TheGameCreators - CodeBase

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Category: Sprite

Version: 1.0

Information

Uploaded: 19th Oct 2011 15:37

Modified: 1st Jan 1970 01:00

Author: Jcamden

Summary

Simple 2d style AI Movement

Full Description

The AI.h header contains very simple AI movement using dbSprite and dbMoveSprite functions. You can use any image for your player and enemy. This is just for testing so anyone can understand the basic functions. The MoveEnemy(e) function does not have any collision detection but the MoveEnemyWithAngle(e) does.

C++ Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

// AI header file //

// This is a very basic AI enemy that locates a player //

#define NONE			(-1)

#define PLAYER_ID		(1)

#define ENEMY_ID		(2)

#define RIGHT_ANGLE		(270)

#define LEFT_ANGLE		(90)

#define RESET_ANGLE		(0)

typedef struct Enemy_

{

WORD id;				// Enemy id, usually same as image id

WORD x;					// x coord of enemy

WORD y;					// y coord of enemy

float speed;			// velocity if we are using dbMoveSprite

WORD Player_To_Follow;	// Player Id to follow

}Enemy;

void InitializeEnemy(Enemy *e, WORD Id, WORD x, WORD y, float vel)	// Initializes the starting points for the enemy

{

e->id				= Id;

e->x				= x;

e->y				= y;

e->speed			= vel;

e->Player_To_Follow = NONE;

dbSprite(e->id,e->x,e->y,e->id);

// Need to offset the sprite so that we can rotate at its center.

dbOffsetSprite(e->id,(dbSpriteWidth(e->id) / 2), (dbSpriteHeight(e->id) / 2));

}

void UpdateEnemyPosition(Enemy *e)

{

e->x = dbSpriteX(e->id);

e->y = dbSpriteY(e->id);

}

void FollowPlayer(Enemy *e, WORD Player) // Sets the Pid of that player to follow

{

e->Player_To_Follow = Player;

}

void FreeMemory(Enemy *e)

{

dbDeleteSprite(e->id);		// this deletes the image we allocated

dbDeleteSprite(PLAYER_ID);	// We need to delete the player id sprite to free the memory

free(e);					// this deletes the memory we allocated

}

// So there are a few ways to track a player //

// you can use the traditional way with dbSprite //

// Or you can use dbMoveSprite for better looking movement //

void MoveEnemy(Enemy *e)

{

if(dbSpriteX(e->Player_To_Follow) > e->x)// so player 1 x coord is greater than the enemy's coord

{

// now we need to increase the x coord of the enemy to get to the player

// remember that we need to rotate the sprite in order to go right and left

e->x++;

dbRotateSprite(e->id, RIGHT_ANGLE);

dbSprite(e->id,e->x,e->y,ENEMY_ID);

dbRotateSprite(e->id, RESET_ANGLE);

}

if(dbSpriteX(e->Player_To_Follow) < e->x)// Player 1 coord is less than the enemy so we need to move the other way now

{

e->x--;

dbRotateSprite(e->id, LEFT_ANGLE);

dbSprite(e->id,e->x,e->y,ENEMY_ID);

dbRotateSprite(e->id, RESET_ANGLE);

}

if(dbSpriteY(e->Player_To_Follow) > e->y)

{

e->y++;

dbSprite(e->id, e->x, e->y, ENEMY_ID);

}

if(dbSpriteY(e->Player_To_Follow) < e->y)

{

e->y--;

dbSprite(e->id, e->x, e->y, ENEMY_ID);

}

// So in this function we will get the angle of the player for a more fluid movement

void MoveEnemyWithAngle(Enemy *e)

{

int PlayerX = dbSpriteX(e->Player_To_Follow);

int PlayerY = dbSpriteY(e->Player_To_Follow);

float Angle = dbWrapValue(dbAtanFull(PlayerX - e->x, e->y - PlayerY));

dbRotateSprite(e->id, Angle);

if(dbSpriteCollision(e->id, e->Player_To_Follow) == 1)

{

// if the enemy sprite collides with the player sprite we need to stop it

dbMoveSprite(e->id, 0);

}

else

{

// if the enemy isn't colliding with any sprites let's move!

dbMoveSprite(e->id, e->speed);

}

#include "DarkGDK.h"

#include "AI.h"

#include "Movement.h"

void DarkGDK ( void )

{

dbSyncOn();

dbSyncRate(60);

dbDisableEscapeKey();

dbSetImageColorKey( 255, 0, 255 );

// Allocate memory for our Player structure

Player *p = (Player*) malloc(sizeof(Player));

Enemy  *e = (Enemy*)  malloc(sizeof(Enemy));

// Load the image

dbLoadImage("Player.bmp", PLAYER_ID);

dbLoadImage("Enemy.bmp", ENEMY_ID);

// Initialize the player on the screen

InitializePlayer(p,PLAYER_ID,200,200,PLAYER_SPEED);

// Initialize the enemy on the screen

InitializeEnemy(e,ENEMY_ID,50,50,ENEMY_SPEED);

// this sets the pid of the player to follow

FollowPlayer(e,PLAYER_ID);

while ( LoopGDK ( ) )

{

UpdateEnemyPosition(e); // Updates enemy x and y coord

MoveEnemyWithAngle(e);  // Moves the enemy to the player

MovePlayerWithAngle(p); // Moves player using keys, rotates player with the mouse

if ( dbEscapeKey ( ) )

break;

dbSync();

}

// Make sure we delete all images and free memory here

FreePlayerMemory(p);

FreeMemory(e);

return;

}

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CodeBase - Simple AI