Talk:High-dynamic-range rendering: Difference between revisions

Revision as of 13:25, 13 December 2011

Revision as of 13:32, 13 December 2011

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::2) <math>final.rgb=(1/255)/0.5=0.00392/0.5=0.007843137;</math> or 2.

::2.1) <math>final.rgb=(1/255)/0.2=0.00392/0.2=1.009607843;</math> or 5. <small><span class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Versatranitsonlywaytofly|Versatranitsonlywaytofly]] ([[User talk:Versatranitsonlywaytofly|talk]] • [[Special:Contributions/Versatranitsonlywaytofly|contribs]]) 21:57, 12 December 2011 (UTC)</span></small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->

:::Note, that algorithm, which using gamma don't matter if is combined with this "final.rgb=color.rgb/average" algorithm or not, still making contrast between say 128 and 64 instead normal 2:1, it making <math>0.2^{1/1.5}/0.1^{1/1.5}=1.5874:1</math> or bigger depending on "average" like <math>0.2^{1/1.25}/0.1^{1/1.25}=1.7411:1</math> instead normal 2:1. So this algorithm graying combined or not with with this "final.rgb=color.rgb/average". But graying all colours equally don't matter they strong or weak and contrast between all colours depending only on "average".

:::Compressed luminance algorithm "final.rgb=(2*color.rgb)/(1+color.rgb)" graying equallythe same don't matter if used before or after this "final.rgb=color.rgb/average" algorithm or used alone. But it graying stronger colours more than weaker and contrast after this "final.rgb=(2*color.rgb)/(1+color.rgb)" algorithm between say 128 and 64 is smaller than between 20 and 10. For example [2*0.2/(1+0.2)]/[2*0.1/(1+0.1)]=[0.4/1.2]/[0.2/1.1]=[0.3333]/[0.1818]=1.83333, so contrast becoming 1.8333:1 after algorithm, compare with noraml 2:1 before algorithm (here was colours 0.1*255=25.5=26 and 0.2*255=51). And if colours are 128/255=0.5 and 64/255=0.25, then [2*0.5/(1+0.5)]/[2*0.25/(1+0.25)]=[1/1.5]/[0.5/1.25]=[0.6667]/[0.4]=1.6667, so contrast between 128 and 64 equal to 1.6667:1 instead normal 2:1. So you can imagine, that there small contrast between 255 and 128 (contrast after algorithm becoming 1.5:1, because [2*1/(1+1)]/[2*0.5/(1+0.5)]=[1]/[1/1.5]=[1]/[0.6667]=1.5).

::But I tell you secret, that average is calculated using only 16 textures centers (pixels) or less likely variant, that each sixteen pixel on screen (width*height/16). So still no so very real average and the slower adaptation, the better. So best of all to use maximum of all 16 pixels and maximum of this pixel all channels RGB instead average and then it will go perfectly in all algorithms. If color=230/255=0.9, colormax=230/255=0.9, then:

::1) <math>final.rgb=0.9^{1/(2-0.9)}/0.9=0.9^{1/1.1}/0.9=0.90866/0.5=1.009624247;</math> or 257.454=>255; 0.5<colormax<1;