osg.FrameBufferAttachment

osg.FrameBufferAttachment 是 OpenSceneGraph 中代表帧缓冲附件的类。它可以用于将图像纹理、渲染缓冲区或纹理数组作为帧缓冲的一部分。

构造函数

    FrameBufferAttachment(Texture* texture, GLenum attachment);
    FrameBufferAttachment(RenderBuffer* renderBuffer, GLenum attachment);

方法

setAttachment

    inline void setAttachment(GLenum attachment) { _attachment=attachment; }

设置帧缓冲附件的 GL 枚举文件中的附件点值。

getAttachment

    inline GLenum getAttachment() const { return _attachment; }

获取帧缓冲附件的 GL 枚举文件中的附件点值。

getTexture

    inline Texture* getTexture() const { return _texture.get(); }

获取帧缓冲附件的纹理。

getRenderBuffer

    inline RenderBuffer* getRenderBuffer() const { return _renderBuffer.get(); }

获取帧缓冲附件的渲染缓冲区。

使用方法

用图像纹理创建帧缓冲附件

  GLuint textureID;
  glGenTextures(1, &textureID);
  glBindTexture(GL_TEXTURE_2D, textureID);
  // ...

  osg::ref_ptr<osg::Texture2D> texture = new osg::Texture2D;
  texture->setTextureSize(width, height);
  texture->setInternalFormat(GL_RGBA);
  texture->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
  texture->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);
  texture->setWrap(osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP_TO_EDGE);
  texture->setWrap(osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP_TO_EDGE);
  texture->setUnRefImageDataAfterApply(true);
  texture->setResizeNonPowerOfTwoHint(false);

  osg::ref_ptr<osg::FrameBufferAttachment> fba = new osg::FrameBufferAttachment(texture, GL_COLOR_ATTACHMENT0);

用渲染缓冲区创建帧缓冲附件

  GLuint renderBufferID;
  glGenRenderbuffers(1, &renderBufferID);
  glBindRenderbuffer(GL_RENDERBUFFER, renderBufferID);
  glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, width, height);

  osg::ref_ptr<osg::RenderBuffer> renderBuffer = new osg::RenderBuffer;
  renderBuffer->setInternalFormat(GL_DEPTH_COMPONENT);
  renderBuffer->setFrameBufferObject(renderBufferID);

  osg::ref_ptr<osg::FrameBufferAttachment> fba = new osg::FrameBufferAttachment(renderBuffer, GL_DEPTH_ATTACHMENT);

参考文献

• OpenSceneGraph Documentation