Businessman Rong: How to make 3D action game with UE4

Gamelook reports/June 5, the third Gamelook Open day, 2015 Unreal Engine special event was formally held in Shanghai, the event was jointly organised by Epic Games and Gamelook.

Action game with a refreshing shock and strong sense of operation has been loved by the players, but some high-quality 3D action game design is actually quite difficult, the domestic market is mostly a horizontal version of 2D games. The event, Megafun founder businessman Rong to share the use of UE4 engine to create 3D horizontal version of the action game experience.

Businessman from the planning point of view analysis of the production process of action games, "first make 2D sketches, through these sketches to verify the rationality of the action, and then into a 3D model, and finally turn these actions into moves." "Then businessman Rong highlighted the powerful features of the notification system in UE4," in-game input judgments, sounds, sound effects, special effects, damage, the state of transmission to the enemy, cancellation mechanisms, camera jitter, fixed frame and so on all things can be done by notification.

"Damage area determination is difficult" businessman introduced the method of design of damage judgment, "by editing all kinds of collision boxes in front of the characters and controlling the switches and transformations of these boxes through notify State" Besides businessman Rong also shared the design of buffer and cancellation mechanism in action game. One is the simple combos, the second is the role of the specific ability to include the role of jumping, and just see the rope hook, you can hook back to the kind, there are some skills, and then design the overall logic of the three ".

At the end of the lecture, the Megafun programmer specifically demonstrated the use of notify State and introduced its advantages, including ensuring that two functions are paired to facilitate the management of the designer.

The following is a transcript of the speech:

businessman Rong: Hello, everyone. Our company is using Unreal 4 engine in a 3D horizontal version of the action game, currently codenamed "TTW Plan", the team in Shenzhen. Currently planned platform only PC and host two, hand tour and did not consider too much. It is also planned to release a demo version of China Joy at the end of July.

First look at a video, because our game is too big, there are more than 20 g, so the video is also I spent an all-nighter time clip, there are a lot of bugs, more rough, we can focus on our next one months version.

Create 2D sketches and then convert to 3D models

This share is mainly about how we use the Unreal 4 engine to do an action game. Classic action games have many, such as the Ares series, Ghost Cry series, as well as domestic rain blood, and so on, are doing a better game in the sense of action strike. But a lot of people in the action game will feel it is particularly difficult to do, can not touch its doorway.

Action Game I do a planning to the point of view is mainly divided into three aspects: visual, auditory, tactile, touch is the feel of the combo operation. Our workflow is this, the first to make 2D action sketches, through the design of these sketches can see the action is reasonable or unreasonable. Then, according to these sketches in the UE4 inside the model of the action, and through the UE4 cascade such a tool to do special effects. Finally turn these actions into a move that will configure the events in the montage, this part of the event is very numerous, very cumbersome, and in the animation sequence configuration effects and sound effects.

This is a simple production flow chart, that is, the task of splitting the work into different people, and all this is the theme of "notice." Whether it is montage or animation sequence will be used in the UE4 inside the unique settings, called notifies, in the following position.

powerful "notification" system to control the insertion of a trick effect

What the notice is for. Notifications are animations in specific locations, specific areas to do specific things. What does a particular thing include? Including the input of the decision, sound, sound, effects, damage, the status of transmission to the enemy, cancellation mechanism, camera jitter, fixed frame and so on all things can be done by notification.

Feel the source of the fact that the first is even the decision to enter the input, when you get a move to the next move, the time to determine whether the reasonable. For the hand-stump, as I am concerned, I will ask for a longer judgment time. But for a master, it may prefer a hard core.

Cushioning our feel is divided into two notifications, including some immediate response and buffering mechanisms. The buffering mechanism is to get the player input, wait for the animation to play to a frame before jumping to the next section of the Recruit. Instant response is to get the player input, immediately jump to the next link.

So how do we configure ourselves in the inside? You can see that this is called attack Anim Notify State is the decision of the buffer mechanism we made, and then the following stop Delay Notify indicates that the key input is not accepted. That is, in this length frame number, the action is allowed to jump to the next move, but the earliest two frames have begun to receive the decision input.

The effect is simple, that is, a specific frame to do the action of the effects, including some brandished sound effects. The sound format is WAV (16bit).

damage Area determination is difficult edit all kinds of collision box

Another important thing is the determination of the damage area, which is the most difficult and core action game. This picture is quoted in the "Street Fighter 4" Inside the box of art screenshots, they are divided into a variety of boxes. And the game box we actually need is not so complicated.

We only need to determine the attack at a certain frame segment, and we will not judge the attack after this frame. By automatically adjusting the size of the decision box, adjust the number of decision boxes to output the status of the attack transmitted to each of the attackers. For example, this call is required to pass it is the state of floating empty, the state of knockdown or normal rigidity.

This is the slnow of the previous preparation table, we use the Slnow configuration table to configure some of the damage box inside the information, this startswing is the notification of damage. Then the UE4 editor adjusts the properties of these collision boxes, and the position of the boxes is the position of the person in front of them.

We can also use the notification system to achieve the role itself to add a series of conditions, for example, in a particular frame to the role of a super armor, can also ignore all collision detection, equivalent to invincible, charge, flight, delay and other states can be implemented by notification. We charge here, is a charge of the notice, indicating that the characters in charge need to repeat the animation.

setting of buffering and cancellation mechanisms

There are also buffering and cancellation mechanisms in action games. Buffering refers to whether the trick can be canceled. I believe you've played DNF. It has a post-hop is forced to cancel all moves and state, is the action game moves, whether you can cancel. is to cancel at once or to wait until the end of this trick is not accepted can be canceled, or your moves by a specific type of moves to cancel it. This set of settings is very central and very thin, but can be done by notification.

We play in three kinds of moves, one is a simple even recruit combos, the second is the role of the specific ability to include the role of jumping, as well as just saw the rope hook, you can hook back to the kind, there are also some skills. The overall logic is that even the strokes themselves cannot be interrupted, but the skills can interrupt your even strokes, the ability to interrupt even strokes, skills can not be interrupted by anything, the ability to ignore the frame number, when the move does not begin to interrupt the current moves.

We have a skilljumping notify here, is the cancellation mechanism of skills, even the abolition of the mechanism has just said that in these two areas can be abolished.

The notice I told you just now is how to configure this series of events for planning purposes, and then the programmer will tell you how it works.

Begin,end,tick and Getnotifyname four ways to rewrite notify state

megafun Programmer: Hello, everyone. Let me tell you a little bit about how to write the notification logic. In the UE4, especially when doing action games, the role of a sword in the past, in a specific frame need to perform a series of operations, and this series of operations will have a lot of functions. We are now going through an example to analyze how we write.

For example, a knife to this side, the damage of the collision lattice should be open, and in the process of opening, for example, he hit the other side, you need to close the box. We use a notify State to control the opening, closing, and transformation of the collision box.

The simple thing to do is to open the Notifystate editing interface by clicking the Open full Blueprint editor. It has 4 methods that can be rewritten, namely Begin,end,tick and Getnotifyname. At the time of the begin, it was stated that I received the events of this event. End is the same. Tick is the event of tick between Begin and end, and it has a parameter deltatime. That getnotifynoame is I want to see which notify is working now, but we don't usually use it.

The detailed logic is that at begin, a lot of collision boxes are hung on the characters, and the box is opened when begin. At tick, we have a curve curve that adjusts the state of the collision box according to the number of changes in the incoming curve, possibly the position, size, and possibly rotation. Find the collision box at end and then close it. Actually the code is troublesome, but in fact the pseudo-code is so a little bit, very simple information.

The configuration is this, there is a begin, a tick event is generated in the middle, and then we use a logic to write the opening and closing of the collision box in the action game. We see here are three pictures, here a test box to carry out such a demonstration, you can see this is in the first frame, found that the first frame is very small, and then there is a tick, and then gradually become larger, this is the collision box we realized, this is the collision box corresponding to an object.

Benefits of Notify state: guaranteed, easy to manage

Why do we use notifystate instead of two notify+player tick functions. The first is that we have the begin, and we are going to have end, called the pair call. It is impossible to cut down a knife, this box is open, or during this period I was beaten, I want not to call this end of the box will be open, so there is an accident.

So we need to keep it as a pair call. In Notifystate, an event interrupted by an animation ensures that it invokes the function of the end of Notifystate, which guarantees a paired call to begin. And it's begin, End, tick. Three of them are in the same BP to facilitate our management. It is recommended to use Notifystate to enable and disable Player collision boxes in action games.

I've been using a collision-box-based weapon attack Point, and I've actually studied it, but I've thought about another scenario, based on a linear Ray detection scheme. For example, any long-handled weapon in the hand, I set two points on the weapon, each frame to detect, once the collision is considered the attack success.

businessman: I've thought about it before, for example, to attach a box directly to a weapon, or to do some testing in a special way, but considering that because we're moving very fast, every time we move is very short. In this process, if a box on a weapon will be very short, there may only be one frame, but I hope our strike frame number is more than 3 frames above the decision.

The other point is that our special effects will be more exaggerated than the action itself. For example, I have a role in fact no displacement, just the video there is a lens, is the forward so large arc, no role displacement, the role is still in place, but in a moment back. This can only be done by placing a box in front of the character.