Landclass information is typically not high enough resolution
to render small beaches and coastline features.
This commit uses the steepness of the elevation mesh
to procedurally generate:
a) sea-cliffs (poorly - just a texture at present)
b) beaches, which mix into translucent shallow water
c) breaking waves (poorly - uses the wind direction rather than the
slope normal)
see also https://wiki.flightgear.org/Nasal_Optimisation#Emesary_real_time_executive
Using a scheduler to manage the invocation of Nasal modules provides a more predictable and efficient way to replace update loops and also optimises property tree access to one access per property per frame by using a hash that contains the property values.
There is a default global object created (emexec.ExecScheduler) that should be used in most circumstances.
Each Nasal object simply has to have an update(notification) method. This will be called on a schedule and the notification will contain any requested property values.
The exec will also adapt the rate to the frame rate; with a maximum of 50hz, but this will drop to as low as 4hz based on the frame rate to optimise workload.
The modules will be called in the order in which they were added; so it is possible to have modules in the right sequence (i.e. an earlier module calculates values that are used by a later module)
A simple example is below. The VSD_device has the update method
------
# list of prooperties to include in the notification hash
var properties_to_monitor = {
OrientationHeadingDeg : "orientation/heading-deg",
OrientationPitchDeg : "orientation/pitch-deg",
OrientationRollDeg : "orientation/roll-deg",
GroundspeedKts : "velocities/groundspeed-kt",
radar2_range : "instrumentation/radar/radar2-range",
target_display : "sim/model/f15/instrumentation/radar-awg-9/hud/target-display",
vc_kts : "instrumentation/airspeed-indicator/true-speed-kt",
};
# create Canvas based device (that has an update method)
VSD = VSD_Device.new(designation, textureImage, notification.Ident, root_node);
# register with the exec;
# - ident
# - proprties to include in notification hash
# - object (with an .update(notification) method
# - rate (4 = 1/4)
emexec.ExecModule.register("F15-VSD", properties_to_monitor, VSD, 4);
Objects like OSM buildings using the `model-combined` effect ignored
the Terrain quality. Rayleigh Fog is computed for the terrain only
at "Ultra" level, but was computed for models at all quality levels,
which led to a visual disparity. The shader now takes into account
the terrain quality before computing rayleigh fog for objects.
The `road` effect also had the same issue and is fixed now.
model-combined-transparent was replaced by calling model-transparent causing the ALS
externel canopy effects to get lost. Call model-combined instead which restores these
effects.
Previously the water shader was separate and executed on a
different mesh.
This adds the water shader as a separate fragment function
(ws30-water.frag) and uses a material parameter passed in
as a Uniform to use it in preference to the usual texel
lookup.
Performance testing found a slight performance improvement
from having a single mesh, but a slight performance impact
from the extra fragment shader complexity.
