Sample Point Cache Operator (#92)

* Initial commit

* Overflow handling options for the user

* Addressing mode for overflow to the choice of the user

* Foldable to Constant value

* Update 09_PointCache.vfx

* Added reference images

* Remove float-to-integer conversion

* Put the choice of the output type in the Inspector only

* Simplify output type handling

* Sample Point cache != Attribute map => two operators

* Update Branch (error .yamato/docs/editor_pinning.png)

* Update SamplePointCache.cs

* Update 09_PointCache.vfx

* Output type set in a cogwheel

* Update 09_PointCache.vfx

* Revert "Update Branch (error .yamato/docs/editor_pinning.png)"

This reverts commit 02f6b6c993c2382bb10669edd16f7d06876a0cbc.

* Restore vfx asset

* Revert back to using generics for type handling

* Update SampleAttributeMap.cs

* Reformating + changelog

* Update 09_PointCache.vfx

* Update SamplePointCache.cs

* Refactor of AttributeFromMap using VFXExpressionSampleAttributeMap

* Merge branch 'vfx/staging' into vfx/feature/sample-point-cache

* Revert "Merge branch 'vfx/staging' into vfx/feature/sample-point-cache"

This reverts commit b4a03e182a3e106c2fabc262777615f9c3b94a7e.

Author: ludovic-theobald

TestProjects/VisualEffectGraph_HDRP/Assets/AllTests/VFXTests/GraphicsTests/09_PointCache.vfx

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 - Added new setting to output nodes to exclude from TAA
 - Changed the "Edit" button so it becomes "New" when no asset is set on a Visual Effect component, in order to save a new visual effect graph asset.
+- New Sample Point cache & Sample Attribute map operators
 
 ### Fixed
 - Forbid incorrect link between incompatible context [Case 1269756](https://issuetracker.unity3d.com/product/unity/issues/guid/1269756/)
@@ -137,6 +138,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Compute culling of particle which have their alive attribute set to false in output
 - Mesh and lit mesh outputs can now have up to 4 differents meshes that can be set per Particle (Experimental)
 - Screen space per particle LOD on mesh and lit mesh outputs (Experimental)
+- Compare operator can take int and uint as inputs
+
+
 
 ### Fixed
 - Moved VFX Event Tester Window visibility to Component Play Controls SceneView Window

TestProjects/VisualEffectGraph_HDRP/Assets/AllTests/VFXTests/GraphicsTests/UnityLogoPrimeCount.pcache

@@ -0,0 +1,28 @@
+using System;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using UnityEngine;
+using UnityEngine.VFX;
+
+namespace UnityEditor.VFX
+{
+    class VFXExpressionSampleAttributeMap<T> : VFXExpression
+    {
+        public VFXExpressionSampleAttributeMap() : this(VFXTexture2DValue.Default, VFXValue<int>.Default, VFXValue<int>.Default)
+        {
+        }
+
+        public VFXExpressionSampleAttributeMap(VFXExpression texture, VFXExpression x, VFXExpression y )
+            : base(Flags.InvalidOnCPU, new VFXExpression[3] { texture, x, y })
+        { }
+
+        sealed public override VFXExpressionOperation operation { get { return VFXExpressionOperation.None; } }
+        sealed public override VFXValueType valueType { get { return VFXExpression.GetVFXValueTypeFromType(typeof(T)); } }
+
+        public sealed override string GetCodeString(string[] parents)
+        {
+            string typeString = VFXExpression.TypeToCode(valueType);
+            return string.Format("({3}){0}.Load(int3({1}, {2}, 0))", parents[0], parents[1], parents[2], typeString);
+        }
+    }
+}