与GLSL中的texture2D（）和OpenGL中的glTexImage2D（）相关的内部格式 [英] internal format related to texture2D() in GLSL and glTexImage2D() in OpenGL

问题描述

我很困惑与GLSL中的texture2D（）和OpenGL中的glTexImage2D（）相关的内部格式，当我使用（注意第三个和第八参数）：

  glTexImage2D（GL_TEXTURE_2D，0，GL_RGBA16F_ARB，WINDOW_SIZE，WINDOW_SIZE ，0，GL_RGBA，
 GL_FLOAT，floatDataPtr）; 
  

我得到了sampler2D的 nonclampedvalue glsl没有被钳位到[0，1]：

pre $ vec4 nonclampedvalue = texture2D（my16floattex2d，texcoord1）;

当我使用时：

  glTexImage2D（GL_TEXTURE_2D，0，GL_RGBA8，WINDOW_SIZE，WINDOW_SIZE，0，GL_RGBA，
 GL_UNSIGNED_BYTE，byteDataPtr）; 
  

我得到了sampler2D的 clampedvalue glsl被钳位为[0，1]：

pre $ vec4 clampedvalue = texuture2D（myunsignedbytetex2d，texcoord2）;

所以我的问题是这样的：

1. 当调用glTexImage2D（夹紧或不夹紧）时，glsl将获得什么值：
   
   

     glTexImage2D（GL_TEXTURE_2D，0，GL_RGBA8，WINDOW_SIZE，WINDOW_SIZE，0，GL_RGBA，
    GL_FLOAT，floatDataPtr）; 
     




2. 当调用glTexImage2D时，我会得到什么样的值（夹紧或不夹紧）：
   
   $ p $ lt; code> glTexImage2D（GL_TEXTURE_2D，0，GL_RGBA16F_ARB，WINDOW_SIZE，WINDOW_SIZE，0，GL_RGBA，
   GL_UNSIGNED_BYTE，byteDataPtr） ;
   




3. 由于我在OpenGL官网上找不到详细的信息，在调用glTexImage2D（）时传递给纹理的数据返回不同的内部格式的sampler2D纹理以及不同的类型（如上面提到的GL_FLOAT或GL_UNSIGNED_BYTE）？什么是规则？
   
   
   

   有没有人可以帮忙？
   

   
   

   当调用glTexImage2D（夹紧或不夹紧）时，我将在glsl中获得什么值：
   
   
   

   这仅受内部格式参数一>。规范化的内部格式是...正常化。他们不存储浮点值;它们将整数值解释为浮点数。最大整数值为1.0，最小值为0.0（如果是SNORM格式，则为-1.0）。
   
   lockquote
   

   因为我找不到OpenGL官方网站上的详细信息
   

   下次看更难;它就在维基上。用于创建内部格式。 org / wiki / Textures＃Texture_Objectsrel =nofollow>纹理和 renderbuffers 。它甚至解释了最后三个参数控制像素转换操作：将数据上传到图像。 p>
   

   I am confused with the internal format related to texture2D() in GLSL and glTexImage2D() in OpenGL, When I use(pay attention to the third and the eighth parameters):

   glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA16F_ARB, WINDOW_SIZE, WINDOW_SIZE, 0, GL_RGBA, 
               GL_FLOAT, floatDataPtr);
   

   I got the nonclampedvalue of sampler2D in the glsl without clamped to [0, 1]:

   vec4 nonclampedvalue = texture2D(my16floattex2d, texcoord1);
   

   When I use:

   glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA8, WINDOW_SIZE, WINDOW_SIZE, 0, GL_RGBA, 
               GL_UNSIGNED_BYTE, byteDataPtr);
   

   I got the clampedvalue of sampler2D in the glsl clamped to [0, 1]:

   vec4 clampedvalue = texuture2D(myunsignedbytetex2d, texcoord2);
   

   So my questions are this:

   1. What value will I get in glsl when invoke the glTexImage2D like this(clamped or not clamped):

      glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA8, WINDOW_SIZE, WINDOW_SIZE, 0, GL_RGBA, 
             GL_FLOAT, floatDataPtr);
      

   2. What value will I get in glsl when invoke the glTexImage2D like this(clamped or not clamped):

      glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA16F_ARB, WINDOW_SIZE, WINDOW_SIZE, 0, GL_RGBA,
              GL_UNSIGNED_BYTE, byteDataPtr);
      

   3. As I can't find the detailed information in OpenGL official website, What value will be return in the sampler2D texture with different internal format as well as different type(such as GL_FLOAT or GL_UNSIGNED_BYTE mentioned above) of the data passed to the texture when invoke the glTexImage2D()? what's all the rules?

   Does anyone can help?

   解决方案

   What value will I get in glsl when invoke the glTexImage2D like this(clamped or not clamped):

   This is governed only by the "internal format" parameter. Normalized internal formats are... normalized. They don't store floating point values; they store integer values which are interpreted as floats. The maximum integer value becomes 1.0 and the minimum becomes 0.0 (or -1.0 if it's an SNORM format).

   As I can't find the detailed information in OpenGL official website

   Look harder next time; it's right there on the Wiki. The "internal format" used for creating textures and renderbuffers. It even explains that the last three parameters govern pixel transfer operations: uploading data to the image.

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