Add climbing #1266

ChibChi · 2025-04-02T19:11:22Z

This pull request adds the climbable: bool block trait, block detection for climbable blocks and player input handeling.

Related to: #1031

…e/climbable

IntegratedQuantum

Instead of doing 4 more collision checks per frame, could you maybe reuse the code from block touch detection added in #1143?

ChibChi · 2025-04-03T20:09:27Z

Climbing on blocks with collision works pretty good. Blocks without collision on the other hand... they start i climb when passing through. Should the player be able to walk through without obstruction?

IntegratedQuantum

Use intersections instead of collisions

I think you misunderstood me. I want you to reuse the intersection results from there, by e.g. adding a touch callback for climbable blocks or something like that.
What you have done here is better than before, but it's still one extra pass that iterates through all blocks in the player's hitbox.

Also sorry for the late review, I had to focus on the new network system.

ChibChi · 2025-04-13T18:46:58Z

I think you misunderstood me. I want you to reuse the intersection results from there, by e.g. adding a touch callback for climbable blocks or something like that. What you have done here is better than before, but it's still one extra pass that iterates through all blocks in the player's hitbox.

I didn't do this because I felt like it would be too restrictive. I'm using a smaller hitbox to prevent the player from skipping gaps.

IntegratedQuantum · 2025-04-23T20:23:50Z

I didn't do this because I felt like it would be too restrictive.

If it's too restrictive, then please improve the interface of touch events.

We can't keep adding a new collision test call for every single addition to the physics system. These are not cheap at all!

I'm using a smaller hitbox to prevent the player from skipping gaps.

According to the code you are using a larger hitbox, also what do you mean by skipping gaps?

ChibChi · 2025-04-24T09:57:59Z

src/game.zig

-			}
-		} else break :isClimbing false;
-	};
+	const footHitbox: collision.Box = .{.min = -Player.outerBoundingBoxExtent, .max = Player.outerBoundingBoxExtent*Vec3d{1, 1, -0.1}};


According to the code you are using a larger hitbox

I did use a smaller hitbox unless I'm missing something.

what do you mean by skipping gaps?

In Minecraft it used to be possible to climb ladders where every other block is a ladder block.

Oh, I see, I was looking at the wrong thing.

In Minecraft it used to be possible to climb ladders where every other block is a ladder block.

In my mind this should be possible, but slower. Mabye we could have a climbing speed parameter that gets averaged of the entire area of the player hitbox in the movement direction. Then you could also assign different climbing speeds to different climbable blocks. E.g. ivy could have a slower climbing speed.

Take a look at the ice code for an example of this averaging on a different axis.

ChibChi · 2025-04-24T10:01:04Z

src/game.zig

-					// TODO Find a way to prevent the entity to skip gaps
-					if(block.?.climbable() and !entity.climbing) {
+					// Prevent the entity from skipping gaps
+					const isBelowTop = posZ < maxZ;


Now i kind of ignore the top blocks which feels cheaty

IntegratedQuantum

Also could you make ivy climbable as an example to make testing easier?

IntegratedQuantum · 2025-05-01T15:47:41Z

src/blocks.zig

@@ -155,6 +157,8 @@ pub fn register(_: []const u8, id: []const u8, zon: ZonElement) u16 {
 	_absorption[size] = zon.get(u32, "absorbedLight", 0xffffff);
 	_degradable[size] = zon.get(bool, "degradable", false);
 	_selectable[size] = zon.get(bool, "selectable", true);
+	_climbable[size] = zon.get(bool, "climbable", false);


Should be implicit (climbSpeed == 0), so we don't need to set two parameters to make something climbable.

IntegratedQuantum · 2025-05-01T15:52:44Z

src/game.zig

+		const maxZ: i32 = @intFromFloat(@floor(boundingBox.max[2]));
+
+		var climbSpeed: f64 = 0;
+		var totalArea: f64 = 0;


These should be f32, since you cast them anyways and there is not much precision to be gained here.

IntegratedQuantum · 2025-05-01T15:54:55Z

src/game.zig

+			return defaultSpeed;
+		}
+
+		return @floatCast(climbSpeed/totalArea);


I would only divide by the totalArea if the totalArea is bigger than the player's hitbox area in that direction.
As it is right now we get the same block skipping problem that you described.

IntegratedQuantum · 2025-05-01T16:03:42Z

src/game.zig

@@ -904,6 +1002,9 @@ pub fn update(deltaTime: f64) void { // MARK: update()
 						movementSpeed = @max(movementSpeed, 5.5);
 						movementDir[2] += 5.5;
 					}
+				} else if(Player.super.climbing) {
+					movementSpeed = @max(movementSpeed, Player.currentClimbSpeed*0.7);


This feels wrong. When jumping next to a climbable block you should be able to keep your jumping speed, slowly slowing down to the ladder speed due to gravity.

Furthermore using @min and @max in collision code is always bad, since it has the ability to cut your velocity instantly as soon as you touch a certain block.
It's better to use friction to slow it down slowly instead.

IntegratedQuantum · 2025-05-01T16:06:35Z

src/game.zig

@@ -904,6 +1002,9 @@ pub fn update(deltaTime: f64) void { // MARK: update()
 						movementSpeed = @max(movementSpeed, 5.5);
 						movementDir[2] += 5.5;
 					}
+				} else if(Player.super.climbing) {
+					movementSpeed = @max(movementSpeed, Player.currentClimbSpeed*0.7);
+					movementDir += up*@as(Vec3d, @splat(walkingSpeed));


movementDir is normalized.
This has the side effect off slowing you down even if you just walk alongside a climbable block.
Up direction should be handled separately here.

IntegratedQuantum · 2025-05-01T16:10:09Z

src/game.zig

@@ -1010,6 +1111,10 @@ pub fn update(deltaTime: f64) void { // MARK: update()
 			move[i] = a/frictionCoefficient*deltaTime - c_1/frictionCoefficient*@exp(-frictionCoefficient*deltaTime) + c_1/frictionCoefficient;
 		}

+		if(Player.super.climbing and Player.crouching and move[2] < 0) {
+			move[2] = 0;


This is bad since it allows you to negate any fall damage by jumping onto a ladder. There should be a velocity limit beyond which you cannot hold onto the climbable block.

Changed it to use a slip velocity of around 3 blocks for now.

IntegratedQuantum · 2025-05-01T16:13:07Z

src/game.zig

+
+					// climbing
+					if(block.?.climbable() and !entity.climbing) {
+						const touchX: bool = isBlockIntersecting(block.?, posX, posY, posZ, center, extendClimableX);


Is there any reason why you cannot use the touchX defined below?

I'm using a different extend (climbAmount) than the original touch extend of 0.01. I could reuse this when I use the same extend. But this makes climbing down really hard.

IntegratedQuantum · 2025-05-01T16:14:12Z

src/game.zig

+
+		var climbAmount: f32 = 0.01;
+		if(!Player.onGround or KeyBoard.key("jump").pressed) {
+			climbAmount = 0.4;


This feels weird in my opinion. Why can you suddenly grab climbable blocks 0.4 meters away?

I made it this big as a QOL feature. With an amount of 0.01 its incredibly difficult to grab onto blocks. It could be smaller of course.

Well, you just have to walk right into it until you hit the hitbox, and then you can just climb.
I don't see how that's difficult.

Climbing up isn't as much of a problem, but trying to get down from higher elevations.

2025-05-02_22-06-15_001.mp4

What if you could crouch off the edge into the ladder? I think that would be a good fix

…g to fast

ikabod-kee · 2025-05-02T20:36:23Z

I was skeptical about this PR at first, but it looks to be better than Minecraft's janky climbing (plus, you added slip velocity! No ladder clutches XD)

ikabod-kee · 2025-05-02T20:42:30Z

Also, I'm glad you made ladder movement different from regular movement. That's always been a pet-peeve of mine. (Source game ladders are the bane of my existence)

ChibChi · 2025-05-02T20:56:28Z

I was skeptical about this PR at first, but it looks to be better than Minecraft's janky climbing (plus, you added slip velocity! No ladder clutches XD)

Being by first PR I also expected this to go differently (my math is rusty)

ikabod-kee

2025-05-02_17-16-23.mp4

Found a bug!

ChibChi · 2025-05-02T22:38:00Z

2025-05-02_17-16-23.mp4

Found a bug!

Fixed

ikabod-kee · 2025-05-03T03:03:48Z

Oops, I love github. I was trying to get rid of my review XD

…ble block

ChibChi · 2025-05-04T19:25:48Z

It is now possible to crouch off of blocks onto climbable blocks. Took me longer than I want to admit. You need to crouch backwards towards the edge and let go of crouch to go down. It's still a little death trap.

careeoki · 2025-05-04T19:46:01Z

Climbing gets really slow when you reach the top of the block?
Also you're not able to crouch forwards against a ledge with ivy on it (it sends you plummeting to your doom)

ikabod-kee · 2025-05-04T20:06:49Z

What if crouching on a climbable made you go down, and not having any inputs kept you still?

ChibChi · 2025-05-04T20:11:03Z

Climbing gets really slow when you reach the top of the block?

It gets slower because it is based on the area of the collision, so you get slowed down with air gaps. I could increase the default climb speed to make it a little faster. How do i differentiate between gaps and platforms without blasting collision checks

careeoki · 2025-05-04T22:48:02Z

It gets slower because it is based on the area of the collision, so you get slowed down with air gaps.

You also get slowed down if you're not centered on the climbable block, which logically makes sense but feels annoying while playing.

Also, it's weird not being able to move backwards while climbing (i.e. to get off the block.)

Oh, and a probably unintended mechanic: you can climb on ceilings with ivy on them! This is fun, I hope you're able to keep it.
(not being able to move backwards is especially weird here)

However, you can also climb on the sides of blocks if they have ivy on the bottom.

and if you're crouching and climbing upwards, then start climbing on a ceiling, you get stuck crouching and can't fall down.

ikabod-kee · 2025-05-05T08:34:19Z

and if you're crouching and climbing upwards, then start climbing on a ceiling, you get stuck crouching and can't fall down.

Yeah, that's exactly why I suggested that crouching on a climbable makes you go down. This is an issue in Minecraft as well XD

You could even have the (backwards key) make you climb down. We'll have to workshop it.

IntegratedQuantum · 2025-05-05T15:28:06Z

How do i differentiate between gaps and platforms without blasting collision checks

You could restrict the climbing collision box to the legs, however that would break the climbing on the ceiling thing.

The alternative would be to detect if there is a ledge, but that is indeed rather complicated (though a nice byproduct of this would be that you would be able to make your own ladders by stacking slabs or fences)

IntegratedQuantum · 2025-05-05T15:30:22Z

What if crouching on a climbable made you go down, and not having any inputs kept you still?

Yes please, that would be great. This has always bothered me in minecraft.
In my opinion not pressing any keys should keep you still, like what if you need to get away from your computer while climbing a big ladder? Or what if you just want to open chat or the inventory?
Now all your progress is gone because it sent you back to the bottom.

IntegratedQuantum · 2025-05-05T15:37:25Z

I could increase the default climb speed to make it a little faster.

Actually instead of increasing the climb speed, you could change the interpolation. e.g. a weighted pythagorean sum is always closer to the largest element than just a weighted sum.

IntegratedQuantum · 2025-05-09T07:33:20Z

The area detection doesn't seem to work correctly. I can climb on the side of an ivy covered pillar:

video-2025-05-09_09.31.28.mp4

IntegratedQuantum · 2025-05-09T07:36:04Z

src/server/Entity.zig

@@ -15,6 +15,8 @@ health: f32 = 8,
 maxHealth: f32 = 8,
 energy: f32 = 8,
 maxEnergy: f32 = 8,
+climbing: bool = false,
+touchingClimbable: bool = false,


This Data should only be stored in the client-side player struct for now.

IntegratedQuantum · 2025-06-04T20:47:44Z

src/game.zig

@@ -509,6 +509,12 @@ pub const collision = struct {

 						entity.touchingClimbable = entity.touchingClimbable or isSideBlock or isBottomBlock;
 						entity.climbing = isSideBlock and (!isBottomBlock or isFullBlock);
+
+						const normal = if (model.internalQuads.len > 0) model.internalQuads[0].quadInfo().normal else break :missingNormal;


Wait, so you cannot make full blocks climbable? That doesn't make sense.
Also does this work on other blocks, like e.g. if you were to make a climbable pole?

ChibChi added 8 commits March 18, 2025 18:59

Add climbable trait to blocks

9b695af

Merge branch 'master' of https://github.com/ChibChi/Cubyz into featur…

de60a67

…e/climbable

Add player climbing detection

9321f92

Add climb speed and player input handling

71799d0

Use base friction

6793846

fmt stuff

b678a54

Add crouching support and lower hitbox max

3b5e783

Check x and y directions for collisions and rename block name

305623f

IntegratedQuantum requested changes Apr 3, 2025

View reviewed changes

ChibChi added 2 commits April 3, 2025 21:53

Use intersections instead of collisions

a2d08df

fmt stuff

139a811

ChibChi requested a review from IntegratedQuantum April 3, 2025 20:09

IntegratedQuantum requested changes Apr 13, 2025

View reviewed changes

Move climb detection to touchBlocks

8a7eeba

ChibChi added 2 commits April 13, 2025 20:48

fmt stuff

afe8c43

Fix skipping of gaps between climbable blocks

8aecff4

ChibChi requested a review from IntegratedQuantum April 14, 2025 16:36

careeoki mentioned this pull request Apr 16, 2025

Add ladder assets #1310

Merged

ChibChi commented Apr 24, 2025

View reviewed changes

ChibChi added 4 commits April 28, 2025 17:05

Add climbSpeed for blocks

1b75076

Add helper for area calculation

adb838b

Add climb speed calculation

1e87589

Use the entire bounding box for climb detection

3804eaf

IntegratedQuantum requested changes May 1, 2025

View reviewed changes

ChibChi added 2 commits May 1, 2025 20:15

Make ivy climbable

1358687

Add slip velocity, so the player can not grab a climbable when fallin…

9db69bf

…g to fast

ChibChi added 2 commits May 2, 2025 21:52

Add climb friction

a42a1fe

Merge remote-tracking branch 'upstream/master' into feature/climbable

1175085

ikabod-kee suggested changes May 2, 2025

View reviewed changes

ChibChi added 2 commits May 3, 2025 00:35

Fix plane rotation models being climable on the ground

b48a2c9

fmt stuff

5734de1

ikabod-kee self-requested a review May 3, 2025 03:03

ChibChi added 2 commits May 4, 2025 21:12

Remove climb amount and store whether the player is touching a climba…

1b025bb

…ble block

Add crouching off onto climbable blocks

84f3fb6

ChibChi added 4 commits May 8, 2025 20:56

Change movement input

e4e5632

Refactor climb detection

53daac5

Change climb friction and remove gravity when climbing

e753467

Refactor edge crouching and crouching down onto climbables

aa9bbfc

ChibChi added 2 commits May 23, 2025 21:17

Fix climb detection

88cbf66

fmt stuff

2ea8a0b

IntegratedQuantum requested changes Jun 4, 2025

View reviewed changes

Add climbing #1266

Are you sure you want to change the base?

Add climbing #1266

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