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You can get the shader here -> https://godotshaders.com/shader/procedural-idyllic-slash/

Alright, I'll explain how to use the shader first and then I'll teach you how to make Oil and Crystals with it.

Setup

Grab the shader and set it up as a material for a quad mesh on a MeshInstance3D. It's a spatial shader so you have to use it in the 3D tab of Godot.

Parameters

Once setup you'll notice the shader has over a hundred parameters and isn't very splashy. I spent a lot of time writing in-line comments which will show up if you hover the property in the inspector. But let's go over the sections and highlight some important parameters that will help you create a bonafide splash.

Note this shader uses a dumb setup for a shared resources. In order to reduce the number of textures you set in this thing, some parameters offer you the option to use a "gc" or generic curve. This means you can point that parameter and others to interpolate with the same curve a bit faster. It's also kind of limiting... sorry!

Section A: Shader Parameters

This section includes two parameters for controlling culling. If you know you don't need the back face, you can set 'back_cull' to true.

Section B: Animate

This section contains animation controls. 'progress' is a manual handcrank that lets you scrub through the shader, but only when 'derive_progress' is set to use it (*Progress).

'derive_progress' lets you define what drives the shader animation. The lift time option (*Lifetime) on this parameter will tell the shader to use particle life time. Useful for when you put this into a particle system.

'custom_ease' will let you define a custom easing curve when 'ease_progress' is set to use it (*Custom Ease). You need to place a curve texture in this parameter.

'time_scale' only alters playback speed when 'derive_progress' is set to use global time (*Time).

Section C: Colorize

This section contains coloring options. 'shading' let's you set the shader's general apperance. Flat is flat, while the Fauxes will darken the edges. Do note, you need to apply a GradientTexture (preferably 1D) to 'color_gradient' to see how 'shading' works.

'color_gradient' lets you set the colors the shader uses. It works on the principle of gradient mapping. The Faux shading methods darken the edges of the image, which will cause the shader to color the edges differently to the center of the image. On the gradient set, colors on the left side will be used to color dark parts of the image. Colors on the right side will be used to color light parts of the image.

Due to how the faux shading is setup there will be a right side bias regarding the color mapping. You can use 'shift_gradient' to account for that kinda. It will alter the sampling to use colors in a new range shifted by the amount you set. This can be animated by setting 'final_shift_gradient' and setting a driver in 'ease_shift_gradient'. This "driver" is simply interpolation instructions. Most animatable parts of the shader are bound to whatever is progress is derived from ('derive_progress').

'emission_intensity' will make the splash glow if you have the correct environment settings (You need a world environment node).

'chunky_color' will posterize the splash and reduce the amount of fidelity. This is good for more stylized effects but works awfully thanks to my bad shader code calculating the shading. Instead of using this parameter you can try changing the interpolation within the GradientTexture set in 'color_gradient' to constant.

Colorize Subsection A: Iridescence

This subsection includes parameters for a very hacky iridescence effect. The sorta thing you see on bubbles or gasoline. The "value" options in 'apply_iridescence' will apply the effect as a multiplier using the grayscale of the usual rainbow.

'iridescence' contains controls to tweak the effect. x is the brightness/value. A higher x value will shift the colors from rgb to cmy. A lower x value will make the effect darker. Y and Z are for defining edges. Y will always influence the effect, while Z only matters for the smoothstep options. Z is a scaling factor... I think, it works differently from 'iridescence_size' though.

Colorize Subsection B: Chromatic Aberration

This one sucks, I wouldn't recommend using it honestly. The effect is great, but my code makes it bad. Due to the "clipping" this shader does, the color banding created by the aberration can be hard to see. In addition due to the fact this already uses a for loop, turning this on requires to perform the intensive for loop multiple times ('chroma_samples' / 2). Otherwise it's alright. Thanks to XOR for explaining how to make it.

Section D: Particle Options

This section is for setting up the particle appearance. You can consider these particles the "droplets" of the splash effect. I would keep particle count ('particles') low since it's directly tied to how many loops this shader has to do per pixel in fragment. 'particle_size' doesn't really matter that much, although it does impact the posterized coloring ('chunky_color') now that I think about it... I like to keep it low.

'size_curve' lets you set custom interpolation instructions (using a CurveTexture) for 'particle_size'. Using these instructions the shader will interpolate between 'particle_size' and zero.

'randomize_size' will randomize the size of the particles in the range you set. This helps with combating the uniformity of the appearance.

'particle_feather' is very important. This effect works based off the feathering falloff to create the appearance of goopy particles. The goopiness is somewhat limited though due to how the implementation works. Feather can be interpolated to zero with custom instructions and randomized like 'particle_size'.

'factor_distance' is a weird property meant to help prevent particles being cutoff when the fly near the edge of the mesh. It works best set to one. 'distance_edges" controls range in which 'factor_distance' operates. The closer the edges are the faster particles will change in size.

Particle Options Subsection A: Trail Options

I added some options for goofy trails to help with more splat looking splashes (eg. blood). But it kinda leaves a lot to be desired.

Section E: System

This section has controls for how the splash originates and moves. 'inital_position' is randomized in a range maxed out by the value. 'maintain_ip_domain' is math stuff that influences the 'inital_position' randomization range. 'ease_ipv' is for interpolating 'inital_velocity'. 'randomness' controls how random numbers are calculated. 'seed' lets you change the randomness state kinda. And 'index_shift_randomness" will factor particle index into the seed. This is useful for ensuring particles in a particle system look different from each other (not the particles in the effect).

System Subsection A: Emission

This subsection contains properties concerning additional particle movements. 'acceleration_curve' is kinda wonky. Probably because my math is bad.

Section F: Blobby

This section contains additional controls for the blobby behaviour. 'blob_step' will tweak appearance by changing how droplets are "clipped". Most important is 'feather_interpolation', you should set this to custom and put a wobbly curve into 'custom_feather_interp' like the one shown below...

This falloff pattern makes the droplets act cool imo. I would experiment a lot with this.

Section G: Overlay

This section let's you set a texture to overlay on the image. The overlay is masked by the droplets. There are multiple samplers to allow you to overlay a combination of textures. This section kinda sucks tho. The overlay just ain't it, distortion seems more useful imo.

Section H: Distortion

This section lets you play around with the UVs a bit. I wouldn't use negative 'fisheye'. I also would use 'uv_scale' to try and bring the edges of the effect closer to the edges of the mesh, blah, blah, overdraw, blah, blah optimization.

Distortion Subsection A: Texture distortion

Similar to overlay in that it provides options to distort with a combination of textures, but instead of overlaying the image. It makes the shapes all sorts of wacky. This is the main component of the beautiful glass shard effect seen above. 'distortion_fix' will be your friend if you set 'txdistort_str' to a high value. I suggest you keep it low though, lower than default, maybe around 0.2.

Section I: Dissolve

This section helps with cleanup near the end of the animation. Set 'alpha_dissolve' to something other than "No" to have the shader "erode" the effect over time depending on the interpolation instructions. You will need to play with the edges to get it work nicely. I suggest using a generic curve also so the dissolve happens with better timing.

Dissolve Subsection A: Proximity Fade

This subsection contains settings for proximity fade. This helps the effect mesh well with other things in the environment. I've added some extra bits to the shader so that the proximity fade is less boring, and it's a bit harder to tell the effect occurs on a flat mesh.

Section J: Vertex

This sections contains settings for manipulating vertices. I suggest using 'billboard' and 'camera_offset' to help with physical layering and visibility of the effect. The rotation stuff is a bit messy, sorry.

Section K: Curves

This section contains samplers for CurveTextures, that you can point other parts of the shader to use when interpolating between values. You only get four because I did not think this through...

Tutorials

Step 0: Get the shader -> https://godotshaders.com/shader/procedural-metaballic-splash/

Step 1: Apply to MeshInstance3D set up with a Quad Mesh (Mesh.Material)

Step 2: Set the parameters:

Open Animate

Start by setting 'derive_progress' to "Lifetime"

Set 'ease_progress' to "Ease Out"

Open Colorize

Set 'shading' to "Faux8"

Set 'color_gradient' to something similar to shown above. You want to start with black, transition into a dark gray, and then transition that dark gray into itself with no alpha. ( #[email protected] , #[email protected] , #[email protected] )

Set 'shift_gradient' to -0.1

--

Open Colorize>Iridescence

Set 'apply_iridescence' to "Smoothstep"

Set "iridescence' to ( -3.0 , 0.2 , 0.0 , 1.0 )

Set "iridescence_size' to 1.0

Open Particle Options

Set 'particle_size' to 0.025

Set 'size_curve' to something similar to shown above. (Left Image) Try and make it like a long slide. ( 0.0,0.0 -> 0.1,1.0 -> 1.0,0.0 )

Set 'randomize_size' to ( 1.0 , 5.0 )

Set 'particle_feather' to 0.5

Set 'randomize_feather' to ( 0.6 , 1.0 )

Set 'feather_curve' to something similar to shown above (Right Image) Sorta a linear ramp up. ( 0.0,0.0 -> 0.9,1.0 )

--

Open System

Set 'inital_particle_velocity" to -0.3

Set 'ease_ipv' to "Progress"

Enable 'index_shift_randomness'

Open System>Emission

Set 'emission_dir' to ( 1.0 , 1.0 )

Set 'acceleration' to ( 0.5 , 0.5 , 0.1 , 0.1 )

Set 'acceleration_curve' to something similar to shown above. ( 0.35,0.0 (rt : 4.0) -> 1.0,0.5 )

Open Blobby

Set 'blob_step' to 0.01

Set 'feather_interpolation' to "Custom"

Set 'custom_feather_interp' to something similar to shown above. ( 0.0,0.0 -> 0.125,0.875 -> 0.25,0.8 -> 0.75,0.875 -> 0.875,0.625 -> 1.0,1.0 (lt : 3.0) )

--

Open Distortion

Set 'fisheye' to ( 4.0 , 0.0 )

--

Open Dissolve

Set 'alpha_dissolve' to "Smoothstep"

Set 'ease_alpha_dissolve' to "gcA"

Set 'alpha_edge' to ( 0.9 , 1.0 )

--

Open Dissolve>Proximity Fade

Set 'proximity_fade_distance' to 0.5

--

Open Vertex

Set 'billboard' to "Yes"

Set 'camera_offset' to 0.25

Open Curves

Set 'generic_curve_a' to something similar to shown above. Ease up sharp drop ( 0.0,0.0 -> 0.95,1.0 (rt : -20.0) -> 1.0,0.0 (lt : -20.0) )

--

Add GPUParticles3D

Copy Mesh Resource from MeshInstance3D and set it as 'pass_1'

Set 'lifetime' to 1.5

Set 'explosiveness' to 0.9

Set 'fixed_fps' to 0

--

Add New ParticleProcessMaterial

Open Particle Flags

Enable 'damping_as_friction'

--

Open Spawn>Velocity

Set 'direction' to ( 0.0 , 1.0 , 0.0 )

Set 'spread' to 40.0

Set 'inital_velocity' to ( 5.0 , 8.0 )

--

Open Accelerations>Damping

Set 'damping' to 15.0

--

Open Display>Scale

Set 'scale' to ( 1.0 , 3.0 )

Open Display>Color Curves

Set 'alpha_curve' to something similar to shown above. Short smoothstep ramp down starting from 0.75. ( 0.0,1.0 -> 0.75,1.0 -> 1.0,0.0 )