glTexStorage2D

From OpenGL Reference
Jump to navigation Jump to search

Simultaneously specify storage for all levels of a two-dimensional or one-dimensional array texture.

C Specification[edit]

void glTexStorage2D( GLenum target, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height );
void glTextureStorage2D( GLuint texture, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height );


Parameters[edit]

target - Specifies the target to which the texture object is bound for glTexStorage2D . Must be one of GL_TEXTURE_2D , GL_TEXTURE_1D_ARRAY , GL_TEXTURE_RECTANGLE , GL_TEXTURE_CUBE_MAP , GL_PROXY_TEXTURE_2D , GL_PROXY_TEXTURE_1D_ARRAY , GL_PROXY_TEXTURE_RECTANGLE , or GL_PROXY_TEXTURE_CUBE_MAP .
texture - Specifies the texture object name for glTextureStorage2D . The effective target of texture must be one of the valid non-proxy target values above.
levels - Specify the number of texture levels.
internalformat - Specifies the sized internal format to be used to store texture image data.
width - Specifies the width of the texture, in texels.
height - Specifies the height of the texture, in texels.


Description[edit]

 glTexStorage2D and glTextureStorage2D specify the storage requirements for all levels of a two-dimensional texture or one-dimensional texture array simultaneously. Once a texture is specified with this command, the format and dimensions of all levels become immutable unless it is a proxy texture. The contents of the image may still be modified, however, its storage requirements may not change. Such a texture is referred to as animmutable-formattexture.

The behavior of glTexStorage2D depends on the target parameter. When target is GL_TEXTURE_2D , GL_PROXY_TEXTURE_2D , GL_TEXTURE_RECTANGLE , GL_PROXY_TEXTURE_RECTANGLE or GL_PROXY_TEXTURE_CUBE_MAP , calling glTexStorage2D is equivalent, assuming no errors are generated, to executing the following pseudo-code:

   for (i = 0; i < levels; i++) {
       glTexImage2D(target, i, internalformat, width, height, 0, format, type, NULL);
       width = max(1, (width / 2));
       height = max(1, (height / 2));
   }

When target is GL_TEXTURE_CUBE_MAP , glTexStorage2D is equivalent to:

   for (i = 0; i < levels; i++) {
       for (face in (+X, -X, +Y, -Y, +Z, -Z)) {
           glTexImage2D(face, i, internalformat, width, height, 0, format, type, NULL);
       }
       width = max(1, (width / 2));
       height = max(1, (height / 2));
   }

When target is GL_TEXTURE_1D_ARRAY or GL_PROXY_TEXTURE_1D_ARRAY , glTexStorage2D is equivalent to:

   for (i = 0; i < levels; i++) {
       glTexImage2D(target, i, internalformat, width, height, 0, format, type, NULL);
       width = max(1, (width / 2));
   }

Calling glTextureStorage2D is equivalent to the above pseudo-code, where target is the effective target of texture and it is as if texture were bound to target for the purposes of glTexImage2D .

Since no texture data is actually provided, the values used in the pseudo-code for format and type are irrelevant and may be considered to be any values that are legal for the chosen internalformat enumerant. internalformat must be one of the sized internal formats given in Table 1 below, one of the sized depth-component formats GL_DEPTH_COMPONENT32F , GL_DEPTH_COMPONENT24 , or GL_DEPTH_COMPONENT16 , one of the combined depth-stencil formats, GL_DEPTH32F_STENCIL8 , or GL_DEPTH24_STENCIL8 , or the stencil-only format, GL_STENCIL_INDEX8 . Upon success, the value of GL_TEXTURE_IMMUTABLE_FORMAT becomes GL_TRUE . The value of GL_TEXTURE_IMMUTABLE_FORMAT may be discovered by calling glGetTexParameter with pname set to GL_TEXTURE_IMMUTABLE_FORMAT . No further changes to the dimensions or format of the texture object may be made. Using any command that might alter the dimensions or format of the texture object (such as glTexImage2D or another call to glTexStorage2D ) will result in the generation of a GL_INVALID_OPERATION error, even if it would not, in fact, alter the dimensions or format of the object.



Notes[edit]

 GL_STENCIL_INDEX8 is accepted for internalformat only if the GL version is 4.4 or higher.


Errors[edit]

 GL_INVALID_OPERATION is generated by glTexStorage2D if zero is bound to target .

 GL_INVALID_OPERATION is generated by glTextureStorage2D if texture is not the name of an existing texture object.

 GL_INVALID_ENUM is generated if internalformat is not a valid sized internal format.

 GL_INVALID_ENUM is generated if target or the effective target of texture is not one of the accepted targets described above.

 GL_INVALID_VALUE is generated if width , height or levels are less than 1.

 GL_INVALID_OPERATION is generated if target is GL_TEXTURE_1D_ARRAY or GL_PROXY_TEXTURE_1D_ARRAY and levels is greater than [math]⌊⌋+1[/math] .

 GL_INVALID_OPERATION is generated if target is not GL_TEXTURE_1D_ARRAY or GL_PROXY_TEXTURE_1D_ARRAY and levels is greater than [math]⌊⌋+1[/math] .


Version Support[edit]

 glTexStorage2D  4.2+
 glTextureStorage2D  4.5+

See Also[edit]

 glTexImage2D , glTexStorage1D , glTexStorage3D .


Copyright[edit]

Copyright© 2011-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.