evil-inside/src/ei/engine/scene/Sprite.java

package ei.engine.scene;

import java.io.IOException;

import org.lwjgl.opengl.GL11;

import ei.engine.texture.Texture;
import ei.engine.texture.TextureLoader;

/**
 * Implementation of sprite that uses an OpenGL quad and a texture
 * to render a given image to the screen.
 * 
 * @author Kevin Glass
 * @author Brian Matzon
 * @author Ziver Koc
 */
public class Sprite extends Entity {
	/** The texture that stores the image for this sprite */
	private Texture texture;
	
	/**
	 * Create a new empty sprite
	 * 
	 * @param window The window in which the sprite will be displayed
	 * @param ref A reference to the image on which this sprite should be based
	 */
	public Sprite(String name) {
		super(name);		
		texture = null;			
	}
	
	/**
	 * Create a new sprite from a specified texture.
	 * 
	 * @param name The name of the sprite
	 * @param texture The texture to use
	 */
	public Sprite(String name, Texture texture) {
		super(name);
		this.texture = texture;			
	}
	
	/**
	 * Create a new sprite from a specified image.
	 * 
	 * @param name The name of the sprite
	 * @param ref A reference to the image on which this sprite should be based
	 */
	public Sprite(String name, String ref) {
		super(name);
		try {
			this.texture = TextureLoader.getTextureLoaderInstance().getTexture(ref);
		
		} catch (IOException e) {
			// a tad abrupt, but our purposes if you can't find a 
			// sprite's image you might as well give up.
			System.err.println("Unable to load texture: "+ref);
			System.exit(0);
		}
	}
	
	/**
	 * Get the width of this sprite in pixels
	 * 
	 * @return The width of this sprite in pixels
	 */
	public int getWidth() {
		if(texture == null){
			return 0;
		}
		return texture.getImageWidth();
	}

	/**
	 * Get the height of this sprite in pixels
	 * 
	 * @return The height of this sprite in pixels
	 */
	public int getHeight() {
		if(texture == null){
			return 0;
		}
		return texture.getImageHeight();
	}
	
	/**
	 * Draw the sprite
	 */
	public void render() {
		// store the current model matrix
		GL11.glPushMatrix();

		// bind to the appropriate texture for this sprite
		texture.bind();

		// translate to the right location and prepare to draw
		GL11.glTranslatef((int)getLocation().getX(), (int)getLocation().getY(), 0);		
		GL11.glColor3f(1,1,1);

		// draw a quad textured to match the sprite
		GL11.glBegin(GL11.GL_QUADS);
		{
			GL11.glTexCoord2f(0, 0);
			GL11.glVertex2f(0, 0);
			GL11.glTexCoord2f(0, texture.getHeight());
			GL11.glVertex2f(0, texture.getImageHeight());
			GL11.glTexCoord2f(texture.getWidth(), texture.getHeight());
			GL11.glVertex2f(texture.getImageWidth(),texture.getImageHeight());
			GL11.glTexCoord2f(texture.getWidth(), 0);
			GL11.glVertex2f(texture.getImageWidth(),0);
		}
		GL11.glEnd();

		// restore the model view matrix to prevent contamination
		GL11.glPopMatrix();
	}
	
}