c - 在动画期间获取 OpenGL 中的鼠标点击坐标？

Question

我想制作一个游戏，当有人点击移动的球时，它会爆炸。我已经添加了动画和鼠标点击事件的代码，但是当动画进行时，点击功能不起作用。当我在没有动画的情况下尝试时，它工作正常。我想知道为什么会这样。

#include<stdio.h> 
#include<GL/glut.h> 
#include<unistd.h>
#include<math.h> 

int x, y;
float mx, my;
float i, j;

void mouse(int button, int state, int mousex, int mousey)
{
    if(button==GLUT_LEFT_BUTTON && state==GLUT_DOWN)
    {
        mx = mousex;
        my = mousey;
        printf("%f %f\n",mx,my);
        glutPostRedisplay();
    }
}

void init() 
{ 
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glColor3f(0.0, 1.0, 0.0); 
    glPointSize(1.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, 1560, 0, 840); 
} 

int randValue()
{
    int i = rand();
    int num = i%1000;
    return num;
}

void blast(int x, int y)
{
    glBegin(GL_POLYGON);
    glColor3f(1.0f,0.0f,0.0f);
    glVertex2i(x-100, y-100);
    glVertex2i(x, y-100);
    glVertex2i(x-22, y-20);
    glVertex2i(x-100, y-30);
    glVertex2i(x-30, y-40);
    glVertex2i(x-150, y-80);
    glVertex2i(x-20, y);
    glVertex2i(x, y-40);
    glVertex2i(x-66, y-125);
    glVertex2i(x-34, y-32);
    glVertex2i(x-32, y-55);
    glVertex2i(x-32, y);
    glVertex2i(x-60, y-57);
    glVertex2i(x-75, y-69);
    glVertex2i(x-100, y);
    glEnd();
    glFlush();
}

void display() 
{
    int j = 0, k = 0, l = 1;
    while(1)
    {
        glClear(GL_COLOR_BUFFER_BIT);

        glColor3f(0.0, 1.0, 0.0);
        glBegin(GL_POINTS);

        for (i = 0;i < 6.29;i += 0.001)
        {
            x = 100 * cos(i);
            y = 100 * sin(i);
            glVertex2i(x / 2 + j, y / 2 + k);
            if((x / 2 + j) >= 1560 || (y / 2 + k) >= 840)
            {
                glEnd();
                glFlush();
                glClear(GL_COLOR_BUFFER_BIT);
                blast(x / 2 + j, y / 2 + k);
                sleep(2);
                j = randValue();
                k = 0;
            }
        }
        j = j + 3;
        k = k + 5;
        glEnd();
        glFlush();
    }
}

int main (int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(1360, 768);
    glutInitWindowPosition(0, 0);
    glutCreateWindow("{Project}");
    init();
    glutDisplayFunc(display);
    glutMouseFunc(mouse);
    glutMainLoop();
}

Answer 1

您的代码在 display 函数中有一个无限循环，因此您永远不会将控制权交还给 GLUT。 GLUT 在 glutMainLoop 中已经有一个无限循环。

相反，您应该在 display 中只渲染 ONE 帧，发布 glutPostRedisplay 并返回:

void display() 
{
    glClear(GL_COLOR_BUFFER_BIT);
    // ... draw the frame here ...

    // for exmaple:
    i += 0.001;
    float x = 100 * cos(i);
    float y = 100 * sin(i);
    glColor3f(0.0, 1.0, 0.0);
    glBegin(GL_POINTS);
    glVertex2f(x, y);
    glEnd();

    glFlush();
    glutPostRedisplay();
}

然后您的鼠标函数将被调用，您将能够根据需要更新状态。