Improve GL UI

assets/Shaders/rectangle.frag

@@ -1,17 +1,39 @@
 #version 150 core
 in vec2 textureCoord;
+in vec2 fragOffset;
 uniform vec2 uAlphaTest;
 uniform bool uRectangleHasColour;
 uniform vec4 uColor;
 uniform sampler2D uTexture;
+uniform vec2 uSize;
+uniform float uCornerRadius;
 out vec4 fragColor;
 
+float roundSDF(vec2 p, vec2 b, float r) 
+{
+    vec2 q = abs(p) - b + r;
+    return length(max(q, 0.0)) + min(max(q.x, q.y), 0.0) - r;
+}
+
 void main(void)
 {
 	vec4 textureColour = texture(uTexture, textureCoord);
-
 	vec4 finalColor = textureColour * uColor;
 
+	if (uCornerRadius > 0.0)
+	{
+		vec2 halfSize = uSize * 0.5;
+		vec2 pos = (fragOffset - 0.5) * uSize;
+		float dist = roundSDF(pos, halfSize, uCornerRadius);
+
+		float alpha = 1.0 - smoothstep(-0.5, 0.5, dist);
+		if (alpha <= 0.0)
+		{
+			discard;
+		}
+		finalColor.a *= alpha;
+	}
+
 	/*
 	 * NOTES:
 	 * Unused alpha functions must not be added to the shader

assets/Shaders/rectangle.vert

@@ -5,40 +5,24 @@ uniform vec2 uPoint;
 uniform vec2 uSize;
 uniform vec2 uCoordinates;
 out vec2 textureCoord;
-vec4 viewPos = vec4(0,0,0,0);
+out vec2 fragOffset;
+
+// Offset lookup table to map gl_VertexID to quad corners without branching
+const vec2 offsets[6] = vec2[](
+	vec2(0.0, 0.0), // Top-left
+	vec2(1.0, 0.0), // Top-right
+	vec2(1.0, 1.0), // Bottom-right
+	vec2(0.0, 0.0), // Top-left (second triangle)
+	vec2(0.0, 1.0), // Bottom-left
+	vec2(1.0, 1.0)  // Bottom-right
+);
 
 void main()
 {
-	if(gl_VertexID == 0)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x, uPoint.y, 0), 1.0);
-		textureCoord = vec2(0,0);
-	}
-	else if (gl_VertexID == 1)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x + uSize.x, uPoint.y, 0), 1.0);
-		textureCoord = vec2(uCoordinates.x,0);
-	}
-	else if (gl_VertexID == 2)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x + uSize.x, uPoint.y + uSize.y, 0), 1.0);
-		textureCoord = uCoordinates;
-	}
-	else if (gl_VertexID == 3)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x, uPoint.y, 0), 1.0);
-		textureCoord = vec2(0,0);
-	}
-	else if (gl_VertexID == 4)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x, uPoint.y + uSize.y, 0), 1.0);
-		textureCoord = vec2(0, uCoordinates.y);
-	}
-	else if (gl_VertexID == 5)
-	{
-		viewPos = uCurrentModelViewMatrix * vec4(vec3(uPoint.x + uSize.x, uPoint.y + uSize.y, 0), 1.0);
-		textureCoord = uCoordinates;
-	}
-
+	// Calculate vertex position and texture coordinates based on current vertex ID offsets
+	vec2 offset = offsets[gl_VertexID];
+	vec4 viewPos = uCurrentModelViewMatrix * vec4(uPoint + offset * uSize, 0.0, 1.0);
+	textureCoord = offset * uCoordinates;
+	fragOffset = offset;
 	gl_Position = uCurrentProjectionMatrix * viewPos;
 }

source/LibRender2/BaseRenderer.cs

@@ -27,6 +27,7 @@
 using OpenBveApi.FileSystem;
 using OpenBveApi.Hosts;
 using OpenBveApi.Interface;
+using OpenBveApi.Graphics;
 using OpenBveApi.Math;
 using OpenBveApi.Objects;
 using OpenBveApi.Routes;
@@ -42,7 +43,7 @@
 
 namespace LibRender2
 {
-	public abstract class BaseRenderer
+	public abstract class BaseRenderer : OpenBveApi.Graphics.IGLRenderer
 	{
 		// constants
 		protected const float inv255 = 1.0f / 255.0f;
@@ -1873,5 +1874,29 @@ public void RunInRenderThread(ThreadStart job, int timeout)
 				Monitor.Wait(job, timeout);
 			}
 		}
+
+		/// <inheritdoc />
+		public bool LoadTexture(ref Texture texture, OpenGlTextureWrapMode wrapMode)
+		{
+			return currentHost.LoadTexture(ref texture, wrapMode);
+		}
+
+		/// <inheritdoc />
+		public void DrawRectangle(Texture texture, Vector2 location, Vector2 size, Color128 color, OpenGlTextureWrapMode? wrapMode = null, float cornerRadius = 0f)
+		{
+			Rectangle.Draw(texture, location, size, color, null, wrapMode, cornerRadius);
+		}
+
+		/// <inheritdoc />
+		public void DrawRectangleAlpha(Texture texture, Vector2 location, Vector2 size, Color128 color, Vector2 scale, OpenGlTextureWrapMode? wrapMode = null, float cornerRadius = 0f)
+		{
+			Rectangle.DrawAlpha(texture, location, size, color, scale, wrapMode, cornerRadius);
+		}
+
+		/// <inheritdoc />
+		public void DrawText(string text, Vector2 location, Color128 color)
+		{
+			OpenGlString.Draw(Fonts.NormalFont, text, location, TextAlignment.TopLeft, color);
+		}
 	}
 }

source/LibRender2/LibRender2.csproj

@@ -100,6 +100,7 @@
     <Compile Include="Primitives\Button.cs" />
     <Compile Include="Primitives\Cube.cs" />
     <Compile Include="Primitives\GLControl.cs" />
+    <Compile Include="Primitives\VerticalLayoutGroup.cs" />
     <Compile Include="Primitives\Label.cs" />
     <Compile Include="Primitives\Particle.cs" />
     <Compile Include="Primitives\Picturebox.cs" />

source/LibRender2/Primitives/Button.cs

@@ -1,4 +1,4 @@
-//Simplified BSD License (BSD-2-Clause)
+//Simplified BSD License (BSD-2-Clause)
 //
 //Copyright (c) 2023, Christopher Lees, The OpenBVE Project
 //
@@ -38,7 +38,7 @@ public string Text
 			set
 			{
 				_text = value;
-				Size = Font.MeasureString(Text) * 1.5 * Renderer.currentOptions.UserInterfaceScaleFactor;
+				Size = Font.MeasureString(Text) * 1.5 * baseRenderer.currentOptions.UserInterfaceScaleFactor;
 			}
 		}
 
@@ -57,9 +57,11 @@ public string Text
 		/// <summary>The font for the button</summary>
 		public OpenGlFont Font;
 
-		public Button(BaseRenderer renderer, string text) : base(renderer)
+		private BaseRenderer baseRenderer => Renderer as BaseRenderer;
+
+		public Button(IGLRenderer renderer, string text) : base(renderer)
 		{
-			Font = Renderer.Fonts.LargeFont;
+			Font = baseRenderer.Fonts.LargeFont;
 			Text = text;
 			Enabled = true;
 			// default colors to match GLMenu
@@ -75,12 +77,12 @@ public override void Draw()
 			{
 				return;
 			}
-			Renderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor);
+			baseRenderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor, null, null, CornerRadius);
 			if (CurrentlySelected && Enabled)
 			{
-				Renderer.Rectangle.Draw(Texture, Location + Size * 0.1, Size - (Size * 0.2), HighlightColor);
+				baseRenderer.Rectangle.Draw(Texture, Location + Size * 0.1, Size - (Size * 0.2), HighlightColor, null, null, CornerRadius * 0.8f);
 			}
-			Renderer.OpenGlString.Draw(Font, Text, Location + (Size * 0.15), TextAlignment.TopLeft, Enabled ?  EnabledTextColor : DisabledTextColor);
+			baseRenderer.OpenGlString.Draw(Font, Text, Location + (Size * 0.15), TextAlignment.TopLeft, Enabled ?  EnabledTextColor : DisabledTextColor);
 		}
 
 		public override void MouseMove(int x, int y)

source/LibRender2/Primitives/GLControl.cs

@@ -1,4 +1,4 @@
-//Simplified BSD License (BSD-2-Clause)
+//Simplified BSD License (BSD-2-Clause)
 //
 //Copyright (c) 2023, Christopher Lees, The OpenBVE Project
 //
@@ -24,6 +24,7 @@
 
 using System;
 using OpenBveApi.Colors;
+using OpenBveApi.Graphics;
 using OpenBveApi.Math;
 using OpenBveApi.Textures;
 
@@ -32,8 +33,8 @@ namespace LibRender2.Primitives
 	/// <summary>An abstract OpenGL based control</summary>
 	public abstract class GLControl
 	{
-		/// <summary>Holds a reference to the base renderer</summary>
-		internal readonly BaseRenderer Renderer;
+		/// <summary>Holds a reference to the base renderer interface</summary>
+		public readonly IGLRenderer Renderer;
 		/// <summary>The background color for the control</summary>
 		public Color128 BackgroundColor;
 		/// <summary>The texture for the control</summary>
@@ -42,14 +43,16 @@ public abstract class GLControl
 		public Vector2 Location;
 		/// <summary>The stored size for the control</summary>
 		public Vector2 Size;
+		/// <summary>The corner radius for rounded corners (in pixels)</summary>
+		public float CornerRadius;
 		/// <summary>Whether the control is currently selected by the mouse</summary>
 		public bool CurrentlySelected;
 		/// <summary>The event handler for the OnClick event</summary>
 		public EventHandler OnClick;
 		/// <summary>Whether the control is currently visible</summary>
 		public bool IsVisible;
 
-		protected GLControl(BaseRenderer renderer)
+		protected GLControl(IGLRenderer renderer)
 		{
 			Renderer = renderer;
 		}

source/LibRender2/Primitives/Label.cs

@@ -1,4 +1,4 @@
-//Simplified BSD License (BSD-2-Clause)
+//Simplified BSD License (BSD-2-Clause)
 //
 //Copyright (c) 2022, Christopher Lees, The OpenBVE Project
 //
@@ -37,10 +37,12 @@ public class Label : GLControl
 		/// <summary>The font for the label</summary>
 		public OpenGlFont Font;
 
-		public Label(BaseRenderer renderer, string text) : base(renderer)
+		private BaseRenderer baseRenderer => Renderer as BaseRenderer;
+
+		public Label(IGLRenderer renderer, string text) : base(renderer)
 		{
 			Text = text;
-			Font = Renderer.Fonts.LargeFont;
+			Font = baseRenderer.Fonts.LargeFont;
 			Size = Font.MeasureString(Text) * 1.5;
 			// default colors to match GLMenu
 			BackgroundColor = Color128.Black;
@@ -49,8 +51,8 @@ public Label(BaseRenderer renderer, string text) : base(renderer)
 
 		public override void Draw()
 		{
-			Renderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor);
-			Renderer.OpenGlString.Draw(Font, Text, Location + (Size * 0.15), TextAlignment.TopLeft, TextColor);
+			baseRenderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor, null, null, CornerRadius);
+			baseRenderer.OpenGlString.Draw(Font, Text, Location + (Size * 0.15), TextAlignment.TopLeft, TextColor);
 		}
 	}
 }

source/LibRender2/Primitives/Picturebox.cs

@@ -1,4 +1,5 @@
 using OpenBveApi.Colors;
+using OpenBveApi.Graphics;
 using OpenBveApi.Math;
 using OpenBveApi.Textures;
 using OpenTK.Graphics.OpenGL;
@@ -13,14 +14,14 @@ public class Picturebox : GLControl
 		private bool flipX;
 		private bool flipY;
 
-		public Picturebox(BaseRenderer renderer) : base(renderer)
+		public Picturebox(IGLRenderer renderer) : base(renderer)
 		{
 			SizeMode = ImageSizeMode.Zoom;
 		}
 
 		public override void Draw()
 		{
-			if (!Renderer.currentHost.LoadTexture(ref Texture, OpenGlTextureWrapMode.ClampClamp))
+			if (!Renderer.LoadTexture(ref Texture, OpenGlTextureWrapMode.ClampClamp))
 			{
 				return;
 			}
@@ -31,7 +32,7 @@ public override void Draw()
 			{
 				case ImageSizeMode.Normal:
 					//Draw box containing backing color first
-					Renderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor);
+					Renderer.DrawRectangle(Texture, Location, Size, BackgroundColor);
 					//Calculate the new size
 					newSize = Texture.Size;
 					if (newSize.X > Size.X)
@@ -44,11 +45,11 @@ public override void Draw()
 						newSize.Y = Size.Y;
 					}
 					//Two-pass draw the texture in appropriate place
-					Renderer.Rectangle.DrawAlpha(Texture, Location, newSize, Color128.White, new Vector2(newSize / Size));
+					Renderer.DrawRectangleAlpha(Texture, Location, newSize, Color128.White, new Vector2(newSize / Size));
 					break;
 				case ImageSizeMode.Center:
 					//Draw box containing backing color first
-					Renderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor);
+					Renderer.DrawRectangle(Texture, Location, Size, BackgroundColor);
 					//Calculate the new size
 					newSize = Texture.Size;
 					if (newSize.X > Size.X)
@@ -61,15 +62,15 @@ public override void Draw()
 						newSize.Y = Size.Y;
 					}
 					//Two-pass draw the texture in appropriate place
-					Renderer.Rectangle.DrawAlpha(Texture, Location + new Vector2(newSize - Size) / 2, newSize, Color128.White, new Vector2(newSize / Size));
+					Renderer.DrawRectangleAlpha(Texture, Location + new Vector2(newSize - Size) / 2, newSize, Color128.White, new Vector2(newSize / Size));
 					break;
 				case ImageSizeMode.Stretch:
 					//No need to draw a backing color box as texture covers the whole thing
-					Renderer.Rectangle.Draw(Texture, Location, Size, BackgroundColor);
+					Renderer.DrawRectangle(Texture, Location, Size, BackgroundColor);
 					break;
 				case ImageSizeMode.Zoom:
 					//Draw box containing backing color first
-					Renderer.Rectangle.Draw(null, Location, Size, BackgroundColor);
+					Renderer.DrawRectangle(null, Location, Size, BackgroundColor);
 					//Calculate the new size
 					Vector2 ratio = Size / Texture.Size;
 					double newRatio = ratio.X < ratio.Y ? ratio.X : ratio.Y;
@@ -84,7 +85,7 @@ public override void Draw()
 					{
 						wrapMode = wrapMode == OpenGlTextureWrapMode.RepeatClamp ? OpenGlTextureWrapMode.RepeatRepeat : OpenGlTextureWrapMode.ClampRepeat;
 					}
-					Renderer.Rectangle.DrawAlpha(Texture, new Vector2(Location.X + (Size.X - newSize.X) / 2,Location.Y + (Size.Y - newSize.Y) / 2), newSize, Color128.White, new Vector2(flipX ? -1 : 1,flipY ? -1 : 1), wrapMode);
+					Renderer.DrawRectangleAlpha(Texture, new Vector2(Location.X + (Size.X - newSize.X) / 2,Location.Y + (Size.Y - newSize.Y) / 2), newSize, Color128.White, new Vector2(flipX ? -1 : 1,flipY ? -1 : 1), wrapMode);
 					break;
 			}
 		}