From 907b3ffc4ae2af0076f61e85096e622e97db4621 Mon Sep 17 00:00:00 2001
From: Octal <oliver@olivermakesco.de>
Date: Sun, 15 Oct 2023 22:30:25 -0500
Subject: [PATCH] Rearrange some stuff in Raycast.cs

---
 Common/Util/PositionExtensions.cs |  6 +-
 Common/World/Raycast.cs           | 92 +++++++++++++------------------
 2 files changed, 41 insertions(+), 57 deletions(-)

diff --git a/Common/Util/PositionExtensions.cs b/Common/Util/PositionExtensions.cs
index 9557f26..0c95338 100644
--- a/Common/Util/PositionExtensions.cs
+++ b/Common/Util/PositionExtensions.cs
@@ -20,10 +20,8 @@ public static ivec3 WorldToChunkPosition(this dvec3 worldPosition) {
     public static ivec3 BlockToChunkPosition(this ivec3 worldPosition)
         => WorldToChunkPosition(worldPosition);
 
-    public static ivec3 WorldToBlockPosition(this dvec3 worldPosition) {
-        var floored = dvec3.Floor(worldPosition);
-        return new((int)floored.x, (int)floored.y, (int)floored.z);
-    }
+    public static ivec3 WorldToBlockPosition(this dvec3 worldPosition)
+        => (ivec3)dvec3.Floor(worldPosition);
 
     public static dvec3 ChunkToWorldPosition(this ivec3 chunkPosition)
         => (dvec3)chunkPosition * ChunkSize;
diff --git a/Common/World/Raycast.cs b/Common/World/Raycast.cs
index 564f729..411a932 100644
--- a/Common/World/Raycast.cs
+++ b/Common/World/Raycast.cs
@@ -1,8 +1,5 @@
 // Based off of this paper: http://www.cse.yorku.ca/~amana/research/grid.pdf
 
-using System.Reflection.Metadata.Ecma335;
-using System.Security.Cryptography;
-using FastNoiseOO.Generators;
 using GlmSharp;
 using Voxel.Common.Util;
 using Voxel.Common.World.Views;
@@ -10,21 +7,7 @@
 namespace Voxel.Common.World;
 
 public static class Raycast {
-    private static double Mod1(double a)
-        => (a % 1 + 1) % 1;
-
-    private static double GetTMax(double start, double tDelta, double step)
-        => FixNaN(tDelta * (step > 0 ? 1 - Mod1(start) : Mod1(start)));
-
-    private static double FixNaN(double d)
-        => double.IsNaN(d) ? 0 : d;
-
-    public static HitResult? Cast(this BlockView world, dvec3 start, dvec3 end, ivec3 looking) {
-        var startPos = start.WorldToBlockPosition();
-        
-        if (world.GetBlock(startPos).IsSolidBlock)
-            return new(startPos, start);
-
+    public static HitResult? Cast(this BlockView world, dvec3 start, dvec3 end, ivec3 looking) { 
         var delta = end - start;
 
         double
@@ -54,33 +37,13 @@ private static double FixNaN(double d)
         var yAxis = stepY > 0 ? ivec3.UnitY : -ivec3.UnitY;
         var zAxis = stepZ > 0 ? ivec3.UnitZ : -ivec3.UnitZ;
 
-        var endPos = (ivec3)end;
+        var endPos = end.WorldToBlockPosition();
+        var axis = looking;
 
         while (true) {
-            ivec3 axis;
-
-            switch (tMaxX < tMaxY) {
-                case true when tMaxX < tMaxZ:
-                    axis = xAxis;
-                    x += stepX;
-                    tMaxX += tDeltaX;
-                    break;
-                case false when tMaxY < tMaxZ:
-                    axis = yAxis;
-                    y += stepY;
-                    tMaxY += tDeltaY;
-                    break;
-                default:
-                    axis = zAxis;
-                    z += stepZ;
-                    tMaxZ += tDeltaZ;
-                    break;
-            }
-            
             var blockPos = new dvec3(x, y, z).WorldToBlockPosition();
 
             if (world.GetBlock(blockPos).IsSolidBlock) {
-                
                 // TODO: Account for non-cubic colliders at some point
                 // Gets the one integer intersection coordinate
                 // axis * blockPos isolates one coordinate from blockPos
@@ -93,36 +56,59 @@ private static double FixNaN(double d)
                     double time = (start.x - worldPos.x) / direction.x;
                     worldPos.y = (int)(direction.y * time);
                     worldPos.z = (int)(direction.z * time);
+                    return new(blockPos, worldPos, axis);
                 }
-                // intersect with a xz plane
-                else if (axis.y != 0) {
+                // intersect with an xz plane
+                if (axis.y != 0) {
                     double time = (start.y - worldPos.y) / direction.y;
                     worldPos.x = (int)(direction.x * time);
                     worldPos.z = (int)(direction.z * time);
+                    return new(blockPos, worldPos, axis);
                 }
                 // intersect with a xy plane
-                else if (axis.z != 0) {
+                if (axis.z != 0) {
                     double time = (start.z - worldPos.z) / direction.z;
                     worldPos.x = (int)(direction.x * time);
                     worldPos.y = (int)(direction.y * time);
+                    return new(blockPos, worldPos, axis);
                 }
-                else continue;
-                
-                return new(blockPos, worldPos);
             }
                 
             if (blockPos == endPos)
                 return null;
+            
+            switch (tMaxX < tMaxY) {
+                case true when tMaxX < tMaxZ:
+                    axis = xAxis;
+                    x += stepX;
+                    tMaxX += tDeltaX;
+                    break;
+                case false when tMaxY < tMaxZ:
+                    axis = yAxis;
+                    y += stepY;
+                    tMaxY += tDeltaY;
+                    break;
+                default:
+                    axis = zAxis;
+                    z += stepZ;
+                    tMaxZ += tDeltaZ;
+                    break;
+            }
         }
     }
+    
+    private static double Mod1(double a)
+        => (a % 1 + 1) % 1;
 
-    public record struct HitResult {
-        public readonly ivec3 BlockPos;
-        public readonly dvec3 WorldPos;
+    private static double GetTMax(double start, double tDelta, double step)
+        => FixNaN(tDelta * (step > 0 ? 1 - Mod1(start) : Mod1(start)));
 
-        public HitResult(ivec3 block, dvec3 world) {
-            BlockPos = block;
-            WorldPos = world;
-        }
+    private static double FixNaN(double d)
+        => double.IsNaN(d) ? 0 : d;
+
+    public record struct HitResult(ivec3 BlockPos, dvec3 WorldPos, ivec3 Axis) {
+        public readonly ivec3 BlockPos = BlockPos;
+        public readonly dvec3 WorldPos = WorldPos;
+        public readonly ivec3 Axis = Axis;
     }
 }