How to implement water ripples?

Question

I'm working on an iphone game. In that i had to produce water ripples. I dont know how to get that. I heard thatit can be done with openGL. I am very new to this concept. Can any one guide me?

Marmite

Did you achieve the effect, after all? – Infectious

Answer 1

Here are some resources I found:

Language Agnostic 2d Water Ripple Algorithm

_{(source: virgin.net)
(source: virgin.net)}

OpenGL Project with Water Ripples (Source)

_{(source: sulaco.co.za)}

You also might want to swing by GameDev's FAQ. Scroll down to the "Water Rendering" section.

Increate

Answer 2

jk:

z=sin(x)+cos(y)

More seriously, doesn't the Quartz Composer basically do ripples for you as one of the effects layers? Or was that announced only for the iPhone 3.0 SDK?

Gymnasiast

That's a really expensive routine. It would absolutely kill OpenGL in a game. I'm guessing he wants a decent water effect, which means old-school texture mapping tricks. – Bethel

Pardon; I know. I was joking. – Gymnasiast

Answer 3

I found the source code of the water ripple effect so following code to implement into your project and solove your problem also.

import "HelloWorldLayer.h"

// HelloWorldLayer implementation
@implementation HelloWorldLayer

+(CCScene *) scene
{
    // 'scene' is an autorelease object.
    CCScene *scene = [CCScene node];
    
    // 'layer' is an autorelease object.
    HelloWorldLayer *layer = [HelloWorldLayer node];
    
    // add layer as a child to scene
    [scene addChild: layer];
    
    // return the scene
    return scene;
}

// on "init" you need to initialize your instance
-(id) init
{
    
    if( (self=[super init])) {

        rippleImage = [ pgeRippleSprite ripplespriteWithFile:@"image_old.png" ];
        [ self addChild:rippleImage ];
        CCLabelTTF *label = [CCLabelTTF labelWithString:@"Hello Cocos2D Forum" fontName:@"Marker Felt" fontSize:16];
        label.position = ccp( 80 , 300 );
        [self addChild: label];
        [ [ CCTouchDispatcher sharedDispatcher ] addTargetedDelegate:self priority:0 swallowsTouches:YES ]; 
        
        // schedule update
        [ self schedule:@selector( update: ) ];    
                
    }
    return self;
}

float runtime = 0;

-( BOOL )ccTouchBegan:( UITouch* )touch withEvent:( UIEvent* )event {
    runtime = 0.1f;
    [ self ccTouchMoved:touch withEvent:event ];
    return( YES );
}

-( void )ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event {
    CGPoint pos;
    
    if ( runtime >= 0.1f ) {
        
        runtime -= 0.1f;
        
        // get touch position and convert to screen coordinates
        pos = [ touch locationInView: [ touch view ] ];
        pos = [ [ CCDirector sharedDirector ] convertToGL:pos ];
    
        // [ rippleImage addRipple:pos type:RIPPLE_TYPE_RUBBER strength:1.0f ];    
        [ rippleImage addRipple:pos type:RIPPLE_TYPE_WATER strength:2.0f ];  
        
        
    }
}

-( void )update:( ccTime )dt {
    
    runtime += dt;
    
    [ rippleImage update:dt ];
}

// on "dealloc" you need to release all your retained objects
- (void) dealloc
{
    // in case you have something to dealloc, do it in this method
    // in this particular example nothing needs to be released.
    // cocos2d will automatically release all the children (Label)
    
    // don't forget to call "super dealloc"
    [super dealloc];
}
@end

Also you can download the source code from the Git

Scrivens