【OpenCV】基本纹理映射，纹理平铺效果-CFANZ编程社区

【OpenCV】基本纹理映射，纹理平铺效果

1.绘制目标
2.核心代码
3.运行结果

1.绘制目标

2.核心代码

// 处理加载进来的图像
Mat LoadImage(const string& fname, bool bAlpha = true) 
{
  if (bAlpha) 
  {
    Mat img_bgra = imread(fname, IMREAD_UNCHANGED);
    if (img_bgra.empty()) 
    {
      cout << "Failed load the image!" << endl;
      return img_bgra;
    }
    flip(img_bgra, img_bgra, 0);
    Mat img_rgba;
    cvtColor(img_bgra, img_rgba, COLOR_BGRA2RGBA);
    return img_rgba;
  }
  else 
  {
    Mat img_bgr = imread(fname, IMREAD_COLOR);
    if (img_bgr.empty()) 
    {
      cout << "Failed load the image!" << endl;
      return img_bgr;
    }
    flip(img_bgr, img_bgr, 0);
    Mat img_rgb;
    cvtColor(img_bgr, img_rgb, COLOR_BGR2RGB);
    return img_rgb;
  }
}

// 加载外部的纹理图 
void LoadExternalTexture() 
{
  // 加载纹理图
  //Mat img_rgba = LoadImage("Brick.jpg", true);
  //Mat img_rgba = LoadImage("smile.png", true);
  Mat img_rgba = LoadImage("monkey.png", true);

  // 绑定纹理图
  glBindTexture(GL_TEXTURE_2D, TEXTURE_ID);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, img_rgba.size[1], img_rgba.size[0], 0, GL_RGBA, GL_UNSIGNED_BYTE, img_rgba.data);

  // 设置纹理平铺属性
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

  // 设置纹理滤波属性
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}

void init() {
  glClearColor(1.f, 1.f, 1.f, 0.f);

  // 创建纹理图ID
  glGenTextures(1, &TEXTURE_ID);

  // 加载纹理图
  LoadExternalTexture();

  // 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 NewFunction5_2()
{
  glBegin(GL_TRIANGLE_STRIP);
  glTexCoord2f(0.5f, 2.f); glVertex2f(-175.f, 175.f);
  glTexCoord2f(0.5f, 0.f); glVertex2f(-175.f, -175.f);
  glTexCoord2f(1.f, 2.f); glVertex2f(-125.f, 175.f);
  glTexCoord2f(1.f, 0.f); glVertex2f(-125.f, -175.f);
  glEnd();

  glBegin(GL_TRIANGLE_STRIP);
  glTexCoord2f(0.f, 2.f); glVertex2f(-125.f, 175.f);
  glTexCoord2f(0.0f, 0.f); glVertex2f(-125.f, -175.f);
  glTexCoord2f(3.f, 2.f); glVertex2f(175.f, 175.f);
  glTexCoord2f(3.f, 0.f); glVertex2f(175.f, -175.f);
  glEnd();
}