Difference between revisions of "Lesson 6 - prime directive"

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(Created page with "==== Summary ==== This lesson we Level of difficulty: Easy<br> Time required: 30 minutes <br> <br> [http://youtu.be/gR2FKk1hz4c <u>Video Walkthrough on YouTube, pt 1</u>] ....")
 
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==== Summary ====
 
==== Summary ====
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This lesson we
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Now it's time to talk about how stereo 3D is created, and the math behind it.
  
  
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==== Objective ====
 
==== Objective ====
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Experiment on
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Review and understand the principles behind stereoscopy.
 
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Fix the lava s
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Learn about the prime directive formula, and how to apply it.
  
 
==== Quiz====
 
==== Quiz====
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Fix the water
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??
  
  
 
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After we've found a broken shader, we want to disable or fix them. We can't always do the easiest fix though, and this is where experimentation comes in. This is the puzzle aspect of fixing shaders, where it's not always clear how to fix a shader, even after having seen a lot of variants.
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After we've found a broken shader, we want to disable or fix them. We can't always do the easiest fix though, and this is where ..
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The basic premise is to experiment on the shader by commenting out pieces of the code, and reloading it live with F10, and see any change.  As you do these experiments, you can get a feel for what pieces of code affect what part of the image, which can lead you to the best fix. 
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It can be quite a bit of trial and error, but can allow you to figure out fixes that don't match common patterns, or to find the right spot for a common pattern.
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Let's take a look at the basics of 3D graphics, so you can have a very rough idea of how the pieces fit together.  This will give you some understanding of how shaders work.
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We'll step back into The Ball for a minute to get a first glimpse of the 3D formula.
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* Play with the ''Principles of Shading'' demo.
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*# Get the demo from [http://stage.nvidia.com/coolstuff/demos#!/principles-of-shading here]
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*# Run the demo and get an understanding of the wireframe vertexes versus the textures.
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*# Look at the Display menu in particular.
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*# Take a first look at the 0.5*D*T formula as a basic building block.
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*# Example of texture painted onto triangle [http://www.riemers.net/images/Tutorials/DirectX/Csharp/Series3/DirectX%20Tutorial%206%20-%20Textured%20Triangle.jpg here]
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*# Take a look at the graphics pipeline [http://rbwhitaker.wikidot.com/intro-to-shaders here]
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*# Get a basic idea of the flow of graphics operations, especially noting VertexShaders run before PixelShaders.
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After playing with this demo you should have a sense for how 3D graphics are built out of a list of vertices, that make up an array of triangles, that have textures applied to the triangles.
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* Fix Lava effect, not just disable it.
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*# Lava in The Ball is perfectly usable now, but we saw the Unreal fix earlier.
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*# Unreal fix did not function, but we can make it work, using HelixMod inputs.
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*# Edit shader file to use HelixMod stereo texture, instead of game based one.
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*# Fixed in 3D, not just disabling a piece of it.
  
  

Revision as of 23:00, 18 September 2014

Summary

Now it's time to talk about how stereo 3D is created, and the math behind it.


Level of difficulty: Easy
Time required: 30 minutes

Video Walkthrough on YouTube, pt 1 ... Video Walkthrough direct download link, pt 1
Video Walkthrough on YouTube, pt 2 ... Video Walkthrough direct download link, pt 2

Objective

Review and understand the principles behind stereoscopy.
Learn about the prime directive formula, and how to apply it.

Quiz

??


After we've found a broken shader, we want to disable or fix them. We can't always do the easiest fix though, and this is where ..

We'll step back into The Ball for a minute to get a first glimpse of the 3D formula.

  • Fix Lava effect, not just disable it.
    1. Lava in The Ball is perfectly usable now, but we saw the Unreal fix earlier.
    2. Unreal fix did not function, but we can make it work, using HelixMod inputs.
    3. Edit shader file to use HelixMod stereo texture, instead of game based one.
    4. Fixed in 3D, not just disabling a piece of it.


Sometimes we will run into an effect that really cannot be disabled without making the game a lot worse.

In this game, the Lava effect is an example. It's annoyingly broken, and makes those parts of the games unplayable. But, disabling it altogether removes the visual cue of the dangerous areas.

Let's experiment with it, to see if we can make something better.


  • Experiment on lava shaders.
    1. Inspect and experiment on lava in PS.
    2. In pixel shader, try changing each texld to invisible.
    3. Those don't work, look next at the input section with interesting stereo fix.
    4. See that v1 is an input location.
    5. Experiment by changing v1 to null.
    6. Fix lava by killing one texture instead of the entire shader.
    7. optional: Fix the lava from the VertexShader output side, where v1 is created.


Quiz: Go to the end of the demo, and figure out a way to fix the broken water.

  • Fix the water shader at the last level.
    1. Play through to the giant worm at the end, it's not far.
    2. See the water has double-imaging like the water in the hall earlier.
    3. Find the shader for the water effect.
    4. Disable it. Note that it's really not good enough disabled.
    5. Experiment with it to fix it to where it's acceptable.
    6. Save a screenshot to your personal page.


  • optional: Fix the entire game.
    1. Go through at least 3 levels, and find and mark all broken effects.
    2. Disable all broken effects.
    3. Fix the lava effect by disabling the texture.
    4. Save your complete list of modified shaders to your personal page.


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