如何检查GLUT中是不是未按下键？
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【中文标题】如何检查GLUT中是不是未按下键？【英文标题】：How to check if key not pressed in GLUT?如何检查GLUT中是否未按下键？ 【发布时间】：2021-05-27 17:53:07 【问题描述】：我在 OpenGL 中制作游戏，现在我的相机出现错误：
如果我按shift+l 或shift+k（移动相机），相机将一直移动，直到我按下另一个键。
要测试我的相机，请在 if 语句中的 playerCameraFunc() 函数之后的显示函数中添加 createKillerBlock(x, y)（例如，createKillerBlock(20, 20)）。
这是我的代码：
#include <stdbool.h>
#include <GL/glut.h>
#define WINDOW_X 1920
#define WINDOW_Y 1080
#define DEFAULT_PLAYER_SPAWN_X 3.0
#define DEFAULT_PLAYER_SPAWN_Y 3.0
#define DEFAULT_CAMERA_X 0.0
#define DEFAULT_CAMERA_Y 0.0
#define UNKILLABLE_LOCATION 1.01
bool isGameStart = false;
int shiftLPresses = 0;
int shiftKPresses = 0;
int shiftXPresses = 0;
int shiftCPresses = 0;
char pressedKey1, pressedKey2;
float blockSize = 10;
float playerX = DEFAULT_PLAYER_SPAWN_X;
float playerY = DEFAULT_PLAYER_SPAWN_Y;
float playerR = 255;
float playerG = 255;
float playerB = 255;
float playerMoveSpeed = 0.7;
float cameraX = DEFAULT_CAMERA_X;
float cameraY = DEFAULT_CAMERA_Y;
float cameraMoveSpeed = 7.1;
float killerBlockX = UNKILLABLE_LOCATION;
float killerBlockY = UNKILLABLE_LOCATION;
float killerBlockR = 255;
float killerBlockG = 0;
float killerBlockB = 0;
void gameMenu()
if (isGameStart == false)
glBegin(GL_LINES);
glColor3f(1.0, 1.0, 1.0);
glVertex2f(-0.2, -0.2);
glVertex2f(0.2, -0.2);
glVertex2f(0.2, -0.2);
glVertex2f(0.2, 0.2);
glVertex2f(0.2, 0.2);
glVertex2f(-0.2, 0.2);
glVertex2f(-0.2, 0.2);
glVertex2f(-0.2, -0.2);
glEnd();
glBegin(GL_POLYGON);
glVertex2f(-0.1, -0.1);
glVertex2f(0.1, 0.0);
glVertex2f(-0.1, 0.1);
glEnd();
void startGame()
isGameStart = true;
void spawnPlayer()
glBegin(GL_POLYGON);
glColor3f(playerR / 255, playerG / 255, playerB / 255);
glVertex2f(-1.0 + (playerX * (blockSize / WINDOW_X)), -1.0 + (playerY * (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (playerX * (blockSize / WINDOW_X) + (blockSize / WINDOW_X)), -1.0 + (playerY * (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (playerX * (blockSize / WINDOW_X) + (blockSize / WINDOW_X)), -1.0 + (playerY * (blockSize / WINDOW_Y) + (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (playerX * (blockSize / WINDOW_X)), -1.0 + (playerY * (blockSize / WINDOW_Y) + (blockSize / WINDOW_Y)));
glEnd();
void playerCameraFunc()
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glTranslatef(cameraX * (blockSize / WINDOW_X), cameraY * (blockSize / WINDOW_Y), 0);
void killPlayer()
isGameStart = false;
pressedKey1 = '\0';
pressedKey2 = '\0';
playerX = DEFAULT_PLAYER_SPAWN_X;
playerY = DEFAULT_PLAYER_SPAWN_Y;
cameraX = DEFAULT_CAMERA_X;
cameraY = DEFAULT_CAMERA_Y;
glutPostRedisplay();
void playerKillFunc()
if (playerX >= killerBlockX - 1.0 & playerY >= killerBlockY - 1.0 & playerX < killerBlockX + 1.0 & playerY <= killerBlockY + 1.0)
if (killerBlockX != UNKILLABLE_LOCATION & killerBlockY != UNKILLABLE_LOCATION)
killPlayer();
void createKillerBlock(int x, int y)
killerBlockX = x;
killerBlockY = y;
glBegin(GL_POLYGON);
glColor3f(killerBlockR / 255, killerBlockG / 255, killerBlockB / 255);
glVertex2f(-1.0 + (x * (blockSize / WINDOW_X)), -1.0 + (y * (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (x * (blockSize / WINDOW_X) + (blockSize / WINDOW_X)), -1.0 + (y * (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (x * (blockSize / WINDOW_X) + (blockSize / WINDOW_X)), -1.0 + (y * (blockSize / WINDOW_Y) + (blockSize / WINDOW_Y)));
glVertex2f(-1.0 + (x * (blockSize / WINDOW_X)), -1.0 + (y * (blockSize / WINDOW_Y) + (blockSize / WINDOW_Y)));
glEnd();
playerKillFunc();
void timer1()
glutTimerFunc(1000 / 60, timer1, 0);
switch (pressedKey1)
case 'w':
if (isGameStart == true)
playerY += playerMoveSpeed / (60 * (shiftXPresses + 1) / (shiftCPresses + 1));
break;
case 'a':
if (isGameStart == true)
playerX -= playerMoveSpeed / (60 * (shiftXPresses + 1) / (shiftCPresses + 1));;
break;
case 's':
if (isGameStart == true)
playerY -= playerMoveSpeed / (60 * (shiftXPresses + 1) / (shiftCPresses + 1));
break;
case 'd':
if (isGameStart == true)
playerX += playerMoveSpeed / (60 * (shiftXPresses + 1) / (shiftCPresses + 1));
break;
glutPostRedisplay();
void timer2()
glutTimerFunc(1000 / 60, timer2, 0);
switch (pressedKey2)
case 76:
if (isGameStart == true)
cameraX -= cameraMoveSpeed / (60 * (shiftLPresses + shiftKPresses + 1));
playerX += cameraMoveSpeed / (60 * (shiftLPresses + shiftKPresses + 1));
break;
case 75:
if (isGameStart == true)
cameraX += cameraMoveSpeed / (60 * (shiftKPresses + shiftLPresses + 1));
playerX -= cameraMoveSpeed / (60 * (shiftKPresses + shiftLPresses + 1));
break;
glutPostRedisplay();
void display()
glClear(GL_COLOR_BUFFER_BIT);
gameMenu();
if (isGameStart == true)
spawnPlayer();
playerCameraFunc();
glFlush();
void keyboard(unsigned char key, int x, int y)
switch (key)
case 'w':
if (isGameStart == true)
pressedKey1 = 'w';
pressedKey2 = '\0';
timer1();
break;
case 'a':
if (isGameStart == true)
pressedKey1 = 'a';
pressedKey2 = '\0';
timer1();
break;
case 's':
if (isGameStart == true)
pressedKey1 = 's';
pressedKey2 = '\0';
timer1();
break;
case 'd':
if (isGameStart == true)
pressedKey1 = 'd';
pressedKey2 = '\0';
timer1();
break;
case 76:
if (isGameStart == true)
shiftLPresses += 1;
pressedKey2 = 76;
timer2();
break;
case 75:
if (isGameStart == true)
shiftKPresses += 1;
pressedKey2 = 75;
timer2();
break;
case 88:
if (isGameStart == true)
shiftXPresses += 1;
pressedKey2 = '\0';
timer1();
break;
case 67:
if (isGameStart == true)
shiftCPresses += 1;
pressedKey2 = '\0';
timer1();
break;
case 13:
if (isGameStart == false)
startGame();
timer1();
break;
default:
pressedKey2 = '\0';
glutPostRedisplay();
int main(int argc, char **argv)
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE);
glutCreateWindow("OpenAttack1");
glutFullScreen();
glutDisplayFunc(display);
glutKeyboardFunc(keyboard);
glutSetCursor(GLUT_CURSOR_NONE);
glutMainLoop();
编辑
如果按下shift+l 或shift+k 键，我想移动相机，但如果未按下shift+l 或shift+k，则停止移动相机。
【问题讨论】：
你为什么在playerCameraFunc()之前调用spawnPlayer()？
我尝试在playerCameraFunc() 之后拨打spawnPlayer()。但什么都没有改变。
您正在增加名称为shiftKPresses 的变量，但我看不到它们在哪里减少或设置为零。我猜这就是事情失控的原因。
@TimRandall 我认为您没有完全阅读我的代码。你读过吗？这个 (cameraX -= cameraMoveSpeed / (60 * (shiftLPresses + shiftKPresses + 1));) 行？
@TimRandall 我的问题不是速度。我的问题是除非我按另一个键，否则相机不会停止移动。
【参考方案1】：
升级到 GLUT 4+ 实现，例如 FreeGLUT 并注册 glutKeyboardUpFunc()/glutSpecialUpFunc() 回调以在释放键时获得通知：
3.4.4 Changes to Callbacks
添加了几个新的回调，并且几个特定于 Silicon Graphics 硬件的回调尚未实现。大多数或所有新回调都列在 GLUT 版本 4“glut.h”头文件中，但未将其纳入文档。 新的回调包括常规和特殊的按键释放回调、一个操纵杆回调、一个菜单状态回调（一个参数，不同于具有三个参数的菜单状态回调）、一个窗口状态回调（也一个参数）和一个窗口位置回调。不支持的回调是两个 Tablet 回调。如果用户需要不支持的回调，他应该联系 freeglut 开发团队。
Usage example.
【讨论】：
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