Ripple Effect

[siddharth3322]

I was developing tower of defense game for a long time.
It was about to complete but I have to create ripple effect for one of the weapon that I have used.

I don't able to think what I have to do for ripple effect that affect enemy wave.

So anybody have an idea then please share with me.

Thank for your kind support.

[thepi]

gles2-shaderprograms/ripple-shader-t6150.html

EDIT: Sorry, I missed (again ) this is GLES1. I believe shaders work on GLES2 only.

[ViktorS]

I believe this question was asked on this forum several times, and I have never seen it resolved. It's just too much trouble for anyone to actually bother with this. Even though it should be possible by the means of OpenGL. The implementations I've seen of this for android using OpenGL ES1, were not good enough to bother to port for andengine. So please kindly rethink this choice. Even if you do manage to port it, I'm quite sure extensive rippling effects will lag as hell.

[Siddharth]

http://www.andengine.org/forums/gles2-shaderprograms/ripple-shader-t6150.html

EDIT: Sorry, I missed (again ) this is GLES1. I believe shaders work on GLES2 only.

If I port my game to GLES2 then this suggested example work for as weapon effect or not?
I was ready to convert my game into GLES2.

Please suggest me on this.

[ViktorS]

Well if you don't mind ditching all gles2 incapable devices, I don't see why not.

[Siddharth]

I have created a ripple effect based on above suggestion.
But it was in live wall paper.

So I want to ask that is it possible that I can create same effect in normal activity?
And also is it feasible to apply ripple effect for weapon?

I was not able to understand many things from it. If any one has some knowledge on this then please provide.

I was developing another tower of defence type game.

[Siddharth]

I finally decide to set as bounty to this question.
I hope I get some useful outcome from this and I definitely share this thing with you guys.

http://gamedev.stackexchange.com/questions/48973/programmatically-and-efficiently-create-a-graphical-ripple-effect

[thepi]

I successfully used this shader with a GLES2 game. If you're interested exactly how, I'll have to dig a little bit, since it was a while ago.
It is true however, it dramatically reduces fps, so I suggest for an action game like defense, better use animated ripple sprite.

[siddharth3322]

I successfully used this shader with a GLES2 game. If you're interested exactly how, I'll have to dig a little bit, since it was a while ago.
It is true however, it dramatically reduces fps, so I suggest for an action game like defense, better use animated ripple sprite.

Thanks for your support.
Now you have to do this stuff for not me but also for lots of other users.
This problem cost my lot of time so I any how want this effect to work. I know this effect creates a lot of load. But now my sole purpose is to create this effect.

The thing does not matter you create it for GLES1 or GLES2.

Please do something for this.

[thepi]

This is how it works on GLES2.
The shader extends through whole screen. You need to tweak it for custom radius.

This code goes into main class/activity:

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1. private float mShockwaveTime = 0f;
2.  
3.  
4. @Override
5. public Engine onCreateEngine(final EngineOptions pEngineOptions) {
6.         return new Engine(pEngineOptions) {
7.                 private boolean mRenderTextureInitialized;
8.  
9.                 private RenderTexture mRenderTexture;
10.                 private UncoloredSprite mRenderTextureSprite;
11.                
12.                 @Override
13.                 public void onDrawFrame(GLState pGLState)
14.                                 throws InterruptedException {
15.                        
16.                         if (mShockwaveTime > 0f && mShockwaveTime < 10f) {
17.                                
18.                                 if (!mRenderTextureInitialized) {
19.                                         initRenderTexture(pGLState);
20.                                         mRenderTextureInitialized = true;
21.                                 }
22.                                
23.                                 mRenderTexture.begin(pGLState, false, true, Color.TRANSPARENT);
24.                                 {              
25.                                         super.onDrawFrame(pGLState);
26.                                 }
27.                                 mRenderTexture.end(pGLState);
28.                                                                
29.                                 pGLState.pushProjectionGLMatrix();
30.                                 pGLState.orthoProjectionGLMatrixf(0, CAMERA_WIDTH, 0, CAMERA_HEIGHT, -1, 1);
31.                                 {
32.                                         mRenderTextureSprite.onDraw(pGLState, mCamera);
33.                                 }
34.                                 pGLState.popProjectionGLMatrix();      
35.                         } else {
36.                                 super.onDrawFrame(pGLState);
37.                         }
38.                 }
39.                
40.                 private void initRenderTexture(GLState pGLState) {
41.                         mRenderTexture = new RenderTexture(getTextureManager(), mCamera.getSurfaceWidth(), mCamera.getSurfaceHeight(), PixelFormat.RGBA_4444);
42.                         mRenderTexture.init(pGLState);
43.                         mRenderTextureSprite = new UncoloredSprite(0f, 0f, TextureRegionFactory.extractFromTexture(mRenderTexture), getVertexBufferObjectManager()) {
44.                                 @Override
45.                                 protected void preDraw(GLState pGLState, Camera pCamera) {
46.                                         super.preDraw(pGLState, pCamera);
47.                                         if (mShockwaveTime > 0f && mShockwaveTime < 10f) GLES20.glUniform1f(ShockwaveShaderProgram.sUniformTimeLocation, mShockwaveTime);
48.                                 }
49.                         };
50.                         mRenderTextureSprite.setShaderProgram(ShockwaveShaderProgram.getInstance());                           
51.                 }
52.         };
53. }

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This line goes inside onLoadResources:

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1. this.getShaderProgramManager().loadShaderProgram(ShockwaveShaderProgram.getInstance());

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I put shader class code to the end of my main class:

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1. public static class ShockwaveShaderProgram extends ShaderProgram {
2.        
3.         private static ShockwaveShaderProgram instance;
4.        
5.         public static ShockwaveShaderProgram getInstance() {
6.                 if (instance == null) instance = new ShockwaveShaderProgram();
7.                 return instance;
8.         }
9.                        
10.         public static final String FRAGMENTSHADER =
11.         "precision lowp float;\n" +
12.  
13.         "uniform lowp sampler2D " + ShaderProgramConstants.UNIFORM_TEXTURE_0 + ";\n" +
14.         "varying mediump vec2 " + ShaderProgramConstants.VARYING_TEXTURECOORDINATES + ";\n" +
15.        
16.         "uniform vec2 center;\n" +
17.         "uniform float time;\n" +
18.         "const vec3 params = vec3(10.0, 0.8, 0.02);\n" +
19.  
20.         "void main()    \n" +
21.         "{                              \n" +
22.         "       mediump vec2 texCoord = " + ShaderProgramConstants.VARYING_TEXTURECOORDINATES + ";\n" +
23.         "       float distance = distance(texCoord, center);\n" +
24.         "       if ( (distance <= (time + params.z)) && (distance >= (time - params.z)) )\n" +
25.         "       {\n" +         
26.         "               float diff = (distance - time);\n" +
27.         "               float powDiff = 1.0 - pow(abs(diff*params.x), params.y);\n" +
28.         "               float diffTime = diff  * powDiff;\n" +
29.         "               vec2 diffUV = normalize(texCoord - center);\n" +
30.         "               texCoord = texCoord + (diffUV * diffTime);\n" +
31.         "       }\n" +
32.         "       gl_FragColor = texture2D(" + ShaderProgramConstants.UNIFORM_TEXTURE_0 + ", texCoord);\n" +
33.         "}              \n";
34.  
35.          
36.         private ShockwaveShaderProgram() {
37.                 super(PositionTextureCoordinatesShaderProgram.VERTEXSHADER, FRAGMENTSHADER);
38.         }
39.        
40.         public static int sUniformModelViewPositionMatrixLocation = ShaderProgramConstants.LOCATION_INVALID;
41.         public static int sUniformTexture0Location = ShaderProgramConstants.LOCATION_INVALID;
42.         public static int sUniformCenterLocation = ShaderProgramConstants.LOCATION_INVALID;
43.         public static int sUniformTimeLocation = ShaderProgramConstants.LOCATION_INVALID;
44.        
45.         @Override
46.         protected void link(final GLState pGLState) throws ShaderProgramLinkException {
47.                 GLES20.glBindAttribLocation(this.mProgramID, ShaderProgramConstants.ATTRIBUTE_POSITION_LOCATION, ShaderProgramConstants.ATTRIBUTE_POSITION);
48.                 GLES20.glBindAttribLocation(this.mProgramID, ShaderProgramConstants.ATTRIBUTE_TEXTURECOORDINATES_LOCATION, ShaderProgramConstants.ATTRIBUTE_TEXTURECOORDINATES);
49.  
50.                 super.link(pGLState);
51.  
52.                 ShockwaveShaderProgram.sUniformModelViewPositionMatrixLocation = this.getUniformLocation(ShaderProgramConstants.UNIFORM_MODELVIEWPROJECTIONMATRIX);
53.                 ShockwaveShaderProgram.sUniformTexture0Location = this.getUniformLocation(ShaderProgramConstants.UNIFORM_TEXTURE_0);
54.                 ShockwaveShaderProgram.sUniformCenterLocation = this.getUniformLocation("center");
55.                 ShockwaveShaderProgram.sUniformTimeLocation = this.getUniformLocation("time");
56.         }
57.        
58.         @Override
59.         public void bind(final GLState pGLState, final VertexBufferObjectAttributes pVertexBufferObjectAttributes) {
60.                 GLES20.glDisableVertexAttribArray(ShaderProgramConstants.ATTRIBUTE_COLOR_LOCATION);
61.                 super.bind(pGLState, pVertexBufferObjectAttributes);
62.                 GLES20.glUniformMatrix4fv(ShockwaveShaderProgram.sUniformModelViewPositionMatrixLocation, 1, false, pGLState.getModelViewProjectionGLMatrix(), 0);
63.                 GLES20.glUniform1i(ShockwaveShaderProgram.sUniformTexture0Location, 0);
64.                 GLES20.glUniform2f(ShockwaveShaderProgram.sUniformCenterLocation, 0.5f, 0.5f);
65.         }
66.  
67.  
68.         @Override
69.         public void unbind(final GLState pGLState) throws ShaderProgramException {
70.                 GLES20.glEnableVertexAttribArray(ShaderProgramConstants.ATTRIBUTE_COLOR_LOCATION);
71.                 super.unbind(pGLState);
72.         }
73. }

Parsed in 0.046 seconds, using GeSHi 1.0.8.4

Put this code where you want to trigger it:

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1. mScene.registerUpdateHandler(new TimerHandler(0.08f, true, new ITimerCallback() {
2.         @Override
3.         public void onTimePassed(TimerHandler pTimerHandler) {
4.                 mShockwaveTime += 0.02f;
5.                 if (mShockwaveTime > 1.2f) {
6.                         mScene.unregisterUpdateHandler(pTimerHandler);
7.                         mShockwaveTime = 0.0f;
8.                 }
9.         }
10. }));

Parsed in 0.035 seconds, using GeSHi 1.0.8.4