From b012c65990fc46c219ff267035707627d444321a Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Tue, 2 Aug 2022 23:56:18 +0200
Subject: [PATCH] Allow data texture atlas pivots and offsets to be negative

---
 CHANGELOG.md                   | 3 +++
 MLEM.Data/DataTextureAtlas.cs  | 2 +-
 Tests/Content/Texture.atlas    | 4 ++++
 Tests/DataTextureAtlasTests.cs | 7 ++++++-
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a267aa..43f519f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,9 @@ Improvements
 - Close other dropdowns when opening a dropdown
 
 ### MLEM.Data
+Improvements
+- Allow data texture atlas pivots and offsets to be negative
+
 Fixes
 - Fixed data texture atlases not allowing most characters in their region names
 
diff --git a/MLEM.Data/DataTextureAtlas.cs b/MLEM.Data/DataTextureAtlas.cs
index 18cbd95..5e1b9d2 100644
--- a/MLEM.Data/DataTextureAtlas.cs
+++ b/MLEM.Data/DataTextureAtlas.cs
@@ -86,7 +86,7 @@ namespace MLEM.Data {
             var atlas = new DataTextureAtlas(texture);
 
             // parse each texture region: "<names> loc <u> <v> <w> <h> [piv <px> <py>] [off <ox> <oy>]"
-            foreach (Match match in Regex.Matches(text, @"(.+)\s+loc\s+([0-9]+)\s+([0-9]+)\s+([0-9]+)\s+([0-9]+)\s*(?:piv\s+([0-9.]+)\s+([0-9.]+))?\s*(?:off\s+([0-9.]+)\s+([0-9.]+))?")) {
+            foreach (Match match in Regex.Matches(text, @"(.+)\s+loc\s+([0-9+]+)\s+([0-9+]+)\s+([0-9+]+)\s+([0-9+]+)\s*(?:piv\s+([0-9.+-]+)\s+([0-9.+-]+))?\s*(?:off\s+([0-9.+-]+)\s+([0-9.+-]+))?")) {
                 // offset
                 var off = !match.Groups[8].Success ? Vector2.Zero : new Vector2(
                     float.Parse(match.Groups[8].Value, CultureInfo.InvariantCulture),
diff --git a/Tests/Content/Texture.atlas b/Tests/Content/Texture.atlas
index 831462e..fd90b79 100644
--- a/Tests/Content/Texture.atlas
+++ b/Tests/Content/Texture.atlas
@@ -9,6 +9,10 @@ piv 80 16
 Plant
 loc 96 0 16 32
 
+TestRegionNegativePivot
+loc 0 32 +16 16
+piv -32 +46
+
 LongTableUp
 loc 0 32 64 48
 piv 16 48
diff --git a/Tests/DataTextureAtlasTests.cs b/Tests/DataTextureAtlasTests.cs
index beccba6..551e9ae 100644
--- a/Tests/DataTextureAtlasTests.cs
+++ b/Tests/DataTextureAtlasTests.cs
@@ -13,7 +13,7 @@ namespace Tests {
             using var game = TestGame.Create();
             using var texture = new Texture2D(game.GraphicsDevice, 1, 1);
             var atlas = DataTextureAtlas.LoadAtlasData(new TextureRegion(texture), game.RawContent, "Texture.atlas");
-            Assert.AreEqual(atlas.Regions.Count(), 7);
+            Assert.AreEqual(atlas.Regions.Count(), 8);
 
             // no added offset
             var table = atlas["LongTableUp"];
@@ -24,6 +24,11 @@ namespace Tests {
             var table2 = atlas["LongTableLeft"];
             Assert.AreEqual(table2.Area, new Rectangle(64, 32, 64, 48));
             Assert.AreEqual(table2.PivotPixels, new Vector2(112 - 64, 48 - 32));
+
+            // negative pivot
+            var negativePivot = atlas["TestRegionNegativePivot"];
+            Assert.AreEqual(negativePivot.Area, new Rectangle(0, 32, 16, 16));
+            Assert.AreEqual(negativePivot.PivotPixels, new Vector2(-32, 46 - 32));
         }
 
     }