【图形学】立方体建模及显示

【图形学】立方体建模及显示

• ​​1.绘制目标​​
• ​​2.核心代码​​
• ​​3.运行结果​​

1.绘制目标

建模并显示下图所示的立方体，要能响应键盘操作以旋转该立方体：
‘x’:绕x轴旋转
‘y’:绕y轴旋转
‘z’:绕z轴旋转
‘r’:复原

2.核心代码

/**********************自定义变量**********************/
cv::Mat img[6];
int Pw = 0, Ph = 0;
const string picture[] = {
  "side1.png",
  "side2.png",
  "side3.png",
  "side4.png",
  "side5.png",
  "side6.png",
};
/******************************************************/

void loadTexture() {
  /// TO DO 
  ///加载立方体六个面的纹理并设置纹理属性//

  for (int i = 0; i < 6; i++)
  {
    img[i] = loadImage(picture[i], Pw, Ph);
  }

  // 设置纹理属性
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_REPEAT);

  // 设置线形滤波
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}

void init()
{
  glClearColor(0.f, 0.f, 0.f, 0.f);
  glEnable(GL_DEPTH_TEST);//开启深度测试

  / TO DO /
  //申请纹理ID、加载纹理、设置纹理环境/
  // 申请纹理ID
  glGenTextures(6, TEXTURE_IDS);

  // 加载纹理
  loadTexture();

  // 设置纹理环境
  glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

  // 开启纹理映射
  glEnable(GL_TEXTURE_2D);
}

void drawCube()
{
  /// TO DO 
  // 绘制立方体/
  //需要设计立方体六个面的三维顶点以及对应的纹理坐标///
  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[0]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[0].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(-50, 50, 50);
  glTexCoord2f(0.f, 0.f); glVertex3f(-50, -50, 50);
  glTexCoord2f(1.f, 0.f); glVertex3f(50, -50, 50);
  glTexCoord2f(1.f, 1.f); glVertex3f(50, 50, 50);
  glEnd();

  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[1]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[1].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(-50, -50, 50);
  glTexCoord2f(0.f, 0.f); glVertex3f(-50, -50, -50);
  glTexCoord2f(1.f, 0.f); glVertex3f(50, -50, -50);
  glTexCoord2f(1.f, 1.f); glVertex3f(50, -50, 50);
  glEnd();

  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[2]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[2].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(-50, 50, -50);
  glTexCoord2f(0.f, 0.f); glVertex3f(-50, -50, -50);
  glTexCoord2f(1.f, 0.f); glVertex3f(-50, -50, 50);
  glTexCoord2f(1.f, 1.f); glVertex3f(-50, 50, 50);
  glEnd();

  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[3]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[3].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(-50, -50, -50);
  glTexCoord2f(0.f, 0.f); glVertex3f(-50, 50, -50);
  glTexCoord2f(1.f, 0.f); glVertex3f(50, 50, -50);
  glTexCoord2f(1.f, 1.f); glVertex3f(50, -50, -50);
  glEnd();

  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[4]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[4].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(-50, 50, -50);
  glTexCoord2f(0.f, 0.f); glVertex3f(-50, 50, 50);
  glTexCoord2f(1.f, 0.f); glVertex3f(50, 50, 50);
  glTexCoord2f(1.f, 1.f); glVertex3f(50, 50, -50);
  glEnd();

  glBindTexture(GL_TEXTURE_CUBE_MAP, TEXTURE_IDS[5]);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, Pw, Ph, 0, GL_RGB, GL_UNSIGNED_BYTE, img[5].data);
  glBegin(GL_TRIANGLE_FAN);
  glTexCoord2f(0.f, 1.f); glVertex3f(50, 50, 50);
  glTexCoord2f(0.f, 0.f); glVertex3f(50, -50, 50);
  glTexCoord2f(1.f, 0.f); glVertex3f(50, -50, -50);
  glTexCoord2f(1.f, 1.f); glVertex3f(50, 50, -50);
  glEnd();
}

void display()
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

   TO DO /
  / 设置模型、视点变换以及立方体显示 /
  gluLookAt(0.0, 0.0, 260.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

  glRotatef(ZROT, 0.0f, 0.0f, 1.0f);
  glRotatef(YROT, 0.0f, 1.0f, 0.0f);
  glRotatef(XROT, 1.0f, 0.0f, 0.0f);

  glScalef(1, 1, 1);

  drawCube();

  glutSwapBuffers();
  glFlush();
}

void reshape(int w, int h)
{
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  // TO DO /
   设置三维透视投影/
  gluPerspective(60, float(w) / float(h), 10.0, 1000.0);
}

// 键盘按键回掉函数
void keyboard(unsigned char key, int x, int y) {
  switch (key) {
  case 'x':
    / TO DO /
    //设置绕x轴的旋转角度
    XROT += 1.0f;

    glutPostRedisplay(); //更新显示内容
    break;
  case 'y':
    / TO DO /
    //设置绕y轴的旋转角度
    YROT += 1.0f;

    glutPostRedisplay();
    break;
  case 'z':
    / TO DO /
    //设置绕z轴的旋转角度
    ZROT += 1.0f;

    glutPostRedisplay();
    break;
  case 'r':
    / TO DO /
    //复原所有旋转角度///
    XROT = 0.0f;
    YROT = 0.0f;
    ZROT = 0.0f;

    glutPostRedisplay();
  default:
    break;
  }
}

3.运行结果