Gamma - Revision history

Vegard: add link

2021-12-28T10:21:17Z

add link

← Older revision		Revision as of 10:21, 28 December 2021
Line 3:		Line 3:
	* sRGB = gamma space		* sRGB = gamma space
	* most image files store sRGB		* most image files store sRGB
	* sRGB is unfit for blending		* sRGB is unfit for blending, blurring, etc.

	The corollary is:		The corollary is:
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	* https://unlimited3d.wordpress.com/2020/01/08/srgb-color-space-in-opengl/		* https://unlimited3d.wordpress.com/2020/01/08/srgb-color-space-in-opengl/
	* https://mynameismjp.wordpress.com/2012/10/24/msaa-overview/ ("Working with HDR and Tone Mapping")		* https://mynameismjp.wordpress.com/2012/10/24/msaa-overview/ ("Working with HDR and Tone Mapping")
			* https://iquilezles.org/www/articles/gamma/gamma.htm

	[[Category:Graphics programming]]		[[Category:Graphics programming]]

Vegard: add link

2020-11-28T08:58:47Z

add link

← Older revision		Revision as of 08:58, 28 November 2020
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	* http://chilliant.blogspot.com/2012/08/srgb-approximations-for-hlsl.html		* http://chilliant.blogspot.com/2012/08/srgb-approximations-for-hlsl.html
	* https://unlimited3d.wordpress.com/2020/01/08/srgb-color-space-in-opengl/		* https://unlimited3d.wordpress.com/2020/01/08/srgb-color-space-in-opengl/
			* https://mynameismjp.wordpress.com/2012/10/24/msaa-overview/ ("Working with HDR and Tone Mapping")

	[[Category:Graphics programming]]		[[Category:Graphics programming]]

Vegard: add link

2020-11-28T07:57:52Z

add link

← Older revision		Revision as of 07:57, 28 November 2020
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	* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm		* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm
	* http://chilliant.blogspot.com/2012/08/srgb-approximations-for-hlsl.html		* http://chilliant.blogspot.com/2012/08/srgb-approximations-for-hlsl.html
			* https://unlimited3d.wordpress.com/2020/01/08/srgb-color-space-in-opengl/

	[[Category:Graphics programming]]		[[Category:Graphics programming]]

Vegard: /* See also */ add link

2020-04-22T18:54:42Z

Vegard: add alpha premultiplication

2019-12-19T10:27:44Z

add alpha premultiplication

← Older revision		Revision as of 10:27, 19 December 2019
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	The corollary is:		The corollary is:
	* Image files loaded as textures should be converted from sRGB to RGB (but some decoders do this for you!)		* Image files loaded as textures should be converted from sRGB to RGB (but some decoders do this for you!)
			* Since alpha is linear, [[Premultiplied alpha\|alpha premultiplication]] should happen in linear space, i.e. after converting to RGB [http://ssp.impulsetrain.com/gamma-premult.html]
	* The shader responsible for putting the final pixels on the screen should have a gamma correction step doing:		* The shader responsible for putting the final pixels on the screen should have a gamma correction step doing:
	:<source lang="GLSL">		:<source lang="GLSL">
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	</source>		</source>

	Note, however, that OpenGL may also perform this step for you on any on-screen framebuffers (i.e. the default framebuffer) if you do <tt>glEnable(GL_FRAMEBUFFER_SRGB)</tt>.		Note, however, that OpenGL may also perform this step for you on any on-screen framebuffers (i.e. the default framebuffer) if you do <code>glEnable(GL_FRAMEBUFFER_SRGB)</code>.

	== See also ==		== See also ==

Vegard: some extra framebuffer info

2019-12-19T06:57:16Z

some extra framebuffer info

← Older revision		Revision as of 06:57, 19 December 2019
Line 20:		Line 20:
	}		}
	</source>		</source>

			Note, however, that OpenGL may also perform this step for you on any on-screen framebuffers (i.e. the default framebuffer) if you do <tt>glEnable(GL_FRAMEBUFFER_SRGB)</tt>.

	== See also ==		== See also ==
	* https://blog.johnnovak.net/2016/09/21/what-every-coder-should-know-about-gamma/		* https://blog.johnnovak.net/2016/09/21/what-every-coder-should-know-about-gamma/
			* https://stackoverflow.com/questions/23026151/do-i-need-to-gamma-correct-the-final-color-output-on-a-modern-computer-monitor
			* https://www.khronos.org/opengl/wiki/Framebuffer#Colorspace
	* https://en.wikipedia.org/wiki/Gamma_correction		* https://en.wikipedia.org/wiki/Gamma_correction
	* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm		* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm

Vegard: new page

2019-12-19T06:42:53Z

new page

New page

Quick rules of thumb, since I can never remember which is which:
* RGB = linear space
* sRGB = gamma space
* most image files store sRGB
* sRGB is unfit for blending

The corollary is:
* Image files loaded as textures should be converted from sRGB to RGB (but some decoders do this for you!)
* The shader responsible for putting the final pixels on the screen should have a gamma correction step doing:
:<source lang="GLSL">
const float gamma = 2.2;

out vec4 color;

void main()
{
// ...

color = pow(color, 1. / gamma);
}
</source>

== See also ==
* https://blog.johnnovak.net/2016/09/21/what-every-coder-should-know-about-gamma/
* https://en.wikipedia.org/wiki/Gamma_correction
* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm

[[Category:Graphics programming]]

← Older revision		Revision as of 18:54, 22 April 2020
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	* https://en.wikipedia.org/wiki/Gamma_correction		* https://en.wikipedia.org/wiki/Gamma_correction
	* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm		* https://www.cambridgeincolour.com/tutorials/gamma-correction.htm
			* http://chilliant.blogspot.com/2012/08/srgb-approximations-for-hlsl.html

	[[Category:Graphics programming]]		[[Category:Graphics programming]]