Heat Haze Ripple Effect

the case you given is just sine / cosine wave.

And this is a simple heat wave made years ago.
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Quote from The_Owl

I've been experimenting a lot with Sin/Cos lately, but how would I use it to make an image distort rather than simply move an object left and right

You need sine / cosine shader, not the built-in expression (unless F3's matrix)

Quote from The_Owl

I don't understand your example?

it's a small trick also used in wind waker, by generating multiple planes with pixel offset, instead of real simulation

The best way to get that effect would be to use a shader or write your own. I generally don't use shaders so I don't know if there is one which does exactly what you want, but I've seen a water effect one in the clickstore, which looks as though it can produce something similar if you play around with the parameters.

The only other way is to use an extension like the Surface Object or Overlay Redux Object, which allows you to directly manipulate the pixels in an image. The performance of either object is going to be far too slow for in-game effects, but should be fine for manipulating a static cutscene image like in the example you shared.

If a shader exists that does what you want, then that would be the easy solution. Shader code is gobbledygook and I personally wouldn't try making a shader myself. But if one exists already, using them is usually extremely simple. There are usually a couple of parameters that you change over time, much like what you'd be doing with sin/cos. I didn't understand defisym's explanation either, but using his shader itself is probably easy.

If it doesn't seem like what you want, have a look on the Clickstore for others. For example Please login to see this link.. Ignore the flames - they're just an additional graphical layer that you wouldn't use - look at the space above them. The background morphs in a more organic way than it does in your example, but you could probably recreate your example if you wanted.

I would guess that example uses the Lens shader. I would recommend playing around with it. I use it in my game to get underwater distortion. You can see the effect in my promo GIF below (look at the middle portion - please excuse the flashing text):

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The way I get that effect is by applying the Lens Effect to a layer, then populating that layer with a bunch of greyscale active objects like this one:

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I have a few dozen instances of blobby shapes like this, spread around the place randomly and overlapping each other. I make them constantly wiggle and rotate around, and that produces the underwater effect. These greyscale objects act sort of like a magnifying glass, with the Lens Effect shifting everything below them according to the brightness of each pixel on the greyscale object: Blacker parts of the object are like the edge of the magnifying glass (they won't produce much shift) while whiter parts are like the stronger centre of the magnifying glass.

To get your desired effect, You could potentially use rectangular shapes with greyscale gradients, moving them side to side. Though you could probably just use a single object with an animation on it: horizontal bars that get darker and brighter in a wave-like pattern, mimicking the movement shown in your example (but not actually moving - just getting brighter/dimmer over time). As each horizontal bar gets brighter over time, it will increasingly push all pixels below it in a particular direction.