[Alka]

I have 2 points origins(P1 and P2) and a third point(P3) that is at distance N from P2. Now what i want to make is to rotate P3 around P2 at X angles. Made a lot of researches and searches but didn't understand so much because of my lack of maths ;s if anyone around knows an answer then thank you.

Some useful info? http://ami.ektf.hu/uploads/papers/fi...om175to186.pdf

Seems like i need rotation matrix / Rodrigues fomula, but i can't find any c/c++ translated functions and practical example to make this work.

Here i have some code that i've found but it doesn't appear to work as intended...

Spoiler

PHP Code:

float vec[3];
SubtractVectors(P1, P2, vec); //don't know exactly what vector to subtract? >.>
float newp[3]; //origin after rotation
float rotation[4][4];
SetupMatrix(90.0, vec, rotation);
MultiplyMatrix(nright, rotation, newp);

stock void MultiplyMatrix(float input[3], float rotation[4][4], float output[3])
{
    float input2[4];
    input2[0] = input[0];
    input2[1] = input[1];
    input2[2] = input[2];
    input2[3] = 1.0;
    
    float output2[4];
    for(int i = 0 ; i < 4 ; i++)
    {
        for(int j = 0 ; j < 4 ; j++)
        {
            output2[i] += rotation[i][j] * input2[j];
        }
    }
    
    output[0] = output2[0];
    output[1] = output2[1];
    output[2] = output2[2];
}

stock void SetupMatrix(float angle, float vector[3], float rotation[4][4])
{
    float L = (vector[0] * vector[0] + vector[1] * vector[1] + vector[2] * vector[2]);
    angle = angle * M_PI / 180.0; //degrees?
    float u2 = vector[0] * vector[0];
    float v2 = vector[1] * vector[1];
    float w2 = vector[2] * vector[2];
    
    rotation[0][0] = (u2 + (v2 + w2) * Cosine(angle)) / L;
    rotation[0][1] = (vector[0] * vector[1] * (1 - Cosine(angle)) - vector[2] * SquareRoot(L) * Sine(angle)) / L;
    rotation[0][2] = (vector[0] * vector[2] * (1 - Cosine(angle)) + vector[1] * SquareRoot(L) * Sine(angle)) / L;
    rotation[0][3] = 0.0; 
    
    rotation[1][0] = (vector[0] * vector[1] * (1 - Cosine(angle)) + vector[2] * SquareRoot(L) * Sine(angle)) / L;
    rotation[1][1] = (v2 + (u2 + w2) * Cosine(angle)) / L;
    rotation[1][2] = (vector[1] * vector[2] * (1 - Cosine(angle)) - vector[0] * SquareRoot(L) * Sine(angle)) / L;
    rotation[1][3] = 0.0; 
    
    rotation[2][0] = (vector[0] * vector[2] * (1 - Cosine(angle)) - vector[1] * SquareRoot(L) * Sine(angle)) / L;
    rotation[2][1] = (vector[1] * vector[2] * (1 - Cosine(angle)) + vector[0] * SquareRoot(L) * Sine(angle)) / L;
    rotation[2][2] = (w2 + (u2 + v2) * Cosine(angle)) / L;
    rotation[2][3] = 0.0; 
    
    rotation[3][0] = 0.0;
    rotation[3][1] = 0.0;
    rotation[3][2] = 0.0;
    rotation[3][3] = 1.0;
} 


EDIT: A more simple version? http://www.engr.uvic.ca/~mech410/lec...RotateArbi.pdf