如何檢查GLUT中是否未按下鍵？

Question

我在 OpenGL 中制作游戲，現在，我的相機中有一個錯誤：

• 如果我按shift+l或shift+k （移動相機），相機將移動，直到我按下另一個鍵。

要測試我的相機，請在if語句中的playerCameraFunc() function 之后的 display function 中添加createKillerBlock(x, y) （例如createKillerBlock(20, 20) ）。

這是我的代碼：

#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();
}

編輯

如果按下shift+l或shift+k鍵，我想移動相機，但如果未按下 shift+ shift+l或shift+k +k，則停止移動相機。

Answer 1

升級到像FreeGLUT這樣的 GLUT 4+ 實現並注冊一個glutKeyboardUpFunc() / glutSpecialUpFunc()回調以在釋放鍵時獲得通知：

3.4.4 回調的變化

添加了幾個新的回調，並且幾個特定於 Silicon Graphics 硬件的回調尚未實現。 大多數或所有新回調都列在 GLUT 版本 4“glut.h”header 文件中，但未將其納入文檔。 新回調包括常規和特殊按鍵釋放回調、操縱桿回調、菜單 state 回調（帶有一個參數，不同於具有三個參數的菜單狀態回調）、一個 window 狀態回調（也帶有一個參數）和一個window position 回調。 不支持的回調是兩個 Tablet 回調。 如果用戶需要不支持的回調，他應該聯系 freeglut 開發團隊。

用法示例。