[GSoC 2012] Off-Screen Particles project - continuation

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Karol Badowski 1989
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Fri Jul 13, 2012 12:13 pm

I'm continuing the same task as yesterday.
I should finish that today/tonight.

In the evening I'll have a train travel back to Gdańsk.
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Topic: "Implementation of Off-Screen Particles"
Project links: Project thread, WIKI page, Code fork for the project
Mentor: Assaf Raman

Karol Badowski 1989
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Sat Jul 14, 2012 12:07 am

When I was in train, I finally achieved modification of shaders input texture (other that pure View from camera) from level of application (modified "penguin" material - it is granted to third miniscreen and to penguin - displaying solid objects texture).

We can see also "regained" transparency thanks to mentioned advices that I'd like to improve (from level of script).

Image

Here is picture of working concatenation that I finally have achieved:

Image

It is material that uses "texture_unit" to define input textures.
From the level of application, texture units names (adctually something different: names of textures of texture_units) are updated back to the same names, however it reloads the pointer to texture.

I'm trying to take a picture that shows ALL importand issues that were to be achieved/mentioned.
Last edited by Karol Badowski 1989 on Sat Jul 14, 2012 12:20 am, edited 2 times in total.
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Topic: "Implementation of Off-Screen Particles"
Project links: Project thread, WIKI page, Code fork for the project
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Karol Badowski 1989
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Sat Jul 14, 2012 12:13 am

Screenshot below presents all topics mentioned during last two days, about transparancy (proof - look at penguins feet. There also halo effects and sharp edges visible + taking a fraction of background color into particles colour (visilbe especially on penguin's jet flame edges that seem to be grey - i did not write it on picture, but it is noticeable).

Image

What am I going to do tomorrow?
Strp by step replace modifications from level of application with my own compositors (that should prevent execution of unneeded calculations and fix the transparency issue).

There is a question:
Alternative way of work for tomorrow could be Sobel filter for preparing stencil map. What would You like to see first?
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Topic: "Implementation of Off-Screen Particles"
Project links: Project thread, WIKI page, Code fork for the project
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Karol Badowski 1989
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Sat Jul 14, 2012 12:29 am

I'd like to make repository revision instantly.

At the moment I am going out, before students club is closed.
I'll look for that thing I lost last friday - perhaps I put it on a chair there.

When I come back in an hour or 2, I'll do next revision to repository (there is rather high amount of changes since last time - in compositors and in *.cpp file).
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Sat Jul 14, 2012 12:42 am

Karol Badowski 1989 wrote: Alternative way of work for tomorrow could be Sobel filter for preparing stencil map. What would You like to see first?
A working compositor.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Sat Jul 14, 2012 12:41 pm

Since 15:00 to 18:00 I'll be taking part in a charity event organised by students community on my university.
We are organising a trip for students who come to Poland on their abroad apprenticeship from other countries, showing them historical places.

Today I'll work in the evening and night. I am going to continue conversion of current commands from application level into a compositor chain.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Sat Jul 14, 2012 1:36 pm

OK. If you have any issue - post them here, it shouldn't be complicated.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Sun Jul 15, 2012 7:36 pm

Tonight I'll continue writing compositor.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Sun Jul 15, 2012 11:29 pm

Can you post a status when you finish working today?
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Tue Jul 17, 2012 8:38 am

I am still looking for a tricky bug in my previous compositor code from 8'th of July (I am comparing current version with last working one from repository to spot the difference) - I should find it soon.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Wed Jul 18, 2012 6:50 pm

Today I am still continuing conversion to compositor with listeners.
Right now I use chain of compositors. Yesterday I managed to fix mentioned bug and make them run again (downsampling seems to run right way now).

Before final compositor is ready, I'll check depth testing (and soft particles) with solid objects set to unvisible and I'll use prepared constant depth map for tests.

Particles are textures faced to camera, so I think that best depth map to observe results is one that goes from maximum to minimum depth from left to right (for normalised float depth it would be 1.0f to 0.0f). It will give right amount of intersections.

When view swiches from visible solid to visible particles... I wonder if "scene_depth_range" changes. If it does, than I'll have to go back to "near_clip_distance" && "far_clip_distance" version.
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Topic: "Implementation of Off-Screen Particles"
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Fri Jul 20, 2012 5:11 pm

This is a screenshot from 8x8 downsampling:
Image

This is debug view of downsampling of depth texture (it is only one channel, but debug compositor rewrites it to other channels).
Image

In maximum of Depth technique, depth of multiple samples is compared - one thread achieves sample even from every pixel on a field it covers (it is not parallel) - it is still a better idea to take constant amount of samples (4 or 9 in one field).

However, an alternative extension for future is to drop from universal (squares/rectangles in two loops - for both dimensions) max of depth search and execute more parallel version with powers of 2 pixels in width and heigth of one sample (multiple executions of 2x2 downsampling shader can give us better - logarythmic - time) - in each of log4(x) iterations taking maximum value from 4 pixels.

This display shows debug of 8x8 downsample (in that debug I've been checking validity, but also the framerate change depending on how many samples I take to find maximum in an iteration - here it is 16 samples, each taken by operation "depthAtOffset = tex2D(depthTexture, offset).r" at different offsets).
Image
What we see is normalised difference between maximum and minimum depth on one square (looks simmilar to Sobel filter, but it is something simpler).

For now I will leave adjustable amount of samples compared by one processing unit (but set to constant value) and come back again to converting the compositor.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Fri Jul 20, 2012 6:03 pm

good work. :D
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Mon Jul 23, 2012 3:16 pm

I'm continuing work on compositor, but today I have to take a day off to prepare an actualisation of presentation for "WGK" game developement conference in Poland.

I got to know that proffesor from my university has sent a shortcut of documentation to physics engine that was created by me and my friend - it appears that it was initially accepted for game developement conference and that we have to prepare and send the actualisation of that presentation today.

Tomorrow I am comming back.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Mon Jul 23, 2012 6:31 pm

What have you completed since your last update?
As you remember - we require daily updates...
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Wed Jul 25, 2012 12:08 pm

update us...
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Re: [GSoC 2012] Off-Screen Particles project

Post by TheSHEEEP » Wed Jul 25, 2012 3:51 pm

Karol must be one of the most busy persons I've ever "seen" :D
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Wed Jul 25, 2012 8:28 pm

I am still continuing conversion to compositor.
I've been trying to make selective rendering working these days (in the compositor version) - I still haven't finished it.
I'm sorry for lack of update on that recently (I thought several times that I'll finally post message "I finally finished selective rendering with use of compositor listeners" any hour).

I came back to figuring out again how is it done in Deferred shading and doing tests on simpler examples to find what is wrong there.
There were more tests and learning than progress.
In the morning I'll post update if I finally managed to achieve that tonight.

I should figure it out finally very soon (I think I'm very close to it).
I need that step to be finished so I could apply my version of joining particles and solid objects texture and check if alpha blending runs correctly (it is supposed to eliminate transparency problem of dark particle effects that was in the "application level" version - result will be visible only on joined textures).

When I achieve it, next step in chronological way are:
-applying alpha blending shader and testing if it works correctly (compositor version of what was done on application level will be finished on that level)
-modification ob binary depth test to soft particles
-run tests of MRT and two pass version.

MIXED RESOLUTION RENDERING:
-applying Sobel filter on particles texture to create mask for stenciling
-learn how stenciling is done in OGRE and apply it to second rendering pass with full resolution.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Wed Jul 25, 2012 10:29 pm

OK, keep us updated every day, what you have done and what is the plan for the next day.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Thu Jul 26, 2012 11:29 am

I'm still doing selective rendering.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Thu Jul 26, 2012 11:55 am

What do you do there? Can you give out more details?
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Fri Jul 27, 2012 12:26 pm

I have divided targets to separate RenderQueueGroupID - it is easy to control order of their rendering now and control to which range of ID's each pass is applied.

I still give objects the material that has a defined pass which uses vertex program (that achieves depth information) and fragment program (that saves it into a texture).

In application version we used separate render passes to create colour texture (based on objects original material) and to create depth buffer.

Here I'm trying to modify original material (I want to preserve original way of achieving colour texture, because it could be different in any material and use various sources and various ways to achieve final result).

Is it a good way to create list of objects, iterate them all and for each add an additional pass that would save previous output to a texture and then calculate depth, saving it to additional texture?

Or is it better to try finding univerrsal way to achieve original sources and pass them to a shader that would calculate colour and depth in one pass?
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Fri Jul 27, 2012 12:31 pm

Is all the code in the repo?
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Re: [GSoC 2012] Off-Screen Particles project

Post by Karol Badowski 1989 » Fri Jul 27, 2012 12:54 pm

I'll upload it in 2 hours (I'll do some changes in it).


EDIT: (16:30, GMT+1)
I'll upload code this evening, I need to make few changes so it is less complicated.

Generally my question was about best tactic to inherit all properties of materials (to provide the same final colour of texture, no matter how complicated that material was, whether it used bump-mapping or not, etcetera) + run own additional shaders.

(Is it better to modify original materials of all objects and give another pass to each materials technique, or is it better to use some other tactic that would let us minimize number of passes).
Last edited by Karol Badowski 1989 on Fri Jul 27, 2012 3:44 pm, edited 4 times in total.
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Re: [GSoC 2012] Off-Screen Particles project

Post by Assaf Raman » Fri Jul 27, 2012 1:03 pm

Also post in more detail on the issues you are having? I am not sure how to help...
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