 1);

    // Acos(dot) returns the angle between start and end,
    // And multiplying that by percent returns the angle between
    // start and the final result.
    float delta = acos(dot);
    float theta = min(1.0f, maxAngle / delta);

    float3 relativeVec = normalize(target - current*dot); // Orthonormal basis

    float3 slerped = ((start*cos(theta)) + (relativeVec*sin(theta)));
}