Question

问题是当我按下'shift'键盘上的其他键时。这是我正在使用的代码（原始代码的功劳归于Nghia Ho）

#include <GL/freeglut.h>
#include <iostream>
#include <cmath>

#include "Camera.h"

using namespace std;

void Display();
void Reshape (int w, int h);
void Keyboard(unsigned char key, int x, int y);
void KeyboardUp(unsigned char key, int x, int y);
void MouseMotion(int x, int y);
void Mouse(int button, int state, int x, int y);
void Timer(int value);
void Idle();

void Grid();

Camera g_camera;
bool g_key[256];
bool g_shift_down = false;
bool g_fps_mode = false;
int g_viewport_width = 0;
int g_viewport_height = 0;
bool g_mouse_left_down = false;
bool g_mouse_right_down = false;

// Movement settings
const float g_translation_speed = 0.05;
const float g_rotation_speed = M_PI/180*0.2;

int main (int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(640, 480);
    glutCreateWindow("FPS demo by Nghia Ho - Hit SPACEBAR to toggle FPS mode");

    glutIgnoreKeyRepeat(1);

    glutDisplayFunc(Display);
    glutIdleFunc(Display);
    glutReshapeFunc(Reshape);
    glutMouseFunc(Mouse);
    glutMotionFunc(MouseMotion);
    glutPassiveMotionFunc(MouseMotion);
    glutKeyboardFunc(Keyboard);
    glutKeyboardUpFunc(KeyboardUp);
    glutIdleFunc(Idle);

    glutTimerFunc(1, Timer, 0);
    glutMainLoop();

    return 0;
}

void Grid()
{
    glPushMatrix();
    glColor3f(1,1,1);

    for(int i=-50; i < 50; i++) {
        glBegin(GL_LINES);
        glVertex3f(i, 0, -50);
        glVertex3f(i, 0, 50);
        glEnd();
    }

    for(int i=-50; i < 50; i++) {
        glBegin(GL_LINES);
        glVertex3f(-50, 0, i);
        glVertex3f(50, 0, i);
        glEnd();
    }

    glPopMatrix();
}

void Display (void) {
    glClearColor (0.0,0.0,0.0,1.0); //clear the screen to black
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //clear the color buffer and the depth buffer
    glLoadIdentity();

    g_camera.Refresh();

    glColor3f(0,1,0);

    glutWireTeapot(0.5);
    Grid();

    glutSwapBuffers(); //swap the buffers
}

void Reshape (int w, int h) {
    g_viewport_width = w;
    g_viewport_height = h;

    glViewport (0, 0, (GLsizei)w, (GLsizei)h); //set the viewport to the current window specifications
    glMatrixMode (GL_PROJECTION); //set the matrix to projection

    glLoadIdentity ();
    gluPerspective (60, (GLfloat)w / (GLfloat)h, 0.1 , 100.0); //set the perspective (angle of sight, width, height, ,depth)
    glMatrixMode (GL_MODELVIEW); //set the matrix back to model
}

void Keyboard(unsigned char key, int x, int y)
{
    if(key == 27) {
        exit(0);
    }

    if(key == ' ') {
        g_fps_mode = !g_fps_mode;

        if(g_fps_mode) {
            glutSetCursor(GLUT_CURSOR_NONE);
            glutWarpPointer(g_viewport_width/2, g_viewport_height/2);
        }
        else {
            glutSetCursor(GLUT_CURSOR_LEFT_ARROW);
        }
    }

    if(glutGetModifiers() == GLUT_ACTIVE_SHIFT) {
        g_shift_down = true;
    }
    else {
        g_shift_down = false;
    }

    g_key[key] = true;
}

void KeyboardUp(unsigned char key, int x, int y)
{
    g_key[key] = false;
}

void Timer(int value)
{
    if(g_fps_mode) {
        if(g_key['w'] || g_key['W']) {
            g_camera.Move(g_translation_speed);
        }
        else if(g_key['s'] || g_key['S']) {
            g_camera.Move(-g_translation_speed);
        }
        else if(g_key['a'] || g_key['A']) {
            g_camera.Strafe(g_translation_speed);
        }
        else if(g_key['d'] || g_key['D']) {
            g_camera.Strafe(-g_translation_speed);
        }
        else if(g_mouse_left_down) {
            g_camera.Fly(-g_translation_speed);
        }
        else if(g_mouse_right_down) {
            g_camera.Fly(g_translation_speed);
        }
    }

    glutTimerFunc(1, Timer, 0);
}

void Idle()
{
    Display();
}

void Mouse(int button, int state, int x, int y)
{
    if(state == GLUT_DOWN) {
        if(button == GLUT_LEFT_BUTTON) {
            g_mouse_left_down = true;
        }
        else if(button == GLUT_RIGHT_BUTTON) {
            g_mouse_right_down = true;
        }
    }
    else if(state == GLUT_UP) {
        if(button == GLUT_LEFT_BUTTON) {
            g_mouse_left_down = false;
        }
        else if(button == GLUT_RIGHT_BUTTON) {
            g_mouse_right_down = false;
        }
    }
}

void MouseMotion(int x, int y)
{
    // This variable is hack to stop glutWarpPointer from triggering an event callback to Mouse(...)
    // This avoids it being called recursively and hanging up the event loop
    static bool just_warped = false;

    if(just_warped) {
        just_warped = false;
        return;
    }

    if(g_fps_mode) {
        int dx = x - g_viewport_width/2;
        int dy = y - g_viewport_height/2;

        if(dx) {
            g_camera.RotateYaw(g_rotation_speed*dx);
        }

        if(dy) {
            g_camera.RotatePitch(g_rotation_speed*dy);
        }

        glutWarpPointer(g_viewport_width/2, g_viewport_height/2);

        just_warped = true;
    }
}

奇怪的是，当我按任何其他键时，它第一次修复它，但它没有第二次修复它万分感谢！

Answer 1

问题是，GLUT键盘功能不会给你键代码，即按下了哪个键和修饰符的数字表示，而是字符代码，即由那个字母形成的字母代码。当然，大写字符具有与其小写字母不同的字符代码。持有班次当然会改变大小写。

实际上，GLUT并不是特别适合您想要的那种输入。使用GLFW或SDL进行此操作要简单得多。但是在您的特定情况下，有一个简单的解决方案：在“按下键”数组中进行索引之前，只需将所有传入的字符代码转换为小写：

#include <ctype.h> /* for tolower */

/* ... */

void Keyboard(unsigned char key, int x, int y)
{
    key = tolower(key); /* <--- */

    if(key == 27) {
        exit(0);
    }

    if(key == ' ') {
        g_fps_mode = !g_fps_mode;

        if(g_fps_mode) {
            glutSetCursor(GLUT_CURSOR_NONE);
            glutWarpPointer(g_viewport_width/2, g_viewport_height/2);
        }
        else {
            glutSetCursor(GLUT_CURSOR_LEFT_ARROW);
        }
    }

    if(glutGetModifiers() == GLUT_ACTIVE_SHIFT) {
        g_shift_down = true;
    }
    else {
        g_shift_down = false;
    }

    g_key[key] = true;
}

freeglut键盘问题

1 个答案: