Camera2D.java

/*    Dice in the dark. D & D app for the blind and seeing impaired,
*    Copyright (C) <2013r>  <Lovisa Irpa Helgadottir>
*
*    This program is free software: you can redistribute it and/or modify
*    it under the terms of the GNU General Public License as published by
*    the Free Software Foundation, either version 3 of the License, or
*    (at your option) any later version.
*
*    This program is distributed in the hope that it will be useful,
*    but WITHOUT ANY WARRANTY; without even the implied warranty of
*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*    GNU General Public License for more details.
*
*    You should have received a copy of the GNU General Public License
*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.plovergames.framework.gl;

import javax.microedition.khronos.opengles.GL10;

import com.plovergames.framework.impl.GLGraphics;
import com.plovergames.framework.math.Vector2;

public class Camera2D {
    public final Vector2 position;
    public float zoom;
    public final float frustumWidth;
    public final float frustumHeight;
    final GLGraphics glGraphics;

    public Camera2D(GLGraphics glGraphics, float frustumWidth, float frustumHeight) {
        this.glGraphics = glGraphics;
        this.frustumWidth = frustumWidth;
        this.frustumHeight = frustumHeight;
        this.position = new Vector2(frustumWidth / 2, frustumHeight / 2);
        this.zoom = 1.0f;
    }

    public void setViewportAndMatrices() {
        GL10 gl = glGraphics.getGL();
        gl.glViewport(0, 0, glGraphics.getWidth(), glGraphics.getHeight());
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glOrthof(position.x - frustumWidth * zoom / 2, 
                    position.x + frustumWidth * zoom/ 2, 
                    position.y - frustumHeight * zoom / 2, 
                    position.y + frustumHeight * zoom/ 2, 
                    1, -1);
        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();
    }

    public void touchToWorld(Vector2 touch) {
        touch.x = (touch.x / (float) glGraphics.getWidth()) * frustumWidth * zoom;
        touch.y = (1 - touch.y / (float) glGraphics.getHeight()) * frustumHeight * zoom;
        touch.add(position).sub(frustumWidth * zoom / 2, frustumHeight * zoom / 2);
    }
}