game.engine.core.CoreModule.java Source code

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Here is the source code for game.engine.core.CoreModule.java

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/**
 * Copyright (c) 2013 Martin Geisse
 *
 * This file is distributed under the terms of the MIT license.
 */

package game.engine.core;

import game.engine.game.Behavior;
import game.engine.game.Behavior.Applicator;
import game.engine.game.EventListener;
import game.engine.game.GameObject;
import game.engine.gfx.Sprite;
import game.engine.gfx.SpriteProvider;

import javax.script.ScriptEngine;

import jdk.nashorn.api.scripting.JSObject;

import org.lwjgl.opengl.GL11;

/**
 * Implements the "core" module.
 */
public final class CoreModule {

    /**
     * the rectangle
     */
    public final Behavior position;

    /**
     * the rectangle
     */
    public final Behavior rectangle;

    /**
     * the leftRight
     */
    public final Behavior leftRight;

    /**
     * the sprite
     */
    public final Behavior sprite;

    /**
     * Constructor.
     * 
     * @param scriptEngine the Nashorn engine
     */
    public CoreModule(ScriptEngine scriptEngine) {
        try {

            final EventListener positionTransformListener = new EventListener(null, "beforeDraw") {
                @Override
                public void handleEvent(GameObject gameObject, Object payload) {
                    PositionData data = (PositionData) gameObject.get(CoreModule.this.position);
                    GL11.glTranslatef(data.x, data.y, 0.0f);
                }
            };

            position = new Behavior(new Applicator() {
                @Override
                public void apply(GameObject target, Object rawParameters, Behavior behavior) {
                    PositionData data = new PositionData();
                    if (rawParameters != null) {
                        JSObject parameters = (JSObject) jdk.nashorn.api.scripting.ScriptUtils.wrap(rawParameters);
                        if (parameters.getMember("x") instanceof Number) {
                            data.x = ((Number) parameters.getMember("x")).floatValue();
                        }
                        if (parameters.getMember("y") instanceof Number) {
                            data.y = ((Number) parameters.getMember("y")).floatValue();
                        }
                    }
                    target.set(CoreModule.this.position, data);
                    target.addListener(positionTransformListener);
                }
            });

            final EventListener drawRectangleListener = new EventListener(null, "draw") {
                @Override
                public void handleEvent(GameObject gameObject, Object payload) {
                    GL11.glColor4ub((byte) 255, (byte) 255, (byte) 255, (byte) 255);
                    GL11.glBegin(GL11.GL_QUADS);
                    GL11.glVertex2f(1.0f, 1.0f);
                    GL11.glVertex2f(1.0f, -1.0f);
                    GL11.glVertex2f(-1.0f, -1.0f);
                    GL11.glVertex2f(-1.0f, 1.0f);
                    GL11.glEnd();
                }
            };

            rectangle = new Behavior(new Applicator() {
                @Override
                public void apply(GameObject target, Object parameters, Behavior behavior) {
                    target.addListener(drawRectangleListener);
                }
            });

            leftRight = new Behavior(new Applicator() {
                @Override
                public void apply(GameObject target, Object parameters, Behavior behavior) {
                    target.set(leftRight, "left");
                }
            });

            final EventListener drawSpriteListener = new EventListener(null, "draw") {
                @Override
                public void handleEvent(GameObject gameObject, Object payload) {
                    SpriteProvider spriteProvider = (SpriteProvider) gameObject.get(sprite);
                    if (spriteProvider != null) {
                        Sprite sprite = spriteProvider.provideSprite(gameObject);
                        if (sprite != null) {
                            sprite.draw();
                        }
                    }
                }
            };

            sprite = new Behavior(new Applicator() {
                @Override
                public void apply(GameObject target, Object parameters, Behavior behavior) {
                    if (parameters instanceof SpriteProvider) {
                        target.set(sprite, parameters);
                    } else {
                        throw new RuntimeException("invalid sprite provider");
                    }
                    target.addListener(drawSpriteListener);
                }
            });

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Contains the per-object data for the position behavior.
     */
    public static final class PositionData {
        public float x, y;
    }

}