求助为什么在while里和while外执行会有差别

void ball(int x,int y,int r,int speed) {
int vx = 0, vy = 0;
while (true) {
if (peekmessage(&msg, EX_KEY)) {}
if (msg.message== WM_KEYDOWN) {
switch (msg.vkcode)
{
case VK_UP:
vy = -1;
break;
case VK_DOWN:
vy = 1;
break;
case VK_RIGHT:
vx = 1;
break;
case VK_LEFT:
vx = -1;
break;
default:
break;
}
}
else if (msg.message== WM_KEYUP) {
switch (msg.vkcode)
{
case VK_UP:
vy = 0;
break;
case VK_DOWN:
vy = 0;
break;
case VK_RIGHT:
vx = 0;
break;
case VK_LEFT:
vx = 0;
break;
default:
break;
}
}
BeginBatchDraw();
cleardevice();
setfillcolor(RED);
solidcircle(x, y, r);
x += speed * vx;
y += speed * vy;
EndBatchDraw();
Sleep(10);
网页链接 = 0;
}
}