public Matrix4x4 lookAt(Vector3 eye, Vector3 center, Vector3 up) {
Vector3 forward = (center.subtract(eye)).normalized();
Vector3 side = Vector3.crossProduct(forward, up).normalized();
Vector3 upVector = Vector3.crossProduct(side, forward);
Matrix4x4 m = new Matrix4x4(1);
m.set_value(0, 0, side.x());
m.set_value(1, 0, side.y());
m.set_value(2, 0, side.z());
m.set_value(3, 0, 0.0f);
m.set_value(0, 1, upVector.x());
m.set_value(1, 1, upVector.y());
m.set_value(2, 1, upVector.z());
m.set_value(3, 1, 0.0f);
m.set_value(0, 2, -forward.x());
m.set_value(1, 2, -forward.y());
m.set_value(2, 2, -forward.z());
m.set_value(3, 2, 0.0f);
m.set_value(0, 3, 0.0f);
m.set_value(1, 3, 0.0f);
m.set_value(2, 3, 0.0f);
m.set_value(3, 3, 1.0f);
Matrix4x4 m2 = this.multiply(m);
m2.translate(-eye.x(), -eye.y(), -eye.z());
return m2;
}
public Vector3 multiply(Vector3 vector) {
double x, y, z, w;
if (this.flagBits == Mathematics.mat_type_Identity) {
return vector;
} else if (this.flagBits == Mathematics.mat_type_Translation) {
return new Vector3(
vector.x() + this.mat4[12], vector.y() + this.mat4[13], vector.z() + this.mat4[14]);
} else if (this.flagBits == (Mathematics.mat_type_Translation | Mathematics.mat_type_Scale)) {
return new Vector3(
vector.x() * this.mat4[0] + this.mat4[12],
vector.y() * this.mat4[5] + this.mat4[13],
vector.z() * this.mat4[10] + this.mat4[14]);
} else if (this.flagBits == Mathematics.mat_type_Scale) {
return new Vector3(
vector.x() * this.mat4[0], vector.y() * this.mat4[5], vector.z() * this.mat4[10]);
} else {
x =
vector.x() * this.mat4[0]
+ vector.y() * this.mat4[4]
+ vector.z() * this.mat4[8]
+ this.mat4[12];
y =
vector.x() * this.mat4[1]
+ vector.y() * this.mat4[5]
+ vector.z() * this.mat4[9]
+ this.mat4[13];
z =
vector.x() * this.mat4[2]
+ vector.y() * this.mat4[6]
+ vector.z() * this.mat4[10]
+ this.mat4[14];
w =
vector.x() * this.mat4[3]
+ vector.y() * this.mat4[7]
+ vector.z() * this.mat4[11]
+ this.mat4[15];
if (w == 1.0f) return new Vector3(x, y, z);
else return new Vector3(x / w, y / w, z / w);
}
}
public void rotate(double angle, Vector3 vector) {
rotate(angle, vector.x(), vector.y(), vector.z());
}
public void scale(Vector3 scale_vector) {
scale(scale_vector.x(), scale_vector.y(), scale_vector.z());
}
public void translate(Vector3 translate_vector) {
translate(translate_vector.x(), translate_vector.y(), translate_vector.z());
}