Fixes issue #3576
* Clouds now take camera position as 3D, not 2D
* Cloud grid filling extracted to gridFilled method
* Clouds detect whether camera is inside cloud
* Camera in cloud changes fog by overriding sky colors
with cloud color
* Sun, moon and stars can be temporarily disabled
with setBodiesVisible
* Disabling fog also disables all "inside cloud" behaviors
* Add Device3D class which will contain IrrlichtDevice interface
move getSupportedVideoDrivers to Device3D
Add Device3D singleton & use it in various places
Rename Device3D to Rendering engine & add helper functions to various device pointers
More singleton work
RenderingEngine owns draw_load_screen
move draw functions to RenderingEngine
Reduce IrrlichtDevice exposure and guienvironment
RenderingEngine: Expose get_timer_time() to remove device from guiEngine
Make irrlichtdevice & scene manager less exposed
* Code style fixes
* Move porting::getVideoDriverName, getVideoDriverFriendlyName, getDisplayDensity, getDisplaySize to RenderingEngine
Fix XORG_USED macro -> RenderingEngine + create_engine_device from RenderingEngine constructor directly
* enum paralax => enum parallax
Default true.
Add 'm_clouds_enabled' bool to sky.h, set from new bool in 'set sky' API.
Make 'getCloudsVisible()' depend on 'm_clouds_enabled' instead of
'm_visible' (whether normal sky is visible).
* Some performance optimizations
This is globally removing some memory useless copy
* use a const ref return on std::string Settings::get to prevent data copy on getters which doesn't need to copy it
* pass some stack created strings to static const as they are not modified anywhere
* Camera: return nametags per const ref instead of a list pointer, we only need to read it
* INodeDefManager: getAll should be a result ref writer instead of a return copy
* INodeDefManager: getAlias should return a const std::string ref
* Minimap: unroll a Scolor creation in blitMinimapPixersToImageRadar to prvent many variable construct/destruct which are unneeded (we rewrite the content in the loop)
* CNodeDefManager::updateAliases: prevent a idef getall copy
* Profiler: constness
* rollback_interface: create real_name later, and use const ref
* MapBlockMesh updateFastFaceRow: unroll TileSpec next_tile, which has a cost of 1.8% CPU due to variable allocation/destruction,
* MapBlockMesh updateFastFaceRow: copy next_tile to tile only if it's a different tilespec
* MapBlockMesh updateFastFaceRow: use memcpy to copy next_lights to lights to do it in a single cpu operation
Clean up nearby code a bit
As a small side effect, it is now possible to add a background texture
to the chat console by simply providing background_chat.jpg, it is no
longer necessary to also add "console_color =" to minetest.conf.
