Characters

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Overview

In Open Surge, you can create your own playable characters. To create a playable characrer, first of all you need to create a character file.

Character files are human-readable configuration files located in the characters/ folder. They have the .chr extension. These files are used to specify the properties of the characters.

Each level has one or more playable characters. You can select which characters appear in which levels.

Structure

Character files are used to specify the following data:

  • the name of the character;
  • the multipliers. These values are used to specify how fast a character runs, how high it jumps, how fast it accelerates, etc. For example, if you set the acceleration to one, it will accelerate by the default rate (set by the game engine). If you set it to two, it will accelerate two times faster than that. If you set it to 0.5, it will accelerate by half of the default rate, and so on. By default, all the multipliers are set to 1.0;
  • the animations for each action the character performs: walk, run, jump, etc., as well as the sprite name. See also: Sprites;
  • the sound effects this character uses: jump, brake, etc.;
  • the abilities this character has: roll, charge, etc.;
  • optionally, the name of one or more companion objects. If defined, companion objects can be used to give custom abilities to characters.

Example 1: Surge the Rabbit

Character file

File: characters/surge.chr (simplified)

character "Surge"
{
    companions                      "Surge's Lightning Boom"

    multipliers
    {
        acceleration                1.0    // modifies the acceleration rate
        deceleration                1.0    // used when moving in opposition to the current movement
        friction                    1.0    // modifies the friction (since version 0.5.0)
        topspeed                    1.0    // modifies how fast the character can run
        jump                        1.0    // modifies how high the character jumps
        gravity                     1.0    // gravity modifier
        slope                       1.0    // affects the physics on slopes
        charge                      1.0    // modifies the charge-and-release speed (since version 0.5.0)
        airacceleration             1.0    // the rate at which the horizontal speed can change while midair (since 0.5.0)
        airdrag                     1.0    // air drag / air friction (since version 0.5.0)
    }
    
    animations
    {
        sprite_name                 "Surge"
        stopped                     0
        walking                     1
        running                     2
        jumping                     3
        springing                   13
        rolling                     18
        charging                    6
        pushing                     14
        gettinghit                  11
        dead                        8
        braking                     7
        ledge                       10
        drowned                     9
        breathing                   12
        waiting                     15
        ducking                     4
        lookingup                   5
        winning                     17
        ceiling                     16
    }
    
    abilities
    {
        roll                        TRUE
        brake                       TRUE
        charge                      TRUE
    }
    
    samples
    {
        jump                        "samples/jump.wav"
        roll                        "samples/roll.wav"
        death                       "samples/death.wav"
        brake                       "samples/brake.wav"
        charge                      "samples/charge.wav"
        release                     "samples/release.wav"
    }    
}

The example above has been simplified for the purpose of explanation. The actual character file of Surge has some additional things in it.

Compatibility notes: animation charging, sounds charge and release, the abilities block, as well as some multipliers (indicated above) are available since Open Surge version 0.5.0.

Companion objects: companions is available since Open Surge version 0.5.0. It is followed by one or more names of objects surrounded by double quotes ("). These objects should be created in SurgeScript. In older versions of the engine, you'd write companion_object instead (it supported only one companion).

Playing as the character

Playing as the character is a matter of adding him/her to the levels of your choice. Using a text editor, open the lev files you choose (they are in the levels/ folder) and add the name of your character to the players entry. For example: in the Sandbox level (file levels/sandbox.lev), change the players entry from:

players "Tux"

to:

players "Surge" "Tux"

Save the file and open the level. You should see two playable characters appear in the level. For more information, refer to: Level specification - players.

Creating custom abilities

One of the exciting features of Open Surge is the possibility to create custom abilities (custom moves) for your characters. You can create these abilities by adding companion objects to your characters. These objects are created in SurgeScript.

To understand better how to create your own custom abilities, let's study the case of a dash movement (affectionally called "Super Peel Out"). If your character is endowed with that ability, you can give it instant speed when it's stopped. In Open Surge, character Tux features that ability. Surge does not. To add this custom move to Surge, add the corresponding object to his companions:

companions                      "Surge's Lightning Boom" "Super Peel Out"

The new companion is defined in a script, a .ss file located in the scripts/ folder. Writing new scripts is beyond the scope of this article, but the script of this move has been reproduced here for clarity (do not copy and paste it - it's already shipped):

using SurgeEngine.Audio.Sound;

//
// This is a dash move that should be configured as a
// companion object in a character definition file (.chr)
//
// When you are stopped, hold up and press jump to charge.
// Release up after 0.3 second and you'll gain a nice boost!
//
object "Super Peel Out" is "companion"
{
    speed = 720;     // dash speed, in pixels/second

    charge = Sound("samples/charge.wav");
    release = Sound("samples/release.wav");
    player = parent; // since this object is configured as a
                     // companion, parent is the reference
                     // to the correct Player object

    // capture the event
    state "main"
    {
        if(player.lookingUp) {
            if(player.input.buttonPressed("fire1")) {
                charge.play();
                state = "charging";
            }
        }
    }

    // charging the dash
    state "charging"
    {
        player.anim = 2; // running animation
        player.animation.speedFactor = 1.85;
        player.frozen = true; // disable physics (temporarily)

        // ready to go?
        if(player.input.buttonReleased("up")) {
            if(timeout(0.3)) {
                player.gsp = speed * player.direction; // dash!!!
                release.play();
            }
            player.frozen = false; // enable physics
            state = "main";
        }
        else if(player.input.buttonPressed("fire1"))
            charge.play();
    }
}

What custom abilities can you add? Whatever you can imagine! Swimming, flying, climbing, wall kicking, you name it! The sky is the limit for those who learn SurgeScript!

Example 2: Speedy the Rollerskater

Swimming in the game Speedy the Rollerskater

We now present Speedy the Rollerskater, an original character created by community member Synfigmaster91. In addition to the basic abilities of braking, rolling, etc., Speedy has a special ability of his own: he can swim. The following files are relevant to this character:

  • the spritesheet: a png image featuring the animations of the sprite. In the image below, the sprites are aligned to a 64x64 grid.
  • the sprite script: a spr file that describes how the animations are laid out in the spritesheet. Read the Sprites page for more information on the subject.
  • the character file: a chr file that describes the character in the way we have just seen.
  • the SurgeScript file(s): these are ss scripts that add new traits to the character - the swimming ability is an example. Inventing new special abilities requires a more in-depth knowledge of the engine and is beyond the scope of this article. If you're interested, you can learn SurgeScript.

File: sprites/speedy.png

Speedy the Rollerskater. Author: Synfigmaster91. License: CC-BY 3.0.


File: sprites/players/speedy.spr

sprite "Speedy"
{
    source_file     "images/speedy.png"
    source_rect     0 0 512 704
    frame_size      64 64
    hot_spot        32 44    // hot_spot.y is (frame_size.y - 20)

    // stopped
    animation 0
    {
        repeat      TRUE
        fps         8
        data        0
    }

    // walking
    animation 1
    {
        repeat      TRUE
        fps         16
        data        3 4 5 4 3 2 1 2
    }

    // running
    animation 2
    {
        repeat      TRUE
        fps         16
        data        8 9 10 9 8 7 6 7   
    }

    // jumping / rolling
    animation 3
    {
        repeat      TRUE
        fps         16
        data        11 12 13 14
    }

    // ducking
    animation 4
    {
        repeat      FALSE
        fps         12
        data        19
    }

    // looking up
    animation 5
    {
        repeat      FALSE
        fps         8
        data        16 
    }

    // charging
    animation 6
    {
        repeat      TRUE
        fps         32
        data        35 36
    }

    // braking
    animation 7
    {
        repeat      FALSE
        fps         8
        data        15
    }

    // dead
    animation 8
    {
        repeat      FALSE
        fps         8
        data        18
    }

    // drowned
    animation 9
    {
        repeat      FALSE
        fps         8
        data        18
    }

    // ledge
    animation 10
    {
        repeat      TRUE
        fps         5
        data        23 24
    }

    // getting hit
    animation 11
    {
        repeat      FALSE
        fps         8
        data        20
    }

    // breathing
    animation 12
    {
        repeat      FALSE
        fps         8
        data        21
    }

    // springing
    animation 13
    {
        repeat      TRUE
        fps         8
        data        17
    }

    // pushing
    animation 14
    {
        repeat      TRUE
        fps         8
        data        28 29 28 27
    }

    // waiting
    animation 15
    {
        repeat      TRUE
        fps         6
        data        25 26
    }

    // ceiling (being carried)
    animation 16
    {
        repeat      TRUE
        fps         8
        data        22
    }

    // winning (victory)
    animation 17
    {
        repeat      TRUE
        fps         8
        data        34
    }

    // rolling
    animation 18
    {
        repeat      TRUE
        fps         8
        data        30 31 32 33
    }

    // falling
    animation 20
    {
        repeat      TRUE
        fps         8
        data        22
    }

    // swimming	
    animation 21
    {
        repeat      TRUE
        fps         8
        data        37 38 39 38
    }
}

File: characters/speedy.chr

character "Speedy"
{
    companions                      "Super Peel Out" "Speedy Swim" "Dash Smoke" "Brake Smoke" "Speedy Falling"
    
    multipliers
    {
        acceleration                1.0
        deceleration                1.0
        friction                    1.0
        topspeed                    1.0
        jump                        1.0
        gravity                     1.0
        slope                       1.0
        charge                      1.0
        airacceleration             1.0
        airdrag                     1.0
    }
    
    animations
    {
        sprite_name                 "Speedy"
        stopped                     0
        walking                     1
        running                     2
        jumping                     3
        springing                   13
        rolling                     18
        pushing                     14
        gettinghit                  11
        dead                        8
        braking                     7
        ledge                       10
        drowned                     9
        breathing                   12
        waiting                     15
        ducking                     4
        lookingup                   5
        winning                     17
        ceiling                     16
        charging                    6
    }

    abilities
    {
        roll                        TRUE
        brake                       TRUE
        charge                      TRUE
    }
    
    samples
    {
        jump                        "samples/jump-7408.wav" // <-- notice that Speedy uses a jump sound of his own
        roll                        "samples/roll.wav"
        death                       "samples/death.wav"
        brake                       "samples/brake.wav"
        charge                      "samples/charge.wav"
        release                     "samples/release.wav"
    }
}

File: scripts/players/speedyfalling.ss

//
// We modify Speedy's animation:
// 1. when he falls down after hitting a spring
// 2. after breathing an air bubble
//

using SurgeEngine.Player;

object "Speedy Falling" is "companion"
{
    player = parent;
    falling = 20;
    springing = 13;

    state "main"
    {
        // The player may be in the springing state,
        // but that alone doesn't mean he has just
        // been hit by a spring. We use the springing
        // state to create other things, like the double
        // jump, so we need to check player.anim as well
        if(player.springing && player.anim == springing)
            state = "watching";

        // From breathing to falling
        else if(player.breathing)
            state = "watching";
    }

    state "watching"
    {
        // Now the player is midair and will fall
        // down. We'll capture this event and
        // change the animation accordingly
        if(player.ysp >= 0 && player.midair) {
            player.anim = falling;
            state = "falling";
        }
        else if(!player.springing && !player.breathing)
            state = "main";
    }

    state "falling"
    {
        if(player.ysp >= 0 && player.midair)
            player.anim = falling;
        else
            state = "main";
    }
}

File: scripts/players/speedyswim.ss

//
// This is a swimming move that should be configured as a
// companion object in Speedy's character definition file (.chr)
//
// When you are underwater, jump and press fire1.
// Speedy will swim and if you press fire1 repeatdly he will keep swimming!
//

using SurgeEngine.Player;

object "Speedy Swim" is "companion"
{
    player = parent;
    timeMidAir = 0;

    state "main"
    {
        state = "nounderwater";
    }

    state "nounderwater" // out of water
    {
        if(player.underwater) {
            state = "underwater";
        }
    }

    state "underwater" // underwater but not swimming
    {
        timeMidAir += (player.midair ? Time.delta : -timeMidAir);
        if(timeMidAir >= 0.1 && player.underwater) {
            if(player.input.buttonPressed("fire1")) {
                state = "swim";
            }
            else if(!player.underwater) {
                state = "nounderwater";
            }
        }
    }

    state "swim" // swimming
    {
        player.springify(); // make it vulnerable to attack
        player.anim = 21;
        player.ysp = -90;
        state = "swim2";
    }

    state "swim2"
    {
        player.anim = 21;
        if(!player.underwater) { // got out of water
            state = "nounderwater";
        }
        else if(!player.midair) { // landed on the ground
            state = "underwater";
        }
        else if(player.input.buttonPressed("fire1")) { // swim more
            state = "swim";
        }
        else if(player.dying) {
            destroy();
        }
    }
}

Curiosity: regular platformers

Even though Open Surge provides built-in 360º physics (with curvy roads, loops, and so on), careful modification of the character files can make it behave like a regular platformer. Example: if you create a character named SuperTux without the special abilities listed above (rolling, charging, etc.), set its slope multiplier to zero (and adjust the others), as well as build levels mainly out of rectangular platforms, you'll end up with a platformer like SuperTux. Additionally, companion object "Lock Angle" prevents the character from rotating on slopes.

SuperTux, a jump'n run inspired by Mario