OpenGL 在实心球体上绘制透明球体

Question

我有一个带有地球纹理的小球体，我想要一个稍微大一点的球体，上面有云层纹理，它是透明的。

我画的对象是这样的

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glLoadIdentity();

  glDisable(GL_DEPTH_TEST);
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  glPushMatrix();
  auto sphere = gluNewQuadric();
  gluQuadricDrawStyle(sphere, GLU_FILL);
  gluQuadricTexture(sphere, true);
  gluQuadricNormals(sphere, GLU_SMOOTH);
  th4->bind(); // Cloud texture
  gluSphere(sphere, 0.42, 32, 32);
  glPopMatrix();
  glDisable(GL_BLEND);

  glEnable(GL_DEPTH_TEST);
  glPushMatrix();
  sphere = gluNewQuadric();
  gluQuadricDrawStyle(sphere, GLU_FILL);
  gluQuadricTexture(sphere, true);
  gluQuadricNormals(sphere, GLU_SMOOTH);
  th2->bind(); // Earth texture
  gluSphere(sphere, 0.4, 32, 32);
  glPopMatrix();

  glutSwapBuffers();

我这样初始化过剩

  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);

问题是，如果我按这个顺序绘制它们，我的地球球会出现在云纹理球的前面，如果我交换绘制顺序，我就再也无法透过我的云球看到我的地球球了。

更新代码：

  glCullFace(GL_BACK);
  glEnable(GL_CULL_FACE);
  glEnable(GL_DEPTH_TEST);
  glDisable(GL_BLEND);
  glPushMatrix();
  auto sphere = gluNewQuadric();
  gluQuadricDrawStyle(sphere, GLU_FILL);
  gluQuadricTexture(sphere, true);
  gluQuadricNormals(sphere, GLU_SMOOTH);
  th2->bind();
  gluSphere(sphere, 0.4, 32, 32);
  glPopMatrix();


  glDisable(GL_DEPTH_TEST);
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  glPushMatrix();
  sphere = gluNewQuadric();
  gluQuadricDrawStyle(sphere, GLU_FILL);
  gluQuadricTexture(sphere, true);
  gluQuadricNormals(sphere, GLU_SMOOTH);
  th4->bind();
  gluSphere(sphere, 0.42, 32, 32);
  glPopMatrix();
  glDisable(GL_BLEND);

Answer 1

执行以下操作：

启用backface culling
启用depth test
禁用blending
绘制实心地球
启用blending
绘制透明的云彩

OpenGL 在实心球体上绘制透明球体

OpenGL draw transparent sphere over solid sphere

c++

opengl

glut