Project 5: Shaders

Project Instructions

Implement at least 75 points worth of shaders from the following list. We reserve the right to grant only partial credit for shaders that do not meet our standards, as well as extra credit for shaders that we find to be particularly impressive.

Some of these shading effects were covered in lecture -- some were not. If you wish to implement the more complex effects, you will have to perform some extra research. Of course, we encourage such academic curiosity which is why we’ve included these advanced shaders in the first place!

Document each shader you implement in your README with at least a sentence or two of explanation. Well-commented code will earn you many brownie (and probably sanity) points.

If you use shadertoy or any materials as reference, please properly credit your sources in the README and on top of the shader file. Failing to do so will result in plagiarism and will significantly reduce your points.

Examples: https://cis700-procedural-graphics.github.io/Project5-Shaders/

15 points each: Instagram-like filters

Tone mapping:
- Linear (5 points)
- Reinhard (5 points)
- Filmic (5 points)
Gaussian blur (no double counting with Bloom)
Iridescence
Pointilism
Vignette
Fish-eye bulge

25 points each:

Bloom
Noise Warp
Hatching
Edge detection with Sobel filtering
Lit Sphere ( paper )
Uncharted 2 customizable filmic curve, following John Hable’s presetantion.
- Without Linear, Reinhard, filmic (10 points)
- With all of linear, Reinhard, filmic (10 points)
- Customizable via GUI: (5 points total)
  - Controlling Exposure
  - Side by side comparison between linear, Reinhard, filmic, and Uncharted2 .

37.5 points each:

K-means color compression (unless you are extremely clever, the k-means clusterer has to be CPU side)
Dithering

5 points - Interactivity

Implement a dropdown GUI to select different shader effects from your list.

??? points

Propose your own shading effects!

For the overachievers:

Weave all your shading effects into one aesthetically-coherent scene, perhaps by incorporating some of your previous assignments!

Getting Started

main.js

main.js is responsible for setting up the scene with the Mario mesh, initializing GUI and camera, etc.

Adding Shaders

To add a shader, you'll want to add a file to the src/shaders or src/post folder. As examples, we've provided two shaders lambert.js and grayscale.js. Here, I will give a brief overview of how these work and how everything hooks together.

shaders/lambert.js

IMPORTANT: I make my lambert shader available by exporting it in shaders/index.js.

export {default as Lambert} from './Lambert'

Each shader should export a function that takes in the renderer, scene, and camera. That function should return a Shader Object.

Shader.initGUI is a function that will be called to initialize the GUI for that shader. in lambert.js, you can see that it's here that I set up all the parameters that will affect my shader.

Shader.material should be a THREE.ShaderMaterial. This should be pretty similar to what you've seen in previous projects. Shader.material.vertexShader and Shader.material.fragmentShader are the vertex and fragment shaders used.

At the bottom, I have the following snippet of code. All it does is bind the Mario texture once it's loaded.

textureLoaded.then(function(texture) {
    Shader.material.uniforms.texture.value = texture;
});

So when you change the Shader parameter in the GUI, Shader.initGUI(gui) will be called to initialize the GUI, and then the Mario mesh will have Shader.material applied to it.

post/grayscale.js

GUI parameters here are initialized the same way they are for the other shaders.

Post process shaders should use the THREE.js EffectComposer. To set up the grayscale filter, I first create a new composer: var composer = new EffectComposer(renderer);. Then I add a a render pass as the first pass: composer.addPass(new EffectComposer.RenderPass(scene, camera));. This will set up the composer to render the scene as normal into a buffer. I add my filter to operate on that buffer: composer.addPass(GrayscaleShader);, and mark it as the final pass that will write to the screen GrayscaleShader.renderToScreen = true;

GrayscaleShader is a EffectComposer.ShaderPass which basically takes the same arguments as THREE.ShaderMaterial. Note, that one uniform that will have to include is tDiffuse. This is the texture sampler which the EffectComposer will automatically bind the previously rendered pass to. If you look at glsl/grayscale-frag.glsl, this is the texture we read from to get the previous pixel color: vec4 col = texture2D(tDiffuse, f_uv);.

IMPORTANT: You initially define your shader passes like so:

var GrayscaleShader = new EffectComposer.ShaderPass({
    uniforms: {
        tDiffuse: {
            type: 't',
            value: null
        },
        u_amount: {
            type: 'f',
            value: options.amount
        }
    },
    vertexShader: require('../glsl/pass-vert.glsl'),
    fragmentShader: require('../glsl/grayscale-frag.glsl')
});

BUT, if you want to modify the uniforms, you need to do so like so: GrayscaleShader.material.uniforms.u_amount.value = val;. Note the extra .material property.

Deploy

Create a gh-pages branch on GitHub
Do npm run build
Commit and add all your changes.
Do npm run deploy