feat: Make clouds respond to average wind speed and direction

Author: twpol

Source/RunActivity/Content/SkyShader.fx

@@ -1,21 +1,21 @@
-// COPYRIGHT 2010, 2011, 2012, 2013 by the Open Rails project.
-// 
+// COPYRIGHT 2009 - 2023 by the Open Rails project.
+//
 // This file is part of Open Rails.
-// 
+//
 // Open Rails is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
-// 
+//
 // Open Rails is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU General Public License for more details.
-// 
+//
 // You should have received a copy of the GNU General Public License
 // along with Open Rails.  If not, see <http://www.gnu.org/licenses/>.
 
-// This file is the responsibility of the 3D & Environment Team. 
+// This file is the responsibility of the 3D & Environment Team.
 
 ////////////////////////////////////////////////////////////////////////////////
 //                     S H A D O W   M A P   S H A D E R                      //
@@ -27,7 +27,7 @@ float4x4 WorldViewProjection;  // model -> world -> view -> projection
 float4   LightVector;  // Direction vector to sun, w = 1/length of vector
 float    Time;  // Used for moving textures across the sky
 float4   Overcast;  // x = alpha, y = contrast, z = brightness, w = !Overcast.y && !Overcast.z
-float2   WindDisplacement;
+float4   CloudScalePosition;
 float3   SkyColor;
 float3   FogColor;
 float4   Fog;
@@ -255,10 +255,7 @@ float4 PSMoon(VERTEX_OUTPUT In) : COLOR
 
 float4 PSClouds(VERTEX_OUTPUT In) : COLOR
 {
-	// Get the color information for the current pixel
-	// Cloud map is tiled. Tiling factor: 4
-	// Move cloud map to suit wind conditions
-	float2 TexCoord = float2(In.TexCoord.x * 4 + WindDisplacement.x, In.TexCoord.y * 4 + WindDisplacement.y);
+	float2 TexCoord = In.TexCoord.xy * CloudScalePosition.xy - CloudScalePosition.zw;
 	float4 cloudColor = tex2D(CloudMapSampler, TexCoord);
 	float alpha = cloudColor.a;
 

Source/RunActivity/Viewer3D/MSTSSky.cs

@@ -585,8 +585,7 @@ public override void Render(GraphicsDevice graphicsDevice, IEnumerable<RenderIte
             MSTSSkyShader.MoonScale = MSTSSkyConstants.skyRadius / 20;
             MSTSSkyShader.Overcast = Viewer.World.MSTSSky.mstsskyovercastFactor;
             MSTSSkyShader.SetFog(Viewer.World.MSTSSky.mstsskyfogDistance, ref SharedMaterialManager.FogColor);
-            MSTSSkyShader.WindSpeed = Viewer.World.MSTSSky.mstsskywindSpeed;
-            MSTSSkyShader.WindDirection = Viewer.World.MSTSSky.mstsskywindDirection; // Keep setting this after Time and Windspeed. Calculating displacement here.
+            MSTSSkyShader.CloudScalePosition = Viewer.World.WeatherControl.CloudScalePosition;
 
             for (var i = 0; i < 5; i++)
                 graphicsDevice.SamplerStates[i] = SamplerState.LinearWrap;

Source/RunActivity/Viewer3D/Shaders.cs

@@ -1,29 +1,29 @@
-// COPYRIGHT 2009, 2010, 2011, 2012, 2013 by the Open Rails project.
-// 
+// COPYRIGHT 2009 - 2023 by the Open Rails project.
+//
 // This file is part of Open Rails.
-// 
+//
 // Open Rails is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
 // the Free Software Foundation, either version 3 of the License, or
 // (at your option) any later version.
-// 
+//
 // Open Rails is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU General Public License for more details.
-// 
+//
 // You should have received a copy of the GNU General Public License
 // along with Open Rails.  If not, see <http://www.gnu.org/licenses/>.
 
-// This file is the responsibility of the 3D & Environment Team. 
+// This file is the responsibility of the 3D & Environment Team.
 
 using System;
 using System.IO;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Content.Pipeline;
 using Microsoft.Xna.Framework.Graphics;
-using Orts.Viewer3D.Processes;
 using ORTS.Common;
+using Orts.Viewer3D.Processes;
 
 namespace Orts.Viewer3D
 {
@@ -308,7 +308,7 @@ public class SkyShader : Shader
         readonly EffectParameter lightVector;
         readonly EffectParameter time;
         readonly EffectParameter overcast;
-        readonly EffectParameter windDisplacement;
+        readonly EffectParameter cloudScalePosition;
         readonly EffectParameter skyColor;
         readonly EffectParameter fogColor;
         readonly EffectParameter fog;
@@ -382,16 +382,7 @@ public float Overcast
             }
         }
 
-        public float WindSpeed { get; set; }
-
-        public float WindDirection
-        {
-            set 
-            {
-                var totalWindDisplacement = 50 * WindSpeed * _time; // This exaggerates the wind speed, but it is necessary to get a visible effect
-                windDisplacement.SetValue(new Vector2(-(float)Math.Sin(value) * totalWindDisplacement, (float)Math.Cos(value) * totalWindDisplacement));
-            }
-        }
+        public Vector4 CloudScalePosition { set => cloudScalePosition.SetValue(value); }
 
         public float MoonScale { get; set; }
 
@@ -427,7 +418,7 @@ public SkyShader(GraphicsDevice graphicsDevice)
             lightVector = Parameters["LightVector"];
             time = Parameters["Time"];
             overcast = Parameters["Overcast"];
-            windDisplacement = Parameters["WindDisplacement"];
+            cloudScalePosition = Parameters["CloudScalePosition"];
             skyColor = Parameters["SkyColor"];
             fogColor = Parameters["FogColor"];
             fog = Parameters["Fog"];

Source/RunActivity/Viewer3D/Sky.cs

@@ -31,8 +31,6 @@ namespace Orts.Viewer3D
     public class SkyViewer
     {
         internal readonly SkyPrimitive Primitive;
-        internal readonly float WindSpeed;
-        internal readonly float WindDirection;
         internal int MoonPhase;
         internal Vector3 SolarDirection;
         internal Vector3 LunarDirection;
@@ -54,11 +52,6 @@ public SkyViewer(Viewer viewer)
 
             // Instantiate classes
             Primitive = new SkyPrimitive(Viewer.RenderProcess);
-
-            // Default wind speed and direction
-            // TODO: We should be using Viewer.Simulator.Weather instead of our own local weather fields
-            WindSpeed = 5.0f; // m/s (approx 11 mph)
-            WindDirection = 4.7f; // radians (approx 270 deg, i.e. westerly)
         }
 
         public void PrepareFrame(RenderFrame frame, ElapsedTime elapsedTime)
@@ -389,8 +382,7 @@ public override void Render(GraphicsDevice graphicsDevice, IEnumerable<RenderIte
             SkyShader.MoonScale = SkyPrimitive.RadiusM / 20;
             SkyShader.Overcast = Viewer.Simulator.Weather.CloudCoverFactor;
             SkyShader.SetFog(Viewer.Simulator.Weather.VisibilityM, ref SharedMaterialManager.FogColor);
-            SkyShader.WindSpeed = Viewer.World.Sky.WindSpeed;
-            SkyShader.WindDirection = Viewer.World.Sky.WindDirection; // Keep setting this after Time and Windspeed. Calculating displacement here.
+            SkyShader.CloudScalePosition = Viewer.World.WeatherControl.CloudScalePosition;
 
             for (var i = 0; i < 5; i++)
             {

Source/RunActivity/Viewer3D/Weather.cs

@@ -47,6 +47,10 @@ public class WeatherControl
         public readonly List<SoundSourceBase> SnowSound;
         public readonly List<SoundSourceBase> WeatherSounds = new List<SoundSourceBase>();
 
+        public Vector4 CloudScalePosition { get => new Vector4(CloudScale.X, CloudScale.Y, CloudPositionM.X / SkyPrimitive.RadiusM, CloudPositionM.Y / SkyPrimitive.RadiusM); }
+
+        Vector2 CloudScale;
+        Vector2 CloudPositionM;
         WorldLocation CameraWorldLocation;
 
         public bool weatherChangeOn = false;
@@ -186,6 +190,7 @@ public void UpdateWeatherParameters()
 
             Weather.WindAverageDirectionRad = (float)Viewer.Random.NextDouble() * MathHelper.TwoPi;
             Weather.WindAverageSpeedMpS = (float)Viewer.Random.NextDouble() * WeatherConstants.WindSpeedBeaufortMpS[WindSpeedBeaufort];
+            CloudScale = new Vector2(4, 4);
         }
 
         void UpdateSoundSources()
@@ -242,6 +247,8 @@ private void UpdateWind(ElapsedTime elapsedTime)
                 WindUpdateTimer -= WindGustUpdateTimeS;
             }
 
+            WorldLocation.GetDistance(CameraWorldLocation, Viewer.Camera.CameraWorldLocation).Deconstruct(out var x, out var _, out var y);
+            CloudPositionM += elapsedTime.ClockSeconds * Weather.WindAverageDirection * Weather.WindAverageSpeedMpS - new Vector2(x, y);
             CameraWorldLocation = Viewer.Camera.CameraWorldLocation;
         }