如何在空中添加跳跃Dash？

我已经在下方添加了一个破坏点，但我不知道如何在空中添加一个破坏点。

我的角色精灵：

//精灵
maskSpr = spr_Waluigi;
idleSpr = spr_Waluigi;
walkSpr = spr_waluigi_run;
runSpr = spr_waluigi_dash;
jumpSpr = spr_waluigi_jump;

.my 精灵控制：

//精灵控制
//走路
if abs(xspd) > 0 { sprite_index = walkSpr; };
//奔跑
if abs(xspd) >= moveSpd[1] { sprite_index = runSpr };
//不移动
if xspd == 0 { sprite_index = idleSpr; };
//在空中
if !onGround { sprite_index = jumpSpr; };
   //设置碰撞掩码
    mask_index = idleSpr;

.my 控制设置脚本：

function controlsSetup()
{
跳跃缓冲时间 = 3;
跳跃键缓冲 = 0;
跳跃键缓冲计时器 = 0;
}


function getControls()
{
//方向键输入
rightKey = keyboard_check (ord("D")) + keyboard_check(vk_right) + gamepad_button_check( 0, gp_padr );
    rightKey = clamp( rightKey, 0, 1 );
    leftKey  = keyboard_check (ord("A")) + keyboard_check ( vk_left ) + gamepad_button_check( 0, gp_padl );
    leftKey = clamp( leftKey, 0, 1 );

//动作输入
jumpKeyPressed = keyboard_check_pressed( vk_space ) +  gamepad_button_check_pressed( 0, gp_face1 )
        jumpKeyPressed = clamp( jumpKeyPressed, 0, 1 );
    jumpKey = keyboard_check(vk_space) + gamepad_button_check ( 0, gp_face1 );
       jumpKey = clamp( jumpKey, 0, 1 );
runKey = keyboard_check(ord("Z")) + gamepad_button_check( 0, gp_face3 );
   runKey = clamp( runKey, 0, 1);

    //跳跃键缓冲
if jumpKeyPressed
{
    jumpKeyBufferTimer = jumpBufferTime;
}
if jumpKeyBufferTimer > 0
{
    jumpKeyBuffered = 1;
jumpKeyBufferTimer--;
} else {
jumpKeyBuffered = 0;
}
}