Distance fog #72

lyonsno · 2020-02-18T17:55:12Z

Add a fog scale parameter to the module. Default value is zero, which applies no fog. Fog works by blending objects into the env map as they appear further away. Values above zero will specify the ray distance at which objects are fully obscured by fog, i.e. replaced by the envmap in that direction.

Also adds a few params which allow for external fine-tuning of temporal filtering and sampling settings .

Image(s) or GIFs (if applicable)

Pull Request Guidelines

I have added pull requests labels which describe my contribution.
All existing tests passed.
- I have added tests to cover my changes, of which pass.
I have compared the render output of my branch to master.
My code has passed the ESLint configuration for this project.
My change requires modifications to the documentation.
- I have updated the documentation accordingly.


        test next event estimation


        Merge branch 'master' into next-event-estimation


        start implementing shadow catcher


        add shadow catcher support (kindof)


        big cleanup


        Merge branch 'master' into next-event-estimation


        more tweaks


        revert scene changes


        set strataCount back to default


        add new params to module, including fogscale and ability to add fog

jaxry · 2020-02-18T19:33:32Z

src/renderer/RenderingPipeline.js

+  const fogScale = renderingParams.fogScale;
+
+  const bounces = renderingParams.bounces; // number of global illumination bounces
+


We could destructure these too if you like that idea.

jaxry · 2020-02-18T19:33:32Z

src/renderer/glsl/chunks/intersect.glsl

@@ -205,6 +205,7 @@ void intersectScene(inout Ray ray, inout SurfaceInteraction si) {
        int materialIndex = floatBitsToInt(r2.w);
        vec3 faceNormal = r2.xyz;
        surfaceInteractionFromBVH(si, tri, hit.barycentric, index, faceNormal, materialIndex);
+        ray.distance = length(ray.o - si.position);


I believe this value is already stored in ray.tMax, so no need to compute it here. It's a weird variable name but it's what pbrt uses.

Edit: Actually, ray.t stores the distance too and that's the property we should be using. It's a parametric ray, where ray.o is the origin, and ray.t is the length.

jaxry · 2020-02-18T19:33:32Z

src/renderer/glsl/chunks/envmap.glsl

+  #ifdef FOG_SCALE
+
+    float fogWeight = max(0.0, 1.0 - ((max(0.0, distance)) / FOG_SCALE));
+    fogWeight = pow(fogWeight, 2.0);


If we're always doing a pow of 2.0 because it looks nice, fogWeight *= fogWeight would at least be as performant if not more so.

jaxry · 2020-02-18T19:33:32Z

src/renderer/glsl/chunks/envmap.glsl

+vec3 applyFog(vec3 li, float distance, vec3 direction, inout vec3 beta) {
+  #ifdef FOG_SCALE
+
+    float fogWeight = max(0.0, 1.0 - ((max(0.0, distance)) / FOG_SCALE));


I'm not sure how different it looks, but supposedly a more "realistic" fog is exponential fog.

https://catlikecoding.com/unity/tutorials/rendering/part-14/

The weight would be 1 / pow(2.0, distance * scaleConstant), where the constant is some low number like 0.001.

jaxry · 2020-02-18T20:18:44Z

Would it make sense to implement Scene.fog as best we can? We could use the near and far values. For color, we could either ignore it, or we implement it, and if it's set to null that's when we blend with the envmap?

jaxry · 2020-02-18T22:30:59Z

src/RayTracingRenderer.js

+    const renderingParams = {
+      reprojectedSamples: module.reprojectedSamples,
+      initialUniformSamples: module.initialUniformSamples,
+      previewTime: module.previewTime,


I'm hesitant to expose these values to the user

They are highly dependent on the current pipeline. Any change to the pipeline necessarily requires changes to these numbers, and if the user overrides them, their renderer will break when they update to the latest pipeline.

They are scene independent. There are ideal numbers that work on the majority of devices that work better than other numbers. It's not opinionated in other words, so if our current numbers are off, it would be better to fix them with a PR than with user-overwritten values.

Thoughts?

Hmm. I definitely see your point here. It has been very convenient for me to easily modify them in my work when using ray tracing renderer as a dependency though.. Ideas?

That makes sense. What about exposing these params prefixed with an underscore (or something to denote they're "private"), and not documenting them in the wiki? That gives us the power to add/remove params when necessary (for example, previewTime might not be used with benchmark redesign), and we don't have to worry about supporting them. But we can still tweak the numbers as a dependency, from a dev perspective, to hone in on good values to merge with a PR?

Just throwing ideas here.

lyonsno · 2020-02-18T22:31:59Z

Would it make sense to implement Scene.fog as best we can? We could use the near and far values. For color, we could either ignore it, or we implement it, and if it's set to null that's when we blend with the envmap?

yes! great idea.

jaxry · 2020-02-18T22:32:48Z

src/renderer/glsl/chunks/sampleMaterial.glsl

-  vec2 uv;
-  vec3 lightDir = sampleEnvmap(random, uv, lightPdf);
+  float originalRayDistance = path.ray.distance;
+  vec3 originalRayDirection = path.ray.d;


Instead of copying these values, what about keeping them as they are, and instead using a separate Ray for the shadow intersection? That takes less code I believe.

Edit: We could also do the fog calcs before the shadow intersection, letting us use the same ray for everything. Not sure if that micro-optimization would have any benefit though.


        add exp fog option and fog near


        build file

jaxry and others added 10 commits Feb 5, 2020

test next event estimation

Loading status checks…

70a204e

Merge branch 'master' into next-event-estimation

b859fa5

start implementing shadow catcher

Loading status checks…

d52b6cd

add shadow catcher support (kindof)

Loading status checks…

51e4eb0

big cleanup

Loading status checks…

a260cc8

Merge branch 'master' into next-event-estimation

Loading status checks…

2eaf209

more tweaks

Loading status checks…

bc0f5a3

revert scene changes

Loading status checks…

114df64

set strataCount back to default

Loading status checks…

087196c

add new params to module, including fogscale and ability to add fog

Loading status checks…

b0588cf

lyonsno requested review from carlos-lopez-garces, elfrank, jaxry and santiagoroca as code owners Feb 18, 2020

lyonsno added enhancement good first issue labels Feb 18, 2020

jaxry reviewed Feb 18, 2020

View changes

lyonsno added 2 commits Feb 20, 2020

add exp fog option and fog near

5ec8b4e

build file

Loading status checks…

c449798

elfrank added the on hold label May 17, 2020

elfrank marked this pull request as draft May 29, 2020

hoverinc / ray-tracing-renderer

Distance fog #72

Distance fog #72

lyonsno commented Feb 18, 2020

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

jaxry commented Feb 18, 2020

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

lyonsno commented Feb 18, 2020

This comment has been minimized.

		const fogScale = renderingParams.fogScale;

		const bounces = renderingParams.bounces; // number of global illumination bounces

hoverinc / ray-tracing-renderer

Join GitHub today

Distance fog #72

Distance fog #72

Conversation

lyonsno commented Feb 18, 2020

Image(s) or GIFs (if applicable)

Pull Request Guidelines

This comment has been minimized.

jaxry Feb 18, 2020

This comment has been minimized.

jaxry Feb 18, 2020 • edited

This comment has been minimized.

jaxry Feb 18, 2020

This comment has been minimized.

jaxry Feb 18, 2020

jaxry commented Feb 18, 2020

This comment has been minimized.

jaxry Feb 18, 2020

This comment has been minimized.

lyonsno Feb 18, 2020

This comment has been minimized.

jaxry Feb 18, 2020 • edited

lyonsno commented Feb 18, 2020

This comment has been minimized.

jaxry Feb 18, 2020 • edited

jaxry Feb 18, 2020 •

edited

jaxry Feb 18, 2020 •

edited

jaxry Feb 18, 2020 •

edited