module entity.camera;

import
    ws.math.math,
    ws.math.angle,
    ws.math.quaternion,
    ws.math.vector,
    ws.math.matrix,
    entity.entity,
    engine;


class Camera: Entity {

    this(Engine e){
        super(e);
        matrix = new Matrix!(4,4);
        fov = 45;
        near = 1;
        far = 10000;
        update();
    }

    void setAspect(float aspect){
        this.aspect = aspect;
        update;
    }

    void setFov(float fov){
        this.fov = fov;
        update;
    }

    void setBounds(float near, float far){
        this.near = near;
        this.far = far;
        update;
    }

    void update(){
        float xmin, xmax, ymin, ymax;
        ymax = near * tan(fov*PI/360.0);
        ymin = -ymax;
        xmin = ymin * aspect;
        xmax = -xmin;
        matrix[0] = (2*near)/(xmax - xmin);
        matrix[5] = (2*near)/(ymax - ymin);
        matrix[8] = (xmax + xmin) / (xmax - xmin);
        matrix[9] = (ymax + ymin) / (ymax - ymin);
        matrix[10] = -((far + near)/(far - near));
        matrix[11] = -1;
        matrix[14] = -((2*far*near)/(far-near));
        matrix[15] = 0;
    }

    Matrix!(4,4) getProjection(){
        auto m = matrix.dup();
        Angle a = angle.euler();
        a.r *= -1;
        a.y *= -1;
        m.rotate(Quaternion.euler(a));
        m.translate(Vector!3(position.x, -position.y, position.z));
        return m;
    }

    protected {
        float aspect, fov, near, far;
        Matrix!(4,4) matrix;
    }

}