glCompressedTexSubImage2D()

This topic contains 5 replies, has 2 voices, and was last updated by  iseno 8 years, 12 months ago.

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  • #29615

    iseno
    Member

    Hi,

     

    I support developping Embedded Graphics System.

    I use OpenGL ES 1.1 on Freescale i.MX31 (ARM11+MBX 533MHz).

     

    I want to know if MBX’s OpenGLES 1.1 supports ” glCompressedTexSubImage2D()”.

    If it is true, I want the detail about this function.< ?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

    Because I cannot find any information on public document as follows.

    http://www.khronos.org/opengles/documentation/opengles1_0/html/glCompressedTexSubImage2D.html

     


    >

     format

     Specifies the format of the pixel data. Currently, there is no supported format.

     

    Can anyone help me?

    #32423

    Hello,

    No, MBX does not supports glCompressedTexSubImage2D(). Texture compression is a very expensive operation that cannot be done on the fly. Besides, It is not possible just to upload part of a PVRTC texture as all adjacent blocks contribute to the colour.

    Regards.

    Carlos.

    #32424

    iseno
    Member

    Hi Carlos,< ?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

     

    I am sorry my late response.

    Thanks for your information. This is very important.

     

    I’ve never heard that MBX is NOT support glCompressedTexSubImage2D() from the vendor in < ?: prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Japan.

     

     

     Akihiro Iseno

     TOMEN Electronics Corp. <http://www.tomen-ele.co.jp&gt;

         Engineering Dept.

         Amusement SBU, Sales Division II

    #32425

    iseno
    Member

    Hi Carlos,< ?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

     

    You said that “Texture compression is a very expensive operation that cannot be done on the fly.”

     

    Does MBX support glCompressedTexImage2D() operation?

    Which operation is speedy, glCompressedTexImage2D() or glTexImage2D() on MBX?

     

       Akihiro Iseno

    #32426

    Dear Iseno-san,
    Texture compression is done offline by our PVRTC Utility. The API uses glCompressedTexImage2D just to upload the pre-compressed data in memory, so it is as fast as glTexImage2D.
    The user cannot not modify this data on any way because it is expensive to re-compress so glCompressedTexSubImage2D is not supported. If this kind of functionality is required please use a 16-bit texture format.

    Best regards.

    Carlos.

    #32427

    iseno
    Member

    Dear Carlos-san,< ?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

     

    Thanks for good information.

    I will try to do it. 🙂

     

    Yours sincerely,

     

    Akihiro Iseno

     TOMEN Electronics Corp. <http://www.tomen-ele.co.jp&gt;

         Engineering Dept.

         Amusement SBU, Sales Division II

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