test

My project/Library/PackageCache/com.unity.inputsystem/InputSystem/Utilities/SpriteUtilities.cs

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+using Unity.Collections.LowLevel.Unsafe;
+using UnityEngine.Experimental.Rendering;
+
+namespace UnityEngine.InputSystem.Utilities
+{
+    internal static class SpriteUtilities
+    {
+        public static unsafe Sprite CreateCircleSprite(int radius, Color32 colour)
+        {
+            // cache the diameter
+            var d = radius * 2;
+
+            var texture = new Texture2D(d, d, DefaultFormat.LDR, TextureCreationFlags.None);
+            var colours = texture.GetRawTextureData<Color32>();
+            var coloursPtr = (Color32*)colours.GetUnsafePtr();
+            UnsafeUtility.MemSet(coloursPtr, 0, colours.Length * UnsafeUtility.SizeOf<Color32>());
+
+            // pack the colour into a ulong so we can write two pixels at a time to the texture data
+            var colorPtr = (uint*)UnsafeUtility.AddressOf(ref colour);
+            var colourAsULong = *(ulong*)colorPtr << 32 | *colorPtr;
+
+            float rSquared = radius * radius;
+
+            // loop over the texture memory one column at a time filling in a line between the two x coordinates
+            // of the circle at each column
+            for (var y = -radius; y < radius; y++)
+            {
+                // for the current column, calculate what the x coordinate of the circle would be
+                // using x^2 + y^2 = r^2, or x^2 = r^2 - y^2. The square root of the value of the
+                // x coordinate will equal half the width of the circle at the current y coordinate
+                var halfWidth = (int)Mathf.Sqrt(rSquared - y * y);
+
+                // position the pointer so it points at the memory where we should start filling in
+                // the current line
+                var ptr = coloursPtr
+                    + (y + radius) * d  // the position of the memory at the start of the row at the current y coordinate
+                    + radius - halfWidth;   // the position along the row where we should start inserting colours
+
+                // fill in two pixels at a time
+                for (var x = 0; x < halfWidth; x++)
+                {
+                    *(ulong*)ptr = colourAsULong;
+                    ptr += 2;
+                }
+            }
+
+            texture.Apply();
+
+            var sprite = Sprite.Create(texture, new Rect(0, 0, d, d), new Vector2(radius, radius), 1, 0, SpriteMeshType.FullRect);
+            return sprite;
+        }
+    }
+}