From 3d1c2f4e29f7389462ae0f77c8dd5021bc2d3251 Mon Sep 17 00:00:00 2001
From: mix <mixiate@proton.me>
Date: Sun, 27 Apr 2025 02:16:25 +0100
Subject: [PATCH] Revert "Nuke the bad culling, causes just odd artifacts, fast
 enough now"

This reverts commit 105d0e6c4ff5763610b2d42281a74f9a4655a061.
---
 src/openrct2/paint/Paint.cpp | 49 ++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/src/openrct2/paint/Paint.cpp b/src/openrct2/paint/Paint.cpp
index 58f94b666c..2f13fdf333 100644
--- a/src/openrct2/paint/Paint.cpp
+++ b/src/openrct2/paint/Paint.cpp
@@ -103,6 +103,43 @@ static void PaintSessionAddPSToQuadrant(PaintSession& session, PaintStruct* ps)
     session.QuadrantFrontIndex = std::max(session.QuadrantFrontIndex, paintQuadrantIndex);
 }
 
+static constexpr bool ImageWithinDPI(const ScreenCoordsXY& imagePos, const G1Element& g1, const DrawPixelInfo& dpi)
+{
+    int32_t left = imagePos.x + g1.x_offset;
+    int32_t bottom = imagePos.y + g1.y_offset;
+
+    int32_t right = left + g1.width;
+    int32_t top = bottom + g1.height;
+
+    // mber: It is possible to use only the bottom else block here if you change <= and >= to simply < and >.
+    // However, since this is used to cull paint structs, I'd prefer to keep the condition strict and calculate
+    // the culling differently for minifying and magnifying.
+    auto zoom = dpi.zoom_level;
+    if (zoom > ZoomLevel{ 0 })
+    {
+        if (right <= dpi.WorldX())
+            return false;
+        if (top <= dpi.WorldY())
+            return false;
+        if (left >= dpi.WorldX() + dpi.WorldWidth())
+            return false;
+        if (bottom >= dpi.WorldY() + dpi.WorldHeight())
+            return false;
+    }
+    else
+    {
+        if (zoom.ApplyInversedTo(right) <= dpi.x)
+            return false;
+        if (zoom.ApplyInversedTo(top) <= dpi.y)
+            return false;
+        if (zoom.ApplyInversedTo(left) >= dpi.x + dpi.width)
+            return false;
+        if (zoom.ApplyInversedTo(bottom) >= dpi.y + dpi.height)
+            return false;
+    }
+    return true;
+}
+
 static constexpr CoordsXYZ RotateBoundBoxSize(const CoordsXYZ& bbSize, const uint8_t rotation)
 {
     auto output = bbSize;
@@ -146,6 +183,12 @@ static PaintStruct* CreateNormalPaintStruct(
     swappedRotCoord += session.SpritePosition;
 
     const auto imagePos = Translate3DTo2DWithZ(session.CurrentRotation, swappedRotCoord);
+
+    if (!ImageWithinDPI(imagePos, *g1, session.DPI))
+    {
+        return nullptr;
+    }
+
     const auto rotBoundBoxOffset = CoordsXYZ{ boundBox.offset.Rotate(swappedRotation), boundBox.offset.z };
     const auto rotBoundBoxSize = RotateBoundBoxSize(boundBox.length, session.CurrentRotation);
 
@@ -188,6 +231,12 @@ static PaintStruct* CreateNormalPaintStructHeight(
     swappedRotCoord += session.SpritePosition;
 
     const auto imagePos = Translate3DTo2DWithZ(session.CurrentRotation, swappedRotCoord);
+
+    if (!ImageWithinDPI(imagePos, *g1, session.DPI))
+    {
+        return nullptr;
+    }
+
     const auto rotBoundBoxOffset = CoordsXYZ{ boundBox.offset.Rotate(swappedRotation), boundBox.offset.z + height };
     const auto rotBoundBoxSize = RotateBoundBoxSize(boundBox.length, session.CurrentRotation);