混乱的精灵不会改变

Question

我正在使用 Gamemaker: Studio 开发一款游戏，并且遇到了一个令人讨厌的问题，即玩家的精灵没有改变。我希望尽快得到反馈。没有变化的“玩家”的精灵是 spr_playerboom。这个想法是，当玩家点击 Z 时，精灵会发生变化。

image_speed = 0.2;

var zpress = keyboard_check(ord('Z'));
var rkey = keyboard_check(vk_right);
var lkey = keyboard_check(vk_left);
var jkey = keyboard_check(vk_space);

if(zpress){
sprite_index = spr_playerboom;
}

//Check for ground
if(place_meeting(x, y+1, obj_floor)){
vspd = 0;

//Jumping
if(jkey){
vspd = -jspd;
}
} else {

//Gravity
if(vspd < 10){
vspd += grav;
}

}

//Moving right
if(rkey){
hspd = spd;
sprite_index = spr_playerwalkright;
}

//Moving left
if(lkey){
hspd = -spd;
sprite_index = spr_playerwalkleft;
}



//Check for not moving
if((!rkey && !lkey) || (rkey && lkey) || (!zpress)){
hspd = 0;
sprite_index = spr_playerstand;
}


//Horizontal Collision
if(place_meeting(x+hspd, y, obj_floor)){
while(!place_meeting(x+sign(hspd), y, obj_floor)){
    x+=sign(hspd);
}
hspd = 0;
}

//Moving Horizontally
x += hspd;




 //Vertical Collision
 if(place_meeting(x, y+vspd, obj_floor)){
 while(!place_meeting(x, y+sign(vspd), obj_floor)){
 y+=sign(vspd);
 }
 vspd = 0;
 }
 //Moving Vertically
 y += vspd;

Answer 1

让我们删除不影响精灵的代码。结果将是：

var zpress = keyboard_check(ord('Z'));
var rkey = keyboard_check(vk_right);
var lkey = keyboard_check(vk_left);

if (zpress)
    sprite_index = spr_playerboom;

if (rkey)
    sprite_index = spr_playerwalkright;

if (lkey)
    sprite_index = spr_playerwalkleft;

if ((!rkey && !lkey) || (rkey && lkey) || (!zpress))
{
    sprite_index = spr_playerstand;
}

所以有一个错误。在哪里？前三个条件很简单，不能冲突。所以你需要检查最后一个条件。

(!rkey && !lkey) || (rkey && lkey) || (!zpress)

意思是 如果(both left and rigth keys are not pressed) 或(both left and right keys are pressed) 或(z key is not pressed)。所以如果你按了 Z，但没有按 rkey + lkey，sprite 会在spr_playerstand 上改变，等等。

(((!rkey and !lkey) or (rkey and lkey)) and (!zpress))

在这种情况下，当按下 Z 时，spr_playerstand 上的精灵不会改变