Home | History | Annotate | Download | only in specs 
      1 Name
      2 
      3     MESA_drm_image_formats
      4 
      5 Name Strings
      6 
      7     EGL_MESA_drm_image_formats
      8 
      9 Contributors
     10 
     11     Nicolai Hhnle <Nicolai.Haehnle (a] amd.com>
     12     Qiang Yu <Qiang.Yu (a] amd.com>
     13 
     14 Contact
     15 
     16     Nicolai Hhnle <Nicolai.Haehnle (a] amd.com>
     17 
     18 Status
     19 
     20     Proposal
     21 
     22 Version
     23 
     24     Version 1, January 26, 2017
     25 
     26 Number
     27 
     28     EGL Extension #??
     29 
     30 Dependencies
     31 
     32     This extension requires the EGL_MESA_drm_image extension.
     33 
     34     This extension is written against the wording of EGL_MESA_drm_image
     35     specification.
     36 
     37 Overview
     38 
     39     This extension extends the functionality of EGL_MESA_drm_image by adding
     40     additional formats required by Glamor for use with DRM buffers.
     41 
     42 IP Status
     43 
     44     Open-source; freely implementable.
     45 
     46 New Procedures and Functions
     47 
     48     None
     49 
     50 New Tokens
     51 
     52     Accepted as values for the EGL_IMAGE_FORMAT_MESA attribute:
     53 
     54         EGL_DRM_BUFFER_FORMAT_ARGB2101010_MESA  0x3290
     55         EGL_DRM_BUFFER_FORMAT_ARGB1555_MESA     0x3291
     56         EGL_DRM_BUFFER_FORMAT_RGB565_MESA       0x3292
     57 
     58 Additions to the EGL_MESA_drm_image Specification:
     59 
     60     Remove the sentence "The only format specified ..." from the paragraph
     61     describing eglCreateDRMImageMESA and add the following paragraph:
     62 
     63         The formats specified for use with EGL_DRM_BUFFER_FORMAT_MESA are:
     64 
     65       * EGL_DRM_BUFFER_FORMAT_ARGB32_MESA, where each pixel is a CPU-endian
     66         32-bit quantity, with alpha in the upper 8 bits, then red, then green,
     67         then blue,
     68 
     69       * EGL_DRM_BUFFER_FORMAT_ARGB2101010_MESA, where each pixel is a CPU-
     70         endian, 32-bit quantity, with alpha in the most significant 2 bits,
     71         followed by 10 bits each for red, green, and blue,
     72 
     73       * EGL_DRM_BUFFER_FORMAT_ARGB1555_MESA, where each pixel is a CPU-endian
     74         16-bit quantity, with alpha in the most significant bit, followed by
     75         5 bits each for red, green, and blue, and
     76 
     77       * EGL_DRM_BUFFER_FORMAT_RGB565_MESA, where each pixel is a CPU-endian
     78         16-bit quantity, with red in the 5 most significant bits, followed by
     79         6 bits of green and 5 bits of blue.
     80 
     81 Issues
     82 
     83     1. Should we expose the full set of channel permutations for the formats,
     84        e.g. ABGR2101010, RGBA1010102, and BGRA1010102 in addition to
     85        ARGB2101010?
     86 
     87        RESOLVED: No.
     88 
     89        DISCUSSION: The original extension sets a precedent of only exposing one
     90        of the possible permutations of 8-bit channel formats. It is also not
     91        clear where the additional permutations would be used. For example,
     92        Glamor has a fixed mapping from pixmap/screen depth to format that
     93        doesn't allow for the other permutations.
     94 
     95 Revision History
     96 
     97     Version 1, January, 2017
     98         Initial draft (Nicolai Hhnle)
     99