PaperMC/patches/server/1064-Reduce-work-done-in-CraftMapCanvas.drawImage-by-limi.patch
Spottedleaf 8c5b837e05 Rework async chunk api implementation
Firstly, the old methods all routed to the CompletableFuture method.
However, the CF method could not guarantee that if the caller
was off-main that the future would be "completed" on-main. Since
the callback methods used the CF one, this meant that the callback
methods did not guarantee that the callbacks were to be called on
the main thread.

Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb)
so that the methods with the callback are guaranteed to invoke
the callback on the main thread. The CF behavior remains unchanged;
it may still appear to complete on main if invoked off-main.

Secondly, remove the scheduleOnMain invocation in the async
chunk completion. This unnecessarily delays the callback
by 1 tick.

Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which
will load chunks within an area. This method is provided as a helper
as keeping all chunks loaded within an area can be complicated to
implement for plugins (due to the lacking ticket API), and is
already implemented internally anyways.

Fourthly, remove the ticket addition that occured with getChunkAt
and getChunkAtAsync. The ticket addition may delay the unloading
of the chunk unnecessarily. It also fixes a very rare timing bug
where the future/callback would be completed after the chunk
unloads.
2024-11-18 23:00:59 -08:00

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3.7 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Barnaby <22575741+barnabwhy@users.noreply.github.com>
Date: Sat, 29 Jun 2024 12:06:51 +0100
Subject: [PATCH] Reduce work done in CraftMapCanvas.drawImage by limiting size
of image and using System.arraycopy instead of for loops and use bitwise
operations to do bounds checks.
diff --git a/src/main/java/org/bukkit/craftbukkit/map/CraftMapCanvas.java b/src/main/java/org/bukkit/craftbukkit/map/CraftMapCanvas.java
index ff59f759669620795ef355c988b664bdcda39f52..a5e98571d6d83390761c11e28a0bc3c4415799cd 100644
--- a/src/main/java/org/bukkit/craftbukkit/map/CraftMapCanvas.java
+++ b/src/main/java/org/bukkit/craftbukkit/map/CraftMapCanvas.java
@@ -91,12 +91,41 @@ public class CraftMapCanvas implements MapCanvas {
@Override
public void drawImage(int x, int y, Image image) {
- byte[] bytes = MapPalette.imageToBytes(image);
- for (int x2 = 0; x2 < image.getWidth(null); ++x2) {
- for (int y2 = 0; y2 < image.getHeight(null); ++y2) {
- this.setPixel(x + x2, y + y2, bytes[y2 * image.getWidth(null) + x2]);
+ // Paper start - Reduce work done by limiting size of image and using System.arraycopy
+ int width = 128 - x;
+ int height = 128 - y;
+ if (image.getHeight(null) < height)
+ height = image.getHeight(null);
+
+ // Create a subimage if the image is larger than the max allowed size
+ java.awt.image.BufferedImage temp;
+ if (image.getWidth(null) >= width && image instanceof java.awt.image.BufferedImage bImage) {
+ // If the image is larger than the max allowed size, get a subimage, otherwise use the image as is
+ if (image.getWidth(null) > width || image.getHeight(null) > height) {
+ temp = bImage.getSubimage(0, 0, width, height);
+ } else {
+ temp = bImage;
}
+ } else {
+ temp = new java.awt.image.BufferedImage(width, height, java.awt.image.BufferedImage.TYPE_INT_ARGB);
+ java.awt.Graphics2D graphics = temp.createGraphics();
+ graphics.drawImage(image, 0, 0, null);
+ graphics.dispose();
}
+
+ byte[] bytes = MapPalette.imageToBytes(temp);
+
+ // Since we now control the size of the image, we can safely use System.arraycopy
+ // If x is 0, we can just copy the entire image as width is 128 and height is <=(128-y)
+ if (x == 0) {
+ System.arraycopy(bytes, 0, this.buffer, y * 128, width * height);
+ return;
+ }
+
+ for (int y2 = 0; y2 < height; ++y2) {
+ System.arraycopy(bytes, 0, this.buffer, (y + y2) * 128 + x, width);
+ }
+ // Paper end
}
@Override
diff --git a/src/main/java/org/bukkit/craftbukkit/map/CraftMapRenderer.java b/src/main/java/org/bukkit/craftbukkit/map/CraftMapRenderer.java
index 0cbbd915631904fe8c6effefb92895422b33eff6..cf0920e5f84b35647882fb963e9972af4e8427e0 100644
--- a/src/main/java/org/bukkit/craftbukkit/map/CraftMapRenderer.java
+++ b/src/main/java/org/bukkit/craftbukkit/map/CraftMapRenderer.java
@@ -23,8 +23,10 @@ public class CraftMapRenderer extends MapRenderer {
@Override
public void render(MapView map, MapCanvas canvas, Player player) {
// Map
- for (int x = 0; x < 128; ++x) {
- for (int y = 0; y < 128; ++y) {
+ // Paper start - Swap inner and outer loops here to (theoretically) improve cache locality
+ for (int y = 0; y < 128; ++y) {
+ for (int x = 0; x < 128; ++x) {
+ // Paper end
canvas.setPixel(x, y, this.worldMap.colors[y * 128 + x]);
}
}