From 1ba5410fd6e0d3b73a265d4dc91f1341915d3874 Mon Sep 17 00:00:00 2001
From: punchready <marlin.gorsleben@gmail.com>
Date: Mon, 31 May 2021 22:50:44 +0200
Subject: [PATCH] fix: improve the terrible rasterization code

---
 .../gamelibrary/gamelogic/GameLogic.java      | 64 +++++++++++--------
 1 file changed, 38 insertions(+), 26 deletions(-)

diff --git a/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java b/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
index c79d38e..af5a1c9 100644
--- a/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
+++ b/src/main/java/uulm/teamname/marvelous/gamelibrary/gamelogic/GameLogic.java
@@ -12,6 +12,7 @@ import uulm.teamname.marvelous.gamelibrary.requests.RequestType;
 
 import java.awt.*;
 import java.awt.geom.Line2D;
+import java.awt.geom.Rectangle2D;
 import java.util.*;
 
 /** Contains game logic handling. */
@@ -97,20 +98,14 @@ class GameLogic {
                         }
                         case MindStone -> {
                             EntityType target = data.originEntity.type == EntityType.P1 ? EntityType.P2 : EntityType.P1;
-                            Line2D line = new Line2D.Float(data.originField.getX(), data.originField.getY(), data.targetField.getX(), data.targetField.getY());
-                            for(int i = data.originField.getX(); i <= data.targetField.getX(); i++) {
-                                for(int j = data.originField.getY(); j <= data.targetField.getY(); j++) {
-                                    var cell = new Rectangle.Float(i - 0.5f, j - 0.5f, 1, 1);
-                                    if(line.intersects(cell)) {
-                                        for(Entity entity: state.entities.findByPosition(data.targetField)) {
-                                            if(entity.id.isSameType(target)) {
-                                                result.add(new EventBuilder(EventType.TakenDamageEvent)
-                                                        .withTargetEntity(entity.id)
-                                                        .withTargetField(new IntVector2(i, j))
-                                                        .withAmount(data.value)
-                                                        .buildEntityEvent());
-                                            }
-                                        }
+                            for(IntVector2 pos: rasterize(data.originField, data.targetField)) {
+                                for(Entity entity: state.entities.findByPosition(pos)) {
+                                    if(entity.id.isSameType(target)) {
+                                        result.add(new EventBuilder(EventType.TakenDamageEvent)
+                                                .withTargetEntity(entity.id)
+                                                .withTargetField(pos)
+                                                .withAmount(data.value)
+                                                .buildEntityEvent());
                                     }
                                 }
                             }
@@ -441,18 +436,9 @@ class GameLogic {
      * @return Whether or not the light of sight exists
      */
     private static boolean checkLineOfSight(GameState state, IntVector2 start, IntVector2 end) {
-        //naive code for the win!!! \o/
-        //at least its early exit and probably only O(ln(n*m))
-        //TODO: implement proper line rasterization algorithm in GameLogic.checkLineOfSight
-        Line2D line = new Line2D.Float(start.getX(), start.getY(), end.getX(), end.getY());
-        for(int i = start.getX(); i <= end.getX(); i++) {
-            for(int j = start.getY(); j <= end.getY(); j++) {
-                var cell = new Rectangle.Float(i - 0.5f, j - 0.5f, 1, 1);
-                if(line.intersects(cell)) {
-                    if(state.entities.blocksVision(new IntVector2(i, j))) {
-                        return false;
-                    }
-                }
+        for(IntVector2 pos: rasterize(start, end)) {
+            if(state.entities.blocksVision(pos)) {
+                return false;
             }
         }
         return true;
@@ -866,4 +852,30 @@ class GameLogic {
 
         return result;
     }
+
+    /**
+     * Computes all fields which intersect the line between the center points of the given two fields.
+     * @return The list of intersecting positions
+     */
+    public static ArrayList<IntVector2> rasterize(IntVector2 a, IntVector2 b) {
+        ArrayList<IntVector2> result = new ArrayList<>();
+
+        //TODO: implement proper line rasterization algorithm in GameLogic.rasterize
+
+        int x1 = Math.min(a.getX(), b.getX());
+        int x2 = Math.max(a.getX(), b.getX());
+        int y1 = Math.min(a.getY(), b.getY());
+        int y2 = Math.max(a.getY(), b.getY());
+        Line2D line = new Line2D.Float(x1 + 0.5f, y1 + 0.5f, x2 + 0.5f, y2 + 0.5f);
+        for(int i = x1; i <= x2; i++) {
+            for(int j = y1; j <= y2; j++) {
+                Rectangle2D cell = new Rectangle.Float(i, j, 1, 1);
+                if(line.intersects(cell)) {
+                    result.add(new IntVector2(i, j));
+                }
+            }
+        }
+
+        return result;
+    }
 }