| Name |
| |
| ANGLE_surface_orientation |
| |
| Name Strings |
| |
| EGL_ANGLE_surface_orientation |
| |
| Contributors |
| |
| Geoff Lang, Google |
| |
| Contacts |
| |
| Geoff Lang, Google (geofflang 'at' google 'dot' com) |
| |
| Status |
| |
| Draft |
| |
| Version |
| |
| Version 1, 2015-12-15 |
| |
| Number |
| |
| EGL Extension XXX |
| |
| Extension Type |
| |
| EGL display extension |
| |
| Dependencies |
| |
| Written based on the wording of the EGL 1.5 Specification |
| (August 7 2014). |
| |
| Overview |
| |
| This extension provides a mechanism for querying the most optimal |
| orientation of a window surface and creating window sufraces with |
| non-default orientations for the most performant rendering. |
| |
| New Types |
| |
| None |
| |
| New Procedures and Functions |
| |
| None |
| |
| New Tokens |
| |
| New EGLConfig bitmask attribute name: |
| |
| EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE 0x33A7 |
| |
| Accepted as an attribute name in the <attrib_list> argument of |
| eglCreateWindowSurface and attribute name in the <attribute> |
| argument of eglQuerySurface: |
| |
| EGL_SURFACE_ORIENTATION_ANGLE 0x33A8 |
| |
| Valid bitfields in the EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE bitmask |
| attribute of EGLConfig and EGL_SURFACE_ORIENTATION_ANGLE bitmask attribute |
| of eglCreateWindowSurface: |
| |
| EGL_SURFACE_ORIENTATION_INVERT_X_ANGLE 0x0001 |
| EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE 0x0002 |
| |
| Additions to the EGL Specification |
| |
| Additions to Chapter 3 of the EGL 1.5 Specification (EGL Functions and Errors) |
| |
| Add to table 3.1 (EGLConfig Attributes) |
| |
| Attribute Type Notes |
| ------------------------------------- ------- ---------------------- |
| EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE bitmask Optimal window surface |
| orientation. |
| |
| |
| Add a paragraph to section 3.4, section Other EGLConfig Attribute |
| Descriptions. |
| |
| "EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE is a mask indicating which |
| window surface orientation will provide the best performance." |
| |
| Add to table 3.4 (Default values and match criteria for EGLConfig |
| attributes): |
| |
| Attribute Default Selection Sort Sort |
| Criteria Order Priority |
| ------------------------------------- ------- --------- ------- -------- |
| EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE 0 Exact None |
| |
| Add a paragraph to section 3.5.1, section Creating On-Screen Rendering |
| Surfaces. |
| |
| EGL_SURFACE_ORIENTATION_ANGLE attribute specifies how the surface's content |
| will appear on the screen. If its value contains |
| EGL_SURFACE_ORIENTATION_INVERT_X_ANGLE then all displayed content will be |
| inverted along the vertical axis. Similarly, if its value contains |
| EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE then all displayed content will be |
| inverted along the horizontal axis. |
| |
| Add to table 3.5 (Queryable surface attributes and types): |
| |
| Attribute Type Description |
| ----------------------------- ------- ---------------------- |
| EGL_SURFACE_ORIENTATION_ANGLE bitmask Orientation of surface |
| |
| Add a paragraph to section 3.5.6, Surface Attributes: |
| |
| "Querying EGL_SURFACE_ORIENTATION_ANGLE returns the orientation of the |
| surface. For a window surface, this is the same attribute value specified |
| when the surface was created. For other types of surfaces, it is always |
| 0." |
| |
| Issues |
| |
| 1) What about dirty regions and sub regions specified by extensions such as |
| NV_post_sub_buffer? |
| |
| These regions will be applied to the same region of the window as |
| before because they are often specified based on events from the |
| operating system. The content in these regions will be displayed |
| according to the value of EGL_SURFACE_ORIENTATION_ANGLE. |
| |
| Revision History |
| |
| Version 1, 2015-12-15 (Geoff Lang) |
| - Initial draft |
