Render shadows on entities. #11747

x2048 · 2021-11-01T00:56:46Z

Fixes a number of problems with how shadows are applied to entities:

Bug with mod 'drawers' described in Shadow mapping breaks visuals in minetest-mod-drawers #11326
Colored shadows not being applied properly to entities
Different shader logic being used for entities and nodes
Light and color of entities being calculated and communicated differently from nodes
Entity surface not being shaded correctly when facing way from directional light

What I've done so far:

I've added code to assign SM texture to its texture layer when setting texture in content_cao.
Implemented the same light color contract for entities as for nodes (alpha communicating the balance between natural/artificial). The only difference is that emissiveColor is used as a factor to the vertex color.
Copied the SM logic from node shader and object shader.
Fixed the way colored shadows are applied at small falling angle (cos(alpha) < 0.035 for nodes and 0.14 for objects)

What's left

Fix the way split-normals are loaded, since it causes problems with shading (e.g. MCL2 chests, boats, wolves)
Calibrate offset bias to remove self-shadowing on dropped node stacks (vanilla Minetest)
Fix phantom shadows from entities (looks like a broken world transformation)
(Almost) Fix self-shadowing of banner entities in MCL2 (offsets?)

This PR is Ready for Review

How to test

Add 'drawers' mod
Place three drawers: one in a shadow, one on the edge and one in the sunlight.
Place node of sand into each of the drawers (right-click)
Drawers should display sand inventory image, properly shaded together with the drawer node itself.

Another test:

Place any entity (e.g. animals, chests and boats in MCL2).
Fly/walk over.
Observe your shadow rendered on the entity.

x2048 · 2021-11-04T00:06:41Z

Colored shadows are now correctly applied and shaded at small angles to the surface:

x2048 · 2021-11-04T20:24:47Z

Problem with normals in certain b3d models:

x2048 · 2021-11-08T22:28:06Z

Normals look good with the latest change and minetest/irrlicht#77:

Andrey2470T · 2022-01-01T14:29:20Z

I get the compile-time error when compiling the PR's branch (I use IrrlichtMt from the latest git commit):

rollerozxa · 2022-01-01T14:35:51Z

That's caused by changes made in IrrlichtMt commit 52e03a that required fixes to the engine, and this PR is based off of an older commit of the engine which doesn't contain the fixes. Checkout dd09fd in IrrlichtMt and it should compile without issues (no difference in behavior anyways, it's just unused code removal).

x2048 · 2022-01-01T22:47:25Z

@Andrey2470T @rollerozxa I've rebased the branch to the latest master and checked that it compiles with the current tip of IrrlichtMt.

lhofhansl · 2022-02-08T07:13:44Z

Tested that shadows affect entities and that entities are properly self-shading, including player entities. Pretty cool!

lhofhansl · 2022-02-08T07:16:23Z

@x2048 What's left for this one? Looks good.
I have not observed "phantom" shadows. And MCL2 banners can be fixed in a different PR.
Skimmed the code, looks fine too.

Based on that, set "One Approval". I realize this is marked as WIP, but it seems to work pretty well.

x2048 · 2022-02-09T17:56:36Z

@lhofhansl It was long ago, and I need to review the code myself :)

Phantom shadows appeared as tiny spots at certain angles, when there were nearby entities. I'll look if I can reproduce it.

lhofhansl · 2022-02-09T19:55:29Z

:)

I think this is needed to "complete" shadow functionality.
With blocks and entities working we can then focus on the API and perhaps on LSPSM.

x2048 · 2022-02-12T08:28:47Z

@lhofhansl I've narrowed the phantom shadows to a problem with materials in upright_sprite entities. The most noticeable change is that player has a shadow in devtest now.

I've checked that entities in devtest cast and accept shadows correctly, but extra testing would always help.

I've removed One Approval and requested a review for the new code when you have time.

Add compatibility with colored shadows.

Pass correct natural & artificial light to the shaders Use natural/artificial light ratio for correct rendering of shadows

Detect non-zero normals which point in the opposite direction from the face plane normal.

Fixes shadows of animated sprite entities

Avoid using read only materials in mesh scene node, as it confuses shadow renderer.

lhofhansl · 2022-02-14T05:03:12Z

client/shaders/nodes_shader/opengl_fragment.glsl


 	if (PCFBOUND == 0.0) return 0.0;
 	// Return fast if sharp shadows are requested
+	if (PCFBOUND == 0.0)


Nit: Looks like this a duplicate.

lhofhansl · 2022-02-14T05:09:09Z

The soft-shadow stuff is still weird, and leads to strange artifacts. Also for a different PR - or maybe we just remove that code and/or replace it with something simpler (not depth dependent).

Then we can rethink #11944 and control both strength a softness via an API.

lhofhansl · 2022-02-15T05:19:51Z

Hot air balloons are still weird:

And I still think that we do not have to hold this up for this visual glitch.

lhofhansl · 2022-02-18T01:35:05Z

I do not think we have to wait with this one. If there are bugs, we can file additional PRs. Without this shadows are not visually complete.
Let's merge this one as is. @x2048 you have my +1, so feel free to merge (yours is the second implied +1).

x2048 · 2022-02-19T13:38:39Z

@lhofhansl There's one last change I have in the works while I am on it, and I'll move to merging.

One thing I noticed is that bias0 of 0.9 is very aggressive, causing significant undersampling of all shadows farther than rougly 10% of the shadow distance. Value of 0.8 gives a smoother curve and contributes to removing shadow acne.

lhofhansl · 2022-02-19T18:41:46Z

Sounds good. Do you know what these artifacts are? (see the circle line in the the picture)

Remove use of magic constants. Apply cameraOffset Calculate distance projected on SM plane

x2048 · 2022-02-20T00:47:35Z

For the record, the texelSize expression in the shaders is the solution of the following equation for d:
$\frac{x+d}{(x+d)*b0+b1}-\frac{x}{x*b0+b1}=\frac{1}{r}$

where r is texture resolution, and x is distance between player and vertex projected on the shadow map.

@lhofhansl I have not seen the artifact before, but I guess it is related to the precision of perspective factor transformation, and the center of this circle is the center of the SM texture.

lhofhansl · 2022-02-21T18:36:41Z

One thing I noticed since the last bias change are strange patterns on the player model:

Those stripes are not part of texture.

x2048 · 2022-02-21T19:58:12Z

This is because the normal bias is quite small right now, and PCF filter leaks shadow. I want to adjust perspective bias first, then normal bias, and then PCF filter radius, but not in this PR (and I'm well aware this looks like a regression).

lhofhansl · 2022-02-21T23:27:55Z

@x2048 Cool. Let's merge this one and get it out of the way. :)

x2048 marked this pull request as draft November 3, 2021 23:35

x2048 changed the title ~~Render shadows on entities.~~ WIP Render shadows on entities. Nov 3, 2021

x2048 force-pushed the shadows_entities branch from 3067fe2 to 3a906b3 Compare November 3, 2021 23:55

sfan5 added Feature ✨ PRs that add or enhance a feature Shaders WIP labels Nov 4, 2021

x2048 mentioned this pull request Nov 4, 2021

Shadow mapping breaks visuals in minetest-mod-drawers #11326

Closed

x2048 mentioned this pull request Nov 20, 2021

Light space perspective shadow mapping #11782

Closed

4 tasks

rubenwardy added the Roadmap The change matches an item on the current roadmap label Dec 7, 2021

This was referenced Jan 1, 2022

Recalculate normals before adding mesh to the scene. #11914

Merged

Reset mesh animation state before recalculating normals minetest/irrlicht#90

Merged

x2048 force-pushed the shadows_entities branch from c2be311 to fbd3cdf Compare January 1, 2022 22:46

lhofhansl added the One approval ✅ ◻️ label Feb 8, 2022

x2048 changed the title ~~WIP Render shadows on entities.~~ Render shadows on entities. Feb 12, 2022

x2048 requested a review from lhofhansl February 12, 2022 07:13

x2048 marked this pull request as ready for review February 12, 2022 07:13

x2048 added Testing needed and removed WIP One approval ✅ ◻️ labels Feb 12, 2022

x2048 added 8 commits February 13, 2022 19:41

Improve self-shadowing based on light/normal angle

783b6d3

Add compatibility with colored shadows.

Improve lighting of entities.

387546d

Pass correct natural & artificial light to the shaders Use natural/artificial light ratio for correct rendering of shadows

Detect 'insane' normals in checkMeshNormals.

55033d3

Detect non-zero normals which point in the opposite direction from the face plane normal.

Fix shadow rendering with filtering disabled

51db84f

Use correct indexes when checking mesh normals

caa5b86

Avoid possible buffer overflow when checking face normals

de70f2e

Apply texture matrix when rendering shadowmap

7e811c1

Fixes shadows of animated sprite entities

Fix shadows for upright sprite nodes

cef252b

Avoid using read only materials in mesh scene node, as it confuses shadow renderer.

x2048 force-pushed the shadows_entities branch from f1a5dc2 to cef252b Compare February 13, 2022 18:44

x2048 added 2 commits February 13, 2022 19:45

Ensure nightRatio is greater than zero in object shader

bebf005

Remove debugging code

21c2220

lhofhansl reviewed Feb 14, 2022

View reviewed changes

Change normal bias for entities to avoid shadow acne

a826a4b

x2048 added 2 commits February 20, 2022 00:04

Correct normal bias for entities

5323c2c

Remove use of magic constants. Apply cameraOffset Calculate distance projected on SM plane

Reuse normal offset calculation for nodes

d7f634a

lhofhansl added the One approval ✅ ◻️ label Feb 20, 2022

x2048 added >= Two approvals ✅ ✅ and removed One approval ✅ ◻️ labels Mar 7, 2022

x2048 merged commit b651bbf into luanti-org:master Mar 7, 2022

x2048 deleted the shadows_entities branch March 7, 2022 22:45

x2048 mentioned this pull request Mar 29, 2022

Entities/Objects darken with increasing shadow strength #11804

Closed

Render shadows on entities. #11747

Render shadows on entities. #11747

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