Battle Controller

NOTE

Much of the information in this article was based on code from Deltarune Chapter 3.

The GonerEngine BattleController node and scene aim to replicate the behavior of several battle-related tools in Deltarune:

1. scr_battle(), which starts a battle by creating obj_encounterbasic and obj_battleback and creates enemy markers that enter from the right side of the screen.
2. obj_battleback, which is the purple grid background in battles.
3. obj_encounterbasic, which is is the intro animation that begins the battle.
4. scr_encountersetup(), which sets the types of enemies and other useful battle-related things.
5. obj_battlecontroller, which draws the battle UI and controls the logic of the battle.

The Details

global.heromakex[character_idx] and global.heromakey[character_idx] are the X and Y positions of heroes in battle. global.monstermakex[enemy_idx] and global.monstermakey[enemy_idx] are the X and Y positions of enemies in battle. All four of these arrays are set by scr_encountersetup().

After scr_encountersetup(), obj_encounterbasic's Create event disables obj_mainchara and obj_caterpillarchara, then creates "Hero Markers" that are in the same locations as the party members. These markers are in their "battle jump" sprites and move to the locations specified by the heromake arrays over a duration of 10 frames. On every frame (after the first frame) of this "gliding", the markers make afterimages with a starting opacity of 0.5. An afterimage is created for nine frames, so keep that in mind.

NOTE

The hero markers really DO move over a duration of 10 frames! And they are EXACTLY at their heromake positions by the 10th Step event. For more information about this, check out GameMaker Object Movement.

On the 10th frame, snd_impact is played with a volume of 0.7, and snd_weaponpull_fast is played with a volume of 0.8. All of the hero markers are stopped, and their sprites become "battle intro" sprites. (Note that the image speed of these sprites is set to 0.5, so they are actually played at 15 FPS). 14 frames later, the hero markers and obj_encounterbasic are destroyed, and obj_battlecontroller is created.

After scr_encountersetup(), and after obj_encounterbasic is created, scr_battle() creates "Enemy Markers" that are 300 pixels to the right of the location specified by the monstermake arrays. They move to the location specified by the monstermake arrays over a duration of 20 frames.

The Battle Controller Menu

The part of the menu you are currently in, is determined by the global.bmenuno, global.bmenucoord, and global.charturn variables. global.charturn is the index of the character that is currently selected, so in a battle of Kris, Susie, and Ralsei, if Ralsei is currently selected, then global.charturn is equal to 3.

global.bmenucoord is a 2D array. global.bmenucoord[0][global.charturn] is the index of the currently selected button for the current character. For example, if Susie's "Item" button is currently selected, then global.bmenucoord[0][1] == 2 (since the Item button is the 3rd button, so it is at index 2).

heromake and monstermake Values

All party members have an x-value of 80. If there are three party members, they have y-values of 50, 130, and 210 (note that they are 80 pixels apart). If there are two party members, they have y-values of 100 and 180. If there is one party member, they have a y-value of 140.

The monsters have x-values of 500, 520, and 540 (note that they are 20 pixels apart, horizontally). The monsters have y-values of 40, 130, and 220 (note that they are 90 pixels apart, vertically).

These values are the default values, but can easily be overridden in scr_encountersetup(enemy_id). There is a switch statement in the function that acts on the first argument enemy_id. If the id is zero, it does nothing, but it has many values that correspond to all the different enemies in the game.

blcon

In Deltarune battles, there are "speech bubbles". These are called obj_battleblcon and are created with scr_blcon(x, y, type).

GonerEngine Design of Battle Controller

In GonerEngine, BattleController is a class meant to handle ALL of the needs of battles.

This is a list of every possible action a party member could take in a battle:

• Fight (enemy)
• Act (enemy, act)
• Item (item, recipient)
• Spare (enemy)
• Defend After all party members have selected an action, their turn starts being executed, looking at each action and going from left to right.