c++ - 使用 C++ 在 OpenGL 中移动自动旋转的 3d 多边形

Question

我正在尝试使用这些键将这些拖曳自动旋转的多边形移动到 Right-Left 、Up-Down 和 Front-Back :
对于金字塔，它的键是 ('a','w','s','d','+','-')
对于立方体它的键('←'，'↑'，'→'，'↓'，'PAGE UP'，'PAGE DOWN')
多边形确实在移动，但它们以一种奇怪的方式移动，而不是我希望它们被移动，尤其是当我尝试上下和前后移动它们时
我想知道它们为什么移动，我应该改变什么才能使它们移动正常。

这是代码:

#include <GL\glew.h>
#include <SOIL.h>
#include <GL/glut.h>
float pyramid_x = 0, pyramid_y = 0, pyramid_z = 0;
float cube_x = 0, cube_y = 0, cube_z = 0;
float pyramid_angle = 0.0;
float cube_angle = 0.0;
int refresh = 10;//ms 
float degree = 0;
void cube_right(void)
{
    glLoadIdentity();
    cube_x += 0.1;
}
void cube_left(void)
{
    glLoadIdentity();
    cube_x -= 0.1;
}
void cube_up(void)
{
    glLoadIdentity();
    cube_y += 0.1;
}
void cube_down(void)
{
    glLoadIdentity();
    cube_y -= 0.1;
}
void cube_front(void)
{
    glLoadIdentity();
    cube_z -= 0.1;
}
void cube_back(void)
{
    glLoadIdentity();
    cube_z += 0.1;
}
void pyramid_right(void)
{
    glLoadIdentity();

    pyramid_x += 0.1;
}
void pyramid_left(void)
{
    glLoadIdentity();
    pyramid_x -= 0.1;
}
void pyramid_up(void)
{
    glLoadIdentity();
    pyramid_y += 0.1;
}
void pyramid_down(void)
{
    glLoadIdentity();
    pyramid_y -= 0.1;
}
void pyramid_front(void)
{
    glLoadIdentity();
    pyramid_z -= 0.1;
}
void pyramid_back(void)
{
    glLoadIdentity();
    pyramid_z += 0.1;
}





void keyboard(int buttons, int x, int y)
{

    switch (buttons)

    {
    case GLUT_KEY_LEFT:cube_left(); break;
    case GLUT_KEY_RIGHT:cube_right(); break;
    case GLUT_KEY_UP:cube_up(); break;
    case GLUT_KEY_DOWN:cube_down(); break;
    case GLUT_KEY_PAGE_UP:cube_front(); break;
    case GLUT_KEY_PAGE_DOWN:cube_back(); break;
    }

    glutPostRedisplay();
}
void keyboard(unsigned char buttons, int x, int y)
{
    switch (buttons)
    {
    case 'w':pyramid_front(); break;
    case'a':pyramid_left(); break;
    case's':pyramid_down(); break;
    case'd':pyramid_right(); break;
    case '+':pyramid_front(); break;
    case'-':pyramid_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 drawing_function()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity(); //reset
    glTranslatef(2.0f, 0.0f, -7.0f);
    glRotatef(pyramid_angle, 1.0f, 0.0f, 0.0f);
    glColor3f(1.0, 0.0, 0.0);
    glTranslatef(pyramid_x, pyramid_y, pyramid_z);

    glBegin(GL_TRIANGLES);
    // front
    glTexCoord3f(1, 0, 0);
    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);
    // right
    glTexCoord3f(0, 0, 0);
    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
    glTexCoord3f(0, 1, 0);
    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
    glTexCoord3f(1, 1, 0);
    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);
    glEnd();


    glLoadIdentity();//(Reset model-view matrix)
    glTranslatef(-2.0f, 0.0f, -7.0f);
    glRotatef(cube_angle, 1.0f, 0.0f, 0.0f);
    glTranslatef(cube_x, cube_y, cube_z);
    glBegin(GL_QUADS); //cube

    glColor3f(1.0f, 0.0f, 1.0f);
    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);

    glColor3f(1.0f, 0.5f, 0.0f);
    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);

    glColor3f(0.0f, 0.0f, 1.0f);
    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);

    glColor3f(1.0f, 1.0f, 0.0f);
    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);

    glColor3f(1.0f, 0.0f, 0.0f);
    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);

    glColor3f(0.0f, 1.0f, 0.0f);
    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();
    glutSwapBuffers();
    pyramid_angle += 1.0f;
    cube_angle -= 0.2f;


}
void timer(int deger)
{
    glutPostRedisplay();
    glutTimerFunc(refresh, timer, 0);
}

void view_setting(GLsizei x, GLsizei y)
{
    if (y == 0) y = 1; 
    GLfloat aspect = (GLfloat)x / (GLfloat)y;
    glViewport(0, 0, x, y);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(50.0f, aspect, 1.0f, 20.0f);
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE);
    glutInitWindowPosition(50, 50);
    glutInitWindowSize(800, 600);
    glutCreateWindow("3d");
    glutDisplayFunc(drawing_function);
    glutReshapeFunc(view_setting);
    glutSpecialFunc(keyboard);
    glutKeyboardFunc(keyboard);
    settings();
    glutTimerFunc(0, timer, 0);
    glutMainLoop();
    return 0;
}

Answer 1

更改转换顺序。做旋转然后翻译:

glTranslatef(2.0f, 0.0f, -7.0f);
glTranslatef(pyramid_x, pyramid_y, pyramid_z);
glRotatef(pyramid_angle, 1.0f, 0.0f, 0.0f);

glTranslatef(-2.0f, 0.0f, -7.0f);
glTranslatef(cube_x, cube_y, cube_z);
glRotatef(cube_angle, 1.0f, 0.0f, 0.0f);

矩阵乘法不是 Commutative .操作如 glRotate 和 glTranslate 设置一个新矩阵并将当前矩阵乘以新矩阵。因此，需要首先进行的转换必须是代码中的最后一个。

此外， keyboard 中还有一个错误。 .当 w 被按下时，金字塔必须向上移动而不是向前移动:
case 'w':pyramid_front(); break;

case 'w':pyramid_up(); break;