Engine working

Scenarios/Scenario.cs

@@ -14,7 +14,30 @@ namespace FluidSim.Tests
         protected const double AmbientPressure = 101325.0;
         protected const double AmbientTemperature = 300.0;
 
-        // ---------- Color helper ----------
+        // ---------- Color from pressure (volumes) ----------
+        protected Color PressureColor(double pressurePa)
+        {
+            double bar = pressurePa / 1e5;   // convert to bar for easier mapping
+            byte r, g, b;
+
+            if (bar < 1.0)   // vacuum → blue to green
+            {
+                double factor = Math.Clamp(bar, 0.0, 1.0);
+                r = 0;
+                g = (byte)(255 * factor);
+                b = (byte)(255 * (1.0 - factor));
+            }
+            else   // above ambient → green to red
+            {
+                double factor = Math.Min((bar - 1.0) / 9.0, 1.0);   // 1→10 bar maps to 0→1
+                r = (byte)(255 * factor);
+                g = (byte)(255 * (1.0 - factor));
+                b = 0;
+            }
+            return new Color(r, g, b);
+        }
+
+        // ---------- Color from temperature (pipes) ----------
         protected Color TemperatureColor(double temperature)
         {
             double t = Math.Clamp(temperature, 0.0, 2000.0);
@@ -42,7 +65,7 @@ namespace FluidSim.Tests
         {
             var rect = new RectangleShape(new Vector2f(width, height))
             {
-                FillColor = TemperatureColor(volume.Temperature),
+                FillColor = PressureColor(volume.Pressure),   // ← pressure‑based
                 Position = new Vector2f(centerX - width / 2f, topY)
             };
             target.Draw(rect);
@@ -60,7 +83,7 @@ namespace FluidSim.Tests
         protected void DrawCylinder(RenderWindow target, Cylinder cylinder,
                                     float centerX, float topY, float width, float maxHeight)
         {
-            double fraction = cylinder.PistonFraction;   // 0 = TDC, 1 = BDC
+            double fraction = cylinder.PistonFraction;
             float currentHeight = (float)(maxHeight * fraction);
 
             // Walls
@@ -69,10 +92,10 @@ namespace FluidSim.Tests
             wall.Position = new Vector2f(centerX - width / 2f, topY);
             target.Draw(wall);
 
-            // Gas
+            // Gas – colored by pressure now
             float gasTop = topY;
             var gasRect = new RectangleShape(new Vector2f(width, currentHeight));
-            gasRect.FillColor = TemperatureColor(cylinder.Temperature);
+            gasRect.FillColor = PressureColor(cylinder.Pressure);   // ← pressure‑based
             gasRect.Position = new Vector2f(centerX - width / 2f, gasTop);
             target.Draw(gasRect);
 
@@ -95,7 +118,7 @@ namespace FluidSim.Tests
             target.Draw(exhaustValve);
         }
 
-        // ---------- Draw a pipe ----------
+        // ---------- Draw a pipe (unchanged) ----------
         protected void DrawPipe(RenderWindow target, Pipe1D pipe, float pipeCenterY, float pipeStartX, float pipeEndX)
         {
             int n = pipe.CellCount;
@@ -141,7 +164,7 @@ namespace FluidSim.Tests
             {
                 float x = centers[i];
                 float r = radii[i];
-                Color col = TemperatureColor(temperatures[i]);
+                Color col = TemperatureColor(temperatures[i]);   // pipes still use temperature
 
                 stripVertices[idx++] = new Vertex(new Vector2f(x, pipeCenterY - r), col);
                 stripVertices[idx++] = new Vertex(new Vector2f(x, pipeCenterY + r), col);