From f69787bd236473ec8b828854809dc04f403bcb87 Mon Sep 17 00:00:00 2001
From: Billy Lindeman <billy@lava.io>
Date: Mon, 20 Oct 2014 17:03:35 -0400
Subject: [PATCH] Basic physics updating is completed; Only draws black squares
 for now, but animation is happening in a Transparent OpenGL layer

---
 build.gradle                                  |   1 +
 dust-sample/dust-sample.iml                   |   8 +-
 .../dust/sample/DustActivity.java             |   9 +-
 .../src/main/res/layout/activity_dust.xml     |  15 +--
 dust-sample/src/main/res/raw/confetti.pex     |   4 +-
 dust/build.gradle                             |   8 ++
 dust/dust.iml                                 |   8 +-
 .../dust/layer/GLParticleLayer.java           |  96 ++++++++++++++
 .../dust/layer/ParticleLayer.java             |  25 ----
 .../billylindeman/dust/layer/Rectangle.java   |  50 +++++++
 .../billylindeman/dust/particle/Emitter.java  | 122 +++++++++++++++++-
 .../dust/particle/EmitterConfig.java          |  11 +-
 .../billylindeman/dust/particle/Particle.java |  69 ++++++++--
 .../com/billylindeman/dust/util/Color.java    |  14 +-
 .../com/billylindeman/dust/util/Vector2.java  |  38 ++++++
 15 files changed, 405 insertions(+), 73 deletions(-)
 delete mode 100644 dust/src/main/java/com/billylindeman/dust/layer/ParticleLayer.java
 create mode 100644 dust/src/main/java/com/billylindeman/dust/layer/Rectangle.java
 create mode 100644 dust/src/main/java/com/billylindeman/dust/util/Vector2.java

diff --git a/build.gradle b/build.gradle
index 9b8abe4..c0cfcda 100644
--- a/build.gradle
+++ b/build.gradle
@@ -15,5 +15,6 @@ buildscript {
 allprojects {
     repositories {
         jcenter()
+        mavenCentral();
     }
 }
diff --git a/dust-sample/dust-sample.iml b/dust-sample/dust-sample.iml
index b60e572..fbd5b39 100644
--- a/dust-sample/dust-sample.iml
+++ b/dust-sample/dust-sample.iml
@@ -13,6 +13,7 @@
         <option name="COMPILE_JAVA_TASK_NAME" value="compileDebugJava" />
         <option name="ASSEMBLE_TEST_TASK_NAME" value="assembleDebugTest" />
         <option name="SOURCE_GEN_TASK_NAME" value="generateDebugSources" />
+        <option name="TEST_SOURCE_GEN_TASK_NAME" value="generateDebugTestSources" />
         <option name="ALLOW_USER_CONFIGURATION" value="false" />
         <option name="MANIFEST_FILE_RELATIVE_PATH" value="/src/main/AndroidManifest.xml" />
         <option name="RES_FOLDER_RELATIVE_PATH" value="/src/main/res" />
@@ -37,22 +38,22 @@
       <sourceFolder url="file://$MODULE_DIR$/build/generated/res/rs/test/debug" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/resources" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/aidl" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/jni" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/rs" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/main/assets" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/aidl" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/src/main/assets" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/jni" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/rs" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/res" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/resources" type="java-test-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/assets" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/aidl" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/assets" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/java" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/jni" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/rs" isTestSource="true" />
@@ -79,6 +80,7 @@
     </content>
     <orderEntry type="jdk" jdkName="Android API 19 Platform" jdkType="Android SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" exported="" name="sanselan-0.97-incubator" level="project" />
     <orderEntry type="module" module-name="dust" exported="" />
   </component>
 </module>
diff --git a/dust-sample/src/main/java/com/billylindeman/dust/sample/DustActivity.java b/dust-sample/src/main/java/com/billylindeman/dust/sample/DustActivity.java
index 9be3cca..07668bf 100644
--- a/dust-sample/src/main/java/com/billylindeman/dust/sample/DustActivity.java
+++ b/dust-sample/src/main/java/com/billylindeman/dust/sample/DustActivity.java
@@ -4,8 +4,8 @@
 import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuItem;
-import android.widget.ImageView;
 
+import com.billylindeman.dust.layer.GLParticleLayer;
 import com.billylindeman.dust.particle.Emitter;
 import com.billylindeman.dust.particle.EmitterConfig;
 
@@ -19,9 +19,12 @@ protected void onCreate(Bundle savedInstanceState) {
 
         EmitterConfig config = EmitterConfig.fromStream(getResources().openRawResource(R.raw.confetti));
         Emitter e = new Emitter(config);
+        e.reset();
+
+
+        GLParticleLayer layer = (GLParticleLayer)findViewById(R.id.gl_particle_layer);
+        layer.addEmitter(e);
 
-        ImageView imageView = (ImageView)findViewById(R.id.imageview);
-        imageView.setImageBitmap(config.texture);
     }
 
 
diff --git a/dust-sample/src/main/res/layout/activity_dust.xml b/dust-sample/src/main/res/layout/activity_dust.xml
index 26d3d3a..15ff4b8 100644
--- a/dust-sample/src/main/res/layout/activity_dust.xml
+++ b/dust-sample/src/main/res/layout/activity_dust.xml
@@ -2,16 +2,13 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:paddingLeft="@dimen/activity_horizontal_margin"
-    android:paddingRight="@dimen/activity_horizontal_margin"
-    android:paddingTop="@dimen/activity_vertical_margin"
-    android:paddingBottom="@dimen/activity_vertical_margin"
-    android:background="@android:color/black"
+    android:background="@android:color/holo_green_dark"
     tools:context=".DustActivity">
 
-    <ImageView
-        android:id="@+id/imageview"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content" />
+
+    <com.billylindeman.dust.layer.GLParticleLayer
+        android:id="@+id/gl_particle_layer"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
 
 </RelativeLayout>
diff --git a/dust-sample/src/main/res/raw/confetti.pex b/dust-sample/src/main/res/raw/confetti.pex
index 705ac2e..a8f806a 100644
--- a/dust-sample/src/main/res/raw/confetti.pex
+++ b/dust-sample/src/main/res/raw/confetti.pex
@@ -2,7 +2,7 @@
 <particleEmitterConfig>
     <absolutePosition value="0"></absolutePosition>
     <yCoordFlipped value="1"></yCoordFlipped>
-    <sourcePosition x="150.00" y="50.00"></sourcePosition>
+    <sourcePosition x="180.00" y="480.00"></sourcePosition>
     <sourcePositionVariance x="180.00" y="7.00"></sourcePositionVariance>
     <speed value="0.00"></speed>
     <speedVariance value="30.00"></speedVariance>
@@ -19,7 +19,7 @@
     <startColorVariance red="1.00" green="1.00" blue="1.00" alpha="1.00"></startColorVariance>
     <finishColor red="1.00" green="1.00" blue="1.00" alpha="1.00"></finishColor>
     <finishColorVariance red="1.00" green="1.00" blue="1.00" alpha="1.00"></finishColorVariance>
-    <maxParticles value="2000"></maxParticles>
+    <maxParticles value="600"></maxParticles>
     <startParticleSize value="12.00"></startParticleSize>
     <startParticleSizeVariance value="0.00"></startParticleSizeVariance>
     <finishParticleSize value="12.00"></finishParticleSize>
diff --git a/dust/build.gradle b/dust/build.gradle
index ec21fc6..60e0503 100644
--- a/dust/build.gradle
+++ b/dust/build.gradle
@@ -21,4 +21,12 @@ android {
 
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
+    compile "org.apache.sanselan:sanselan:0.97-incubator"
 }
+
+
+buildscript{
+    repositories{
+        mavenCentral()
+    }
+}
\ No newline at end of file
diff --git a/dust/dust.iml b/dust/dust.iml
index 5f4f7a0..7bda1b8 100644
--- a/dust/dust.iml
+++ b/dust/dust.iml
@@ -13,6 +13,7 @@
         <option name="COMPILE_JAVA_TASK_NAME" value="compileDebugJava" />
         <option name="ASSEMBLE_TEST_TASK_NAME" value="assembleDebugTest" />
         <option name="SOURCE_GEN_TASK_NAME" value="generateDebugSources" />
+        <option name="TEST_SOURCE_GEN_TASK_NAME" value="generateDebugTestSources" />
         <option name="ALLOW_USER_CONFIGURATION" value="false" />
         <option name="MANIFEST_FILE_RELATIVE_PATH" value="/src/main/AndroidManifest.xml" />
         <option name="RES_FOLDER_RELATIVE_PATH" value="/src/main/res" />
@@ -38,22 +39,22 @@
       <sourceFolder url="file://$MODULE_DIR$/build/generated/res/rs/test/debug" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/resources" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/aidl" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/jni" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/debug/rs" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/res" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/main/assets" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/aidl" isTestSource="false" />
-      <sourceFolder url="file://$MODULE_DIR$/src/main/assets" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/jni" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/main/rs" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/res" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/resources" type="java-test-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/assets" type="java-test-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/aidl" isTestSource="true" />
-      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/assets" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/java" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/jni" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/src/androidTest/rs" isTestSource="true" />
@@ -81,6 +82,7 @@
     </content>
     <orderEntry type="jdk" jdkName="Android API 19 Platform" jdkType="Android SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" exported="" name="sanselan-0.97-incubator" level="project" />
   </component>
 </module>
 
diff --git a/dust/src/main/java/com/billylindeman/dust/layer/GLParticleLayer.java b/dust/src/main/java/com/billylindeman/dust/layer/GLParticleLayer.java
index 6fb0f9a..57c8c80 100644
--- a/dust/src/main/java/com/billylindeman/dust/layer/GLParticleLayer.java
+++ b/dust/src/main/java/com/billylindeman/dust/layer/GLParticleLayer.java
@@ -1,19 +1,115 @@
 package com.billylindeman.dust.layer;
 
 import android.content.Context;
+import android.graphics.PixelFormat;
 import android.opengl.GLSurfaceView;
+import android.os.SystemClock;
 import android.util.AttributeSet;
 
+import com.billylindeman.dust.particle.Emitter;
+import com.billylindeman.dust.particle.Particle;
+
+import java.util.ArrayList;
+
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
 /**
  *
  */
 public class GLParticleLayer extends GLSurfaceView {
+    ParticleRenderer particleRenderer;
+
     public GLParticleLayer(Context context) {
         super(context);
+        init();
     }
 
     public GLParticleLayer(Context context, AttributeSet attrs) {
         super(context, attrs);
+        init();
+    }
+
+    private void init() {
+        setZOrderOnTop(true);
+        setEGLConfigChooser(8, 8, 8, 8, 16, 0);
+        getHolder().setFormat(PixelFormat.RGBA_8888);
+
+        particleRenderer = new ParticleRenderer();
+        setRenderer(particleRenderer);
+
+        setRenderMode(RENDERMODE_CONTINUOUSLY);
+    }
+
+    public void addEmitter(final Emitter e) {
+        queueEvent(new Runnable() {
+            @Override
+            public void run() {
+                particleRenderer.addEmitter(e);
+            }
+        });
+    }
+
+
+    class ParticleRenderer implements Renderer {
+        ArrayList<Emitter> emitters = new ArrayList<Emitter>();
+        long lastFrame = SystemClock.elapsedRealtime();
+
+        Rectangle r = new Rectangle();
+
+        @Override
+        public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
+
+        }
+
+        @Override
+        public void onSurfaceChanged(GL10 gl, int w, int h) {
+            gl.glViewport(0, 0, w, h);
+            gl.glOrthof(0,360,0,480,0,1);
+        }
+
+        @Override
+        public void onDrawFrame(GL10 gl) {
+            gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
+
+            if(emitters != null) {
+                float delta = getFrameDeltaTime();
+                for(Emitter emitter : emitters) {
+                    emitter.updateWithDelta(delta);
+                    drawParticlesForEmitter(gl, emitter);
+                }
+            }
+
+        }
+
+        public void addEmitter(Emitter e) {
+            emitters.add(e);
+
+        }
+
+        private float getFrameDeltaTime() {
+            long frameTime = SystemClock.elapsedRealtime();
+            float delta = ((float)frameTime - (float)lastFrame) / 1000;
+            lastFrame = frameTime;
+            return delta;
+        }
+
+        private void drawParticlesForEmitter(GL10 gl, Emitter e) {
+            int count = e.getParticleCount();
+            Particle[] particles = e.getParticles();
+
+            for(int i=0; i<count ; i++) {
+                Particle p = particles[i];
+                gl.glPushMatrix();
+                gl.glTranslatef(p.position.x,p.position.y,0);
+                gl.glColor4f(p.color.r,p.color.g,p.color.b,1.0f);
+                gl.glScalef(p.particleSize,p.particleSize,0);
+                r.draw(gl);
+                gl.glPopMatrix();
+
+            }
+        }
+
     }
 
 
diff --git a/dust/src/main/java/com/billylindeman/dust/layer/ParticleLayer.java b/dust/src/main/java/com/billylindeman/dust/layer/ParticleLayer.java
deleted file mode 100644
index 22733fd..0000000
--- a/dust/src/main/java/com/billylindeman/dust/layer/ParticleLayer.java
+++ /dev/null
@@ -1,25 +0,0 @@
-package com.billylindeman.dust.layer;
-
-import android.content.Context;
-import android.util.AttributeSet;
-import android.view.View;
-
-/**
- * Particle Layer using plain old android views
- */
-public class ParticleLayer extends View{
-    public ParticleLayer(Context context) {
-        super(context);
-    }
-
-    public ParticleLayer(Context context, AttributeSet attrs) {
-        super(context, attrs);
-    }
-
-    public ParticleLayer(Context context, AttributeSet attrs, int defStyleAttr) {
-        super(context, attrs, defStyleAttr);
-    }
-
-
-
-}
diff --git a/dust/src/main/java/com/billylindeman/dust/layer/Rectangle.java b/dust/src/main/java/com/billylindeman/dust/layer/Rectangle.java
new file mode 100644
index 0000000..e1a0b2d
--- /dev/null
+++ b/dust/src/main/java/com/billylindeman/dust/layer/Rectangle.java
@@ -0,0 +1,50 @@
+package com.billylindeman.dust.layer;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+import java.nio.ShortBuffer;
+
+import javax.microedition.khronos.opengles.GL10;
+
+public class Rectangle {
+
+    private float vertices[]={
+            -1.0f, 1.0f, 0.0f,
+            -1.0f,-1.0f,0.0f,
+            1.0f,-1.0f,0.0f,
+            1.0f,1.0f,0.0f
+    };
+
+
+    private short[] indices = {0,1,2,0,2,3};
+
+    private FloatBuffer vertexBuffer;
+    private ShortBuffer indexBuffer;
+
+    public Rectangle(){
+        ByteBuffer vbb  = ByteBuffer.allocateDirect(vertices.length * 4);
+        vbb.order(ByteOrder.nativeOrder());
+        vertexBuffer = vbb.asFloatBuffer();
+        vertexBuffer.put(vertices);
+        vertexBuffer.position(0);
+
+        ByteBuffer ibb = ByteBuffer.allocateDirect(indices.length * 2);
+        ibb.order(ByteOrder.nativeOrder());
+        indexBuffer = ibb.asShortBuffer();
+        indexBuffer.put(indices);
+        indexBuffer.position(0);
+    }
+
+    public void draw(GL10 gl){
+        gl.glFrontFace(GL10.GL_CCW);
+        gl.glEnable(GL10.GL_CULL_FACE);
+        gl.glCullFace(GL10.GL_BACK);
+        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
+        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
+        gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_SHORT, indexBuffer);
+        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
+        gl.glDisable(GL10.GL_CULL_FACE);
+    }
+
+}
\ No newline at end of file
diff --git a/dust/src/main/java/com/billylindeman/dust/particle/Emitter.java b/dust/src/main/java/com/billylindeman/dust/particle/Emitter.java
index 6416628..cd3be97 100644
--- a/dust/src/main/java/com/billylindeman/dust/particle/Emitter.java
+++ b/dust/src/main/java/com/billylindeman/dust/particle/Emitter.java
@@ -1,9 +1,14 @@
 package com.billylindeman.dust.particle;
 
+import com.billylindeman.dust.util.Vector2;
+
 /**
  * This is a particle emitter class
  */
 public class Emitter {
+    public final int kParticleTypeGravity = 0;
+    public final int kParticleTypeRadial = 1;
+
     EmitterConfig config;
 
 
@@ -19,18 +24,24 @@ public class Emitter {
     public Emitter(EmitterConfig c){
         config = c;
 
-        emissionRate = config.maxParticles / config.particleLifespan;
+        particles = new Particle[config.maxParticles];
+        for(int i=0; i<config.maxParticles; i++) {
+            particles[i] = new Particle(config);
+        }
+
+        emissionRate = (float)config.maxParticles / config.particleLifespan;
         emitCounter = 0;
+        active = true;
+
     }
 
-    public void updateWithDelta(float delta) {
+    public synchronized void updateWithDelta(float delta) {
         if(active && emissionRate > 0) {
             float rate = 1.0f / emissionRate;
 
             if(particleCount < config.maxParticles) {
                 emitCounter += delta;
             }
-
             while(particleCount < config.maxParticles && emitCounter > rate) {
                 addParticle();
                 emitCounter -= rate;
@@ -43,19 +54,118 @@ public void updateWithDelta(float delta) {
         }
 
         particleIndex = 0;
-
         while(particleIndex < particleCount) {
+            Particle particle = particles[particleIndex];
+
+            particle.timeToLive -= delta;
+
+            /** If particle is still alive, lets update it */
+            if(particle.timeToLive > 0) {
+
+                /** Update positions based on emitter type*/
+                if(config.emitterType == kParticleTypeRadial) {
+                    particle.angle += particle.degreesPerSecond*delta;
+                    particle.radius += particle.radiusDelta*delta;
+
+                    /** update position */
+                    particle.position.x = config.sourcePosition.x - (float)Math.cos((float)particle.angle) * particle.radius;
+                    particle.position.y = config.sourcePosition.y - (float)Math.sin((float)particle.angle) * particle.radius;
+
+                }else if (config.emitterType == kParticleTypeGravity) {
+                    Vector2 tmp, radial,tangential;
+
+                    radial = new Vector2(0,0);
+
+                    Vector2 positionDifference = Vector2.subtract(particle.startPos, new Vector2());
+                    particle.position = Vector2.subtract(particle.position, positionDifference);
+
+                    if(particle.position.x != 0 || particle.position.y != 0) {
+                        radial = Vector2.normalize(particle.position);
+                    }
+
+                    tangential = radial;
+                    radial = Vector2.multiplyScalar(radial, particle.radialAcceleration);
+                    float newy = tangential.x;
+                    tangential.x = -tangential.y;
+                    tangential.y = newy;
+                    tangential = Vector2.multiplyScalar(tangential, particle.tangentialAcceleration);
+
+                    tmp = Vector2.add(Vector2.add(radial,tangential), config.gravity);
+                    tmp = Vector2.multiplyScalar(tmp, delta);
+                    particle.direction = Vector2.add(particle.direction, tmp);
+                    tmp  = Vector2.multiplyScalar(particle.direction, delta);
+
+                    particle.position = Vector2.add(particle.position, tmp);
+                    particle.position = Vector2.add(particle.position, positionDifference);
+                }
+
+                /** update particles color */
+                particle.color.r += particle.deltaColor.r * delta;
+                particle.color.g += particle.deltaColor.g * delta;
+                particle.color.b += particle.deltaColor.b * delta;
+                particle.color.a += particle.deltaColor.a * delta;
+
+                /** update particle size */
+                particle.particleSize += particle.particleSizeDelta * delta;
+                particle.particleSize = Math.max(0, particle.particleSize);
+
+                /** update rotation */
+                particle.rotation += particle.rotationDelta *delta;
+
+                particleIndex++;
+            }else {
+                /** particle is dead */
+                if(particleIndex != particleCount -1) {
+                    /** swap this particle with the last particle alive in our alive count
+                     * this keeps our particles[] array packed with alive particles first
+                     */
+                    Particle lastAlive = particles[particleCount -1];
+                    Particle thisParticle = particles[particleIndex];
+                    particles[particleIndex] = lastAlive;
+                    particles[particleCount-1] = thisParticle;
+                }
+                particleCount--;
+            }
+
+        }
+
+    }
 
+    private synchronized boolean addParticle() {
+        if(particleCount == config.maxParticles) {
+            return false;
         }
 
+        Particle p = particles[particleCount];
+        p.init();
+
+        particleCount++;
+        return true;
     }
 
-    private void addParticle() {
+    public synchronized void stopEmission() {
+        active = false;
+        elapsedTime = 0;
+        emitCounter = 0;
+    }
 
+    public synchronized void reset() {
+        active = true;
+        elapsedTime =0;
+        for(int i=0; i<particleCount; i++) {
+            particles[i].init();
+            particles[i].timeToLive = 0;
+        }
+        emitCounter = 0;
+        emissionRate = (float)config.maxParticles / config.particleLifespan;
     }
 
-    public void stopEmission() {
+    public Particle[] getParticles() {
+        return particles;
+    }
 
+    public int getParticleCount() {
+        return particleCount;
     }
 
 }
diff --git a/dust/src/main/java/com/billylindeman/dust/particle/EmitterConfig.java b/dust/src/main/java/com/billylindeman/dust/particle/EmitterConfig.java
index f105910..3f32ee0 100644
--- a/dust/src/main/java/com/billylindeman/dust/particle/EmitterConfig.java
+++ b/dust/src/main/java/com/billylindeman/dust/particle/EmitterConfig.java
@@ -2,11 +2,11 @@
 
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
-import android.graphics.PointF;
 import android.util.Base64;
 import android.util.Log;
 
 import com.billylindeman.dust.util.Color;
+import com.billylindeman.dust.util.Vector2;
 
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -27,12 +27,12 @@ public class EmitterConfig {
 
     public Bitmap texture;
 
-    PointF sourcePosition, sourcePositionVariance;
+    Vector2 sourcePosition, sourcePositionVariance;
     float angle, angleVariance;
     float speed, speedVariance;
     float radialAcceleration, tangentialAcceleration;
     float radialAccelVariance, tangentialAccelVariance;
-    PointF gravity;
+    Vector2 gravity;
     float particleLifespan, particleLifespanVariance;
 
     Color startColor, startColorVariance;
@@ -139,12 +139,12 @@ private boolean parseBooleanValueForElement(Document doc, String name) {
         return Boolean.parseBoolean(element.getAttribute("value"));
     }
 
-    private PointF parsePointValueForElement(Document doc, String name) {
+    private Vector2 parsePointValueForElement(Document doc, String name) {
         NodeList elements = doc.getElementsByTagName(name);
         Element element = (Element)elements.item(0);
         float x = Float.parseFloat(element.getAttribute("x"));
         float y = Float.parseFloat(element.getAttribute("y"));
-        return new PointF(x,y);
+        return new Vector2(x,y);
     }
 
     /**
@@ -159,6 +159,7 @@ private Bitmap parseBase64GzippedTextureFromDocument(Document doc) throws Except
 
         byte[] compressedImageBytes = Base64.decode(base64Data, Base64.DEFAULT);
         GZIPInputStream decrompressionStream = new GZIPInputStream(new ByteArrayInputStream(compressedImageBytes));
+
         return BitmapFactory.decodeStream(decrompressionStream);
     }
 
diff --git a/dust/src/main/java/com/billylindeman/dust/particle/Particle.java b/dust/src/main/java/com/billylindeman/dust/particle/Particle.java
index 6c21024..46a0052 100644
--- a/dust/src/main/java/com/billylindeman/dust/particle/Particle.java
+++ b/dust/src/main/java/com/billylindeman/dust/particle/Particle.java
@@ -1,6 +1,7 @@
 package com.billylindeman.dust.particle;
 
-import android.graphics.PointF;
+import com.billylindeman.dust.util.Color;
+import com.billylindeman.dust.util.Vector2;
 
 import java.util.Random;
 
@@ -10,21 +11,20 @@
 public class Particle {
     static Random r = new Random();
 
-
     private EmitterConfig config;
 
-    public PointF position;
-    public PointF direction;
-    public PointF startPos;
-    public int color;
-    public int deltaColor;
+    public Vector2 position = new Vector2();
+    public Vector2 direction = new Vector2();
+    public Vector2 startPos = new Vector2();
+    public Color color;
+    public Color deltaColor;
     public float rotation;
     public float rotationDelta;
     public float radialAcceleration;
     public float tangentialAcceleration;
     public float radius;
     public float radiusDelta;
-    public float angle;
+    public double angle;
     public float degreesPerSecond;
     public float particleSize;
     public float particleSizeDelta;
@@ -44,9 +44,58 @@ public void init() {
 
 
         //Init the direction of particle
-        angle = config.angle + config.angleVariance * randomMinusOneToOne();
+        float newAngle = config.angle + config.angleVariance * randomMinusOneToOne();
+
+        Vector2 vector = new Vector2((float)Math.cos(newAngle),(float)Math.sin(newAngle));
+        float vectorSpeed = config.speed + config.speedVariance * randomMinusOneToOne();
+
+        // calculate direction from angle'd vector multiplied by scalar speed
+        direction = Vector2.multiplyScalar(vector, vectorSpeed);
+
+        timeToLive = Math.max(0, config.particleLifespan + config.particleLifespanVariance*randomMinusOneToOne());
+
+        float startRadius = config.maxRadius + config.maxRadiusVariance*randomMinusOneToOne();
+        float endRadius = config.minRadius + config.minRadiusVariance * randomMinusOneToOne();
+
+        radius = startRadius;
+        radiusDelta = (endRadius - startRadius) / timeToLive;
+        angle = config.angle + config.angleVariance*randomMinusOneToOne();
+        degreesPerSecond = config.rotatePerSecond + config.rotatePerSecondVariance*randomMinusOneToOne();
+
+        radialAcceleration = config.radialAcceleration+config.radialAccelVariance*randomMinusOneToOne();
+        tangentialAcceleration = config.tangentialAcceleration + config.tangentialAccelVariance*randomMinusOneToOne();
+
+        float particleStartSize = config.startParticleSize + config.startParticleSizeVariance*randomMinusOneToOne();
+        float particleFinishSize = config.finishParticleSize + config.finishParticleSizeVariance*randomMinusOneToOne();
+        particleSize = Math.max(0, particleStartSize);
+        particleSizeDelta = ((particleFinishSize - particleStartSize) / timeToLive);
+
+
+        Color startColor = new Color();
+        startColor.r = config.startColor.r + config.startColorVariance.r*randomMinusOneToOne();
+        startColor.g = config.startColor.g + config.startColorVariance.g*randomMinusOneToOne();
+        startColor.b = config.startColor.b + config.startColorVariance.b*randomMinusOneToOne();
+        startColor.a = config.startColor.a + config.startColorVariance.a*randomMinusOneToOne();
+
+        Color endColor = new Color();
+        endColor.r = config.finishColor.r + config.finishColorVariance.r*randomMinusOneToOne();
+        endColor.g = config.finishColor.g + config.finishColorVariance.g*randomMinusOneToOne();
+        endColor.b = config.finishColor.b + config.finishColorVariance.b*randomMinusOneToOne();
+        endColor.a = config.finishColor.a + config.finishColorVariance.a*randomMinusOneToOne();
+
+        color = startColor;
+        deltaColor = new Color();
+        deltaColor.r = ((endColor.r - startColor.r) / timeToLive);
+        deltaColor.g = ((endColor.g - startColor.g) / timeToLive);
+        deltaColor.b = ((endColor.b - startColor.b) / timeToLive);
+        deltaColor.a = ((endColor.a - startColor.a) / timeToLive);
+
+
+        float startA = config.rotationStart + config.rotationStartVariance*randomMinusOneToOne();
+        float endA = config.rotationEnd + config.rotationEndVariance*randomMinusOneToOne();
 
-        PointF vector = new PointF()
+        rotation=startA;
+        rotationDelta = (endA - startA) / timeToLive;
 
     }
 
diff --git a/dust/src/main/java/com/billylindeman/dust/util/Color.java b/dust/src/main/java/com/billylindeman/dust/util/Color.java
index 31bf449..8091746 100644
--- a/dust/src/main/java/com/billylindeman/dust/util/Color.java
+++ b/dust/src/main/java/com/billylindeman/dust/util/Color.java
@@ -4,10 +4,10 @@
  *
  */
 public class Color {
-    byte red;
-    byte green;
-    byte blue;
-    byte alpha;
+    public float r;
+    public float g;
+    public float b;
+    public float a;
 
     public Color() {
 
@@ -18,8 +18,8 @@ public Color(float red, float green, float blue, float alpha) {
     }
 
 
-    public int getPacked() {
-        return (alpha << 24) | (red << 16) | (green << 8) | blue;
-    }
+//    public int getPacked() {
+//        return (alpha << 24) | (red << 16) | (green << 8) | blue;
+//    }
 
 }
diff --git a/dust/src/main/java/com/billylindeman/dust/util/Vector2.java b/dust/src/main/java/com/billylindeman/dust/util/Vector2.java
new file mode 100644
index 0000000..f7f708d
--- /dev/null
+++ b/dust/src/main/java/com/billylindeman/dust/util/Vector2.java
@@ -0,0 +1,38 @@
+package com.billylindeman.dust.util;
+
+/**
+ *
+ */
+public class Vector2 {
+    public float x = 0;
+    public float y = 0;
+
+    public Vector2() {}
+    public Vector2(float x, float y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public float length() {
+        double x= this.x;
+        double y = this.y;
+        return (float)Math.sqrt(x*x +y*y);
+    }
+
+    public static Vector2 normalize(Vector2 in) {
+        float scale = 1.0f / in.length();
+        return new Vector2(in.x*scale, in.y*scale);
+    }
+
+    public static Vector2 multiplyScalar(Vector2 vec, float scalar) {
+        return new Vector2(vec.x*scalar, vec.y*scalar);
+    }
+
+    public static Vector2 subtract(Vector2 left, Vector2 right) {
+        return new Vector2(left.x-right.x,left.y-right.y);
+    }
+
+    public static Vector2 add(Vector2 left, Vector2 right) {
+        return new Vector2(left.x+right.x,left.y+right.y);
+    }
+}