glDeleteTextures似乎没有释放Windows上的纹理内存,有没有解决方案？

Question

我的openGL应用程序在内存不足时出现了一些问题,我正在尝试追踪我的问题.为此,我创建了一个小的测试程序,基本上只是从文件调用glDeleteTextures加载一个巨大的纹理,然后再次加载它,如果我在OSX上运行这个测试程序,这个过程可以运行数百次迭代而没有问题(最多我运行它是1024,这没有问题)但在Windows上大约14次迭代后,我得到一个GLU_OUT_OF_MEMORY错误.我一遍又一遍地装载的纹理是一个巨大的天空圆顶(4096 x 1024和4.9MB).

这是我运行的代码与非lisp倾向的评论:

测试程序:

 (with-glcontext (shared-opengl-view)
   ;;loop 1024 times
   (dotimes (i 1024)
    ;; create a texture and return its texture name
    (let ((texture (create-texture-from-file (truename "lui:resources;sky domes;DarkClouds.png"))))
      ;;Allocate two bytes to pass to glDeleteTextures
      (ccl::rlet ((&texName :long))
        ;; put the texture string into our allocated bytes
        (setf (ccl::%get-long &texName) texture)
          ;; Delete the textures?
          (glDeleteTextures 1 &texName)))))

从文件创建纹理(这个方法的大部分是由openGL调用组成的,所以我认为大多数openGL人员应该对这里发生的事情有一个合理的理解,但我可以澄清任何令人困惑的事情):

(defun CREATE-TEXTURE-FROM-FILE (Filename &key Verbose (Build-Mipmaps t) Repeat (Mag-Filter *Default-OpenGL-Texture-Magnification-Filter*) Forced-Depth) "
in:  Filename {string}, 
&key Verbose {boolean}, Repeat
out: OpenGL-Texture-Name {int}, width, height, depth
Load the <Filename> texture inside the texture directory.
- Ideal file should be 32 bit ARGB compatible, e.g., .png with mask or 24 bit RGB
- 8 bit and 16 bit image will work too 
- Image size must be 2^n x 2^m, at least 64 x 64
- This function must be called with active AGL context, e.g., inside OpenGL-Window INIT     method."
 (declare (ftype function create-image-from-file))
 (rlet ((&texName :long))
   (multiple-value-bind (&Image Width Height Depth) (create-image-from-file Filename :verbose Verbose :flip-vertical t :forced-depth Forced-Depth)
     (unless &Image (return-from create-texture-from-file nil))
     (glPixelStorei GL_UNPACK_ROW_LENGTH Width)  ; Set proper unpacking row length for image
     (glPixelStorei GL_UNPACK_ALIGNMENT 1)       ; Set byte aligned unpacking (needed for 3-byte-per-pixel image)
     (glGenTextures 1 &texName)
     ; Specify the texture's properties.
     (glBindTexture GL_TEXTURE_2D (%get-long &texName))
     (glTexParameteri GL_TEXTURE_2D GL_TEXTURE_WRAP_S (if Repeat GL_REPEAT GL_CLAMP_TO_EDGE))
     (glTexParameteri GL_TEXTURE_2D GL_TEXTURE_WRAP_T (if Repeat GL_REPEAT GL_CLAMP_TO_EDGE))
     (glTexParameteri gl_texture_2d gl_texture_mag_filter Mag-Filter)   ;; make textures look smooth (can be costly)
     ;; Mipmaps: make texture look good at different sizes
     (if Build-Mipmaps
      (glTexParameteri GL_TEXTURE_2D GL_TEXTURE_MIN_FILTER GL_LINEAR_MIPMAP_NEAREST)
      (glTexParameteri GL_TEXTURE_2D GL_TEXTURE_MIN_FILTER GL_LINEAR))
    ;; Experimental: anisotropic filtering to make textures less blurry at angle
    #-:cocotron  (glTexParameterf GL_TEXTURE_2D GL_TEXTURE_MAX_ANISOTROPY_EXT 16.0)
     (let ((PixelFormat (ecase Depth (32 GL_RGBA) (24 GL_RGB)))
         (InternalFormat (ecase Depth (32 GL_RGBA8) (24 GL_RGB8))))
      (glTexImage2D GL_TEXTURE_2D 0 InternalFormat width height 0 PixelFormat GL_UNSIGNED_BYTE &Image)
      (when Build-Mipmaps
        (when Verbose (format t "~%Building Mipmaps~%"))
      (unless 
          ;; The calls to gluBuild2DMipmaps will return GLU_OUT_OF_MEMORY when we run out.
          (zerop (print (gluBuild2DMipmaps GL_TEXTURE_2D InternalFormat width height PixelFormat GL_UNSIGNED_BYTE &Image)))
        (print (get-opengl-error))
        (error "could not create mipmaps"))
      (when Verbose (format t "Completed Mipmaps~%"))))
  ;; OpenGL should have copied now the image data into texture memory: release
  (dispose-vector &Image)
  ;; return the texture handle and image dimensions
  (values
   (%get-long &texName)
   Width 
   Height
   Depth))))

我在其他地方读过glDeleteTextures没有完全处理所有资源,但这些帖子都没有提供任何替代或解决方案.没有这样的解决方案吗？

Answer 1

Windows OpenGL驱动程序的设计假设您的代码实际上会在某些时候绘制内容.因此,当你要求他们完成时,他们倾向于避免做事,将他们推迟到更方便的时间.这就是你在这里遇到的.

仅仅因为你告诉OpenGL你已经完成了一个纹理对象并不意味着OpenGL必须立即放弃那个内存.这样做通常需要一些非常重量级的操作.因此,司机会将此推迟到以后.

的问题是,"后"通常被定义为某种形式的glDraw*命令,glEnd,glFlush/Finish,或一个交换缓冲器命令.或者那种性质的东西.如果您只是坐在循环中并创建/删除纹理,则驱动程序可能无法实际删除任何内容.

尝试减少人工测试.glFinish每个之后添加一个glDeleteTextures.如果这不起作用,请在删除之间绘制内容.

最终,你不能强迫司机做你想做的事.您所能做的就是让您的测试应用程序更像普通应用程序.