Power users looking to profile on different GPUs: the controls and toggles, as well as a guide on how to get accurate results are now in: Shaders/ws30-ALS-landclass-search-functions.frag .
Changelog:
- Move landclass search functions in ws30-ALS-ultra.frag into a shader include: ws30-ALS-landclass-search-functions.frag . These controls should be removed when appropriate.
- 2 development controls to reduce haze and/or lighting are left at the top of ws30-ALS-ultra.frag .
(cherry picked from commit 5196dbd4ebd5f586a7261dc3ae46aa50218caf91)
Squashed commit of the following:
commit e7c89ffb600d1bf5cee2936b7dbff31089452745
Author: vs <vs2009@mail.com>
Date: Fri Nov 5 23:44:35 2021 +1000
WS30 shaders:
- WS30-ALS and WS30-ALS-ultra fargment and vertex shaders: Fix NDotL being used before it is initialised. Rename varying diffuse_term from WS2 terrain shaders to light_diffuse_comp as the full diffuse term is not calculated until the fragment shader.
- WS30-ALS-ultra.frag: Enable haze and lighting by default.
commit 9b55ad051a8d7f3568dfdcd6890655942999e8d0
Author: vs <vs2009@mail.com>
Date: Wed Nov 3 22:50:29 2021 +1000
WS30 terrain shaders: ws30-ALS-ultra.frag
- For power users looking to profile transitions on different GPUs: The test phase toggles and settings for different transition options are available at the start of ws30-ALS-ultra.frag, along with explanations, and how to get accurate profile results on different GPUs. Just need to change a few numbers, save, and debug menu > configure dev extensions > reload shaders to activate.
- Note: at a minimum, small scale transitions to remove the 'squareness' due to the landclass texture need to be used even on old GPUs.
- All transition options are off by default. ws30-ALS-ultra.frag is active when the terrain quality slider is set to Ultra. Start by turning one of small or large scale transitions.
- Texture mixing for small and large scale transitions don't work together, to reduce texture lookups. Turn one off when using the other.
- Landclasses with contrasting colours make transition issues more visble. The driver control panel texture filtering settings reduces issues with seams at landclass borders.
- ws30-ALS.frag is left untouched in this commit, for comparison and reviewing. ws30-ALS.frag is active when terrain quality slider is set High to Low.
Changes:
- Implement large scale transitions and small scale de-pixelisation of landclasses by searching the landclass texture. Several options and quality levels are available for profiling on different GPUs.
- There are fixes for multiple issues dealing with texture rendering.
Changelog:
1.0 - Small-scale transitions:
-- a) Remove squareness due to landclass texture by growing neighbour landclasses onto others depending on a growth priority. This feature uses 2 landclass texture lookups, 1 noise lookup, and only 1 ground texture lookup per point. For now the growth priority is simply the landclass id number. If this approach is used, growth priority would be a materials parameter. A way to set default growth priority by landclass via an xml file would be needed. There is flickering noise at long ranges due to small scale detail in the noise function used for growing landclasses. Partial derivative are used to turn off the feature, but turning off the feature too quickly still shows some square ness in distant landclasses.
-- b) Reduce squareness due to landclass texture by mixing base textures of neighbouring landclasses. This is not perfect, as perfectly square shapes turn into perfectly square shapes with perfectly smudged edges. This uses 2 landclass texture lookups, and 2-3 ground texture lookups.
-- c) - a) and b) can be run at once. This option will also fade the growths gradually with distance. This uses 2 landclass texture lookups, 1 noise lookup, and 2-3 ground texture lookups.
2.0 - Large scale transitions:
-- a) Implemented by searching the landclass texture. The search pattern is current landlcass for the fragment at the center, and n search points in four directions along the s and t axes forming a cross. The search directions are configurable in the code, adn a minimum of 3 directions are needed. The step size is configurable. The fewer the steps, the larger the bands formed in the transitions. There are 1+4*n landclass lookups per n search points. e.g. 1 search point: 5 lookups, 4 search points:17 lookups, 10 search points: 41 lookups.
-- b) An option to dither the transition bands by adding mixing noise is availble. This breaks up the visual impact of bands.
-- c) There is some functionality to grow neighbours on a large scale. No growth priority is used - bothe neighbours will lose definition. A more advanced implementation can use several material parameters to define the nature of the transition: some transitions are very sharp in nature like with agriculture, other transitions can be very gradual, some transitions are patchy. Materials can have competing parameters, to determine which neighbour grows or has a shorter transition on one side. These parameters will need a way of specifying defaults by landclass.
3.0 - Fixes
-- a) - Fix seams at landclass borders. These are caused by different ground textures being stretched by different amounts. At the border, an incorrect mip-map level is looked up, causing a colour disontinuity in addition to the difference between landclasses. The reason the mip-map LoD is incorrect is because GPUs use 4 neighbouring pixels to figure out how fast texture coordinates change with respect to screenspace x and y (i.e. partial derivaitves), and use that information to pick a mip-map level. At a landlcass border, this calculation is incorrect.
-- b) Fix seams at borders caused by the current detiling function. This is due to the detiling function changing the amount textures are stretched, as well as messing with coordinates.
-- c) The solution to a) and b) is to use textureGrad() to lookup textures. It allows specifying partial derivatives. The partial derivatives for the normal texture coordinates are obtained by built-in funcions, and these need to be multiplied by each stretching factor, including different stretching inside conditionals. All future texture lookups that use custom coordinate scaling/manipulation need to use textureGrad. This fixes various signs of incorrect mip-map lod with distance and view angle (textures look stable/solid).
-- d) Fix ground textures being stretched out of proportion in the detiling function. This is caused by tile dimensions not being unequal and texture stretching.
Previous we just applied gl_LightSource[0].ambient without
multiplying it by the texture itself, so it just lightened
everything.
This fixes that. (ws30-ALS-detailed.frag still to do)
commit aca259acaccffbaf1cb264be423dda72c106150e
Author: vs <vs2009@mail.com>
Date: Sat Oct 23 22:55:56 2021 +1000
WS30 shaders: varying fix
commit 91b194f6766d432206cb013d99e0a96cd34ff33b
Author: vs <vs2009@mail.com>
Date: Sat Oct 23 22:17:03 2021 +1000
WS30 ultra shader: port the ambient lighting fix.
Previously only the diffuse term was considered in the fragment
shader, leading to very dark scenery and deep shadows.
Now the ambient light term is also included making the scenery
much closer to the way it should be lit.
commit e131ffaca7b2c934474f0e447b5852cb4c7c8d4a
Author: vs <vs2009@mail.com>
Date: Fri Oct 15 22:19:42 2021 +1000
WS30: landclass and texture lookups in fragment shader:
Changelog:
- Testing: Procedural random landclass function, get_random_landclass(). 1). Avoids a texture lookup for profiling. 2). Creates squares of configurable size with controllable random landclass ranges - to test landclass transition algorithms and quickly profile lots of landclasses in view. It's also possible to put pressure on GPU memory even with 1 lookup of ground textures per fragment, by reducing size to <20m and viewing from altitude.
- Add ALS ultra technique as no 5, move existing ALS technique to no. 6. Add WS30-ALS-ultra frag & vert in preparation for eventual ALS ultra port. Change comments/variables to match using a texture array instead of atlas. Sampler name: atlas -> textureArray.
- Testing/optimisation of de-tiling: WS30-ALS.frag: reorder perlin detiling to make noise source easier to switch. WS30-ALS-ultra.frag: Create alternative to perlin noise used for reducing tiling that avoids a texture lookup - to profile and optimise. This is commented out. The performance difference in the final version depends on memory pressure versus arithmetic load of the full shader. It varies by GPU and what's in view. In future, once a full ALS port is done, maybe it'll be more efficient to run a higher quality de-tiling algorithm all the time to avoid branching overhead due to effects like agriculture which need more de-tiling. De-tiling code in shaders should /eventually/ match CPU-side de-tiling of texture masks used for object and vegetation placement. De-tiling code in GPUs might be subject to precision and numerical artifacts, and if so maybe the texture lookup version would work better. The same applies to noise used for rendering WS3 water waves and collision queries. One option is to use exactly the same glsl code, with a C++ header to convert glsl syntax e.g. https://github.com/g-truc/glm .
The light sprite diminished to zero size as the FOV was decreased
(in sim zoom), and increased considerably as the FOV was increased.
This commit fixed this by taking the FOV into account to keep the light
sprite size roughly constant across the valid FOV range.
- The G-Buffer layout has been redesigned to be 96 bits per pixel. There are 24
unused bits that can be used for extra material parameters later (like
clearcoat).
- Add better debug views for the G-Buffer.
- Use octahedron normal encoding. This yields the same results as the previous
method but uses 16 bits less.
- Use rg11fb10f for the environment mapping cubemaps.
- Tweak the shadow mapping parameters and add a colored debug mode.
- Only render shadow maps for objects that inherit from model-default.eff or
model-pbr.eff instead of having a fallback Effect. Now transparent objects
should be ignored (if they are marked as such with model-transparent or
similar).
- Remove the separate occlusion texture. Now the PBR Effect expects a single
texture where R=occlusion, G=roughness and B=metallic.
- Add an utility linearizeDepth function to help visualize the depth buffer for debug purposes.
- Use 'color0' instead of 'color' for all color attachments.
- Do not write to the HDR buffer if a fragment doesn't need shading (depth = 1).
- Removed the multiple return statements, as they can be problematic with older GLSL 120 compilers
- Removed debug flags
- Moved code to separate functions for readability
- Reduced the band size to 0.1 to make more use of the higher quality cascades
- Added overrides as parameter values for: water floor_colour (vec3 RBG colours. Range: 0 to 1. Defaults: old inland map colour, a blue ocean colour.), water_shallowness (Same as depth map texture. Range: 0 to 1. Defaults: 1.0 inland, 0.7 ocean). The corresponding texture lookup branches are also gated by these uniform flags for performance reasons.
- All non-ALS Effects have been removed (except generic ones from model-default and terrain-default).
- The rendering dialog has been reworked to accomodate the changes.
- All necessary properties have been added to graphics-properties.xml
- Five graphics presets have been added: Minimal, Low, Medium, High and Ultra.
- Some unused properties have been removed from defaults.xml
- Remove all Compositor Effects and Shaders.
- Unify the low-spec and ALS pipelines in a single pipeline called 'Classic'.
- Readd shadow mapping.
- Move the WS30 Effect and fragment shader out of the Compositor-specific directories.
Previously we required 6 shader attributes to pass
in all the required information for the building shader.
By using packing techniques this has been reduced to 4.
This should improve support for integrated graphics cards.
Previously the front and side faces of random/OSM buildings
had identical texture coordinates. This resulted in the sides
of buildings texture mapping being squeezed or stretched.
This change generates a separate texture mapping for the sides
of the buildings.
Previously there was very limited texture variations
as a given texture index was used for both the wall
and ceiling. Now these can be specified separately,
allowing for more variation in both STG defined and
random buildings.
Requires simgear commit 053bda26a43314a91b01b08cd4617da82f7ab807
Replace random buildings with one using proper instancing.
Also implement more control over rendering of random buildings.
see README.scenery for details.
