com.sturdyhelmetgames.dodgethecars.screen.TransitionScreen.java Source code

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Here is the source code for com.sturdyhelmetgames.dodgethecars.screen.TransitionScreen.java

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/*
 * Copyright 2012 Antti Kolehmainen
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.sturdyhelmetgames.dodgethecars.screen;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
import com.sturdyhelmetgames.dodgethecars.DodgeTheCarsGame;

/**
 * Screen that supports simple transitions.
 * 
 * @author Antti 28.6.2012
 * 
 */
public abstract class TransitionScreen extends BasicScreen {

    protected float screenTime;
    private float fadeAlpha = 1f;
    protected Color transitionColor = new Color();
    private final ShapeRenderer renderer = new ShapeRenderer();

    private static final float FADE_OUT_START_TIME = 4f;

    public TransitionScreen(DodgeTheCarsGame game) {
        super(game);
    }

    @Override
    protected void updateScreen(float fixedStep) {
        screenTime += fixedStep;
    }

    @Override
    public void renderScreen(float delta) {
        renderFadeIn(delta);
        renderFadeOut(delta);
    }

    /**
     * Renders fade in transition.
     * 
     * @param delta
     *            delta time
     */
    protected void renderFadeIn(float delta) {
        // a simple fade in transition
        if (screenTime > -1f && screenTime < 0.99f) {
            transitionColor.set(0f, 0f, 0f, fadeAlpha -= delta);

            Gdx.gl.glEnable(GL20.GL_BLEND);
            renderer.begin(ShapeType.FilledRectangle);
            renderer.filledRect(0f, 0f, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), transitionColor,
                    transitionColor, transitionColor, transitionColor);
            renderer.end();
            Gdx.gl.glDisable(GL20.GL_BLEND);
        }
    }

    /**
     * Renders fade out transition.
     * 
     * @param delta
     *            delta time
     */
    protected void renderFadeOut(float delta) {
        if (screenTime > FADE_OUT_START_TIME) {
            transitionColor.set(0f, 0f, 0f, fadeAlpha += delta);

            Gdx.gl.glEnable(GL20.GL_BLEND);
            renderer.begin(ShapeType.FilledRectangle);
            renderer.filledRect(0f, 0f, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), transitionColor,
                    transitionColor, transitionColor, transitionColor);
            renderer.end();
            Gdx.gl.glDisable(GL20.GL_BLEND);
        }
    }

    @Override
    public void dispose() {
        super.dispose();
        renderer.dispose();
    }

}