François
8ec4b99a69
standardize instructions in examples ( #8478 )
...
# Objective
- Standardize on screen instructions in examples:
- top left, bottom left when better
- white, black when better
- same margin (12px) and font size (20)
## Solution
- Started with a few examples, let's reach consensus then document and
open issues for the rest
2023-04-26 19:52:31 +00:00
François
e0e5f3acd4
add a default font ( #8445 )
...
# Objective
- Have a default font
## Solution
- Add a font based on FiraMono containing only ASCII characters and use
it as the default font
- It is behind a feature `default_font` enabled by default
- I also updated examples to use it, but not UI examples to still show
how to use a custom font
---
## Changelog
* If you display text without using the default handle provided by
`TextStyle`, the text will be displayed
2023-04-21 22:30:18 +00:00
Nicola Papale
8df014fbaf
Add parallax mapping to bevy PBR ( #5928 )
...
# Objective
Add a [parallax mapping] shader to bevy. Please note that
this is a 3d technique, NOT a 2d sidescroller feature.
## Solution
- Add related fields to `StandardMaterial`
- update the pbr shader
- Add an example taking advantage of parallax mapping
A pre-existing implementation exists at:
https://github.com/nicopap/bevy_mod_paramap/
The implementation is derived from:
https://web.archive.org/web/20150419215321/http://sunandblackcat.com/tipFullView.php?l=eng&topicid=28
Further discussion on literature is found in the `bevy_mod_paramap`
README.
### Limitations
- The mesh silhouette isn't affected by the depth map.
- The depth of the pixel does not reflect its visual position, resulting
in artifacts for depth-dependent features such as fog or SSAO
- GLTF does not define a height map texture, so somehow the user will
always need to work around this limitation, though [an extension is in
the works][gltf]
### Future work
- It's possible to update the depth in the depth buffer to follow the
parallaxed texture. This would enable interop with depth-based
visual effects, it also allows `discard`ing pixels of materials when
computed depth is higher than the one in depth buffer
- Cheap lower quality single-sample method using [offset limiting]
- Add distance fading, to disable parallaxing (relatively expensive)
on distant objects
- GLTF extension to allow defining height maps. Or a workaround
implemented through a blender plugin to the GLTF exporter that
uses the `extras` field to add height map.
- [Quadratic surface vertex attributes][oliveira_3] to enable parallax
mapping on bending surfaces and allow clean silhouetting.
- noise based sampling, to limit the pancake artifacts.
- Cone mapping ([GPU gems], [Simcity (2013)][simcity]). Requires
preprocessing, increase depth map size, reduces sample count greatly.
- [Quadtree parallax mapping][qpm] (also requires preprocessing)
- Self-shadowing of parallax-mapped surfaces by modifying the shadow map
- Generate depth map from normal map [link to slides], [blender
question]
https://user-images.githubusercontent.com/26321040/223563792-dffcc6ab-70e8-4ff9-90d1-b36c338695ad.mp4
[blender question]:
https://blender.stackexchange.com/questions/89278/how-to-get-a-smooth-curvature-map-from-a-normal-map
[link to slides]:
https://developer.download.nvidia.com/assets/gamedev/docs/nmap2displacement.pdf
[oliveira_3]:
https://www.inf.ufrgs.br/~oliveira/pubs_files/Oliveira_Policarpo_RP-351_Jan_2005.pdf
[GPU gems]:
https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-18-relaxed-cone-stepping-relief-mapping
[simcity]:
https://community.simtropolis.com/omnibus/other-games/building-and-rendering-simcity-2013-r247/
[offset limiting]:
https://raw.githubusercontent.com/marcusstenbeck/tncg14-parallax-mapping/master/documents/Parallax%20Mapping%20with%20Offset%20Limiting%20-%20A%20Per-Pixel%20Approximation%20of%20Uneven%20Surfaces.pdf
[gltf]: https://github.com/KhronosGroup/glTF/pull/2196
[qpm]:
https://www.gamedevs.org/uploads/quadtree-displacement-mapping-with-height-blending.pdf
---
## Changelog
- Add a `depth_map` field to the `StandardMaterial`, it is a grayscale
image where white represents bottom and black the top. If `depth_map`
is set, bevy's pbr shader will use it to do [parallax mapping] to
give an increased feel of depth to the material. This is similar to a
displacement map, but with infinite precision at fairly low cost.
- The fields `parallax_mapping_method`, `parallax_depth_scale` and
`max_parallax_layer_count` allow finer grained control over the
behavior of the parallax shader.
- Add the `parallax_mapping` example to show off the effect.
[parallax mapping]: https://en.wikipedia.org/wiki/Parallax_mapping
---------
Co-authored-by: Robert Swain <robert.swain@gmail.com>
2023-04-15 10:25:14 +00:00
