Merge pull request #38 from courtney-g/171016-clarify-scrgb
Clarify definition of scRGB color space
diff --git a/extensions/EXT/EGL_EXT_gl_colorspace_scrgb.txt b/extensions/EXT/EGL_EXT_gl_colorspace_scrgb.txt
index 59c5312..708fb17 100644
--- a/extensions/EXT/EGL_EXT_gl_colorspace_scrgb.txt
+++ b/extensions/EXT/EGL_EXT_gl_colorspace_scrgb.txt
@@ -27,7 +27,7 @@
Version
- Version 1 - June 21, 2017
+ Version 2 - August 25, 2017
Number
@@ -44,11 +44,12 @@
Overview
- This extension provides a new color space option, scRGB, for applications to
- choose from when creating an EGLSurface. The scRGB color space defines a
- non-linear display referred space. It has the same white point and color
- primaries as sRGB, and thus is backward-compatible with sRGB. Refer to
- the IEC 61966-2-2:2003 standard for details on scRGB color space.
+ This extension provides an extended sRGB (also called scRGB) color
+ space option for applications to choose from when creating an EGLSurface.
+ This extension defines the non-linear display referred scRGB color space.
+ It has the same white point and color primaries as sRGB, and thus is
+ backward-compatible with sRGB. Refer to the IEC 61966-2-2:2003 standard
+ for details on scRGB color space.
This extension chooses to use floating-point formats for scRGB color space.
For each color channel, the floating-point values of 0.0 and 1.0 still
@@ -59,8 +60,8 @@
map to luminance levels by the underlying display pipeline. The expected
mapping is such that a color value of (1.0, 1.0, 1.0) corresponds to a
luminance level of 80 nits on a standardized studio monitor. As the color
- value per channel goes beyond 1.0 and up to 125.0, the corresponding
- luminance levels also increase linearly to a maximum of 10000 nits.
+ value per channel goes beyond 1.0 and up to ~7.83, the corresponding
+ luminance levels also increase to a maximum of 10000 nits.
The application is responsible for applying the extended sRGB transfer
function to color values written to or read from a surface with a
@@ -87,11 +88,12 @@
If its value is EGL_GL_COLORSPACE_SCRGB_EXT, then a non-linear scRGB
color space is assumed. with a corresponding GL_FRAMEBUFFER_ATTACHMENT_-
- COLOR_ENCODING value of GL_SRGB. As defined in IEC 61966-2-2:2003, scRGB
- is a color space and has the same white point and color primaries as
- those of sRGB. The application is responsible for applying the appropriate
- extended sRGB transfer function when reading or writing to this surface.
-
+ COLOR_ENCODING value of GL_LINEAR as neither OpenGL nor OpenGL ES
+ supports framebuffers using an scRGB transfer function.
+ The application is responsible for applying the appropriate extended
+ sRGB transfer function when reading or writing to this buffer.
+ scRGB is defined to use the same primaries and white-point as sRGB.
+ See IEC 61966-2-2:2003 for details.
Add two paragraphs after the 4th paragraph above:
@@ -100,8 +102,7 @@
(1.0, 1.0, 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 up
to 10000 nits, the output values can go beyond 1.0 and to a range of
- [0.0, 125.0] (approximately 7.83 after the extended sRGB transfer function
- applied) for each channel.
+ [0.0, ~7.83] for each channel.
The effective color gamut and luminance range of the content that extend
beyond those of sRGB may be described via EGL_EXT_surface_SMPTE2086_metadata.
@@ -125,5 +126,5 @@
Version 1, 2017/06/21
- Initial draft
- Version 2, 2017/08/17
+ Version 2, 2017/08/25
- Clarify definition of color space
diff --git a/extensions/EXT/EGL_EXT_gl_colorspace_scrgb_linear.txt b/extensions/EXT/EGL_EXT_gl_colorspace_scrgb_linear.txt
index 601edf0..4b906c6 100644
--- a/extensions/EXT/EGL_EXT_gl_colorspace_scrgb_linear.txt
+++ b/extensions/EXT/EGL_EXT_gl_colorspace_scrgb_linear.txt
@@ -8,6 +8,7 @@
Contributors
+ Courtney Goeltzenleuchter
Lauri Hyvarinen
Weiwan Liu
Arun Swain
@@ -26,7 +27,7 @@
Version
- Version 3 - November 22, 2016
+ Version 4 - August 25, 2017
Number
@@ -38,15 +39,17 @@
(August 27, 2014).
This extension requires EGL_KHR_gl_colorspace and EGL_EXT_pixel_format_-
- float, and interacts with EGL_EXT_surface_SMPTE2086_metadata.
+ float, and interacts with EGL_EXT_surface_SMPTE2086_metadata. This extension
+ is closely related to the EGL_EXT_gl_colorspace_scrgb.
Overview
- This extension provides a new color space option, scRGB, for applications to
- choose from when creating an EGLSurface. The scRGB color space defines a
- linear display referred space. It has the same white point and color
- primaries as sRGB, and thus is backward-compatible with sRGB. Refer to
- the IEC 61966-2-2:2003 standard for details on scRGB color space.
+ This extension provides an extended sRGB (also called scRGB) color
+ space option for applications to choose from when creating an EGLSurface.
+ This extension defines the linear display referred scRGB color space.
+ It has the same white point and color primaries as sRGB, and thus is
+ backward-compatible with sRGB. Refer to the IEC 61966-2-2:2003 standard
+ for details on scRGB color space.
This extension chooses to use floating-point formats for scRGB color space.
For each color channel, the floating-point values of 0.0 and 1.0 still
@@ -79,9 +82,8 @@
If its value is EGL_GL_COLORSPACE_SCRGB_LINEAR_EXT, then a linear scRGB
color space is assumed, with a corresponding GL_FRAMEBUFFER_ATTACHMENT_-
- COLOR_ENCODING value of GL_LINEAR. As defined in IEC 61966-2-2:2003, scRGB
- is a color space that has the same white point and color primaries as
- those of sRGB.
+ COLOR_ENCODING value of GL_LINEAR. scRGB is defined to use the same
+ primaries and white-point as sRGB. See IEC 61966-2-2:2003 for details.
Add two paragraphs after the 4th paragraph above:
@@ -120,6 +122,6 @@
Version 3, 2016/11/22
- Change status to complete
- Version 4, 2017/0817
+ Version 4, 2017/08/25
- Clarifications on the definition of scRGB colorspace
