Particle

ParticleRenderer.java

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.util.Random;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import jp.classmethod.komuro.openglsurfaceview.R;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLSurfaceView.Renderer;
import android.opengl.GLUtils;
import android.util.Log;


public class ParticleRenderer implements Renderer {

 
	 // パーティクルを100個生成する
	 public static final int PARTICLE_COUNT = 100;
	 
	 // コンテキスト
	 private Context mContext;
	 
	 private int mWidth;
	 private int mHeight;
	 
	 private Random rand = new Random(System.currentTimeMillis());
	 
	 // パーティクル
	 private Particle[] mParticles = new Particle[PARTICLE_COUNT];
	 private int mParticleTexture;
		 
	 public ParticleRenderer(Context context) {
		 this.mContext = context;
		 
		 for (int i = 0; i < PARTICLE_COUNT; i++) {
			 mParticles[i] = new Particle();
			 mParticles[i].mX = rand.nextFloat() - 0.5f;
			 mParticles[i].mY = rand.nextFloat() - 0.5f;
			 mParticles[i].mSize = rand.nextFloat() * 0.5f;
		 }
	 }
	 
	 public void renderMain(GL10 gl) {
		 // パーティクルをすべて描画する
		 gl.glEnable(GL10.GL_BLEND);
		 gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE);
		 Particle[] particles = mParticles;
		 for (int i = 0; i < PARTICLE_COUNT; i++) {
			 particles[i].draw(gl, mParticleTexture);
		 }
		 gl.glDisable(GL10.GL_BLEND);
	 }

	 public void onDrawFrame(GL10 gl) {
		 
		 gl.glViewport(0, 0, mWidth, mHeight);
		 gl.glMatrixMode(GL10.GL_PROJECTION);
		 
		 gl.glLoadIdentity();
		 gl.glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, 0.5f, -0.5f);
		 gl.glMatrixMode(GL10.GL_MODELVIEW);
		 gl.glLoadIdentity();
		 
		 gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);  // 背景を黒にする
		 gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
		 
		 renderMain(gl);
	 }

	 public void onSurfaceChanged(GL10 gl, int width, int height) {
		 this.mWidth = width;
		 this.mHeight = height;
		 
		 // テクスチャをロードする
		 this.mParticleTexture = loadTexture(gl, mContext.getResources(), R.drawable.ic_launcher);
	 }
	 
	 public int loadTexture(GL10 gl, Resources resource, int drawable) {
		 gl.glEnable(GL10.GL_TEXTURE_2D);
		 int[] buffers = new int[1];
		 gl.glGenTextures(1, buffers, 0);
		 
		 int texture = buffers[0];
		 
		 Bitmap bitmap = BitmapFactory.decodeResource(resource, drawable);
		 
		 // テクスチャ情報の設定
		 gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);
		 GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
		 
		 // Linearアルゴリズムを選択
		 gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
		 gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
		 
		 // Bitmapを破棄
		 bitmap.recycle();
		 
		 return texture;
	 }

	 public void onSurfaceCreated(GL10 gl, EGLConfig config) {
	 // TODO 自動生成されたメソッド・スタブ
	 
	 }

	 public class Particle {
		 
		 public float mX;
		 public float mY;
		 public float mSize;
		 
		 public Particle() {
			 this.mX = 0.0f;
			 this.mY = 0.0f;
			 this.mSize = 1.0f;
		 }
		 
		 
		 public void draw(GL10 gl, int texture) {
			 
			 float[] uv = {
				0.0f, 0.0f,	//左上
				0.0f, 1.0f,	//左下
				1.0f, 0.0f, //右上
				1.0f, 1.0f,	//右下
			 };
			 
			 ByteBuffer byteBuffer = ByteBuffer.allocateDirect(uv.length * 4);	// floatサイズ
			 byteBuffer.order(ByteOrder.nativeOrder());
			 FloatBuffer fb = byteBuffer.asFloatBuffer();
			 fb.put(uv);
			 fb.position(0);
			 
			 gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
			 gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, fb);
			 
			 gl.glColor4f(1.0f, 0f, 0.5f, 0.8f);
			 drawQuad(gl, mX, mY, mSize, mSize);
			 
		 }
		 
		 /**
		  * 描画メソッド
		  * @param gl
		  * @param x
		  * @param y
		  * @param width
		  * @param height
		  */
		 public void drawQuad(GL10 gl, float x, float y, float width, float height) {

Log.d("HOGE", "x : " + x + ", y : " + y + ", width : " + width + ", height : " + height);
			  
//			 float left = ( (float)x / (float)mWidth) * 2.0f - 1.0f;
//			 float top = ( (float)y / (float)mHeight) * 2.0f - 1.0f;
//			 
//			 float right = left + ((float)width / mWidth) * 2.0f;
//			 float bottom = top + ((float)height / mHeight) * 2.0f;

			float left = x;
			float top = y;
			float right = left + width;
			float bottom = top + height;
			 
			 top = -top;
			 bottom = - bottom;
			 
			 float[] positions = {
					 left, top, 0.0f,
					 left, bottom, 0.0f,
					 right, top, 0.0f,
					 right, bottom, 0.0f,
			 };
			 
			 ByteBuffer byteBuffer = ByteBuffer.allocateDirect(positions.length * 4);
			 byteBuffer.order(ByteOrder.nativeOrder());
			 FloatBuffer fb = byteBuffer.asFloatBuffer();
			 fb.put(positions);
			 fb.position(0);
			 
			 gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
			 gl.glVertexPointer(3, GL10.GL_FLOAT, 0, fb);
			 
			 gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
		 }
	}
}