Terrain shader experiments

[Garanas]

Various experiments to the terrain shader for improved fidelity. Currently it tries to implement:

• https://www.gamedeveloper.com/programming/advanced-terrain-texture-splatting
• https://blog.selfshadow.com/publications/blending-in-detail/
• https://www.ronja-tutorials.com/post/010-triplanar-mapping/

Sources:

• https://github.com/bgolus/Normal-Mapping-for-a-Triplanar-Shader
• https://catlikecoding.com/unity/tutorials/advanced-rendering/triplanar-mapping/
• https://www.youtube.com/watch?v=ueC2qGzWrgQ
• https://www.youtube.com/watch?v=V3wghbZ-Vh4
• https://learnopengl.com/PBR/Theory

Instruction counts:

• https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx9-graphics-reference-asm-ps-instructions-ps-2-x
• https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx9-graphics-reference-asm-vs-instructions-vs-2-x

[Garanas]

Adjusted blending

new blending where we use the alpha as a blend mask

old blending being basic linear interpolation

There are still some artifacts - but regardless the blending is a lot more impressive now. You can control the blending with the alpha layer of the albedo texture.

[Garanas]

Some intermediate results - this is an initial draft. Nothing is final yet. Overview of the current texture usage:

|  | Albedo stratum                                              | Normal stratum
|L | R           | G             | B             | A             | R             | G             | B             | A                 |
----            ---             ---             ---             ---             ---             ---             ---                 ---
|0 | R             G               B               Height        | X               Y               Occlusion       Roughness
|1 | R             G               B               Height        | X               Y               Occlusion       Roughness
|2 | R             G               B               Height        | X               Y               Occlusion       Roughness
|3 | R             G               B               Height        | X               Y               Occlusion       Roughness
|4 | R             G               B               Height        | X               Y               Occlusion       Roughness
----            ---             ---             ---             ---             ---             ---             ---                 ---
|5 | R             G               B               Height        | X               Y               Occlusion       Roughness
|6 | R             G               B               Height        | X               Y               Occlusion       Roughness
|7 | Map R         Map G           Map B           Map alpha     | Map X           Map Y           Map Z           Map alpha
|8 | Map wetness   Map shadows     Map Ambient     Map metallic  | 
|9 | ?

Where only stratum layers 7 / 8 are implemented. The others still use the old lighting model.

[Garanas]

That commit is on the wrong branch 😄

[MrRowey]

😆

[Garanas]

Draft 2.0 where I introduced a second map to experiment with.

[Garanas]

Similar screenshots using the old map-wide technique. Note that Auralian (the green map) cheats because it uses 8192x8192 textures, where as the version with the new shaders uses 4096x4096 textures. There was no particular reason for this except ease of work.

A few things to note:

• Shadows are applied on top of terrain lighting computations, therefore it is a lot darker.
• There is no (or little) ambient occlusion in this version as that just makes everything more dark.
• There are bits that receive light but shouldn't because shadows are not part of the computations. I've highlighted one place where this happens (first green image, red box).

[Garanas]

In order to limit the scope of this pull request the focus will be on allowing map-wide content through the stratum layers. This is what you see in the screenshots at the moment. The other effects like advanced stratum interpolation and fixing small issues (like the masks being * 2 by default) will be for another release.

I think having the possibility of shadows and global illumination-like techniques on maps will make a significant difference regardless.

[Cheyans]

Looks like copyright unicode character for copyright got replaced by U+FFFC

[Cheyans]

same here

[MrRowey]

this is going to be the same for a lot of the Lua files in the game not just these few

[Garanas]

Any idea why my editor replaces this every time? I think half of the files with a question mark are my doing at this point 😄

[MrRowey]

so from a search it can be as simple as the VSCode encoding in the blue bar at the bottom switching between UTF-8 & Windows 1252 seems to fix the issues with the C symbol not showing if the diamond is present

[Garanas]

Fixed the branch so that it only involves the relevant changes.

[Garanas]

And I messed up again 😄

[Garanas]

Not as pretty as I wanted it to be but now it is all good 😄

[Garanas]

I tried to upload a test map directly onto Github, but to no avail. Here it is via WeTransfer:

• https://we.tl/t-INSVdHEeLB

[Garanas]

terrain-example-01.mp4

An example of the zoom behavior for cliffs

[Garanas]

Working with better blending patterns for normals and albedo

[Garanas]

The repetitiveness of the ground textures is still a work in progress 😃

[Garanas]

The possibilities are there, but without a fitting editor it is very difficult to work with the new shaders. The majority of suggested changes are already merged in with #4380 by accident.