opengl es 2.0 加速着色器效果

Question

我尝试对我的对象（大约 10 个对象）进行一些模糊效果。但是当我应用效果并移动对象时，它非常慢。例如，当我翻译对象时，九个对象的移动不是同步的，但最后一个在翻译之前也有一秒钟的延迟......

这里是我尝试应用着色器的地方（着色器来自这个网站：https://github.com/Jam3/glsl-fast-gaussian-blur）：

  gettimeofday(&t2, &tz);
  deltatime = (float)(t2.tv_sec - t1.tv_sec + (t2.tv_usec - t1.tv_usec) * 1e-6);
  t1 = t2;

  glBindFramebuffer(GL_FRAMEBUFFER, fbo[0]);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glClearColor(0.0f, 0.0f, 0.f, 1.f);  
  glUseProgram(shaderId);

  glUniformMatrix4fv(glGetUniformLocation(shaderId, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
  glUniformMatrix4fv(glGetUniformLocation(shaderId, "view"), 1, GL_FALSE, glm::value_ptr(view));

  //draw all objects
  _transform->drawAll(shaderId);

  glBindFramebuffer(GL_FRAMEBUFFER, 0);

  GLfloat dir[] = {0.0f, 0.0f};
  GLfloat sizeFbo[] = {float(width), float(height)};

  for(int i = 0; i < valueSigma + 1; i++){
    float timeBlur = sin(deltatime) * 0.5f + 0.5f;
    float resBlur = (valueSigma - i) * timeBlur ;

    glBindFramebuffer(GL_FRAMEBUFFER, fbo[1]);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.0f, 0.0f, 0.f, 1.f);  

    glUseProgram(blurShaderId);

    if(i == 0){
      glActiveTexture(GL_TEXTURE0);

      glBindTexture(GL_TEXTURE_2D, tex[0]);
    }
    quadForm->draw();

    auto resolution = glGetUniformLocation(blurShaderId, "resolution");
    if(resolution < 0){
      std::cerr << "failed resolution" << std::endl;
    }

    auto direction = glGetUniformLocation(blurShaderId, "direction");
    if(direction < 0)
      std::cerr << "failed direction" << std::endl;

    if(i % 2 == 0){
      dir[0] = resBlur;
      dir[1] = 0.0f;
      glUniform2fv(direction, 2, dir);
    }
    else{
      dir[0] = 0.0f;
      dir[1] = resBlur;
    }

    glUniform2fv(resolution, 2, sizeFbo);    

    glBindFramebuffer(GL_FRAMEBUFFER, 0);  
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.0f, 0.0f, 0.f, 1.f);  

    glUseProgram(blurShaderId);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, tex[1]);

    quadForm->draw();

    //    dir[0] = dir[1] = 0.0f;
    glUniform2fv(direction, 2, dir);    
    glUniform2fv(resolution, 2, sizeFbo);
  }

Answer 1

你有很多多余的 opengl 调用； glUseProgram、glGetUniformLocation、glClearColor，可能还有 glClear。摆脱它们并说出你的结果。