PBR improvements

[AMajesticSeaFlapFlap]

to track future improvements/fixes for the PBR material/IBL OP

• fix tangent space generation for cables/display a warning that meshes with normal maps will require exported tangents
• automatically enable use mesh tangents/binormals if a normal map is connected
• implement microsurface interreflections using the filament approach
• add tonemapping
• add lightmap support with rgbe/exr
• add more shader features such as clearcoat/...
• add support for point/spot/directional lights
• add option to also apply geometric roughness on the normal map? :/
• add environment rotation as a parameter to IBL precomputation
• add option for using vertex colours as base colour/AORM/AO/R/M
• fix problem with environment light when opening a patch in a new tab and only tabbing in after a second. this will cause the generated maps to be black.
• generate the BRDF LUT only once per patch and not once per OP
• add even cooler shader features such as SSS/cloth/...
• better sampling algorithm for environment light OP

[tastez]

environment rotation?

[AMajesticSeaFlapFlap]

microsurface interreflections seem to work https://dev.cables.gl/p/QbcBoY but there is still some energy lost somewhere with a furnace test https://dev.cables.gl/p/NF0arY maybe also related to IBL precomputations? swapped out large parts of the shaders and seems to be fine now

[AMajesticSeaFlapFlap]

added the tonemapping operators from https://github.com/BabylonJS/Babylon.js/blob/5e6321d887637877d8b28b417410abbbeb651c6e/src/Shaders/tonemap.fragment.fx

[AMajesticSeaFlapFlap]

made tangent space from mesh default option, removed Gram-Schmidt. I think exposing this option did only help in a tiny amount of cases and leads to more confusion than what its worth.

[AMajesticSeaFlapFlap]

added code for spot/directional/point lights. radius doesnt work properly on specular part yet it seems.

[AMajesticSeaFlapFlap]

added rotation parameter to IBL precompute @tastez . exposed as values from 0-1, not sure if 0-360 would be more intuitive.

[AMajesticSeaFlapFlap]

added vertex colour support:

[tastez]

think i found the reason for the black screen when trying to use lights to generate shadows (from my old example)
Lights have to be placed Below the pbrenvironment/precomputeIBL op, otherwise it will render a black map.

checked the patch where i had the issue and indeed the light is above pbr environment

Connecting it in the editor sometimes will look like it works and then when you reload it doesn't - this might happen if you connected it "correctly" once and then decided to move a light op above the environment texture.

btw - should i switch to using PrecompuleIBL V2 on dev with the updated PBR material?
also - will it be renamed to PBRenvironment later?

[pandrr]

• will it be renamed to PBRenvironment later?
  we could, but isnt it like an ambient light in some form ?

[AMajesticSeaFlapFlap]

yes for testing on dev use precompute IBL v2 until the updated OP is pushed

[pandrr]

it is pushed to dev now, compiled changelog here: #990 (comment)

[tastez]

since PBRmaterial can now be used with just cables lights - would be nice to add exceptions to these warnings..but i guess it is on the lights' end?

[tastez]

Shadows and Rotate in PBR Environment can produce issues -

pbr_rotate_shadow.mp4

PBR Environment texture size sometimes doesnt update until you rotate texture

pbr_rotate_size.mp4

invited @AMajesticSeaFlapFlap to this test patch https://dev.cables.gl/edit/5IYNw-

[AMajesticSeaFlapFlap]

lightmap support and clear coat added in #3555