class BezierSurface {
    mat4 geoMatrix[3];

public:
    void init() {
        geoMatrix[0] = mat4(    0.0f, 0.0f, 0.0f, 0.0f,
                                0.33f, 0.33f, 0.33f, 0.33f,
                                0.66f, 0.66f, 0.66f, 0.66f,
                                1.0f, 1.0f, 1.0f, 1.0f);

        geoMatrix[1] = mat4(    0.0f, 0.33f, 0.66f, 1.0f,
                                0.0f, 0.33f, 0.66f, 1.0f,
                                0.0f, 0.33f, 0.66f, 1.0f,
                                0.0f, 0.33f, 0.66f, 1.0f);

        geoMatrix[2] = mat4(    5.8f, 18.6f, 81.4f, 84.6f,
                                31.0f, 12.1f, 20.6, 54.0f,
                                52.0f, 14.1f, 13.2f, 378.12f,
                                20.0f, 20.1f, 12.0f, 611.23f);

        printf("%f",y(0.0f, 0.33f));
    }

    float x(float u, float v) {
        float temp = 0.0f;
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 4; j++) {
                temp += geoMatrix[0].m[i][j] * Bers(i, u) * Bers(j, v);
            }
        }
        return temp;
    }

    float y(float u, float v) {
        float temp = 0.0f;
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 4; j++) {
                return geoMatrix[1].m[i][j] * Bers(i, u) * Bers(j, v);
            }
        }
        return temp;
    }

    float z(float u, float v) {
        float temp = 0.0f;
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 4; j++) {
                return geoMatrix[2].m[i][j] * Bers(i, u) * Bers(j, v);
            }
        }
        return temp;
    }

    float Bers(int i, float uv) {
        switch (i){
        case 0: return((1 - uv)*(1 - uv)*(1 - uv));
                break;
        case 1: return((3 * uv)*((1 - uv)*(1 - uv)));
                break;
        case 2: return((3 * (uv*uv))*(1 - uv));
                break;
        case 3: return(uv * uv * uv);
                break;
        }
    }
};