| Name |
| |
| EXT_gl_colorspace_bt2020 |
| |
| Name Strings |
| |
| EGL_EXT_gl_colorspace_bt2020_linear |
| EGL_EXT_gl_colorspace_bt2020_pq |
| |
| Contributors |
| |
| Tom Cooksey |
| Andrew Garrard |
| Jesse Hall |
| Mathias Heyer |
| Lauri Hyvarinen |
| Adam Jackson |
| James Jones |
| Daniel Koch |
| Jeff Leger |
| Weiwan Liu |
| Jeff Vigil |
| |
| Contact |
| |
| Weiwan Liu (weiwliu 'at' nvidia.com) |
| |
| IP Status |
| |
| No known IP claims. |
| |
| Status |
| |
| Complete |
| |
| Version |
| |
| Version 7 - Nov 22, 2016 |
| |
| Number |
| |
| EGL Extension #107 |
| |
| Dependencies |
| |
| These extensions are written against the wording of the EGL 1.5 |
| specification (August 27, 2014). |
| |
| These extensions require EGL_KHR_gl_colorspace. |
| |
| Overview |
| |
| Applications may wish to take advantage of a larger color gamut in the |
| BT.2020 (ITU-R Recommendation BT.2020) color space. These extensions allow |
| applications to do so by communicating to the platform the color space the |
| framebuffer data is in, i.e. BT.2020 color space, as well as the encoding |
| of the framebuffer data, which can be either linear or PQ (Dolby Perceptual |
| Quantizer - SMPTE ST 2084) encoding. Applications are expected to prepare |
| the framebuffer data properly. |
| |
| New Procedures and Functions |
| |
| None. |
| |
| New Tokens |
| |
| Accepted as attribute values for EGL_GL_COLORSPACE by |
| eglCreateWindowSurface, eglCreatePbufferSurface and eglCreatePixmapSurface: |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_linear is supported ]] |
| |
| EGL_GL_COLORSPACE_BT2020_LINEAR_EXT 0x333F |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_pq is supported ]] |
| |
| EGL_GL_COLORSPACE_BT2020_PQ_EXT 0x3340 |
| |
| Modifications to the EGL 1.5 Specification |
| |
| Insert below text in the 3rd paragraph on page 33 in 3.5.1 "Creating On- |
| Screen Rendering Surfaces, before "The default value of EGL_GL_COLORSPACE |
| is EGL_GL_COLORSPACE_LINEAR.": |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_linear is supported ]] |
| |
| If its value is EGL_GL_COLORSPACE_BT2020_LINEAR_EXT, then a linear BT.2020 |
| color space is assumed, with a corresponding GL_FRAMEBUFFER_ATTACHMENT_- |
| COLOR_ENCODING value of GL_LINEAR. |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_pq is supported ]] |
| |
| If its value is EGL_GL_COLORSPACE_BT2020_PQ_EXT, then a non-linear, PQ |
| encoded BT.2020 color space is assumed, with a corresponding GL_FRAMEBUFFER- |
| _ATTACHMENT_COLOR_ENCODING value of GL_LINEAR, as neither OpenGL nor OpenGL |
| ES supports PQ framebuffers. Applications utilizing this option need to |
| ensure that PQ encoding is performed on the application side. |
| |
| Modify the 4th paragraph on the same page: |
| |
| Note that the EGL_GL_COLORSPACE_SRGB attribute is used only by OpenGL and |
| OpenGL ES contexts supporting sRGB framebuffers. EGL itself does not |
| distinguish multiple colorspace models. Refer to the "sRGB Conversion" |
| sections of the OpenGL 4.4 and OpenGL ES 3.0 specifications for more |
| information. |
| |
| Add a paragraph after the 4th paragraph above: |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_linear is supported ]] |
| |
| When using a floating-point EGL surface with EGL_GL_COLORSPACE_BT2020_- |
| LINEAR_EXT, the output values in the display-referred range of [0.0, 1.0] |
| correspond to a luminance range of 0 to 80 nits, which is the same luminance |
| range for sRGB. To achieve a larger dynamic range of 0 to 10000 nits, which |
| is the same range for PQ, the display-referred output values can go beyond |
| 1.0 and to a range of [0.0, 125.0], where 0.0 corresponds to 0 nit and 125.0 |
| corresponds to 10000 nits. |
| |
| [[ If EGL_EXT_gl_colorspace_bt2020_pq is supported ]] |
| |
| When using a floating-point EGL surface with EGL_GL_COLORSPACE_BT2020_PQ_- |
| EXT, to achieve the luminance range of 0 to 10000 nits (candela per square |
| meter) as defined by the SMPTE 2084 standard, applications can output values |
| in a display-referred range of [0.0, 1.0], where 0.0 corresponds to 0 nit |
| and 1.0 corresponds to 10000 nits. |
| |
| Errors |
| |
| Modify below error in the "Errors" section on page 34: |
| |
| "If config does not support the OpenVG colorspace or alpha format at- |
| tributes specified in attrib list (as defined for eglCreatePlatformWindow- |
| Surface), an EGL_BAD_MATCH error is generated." |
| |
| To include OpenGL colorspace as well: |
| |
| "If config does not support the OpenGL colorspace, the OpenVG colorspace or |
| alpha format attributes specified in attrib list (as defined for eglCreate- |
| PlatformWindowSurface), an EGL_BAD_MATCH error is generated." |
| |
| Issues |
| |
| 1. When creating an EGL surface, what happens when the specified colorspace |
| is not compatible with or supported by the EGLConfig? |
| |
| RESOLVED: There is currently no way to query the compatibility of a |
| EGLConfig and colorspace pair. So the only option is to define an error |
| case similar to that of OpenVG colorspace, i.e. if config does not |
| support the colorspace specified in attrib list (as defined for egl- |
| CreateWindowSurface, eglCreatePbufferSurface and eglCreatePixmapSurface), |
| an EGL_BAD_MATCH error is generated. |
| |
| Revision History |
| |
| Version 1, 2016/04/27 |
| - Internal revisions |
| |
| Version 2, 2016/05/20 |
| - Rename to EXT |
| |
| Version 3, 2016/05/25 |
| - Add issues |
| |
| Version 4, 2016/06/06 |
| - Split up the extension and put each colorspace option into an individual |
| extension |
| |
| Version 5, 2016/06/17 |
| - Correct the meaning of the data from scene-referred to display-referred |
| |
| Version 6, 2016/10/27 |
| - Mark issue #1 as "RESOLVED" and add an error case |
| |
| Version 7, 2016/11/22 |
| - Change status to complete |
| |
