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cifa

Member Since 29 Feb 2012
Offline Last Active Today, 04:52 PM

#5164806 HDR ToneMapping: Exposure selection

Posted by cifa on 04 July 2014 - 05:09 PM

Hi everyone!

 

I've been trying adding HDR support to my system but I got a couple of questions. I believe what I'm doing before  tone-mapping is fine: 

 

- Setup a RGBA16F Render Target

- Render to that RT

- call the postprocessing tone mapping on the cited RT and display the result on screen. 

 

 

Now to test this I've cranked up a bit my light intensity: 

 

jzHh4q5.png

 

Now if I apply the following tone mapping function (either one, the result is similar)

	col *= exposure;
	col = max(vec3(0.0), col -0.004);
	col = (col *(6.2*col + 0.5)) / (col *(6.2*col +1.7)+0.06);
	return vec4(col ,1.0)

or 

	col *= exposure;
	col = col / (1+col);
	return vec4(col, 1.0);

if the exposure is more than 0.5 for the above image and previous functions the result is pretty flat:

 

7eM68eY.png

 

Where for an exposure value of about 0.4 the result is ok: 

 

QoX5F2O.png

 

Although it's very darkish (unsurprisingly as the exposure is pretty low). 

 

Now the same issue (flatness of the tone-mapped image) is there for a "normal" light intensity which is fine even without using HDR. To get a decent result I have to lower the exposure even for that case, resulting though, again, in a darkish image. 

 

My questions are then two: 

 

- Am I missing something important here? I feel that the result I get is somewhat wrong

- Is there a way to "automatically" select what's considered a good exposure value for a given scene? 

 

 

 

Thank you very much




#5066957 Different results with animation made via shader or bufferSubData

Posted by cifa on 02 June 2013 - 04:47 PM

 
 
 
 
 
EDIT: ERROR FOUND. I was an idiot using different formulas. This topic can be destroyed



#4917930 Some very dumb question from a dreamer

Posted by cifa on 29 February 2012 - 02:10 PM

Hi there,

I'm currently a student in Computer Science at La Sapienza University in Rome, my goal and dream is to get into the industry so I've decided to get a MSc in Hull after my BSc. However my ideas are still very very confused, so I'm asking you some very very dumb questions (of which I may know the answer, but I want to have my ideas clear) :

1- I've noticed that Graphics Programming is actually the core of games programming, but, even if I've a vague idea, I would like to ask if you can expose me a couple of example to understand what is the job of a graphics programmer.

1b- This is a very dumb one; What is the edge between an artists and a graphics programmer ? What artistic skills should a programmer have ?

2- What skills I've to develop from now on ? I'm currently learning C++ (at University we've done a bit of C and Java) and I've heard that also mathematical skills are fundamental (basically linear algebra ? Which other maths ?)... what else ?

I'm so sorry if those are stupid questions, and probably I've also answers for those, but I want to make my mind clear and only experts can help me out.

Oh, and also sorry for my English, I beg you to correct what's wrong.

Thank you so much!

Francesco


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