PlasmaGL

A Windows screensaver that renders GPU-driven effects using OpenGL 3.3 Core shaders. Ships with four built-in visual effects and a live Shader Editor so you can write and preview your own GLSL fragment shaders without leaving the screensaver.

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Gallery

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Features

• GPU-rendered effects – the CPU only ticks a timer and pushes uniforms; all pixel work happens in GLSL
• Ten built-in shaders – Plasma, Ripple, Voronoi Cells, Fire, Wave Interference, Fractal Pyramid, Neon Fractal, Starfield, Fractal Galaxy, and Polka Dot
• User shader library – write custom fragment shaders, save them as named presets, and select them at runtime
• Live Shader Editor – split-pane editor with a real-time GLControl preview; auto-compiles after a 1.5-second debounce, or on-demand with the Compile button
• Screenshots – press F12 at any time to save a render to Pictures\PlasmaGL without interrupting the screensaver
• 11 colour palettes – selectable from the Settings dialog (applies to the built-in Plasma shader)
• Multi-monitor – spawns a full-screen window per display
• 60-second seed rotation – quietly randomises plasma parameters every minute for variety

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Tech Stack

Layer	Technology
Language	VB.NET (Visual Studio, .vbproj)
Target framework	.NET Framework 4.8
UI host	Windows Forms (System.Windows.Forms)
OpenGL	OpenTK 3.3.3 + OpenTK.GLControl 3.3.3 (NuGet packages.config)
Shader language	GLSL 3.30 Core
Settings storage	Windows Registry (HKCU\Software\PlasmaGL)
User shader storage	%APPDATA%\PlasmaGL\shaders\ (.frag files)
Build system	MSBuild / Visual Studio 2019+

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Project Structure

PlasmaGL/
├── PlasmaGL.sln
├── packages/                       ← NuGet restored packages (not in git)
└── PlasmaGL/
    ├── Program.vb                  ← Entry point; routes /s /c /p switches
    ├── PlasmaForm.vb               ← Full-screen GL window; render loop
    ├── PlasmaPreview.vb            ← GLControl subclass for Display-Properties preview
    ├── SettingsForm.vb             ← Modal settings dialog (speed, palette, shader)
    ├── ShaderLibrary.vb            ← Shader catalogue; built-in sources + user-file I/O
    ├── ShaderEditorForm.vb         ← Live GLSL editor with split-pane GL preview
    ├── PlasmaGL.vbproj
    ├── packages.config             ← NuGet package list
    ├── App.config
    ├── OpenTK.dll.config           ← OpenTK platform/driver config (do not delete)
    └── My Project/                 ← Auto-generated VB.NET project metadata

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Screensaver Command-Line Protocol

Windows passes one of three switches when launching a .scr file:

Switch	Meaning	What PlasmaGL does
/s	Run the screensaver	Opens a PlasmaForm per monitor; starts 60-second seed rotation
/c	Show configuration	Opens SettingsForm as a modal dialog
/p <hwnd>	Show preview pane	Embeds PlasmaPreview into the Display Properties preview HWND
(none)	Debug / F5	Falls through to the settings dialog

The compiled .exe must be renamed to .scr and placed in C:\Windows\System32 to be recognised by Windows as a screensaver.

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Shader Library

Built-in Shaders

All built-in shaders accept the same uniform set (see Writing a Custom Shader below).

Name	Description
Plasma (default)	Classic 4-term sine plasma with sinusoidal lens warp and 8 selectable colour palettes
Ripple	Concentric rings expanding from centre with angular wobble driven by seed1/seed2
Voronoi Cells	Animated Voronoi diagram with white cell borders and cosine colour mapping
Fire	Upward-rising fractal Brownian motion (5-octave fBm) mapped to a black→red→orange→yellow→white flame gradient
Wave Interference	Full-screen multi-wave interference pattern with dynamic zoom powered by seed uniforms
Fractal Pyramid	Raymarched 3D fractal structure that rotates and morphs over time
Neon Fractal	Psychedelic glowing rings that iterate fractally from the center
Starfield	Volumetric star field with dynamic nebula-like formations and smooth vignette
Fractal Galaxy	Parallax scrolling fractal galaxy with dynamic noise-driven coloration and stars
Polka Dot	Grid of glowing polka dots with randomized time-varying intensity and preset palette cycling

User Shaders

User shaders are stored as plain .frag files under:

%APPDATA%\PlasmaGL\shaders\

They appear in the Settings dialog below the built-in shaders and are fully editable/deletable. Built-in shader names are reserved and cannot be overwritten.

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Shader Editor

Open the editor from Settings → Edit / New Shader.

• Left pane – RichTextBox GLSL code editor with monospace font and tab support
• Right pane – live GLControl preview running at ~60 FPS
• Auto-compile – triggers 1.5 seconds after the last keystroke
• ▶ Compile & Preview – forces an immediate compile
• Error strip – compiler/linker errors appear in a red banner at the bottom
• Save – enabled only when the current source compiles cleanly; built-in names are rejected
• Editing a built-in shader automatically prompts for a new name (fork behaviour)

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Writing a Custom Shader

Your fragment shader must target GLSL 3.30 Core and declare out vec4 fragColor. The vertex shader is shared (full-screen clip-space quad) and cannot be edited.

All uniforms are optional — only declare the ones you use:

#version 330 core
out vec4 fragColor;

uniform float iTime;       // monotonic animation clock (seconds)
uniform vec2  iResolution; // viewport size in pixels
uniform float seed1;       // random per-axis frequency multiplier (1–5)
uniform float seed2;       // random per-axis frequency multiplier (1–5)
uniform float scale;       // blob/pattern scale (2–60)
uniform float phase;       // same as iTime — drives colour cycling
uniform int   palette;     // user palette selection (0–10)

void main() {
    vec2 uv = gl_FragCoord.xy / iResolution.xy;
    vec3 col = vec3(uv, 0.5 + 0.5 * sin(iTime));
    fragColor = vec4(col, 1.0);
}

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Colour Palettes (Plasma shader)

Selectable via the Settings dialog. The palette uniform is passed to every shader but only the built-in Plasma shader branches on it.

Index	Name	Description
0	RGB Cycle (Acid)	Full RGB cosine cycle with vec3(0, 2.1, 4.2) offset
1	Green	Single cosine on green channel
2	Red	Single cosine on red channel
3	Blue	Handled by the else branch (implicit)
4	Yellow-Orange-Red	Warm cosine blend, gamma-squared
5	Cool Vivid	4-keyframe interpolation: cyan → green → blue → violet
6	Sunset	5-colour weighted cosine blend: indigo/purple/magenta/orange/gold
7	Tropical	4-segment hard colours: cyan/teal/lime/yellow-green
8	Cyberpunk	Linear mix from cyan-blue to magenta
9	Neon Ice	Cosine cycle with vec3(0.263, 0.416, 0.557) offset
10	Galaxy	Custom nonlinear mapping vec3(p^3, p^2, p) for deep cosmic colors

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Settings & Registry Keys

All settings live under HKCU\Software\PlasmaGL:

Value	Type	Default	Meaning
Speed	DWORD	16	Timer interval in ms (lower = faster; 10–200 range in UI)
Palette	DWORD	0	Active palette index (0–7)
Shader	String	"Plasma (default)"	Name of the active shader

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Build & Run

Prerequisites

• Visual Studio 2019 or later (Community edition is fine)
• .NET Framework 4.8 (pre-installed on Windows 10/11)
• NuGet package restore (automatic on first build)

Steps

1. Open PlasmaGL.sln in Visual Studio.
2. Right-click the solution → Restore NuGet Packages (if not done automatically).
3. Debug (F5) – no arguments → falls through to the Settings dialog.
4. Test as screensaver – go to Project → Properties → Debug → Command line arguments and enter /s.
5. Release build – Build → Build Solution in Release configuration.

Deployment

copy PlasmaGL\bin\Release\PlasmaGL.exe C:\Windows\System32\PlasmaGL.scr

Then right-click the desktop → Personalize → Screen saver and select PlasmaGL.

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License

See LICENSE.