2010-05-19 43 views
1

在HLSL中,有没有办法限制编译器使用的常量寄存器的数量?HLSL:在编译时强制执行常量寄存器限制

具体地,如果余有类似:

float4 foobar[300]; 

在vs_2_0顶点着色器,编译器将欢快产生具有超过256个常量寄存器的作用。但是2.0顶点着色器只能保证可以访问256个常量寄存器,所以当我尝试使用这个效果时,它在运行时会以一种模糊和GPU依赖的方式失败。我宁愿让它在编译时失败。

这个问题特别讨厌,因为编译器本身在我要求的场景后面分配常量寄存器。我必须检查大会,看看我是否超出限制。

理想情况下,我想在HLSL(我使用XNA内容管道)中做到这一点,但是如果有一个标志可以传递给编译器,那也会很有趣。

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好问题。自从DirectX开发人员挂在那里以后,我还会在http://forums.xna.com/forums/27.aspx上发布它。 – Stringer 2010-05-19 09:17:18

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谢谢,斯金格贝尔。我按照你的建议将它发布到XNA论坛:http://forums.xna.com/forums/p/53856/326864.aspx – 2010-05-19 22:09:33

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另外:如果在HLSL或编译器中没有办法做到这一点,有没有通过编程方式来计算编译着色器使用的常量寄存器的数量? (理想情况下使用XNA) – 2010-05-19 22:20:03

回答

1

根据Stringer Bell指出的反汇编方法,我掀起了一个小型的构建后工具来分析和检查效果。被警告,这不是很漂亮。它专为XNA 3.1设计,需要the XNA WinForms sampleServiceContainerGraphicsDeviceService类。在命令行上传递内容目录路径而不使用结尾斜杠。

class Program 
{ 
    const int maxRegisters = 256; // Sutiable for VS 2.0, not much else 
    static int retval = 0; 
    static string root; 
    static ContentManager content; 

    static void CheckFile(string path) 
    { 
     string name = path.Substring(root.Length+1, path.Length - (root.Length+1) - @".xnb".Length); 
     Effect effect; 
     try { effect = content.Load<Effect>(name); } 
     catch { return; } // probably not an Effect 
     string effectSource = effect.Disassemble(false); 

     int highest = -1; // highest register allocated 

     var matches = Regex.Matches(effectSource, @" c([0-9]+)"); // quick and dirty 
     foreach(Match match in matches) 
     { 
      int register = Int32.Parse(match.Groups[1].ToString()); 
      if(register > highest) 
       highest = register; 
     } 

     var parameters = Regex.Matches(effectSource, @"^ *// *[a-zA-Z_0-9]+ +c([0-9]+) +([0-9]+)", RegexOptions.Multiline); 
     foreach(Match match in parameters) 
     { 
      int register = Int32.Parse(match.Groups[1].ToString()) + Int32.Parse(match.Groups[2].ToString()) - 1; 
      if(register > highest) 
       highest = register; 
     } 

     if(highest+1 > maxRegisters) 
     { 
      Console.WriteLine("Error: Shader \"" + name + "\" uses " + (highest+1).ToString() + " constant registers, which is TOO MANY!"); 
      retval = 1; 
     } 
     else 
     { 
      Console.WriteLine("Shader \"" + name + "\" uses " + (highest+1).ToString() + " constant registers (OK)"); 
     } 
    } 

    static void CheckDirectory(string path) 
    { 
     try 
     { 
      foreach(string file in Directory.GetFiles(path, @"*.xnb")) 
       CheckFile(file); 
      foreach(string dir in Directory.GetDirectories(path)) 
       CheckDirectory(dir); 
     } 
     catch { return; } // Don't care 
    } 

    static int Main(string[] args) 
    { 
     root = args[0]; 

     Form form = new Form(); // Dummy form for creating a graphics device 
     GraphicsDeviceService gds = GraphicsDeviceService.AddRef(form.Handle, 
       form.ClientSize.Width, form.ClientSize.Height); 

     ServiceContainer services = new ServiceContainer(); 
     services.AddService<IGraphicsDeviceService>(gds); 
     content = new ContentManager(services, root); 

     CheckDirectory(root); 

     return retval; 
    } 
}