C++已知两点求角度:
float angle(float x1, float y1, float x2, float y2) { float angle_temp; float xx, yy; xx = x2 - x1; yy = y2 - y1; if (xx == 0.0) angle_temp = PI / 2.0; else angle_temp = atan(fabs(yy / xx)); if ((xx < 0.0) && (yy >= 0.0)) angle_temp = PI - angle_temp; else if ((xx < 0.0) && (yy < 0.0)) angle_temp = PI + angle_temp; else if ((xx >= 0.0) && (yy < 0.0)) angle_temp = PI * 2.0 - angle_temp; return (angle_temp); }