On the coastal material, change the "Displacement" parameter to a texture and create a new texture. Then change the "MonoFractal" to "BreakWave Displacement".
First of all, let's change the "Ocean Depth" parameter to the same texture as the one used for the "BreakWave Blend". Also, set the "Depth Damping" to the same value as the "Depth Factor" on the "BreakWave Blend".
Wow! Waves are breaking on the beach. But, in this case, their wavelength is too short. This may be adjusted with the "Depth Period" parameter. The rigth value is heavely dependent of the beach slope. Applying the same factor to the default value that you used for the "Depth Damping" should give an acceptable result. On this world, I used a factor of 5, so I set "Depth Period" to 1.0.
Yes, This is better! You may notice that the waves are not parallel to the shore. This effect can be adjusted with the "Spatial Period" parameter. The higher the value, the higher the waves are parallel to the shore. In the next picture, the "Spatial Period" has been multiplied by 4.
The amplitude of the waves is adjustable thanks to the "Amplitude" parameter. It is expressed in meters. Let's check what it looks like if set to 2.0 meters:
The effect is clear, but somewhat exagerated in this case. So, keep the default value of 0.5 meters and go down to see how the things look like from the ground.
Well, these waves fronts are a little bit too smooth and artificial for me. Obviously, there must be some chaos inside them. That is the purpose of the wave noise parameter. Drive it by a voronoi monofractal with a Largest Feature Size of 0.1.
Yes, that's it. Well, maybe this time it is too much chaotic. Change the Front Noise Factor to 0.02.
Could be better. But, hey, this is just a tutorial!
By the way, how does it look from above?
The noise has almost no effect at high altitude. No real surprise.
Now, let's try to make the things more natural by playing with the scatter parameter of the water material.