用C++在OpenGL中用键盘移动3D图形。

问题描述 投票：0回答：1

我想把金字塔和立方体 "分别 "移动到前后、上下和左右，使用箭头和上、下键，但我还不能做到，所有的拖曳形状都没有移动，我的2个问题是：我如何选择这些形状中的哪一个我想移动，以及为什么它们都没有移动？ 谢谢。

#include <GL/glut.h>
float xmove = 0, ymove = 0, zmove = 0;
float degree = 0;
float xscale = 1, yscale = 1, zscale = 1;
void right(void)
{
    glLoadIdentity();//koordinat sistemimizetkilenmesin
    xmove += 0.1;
}
void left(void)
{
    glLoadIdentity();
    xmove -= 0.1;
}
void up(void)
{
    glLoadIdentity();
    ymove += 0.1;
}
void down(void)
{
    glLoadIdentity();
    ymove -= 0.1;
}
void front(void)
{
    glLoadIdentity();
    zmove -= 0.1;
}
void back(void)
{
    glLoadIdentity();
    zmove += 0.1;
}
void keyboard(int button, int x, int y)
{
    switch (button)
    {
    case GLUT_KEY_LEFT:left(); break;
    case GLUT_KEY_RIGHT:right(); break;
    case GLUT_KEY_UP:up(); break;
    case GLUT_KEY_DOWN:down(); break;
    case GLUT_KEY_PAGE_UP:front(); break;
    case GLUT_KEY_PAGE_DOWN:back(); break;
    glutPostRedisplay();
    }
}
void Settings()
{
    glClearColor(1,1,1,0);
    glClearDepth(1.0f);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    glShadeModel(GL_SMOOTH);
    glHint(GL_PERSPECTIVE_CORRECTION_HINT , GL_NICEST);
}
void polygons(void)
{
    glColor3f(1.0, 0.0, 0.0);
    glRotatef(degree, 0.0, 1.0, 0.0);
    glScalef(xscale, yscale, zscale);
    glTranslatef(1.5, 0.0, -8.0);
    glBegin(GL_TRIANGLES);//pyramid
    // fronat face
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, -1.0f, 1.0f);
    // down face
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, -1.0f, 1.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, -1.0f, -1.0f);
    //back
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, -1.0f, -1.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(-1.0f, -1.0f, -1.0f);
    //left 
    glColor3f(1.0f, 0.0f, 0.0f); //reed
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glEnd();
    glLoadIdentity();
    glTranslatef(-1.5, 0.0, -8.0); 
    glBegin(GL_QUADS); //cubic
    glColor3f(1.0f, 0.0f, 1.0f); //pink
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    //down face
    glColor3f(1.0f, 0.5f, 0.0f); //orange
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    //front face
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    //back
    glColor3f(1.0f, 1.0f, 0.0f); //yellow
    glVertex3f(1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);

    //left
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    //right
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    glEnd();
}
void DrawingFunction()//painting
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    gluLookAt(0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    polygons();
    glutSwapBuffers();
}
void AppearanceAdjustment(int x, int y)
{
    int aspect = x / y;
    glViewport(0, 0, x, y);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45,aspect,0.1,20);

}
int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE); 
    glutInitWindowPosition(50, 50);
    glutInitWindowSize(800, 600);
    glutCreateWindow("3d shapes");
    glutDisplayFunc(DrawingFunction);
    glutReshapeFunc(AppearanceAdjustment);
    glutSpecialFunc(keyboard);
    Settings();
    glutMainLoop();
    return 0;
}
c++ opengl 3d glut opengl-compat
1个回答
1
投票

glLoadIdentity() 必须调用在 DrawingFunction:

void DrawingFunction()//painting
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity(); // <----
    gluLookAt(0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    polygons();
    glutSwapBuffers();
}

添加偏移量数组和对象编号。

int object = 0;
float xmove[]{ 0, 0 };
float ymove[]{ 0, 0 };
float zmove[]{ 0, 0 };

增加对象选择按钮，改变所选对象的偏移量。glutPostRedisplay() 必须在switch语句之后执行。

void keyboard(int button, int x, int y)
{
    switch (button)
    {
        case GLUT_KEY_F1: object = 0; break;
        case GLUT_KEY_F2: object = 1; break;
        case GLUT_KEY_LEFT: xmove[object] -= 0.1; break;
        case GLUT_KEY_RIGHT: xmove[object] += 0.1; break;
        case GLUT_KEY_DOWN:  ymove[object] -= 0.1; break;
        case GLUT_KEY_UP: ymove[object] += 0.1; break;
        case GLUT_KEY_PAGE_UP: zmove[object] -= 0.1; break;
        case GLUT_KEY_PAGE_DOWN: zmove[object] += 0.1; break;
    }
    glutPostRedisplay();
}

必须在switch语句之后执行： glTranslatef(xmove[i], ymove[i], zmove[i]). 我建议使用 glPushMatrixglPopMatrix:

void polygons(void)
{
    glPushMatrix();

    glColor3f(1.0, 0.0, 0.0);
    glRotatef(degree, 0.0, 1.0, 0.0);
    glScalef(xscale, yscale, zscale);
    glTranslatef(1.5, 0.0, -8.0);

    glTranslatef(xmove[0], ymove[0], zmove[0]); // <--- translate pyramid

    // draw pyramid
    glBegin(GL_TRIANGLES);//pyramid
    // [...]
    glEnd();

    glTranslatef(-1.5, 0.0, -8.0); 
    glTranslatef(xmove[1], ymove[1], zmove[1]); // <--- translate cube

    glBegin(GL_QUADS); //cubic
    // [...]
    glEnd();

    glPopMatrix();
}

示例代码。

int object = 0;
float xmove[]{ 0, 0 };
float ymove[]{ 0, 0 };
float zmove[]{ 0, 0 };

float degree = 0;
float xscale = 1, yscale = 1, zscale = 1;

void keyboard(int button, int x, int y)
{
    switch (button)
    {
        case GLUT_KEY_F1: object = 0; break;
        case GLUT_KEY_F2: object = 1; break;
        case GLUT_KEY_LEFT: xmove[object] -= 0.1; break;
        case GLUT_KEY_RIGHT: xmove[object] += 0.1; break;
        case GLUT_KEY_DOWN:  ymove[object] -= 0.1; break;
        case GLUT_KEY_UP: ymove[object] += 0.1; break;
        case GLUT_KEY_PAGE_UP: zmove[object] -= 0.1; break;
        case GLUT_KEY_PAGE_DOWN: zmove[object] += 0.1; break;
    }
    glutPostRedisplay();
}

void Settings()
{
    glClearColor(1,1,1,0);
    glClearDepth(1.0f);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    glShadeModel(GL_SMOOTH);
    glHint(GL_PERSPECTIVE_CORRECTION_HINT , GL_NICEST);
}

void polygons(void)
{
    glPushMatrix();

    glColor3f(1.0, 0.0, 0.0);
    glRotatef(degree, 0.0, 1.0, 0.0);
    glScalef(xscale, yscale, zscale);
    glTranslatef(1.5, 0.0, -8.0);

    glTranslatef(xmove[0], ymove[0], zmove[0]); // <--- translate pyramid

    glBegin(GL_TRIANGLES);//pyramid
    // fronat face
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, -1.0f, 1.0f);
    // down face
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, -1.0f, 1.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, -1.0f, -1.0f);
    //back
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, -1.0f, -1.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(-1.0f, -1.0f, -1.0f);
    //left 
    glColor3f(1.0f, 0.0f, 0.0f); //reed
    glVertex3f(0.0f, 1.0f, 0.0f);
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glEnd();

    glPopMatrix();
    glPushMatrix();


    glTranslatef(-1.5, 0.0, -8.0); 
    glTranslatef(xmove[1], ymove[1], zmove[1]); // <--- translate cube


    glBegin(GL_QUADS); //cubic
    glColor3f(1.0f, 0.0f, 1.0f); //pink
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    //down face
    glColor3f(1.0f, 0.5f, 0.0f); //orange
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    //front face
    glColor3f(0.0f, 0.0f, 1.0f); //blue
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    //back
    glColor3f(1.0f, 1.0f, 0.0f); //yellow
    glVertex3f(1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, -1.0f);

    //left
    glColor3f(1.0f, 0.0f, 0.0f); //red
    glVertex3f(-1.0f, 1.0f, 1.0f);
    glVertex3f(-1.0f, 1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, -1.0f);
    glVertex3f(-1.0f, -1.0f, 1.0f);
    //right
    glColor3f(0.0f, 1.0f, 0.0f); //green
    glVertex3f(1.0f, 1.0f, -1.0f);
    glVertex3f(1.0f, 1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, 1.0f);
    glVertex3f(1.0f, -1.0f, -1.0f);
    glEnd();

    glPopMatrix();
}

void DrawingFunction()//painting
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
    polygons();
    glutSwapBuffers();
}

void AppearanceAdjustment(int x, int y)
{
    int aspect = x / y;
    glViewport(0, 0, x, y);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45,aspect,0.1,20);
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE); 
    glutInitWindowPosition(50, 50);
    glutInitWindowSize(800, 600);
    glutCreateWindow("3d shapes");
    glutDisplayFunc(DrawingFunction);
    glutReshapeFunc(AppearanceAdjustment);
    glutSpecialFunc(keyboard);
    Settings();
    glutMainLoop();
    return 0;
}
1
投票

你需要用按键来选择其中一个形状 类似于你如何触发上，下，左，右... ...等功能。等函数。比如说按a键选取第一个形状，然后设置一个全局的int ishape=1，如果按b键则为ishape=2。繪圖函數會檢查 ishape 的值，看看它應該移動哪個形狀。但实际上，你需要为每个形状提供一个移动的向量，否则它们的位移会混在一起，然后你需要使用移动向量对需要位移的形状进行gltranslate。

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