super-snuvi/src/me/hammerle/supersnuvi/entity/Entity.java

package me.hammerle.supersnuvi.entity;

import java.util.List;
import me.hammerle.supersnuvi.entity.components.ai.Controller;
import me.hammerle.supersnuvi.entity.components.Energy;
import me.hammerle.supersnuvi.entity.components.Health;
import me.hammerle.supersnuvi.entity.components.ItemCollector;
import me.hammerle.supersnuvi.entity.components.Movement;
import me.hammerle.supersnuvi.gamelogic.Level;
import me.hammerle.supersnuvi.util.CollisionBox;
import me.hammerle.supersnuvi.util.Face;
import me.hammerle.supersnuvi.util.Utils;

public final class Entity
{
    public static float GRAVITY = 8.0f;
    public static float STEP = 0.0625f;
    
    // the last position is used for interpolation during rendering
    private float lastPosX;
    private float lastPosY;
    // the current position of the entity
    private float posX;
    private float posY;
    
    // the collision box of the entity
    private final CollisionBox box;
    
    // the motion before the movement collision check
    private float preMotionX;
    private float preMotionY;
    // the motion after the movement collision check
    private float motionX;
    private float motionY;
    
    // a flag indicating that the entity is on the ground
    private boolean onGround = false;
    
    // the level of the entity
    private final Level level;
    
    // entity components
    protected Controller controller;
    protected Health health;
    protected Energy energy;
    protected Movement move;
    protected ItemCollector itemCollector;
    
    // face
    private Face face;
    
    protected Entity(Level level, float x, float y, CollisionBox box)
    {
        lastPosX = x;
        lastPosY = y;
        posX = x;
        posY = y;

        // ensure the box cannot be modified from the outside
        this.box = box.copy().offset(x, y);
        
        preMotionX = 0.0f;
        preMotionY = 0.0f;
        motionX = 0.0f;
        motionY = 0.0f;
        
        this.level = level;
        
        // components
        this.controller = Controller.NULL;
        this.health = Health.NULL;
        this.energy = Energy.NULL;
        this.move =  Movement.NULL;
        this.itemCollector =  ItemCollector.NULL;
    }
    
    public Level getLevel()
    {
        return level;
    }   
    
    //--------------------------------------------------------------------------
    // components
    //--------------------------------------------------------------------------
    
    public boolean isAnimated()
    {
        return controller.isAnimated();
    }
    
    public Health getHealth()
    {
        return health;
    }
    
    public Energy getEnergy()
    {
        return energy;
    }
    
    public Movement getMovement()
    {
        return move;
    }
    
    public ItemCollector getItemCollector()
    {
        return itemCollector;
    }
    
    //--------------------------------------------------------------------------
    // basic stuff
    //--------------------------------------------------------------------------
    
    public float getSquaredDistance(Entity e)
    {
        return Utils.getSquaredDistance(
                posX + box.getWidth() * 0.5f, posY + box.getHeight() * 0.5f, 
                e.posX + e.box.getWidth() * 0.5f, e.posY + e.box.getHeight() * 0.5f);
    }
    
    public CollisionBox getBox()
    {
        return box;
    }
    
    public float getX()
    {
        return posX;
    }
    
    public float getY()
    {
        return posY;
    }
    
    public float getLastX()
    {
        return lastPosX;
    }
    
    public float getLastY()
    {
        return lastPosY;
    }
    
    public float getCenterX()
    {
        return posX + box.getWidth() * 0.5f;
    }
    
    public float getCenterY()
    {
        return posY + box.getHeight() * 0.5f;
    }
    
    public Face getFace()
    {
        return face;
    }
    
    public float getMotionX()
    {
        return motionX;
    }
    
    public void setMotionX(float motionX)
    {
        this.motionX = motionX;
    }
    
    public float getMotionY()
    {
        return motionY;
    }
    
    public void setMotionY(float motionY)
    {
        this.motionY = motionY;
    }
    
    public float getPreMotionX()
    {
        return preMotionX;
    }
    
    public float getPreMotionY()
    {
        return preMotionY;
    }
    
    //--------------------------------------------------------------------------
    // ticking
    //--------------------------------------------------------------------------
    
    public void tick() 
    {
        lastPosX = posX;
        lastPosY = posY;
        
        controller.tick();
        energy.tick();
        
        preMotionX = motionX;
        preMotionY = motionY;
        
        if(preMotionX != 0.0f)
        {
            face = preMotionX > 0.0f ? Face.RIGHT : Face.LEFT;
        }
        
        if(move.hasGravity())
        {
            preMotionY += GRAVITY * move.getGravityFactor();
        }

        if(move.canMoveEverywhere())
        {
            motionX = preMotionX;
            motionY = preMotionY;
        }
        else
        {
            CollisionBox testBox = box.copy().expand(preMotionX, preMotionY);
            List<CollisionBox> boxes = level.getMovementBoxesAt(testBox, this);
            if(!boxes.isEmpty())
            {
                float mx = preMotionX;
                float my = preMotionY;
                
                testBox.reset();
                
                float oldX = testBox.getMinX();
                float oldY = testBox.getMinY();
                
                while(mx != 0.0 || my != 0.0)
                {
                    testBox.save();

                    if(mx < 0.0)
                    {
                        if(mx > -STEP)
                        {
                            testBox.offsetX(mx);
                            mx = 0.0f;
                        }
                        else
                        {
                            testBox.offsetX(-STEP);
                            mx += STEP;
                        }
                    }
                    else if(mx > 0.0)
                    {
                        if(mx < STEP)
                        {
                            testBox.offsetX(mx);
                            mx = 0.0f;
                        }
                        else
                        {
                            testBox.offsetX(STEP);
                            mx -= STEP;
                        }
                    }

                    for(CollisionBox cb : boxes)
                    {
                        if(cb.isColliding(testBox))
                        {
                            mx = 0.0f;
                            testBox.reset();
                            break;
                        }
                    }
                    
                    testBox.save();

                    if(my < 0.0)
                    {
                        if(my > -STEP)
                        {
                            testBox.offsetY(my);
                            my = 0.0f;
                        }
                        else
                        {
                            testBox.offsetY(-STEP);
                            my += STEP;
                        }
                    }
                    else if(my > 0.0)
                    {
                        if(my < STEP)
                        {
                            testBox.offsetY(my);
                            my = 0.0f;
                        }
                        else
                        {
                            testBox.offsetY(STEP);
                            my -= STEP;
                        }
                    }

                    for(CollisionBox cb : boxes)
                    {
                        if(cb.isColliding(testBox))
                        {
                            my = 0.0f;
                            testBox.reset();
                            break;
                        }
                    }
                }
                
                motionX = testBox.getMinX() - oldX;
                motionY = testBox.getMinY() - oldY;
            }
            else
            {
                motionX = preMotionX;
                motionY = preMotionY;
            }
        }
        
        posX += motionX;
        posY += motionY;
        box.reset().offset(posX, posY);
        
        onGround = preMotionY > 0.0f && motionY == 0;
        
        move.setInWater(false);
        move.setFrictionFactor(0.6f);
        // apply collision
        CollisionBox cb = box.copy();
        for(Face f : Face.values())
        {
            cb.reset();
            cb.expand(f.getCollisionOffsetX(), f.getCollisionOffsetY());
            level.getEntitiesCollidingWith(this, box).forEach(ent -> ent.controller.onCollideWithEntity(ent, f));
            level.getCollisionBoxesAt(cb).forEach(loc -> 
            {
                controller.onCollideWithTile(loc, f);
                loc.getTile().onEntityCollide(this, loc.getX(), loc.getY(), f.getOpposite());
            });
        }
        
        motionX *= move.getFrictionFactor();
        if(Math.abs(motionX) < 0.3)
        {
            motionX = 0.0f;
        }
        
        health.tick();
    }
    
    public void renderTick(float lag)
    {
        controller.renderTick(lag);
    }
    
    //--------------------------------------------------------------------------
    // gravity, friction
    //--------------------------------------------------------------------------
    
    public boolean isOnGround()
    {
        return onGround;
    }   
}