GLSL Playground

A simple program written in C++ that reads a fragment shader and shades it to the screen. Has basic compatibility with GLSL Sandbox (Heroku) and Shadertoy fragment shaders.

Dependencies

• GLFW3 (tested and works on 3.3.1 on Ubuntu 18.04 LTS)

Compile & Run

Run make to compile the program. Once it is compiled, type in your shader in the playground.fsh file and run the executable to see it in action.

./glsl_playground [width height]

Inputs

GLSL Sandbox (Heroku)

// returns the dimensions of the window
uniform vec2 resolution

// returns the mouse position in the interval [0.0, 1.0] for .xy.
// origin is at bottom-left
uniform vec2 mouse

// returns the time in seconds from when the program started
uniform float time

Shadertoy

// returns the dimensions of the window
uniform vec3 iResolution

// returns the mouse coordinates (when clicked) for .xy
// and the mouse coordinates from last mouse press for .zw
// origin is at bottom-left
uniform vec4 iMouse

// returns the time in seconds from when the program started
uniform float iTime

Note: Please do not type Shadertoy uniform declarations in your shader as they are already included in the shader_toy_inputs.fsh file.

What it can do

• Read and execute custom fragment shaders
• Works with some GLSL Heroku and Shadertoy shaders
• Display time in seconds and frames per second on the title window.
• (not yet implemented) Pressing 1-4 changes resolution factor (1x, 2x, 4x, 8x)
• Pressing R resets timer to zero. Pressing Shift + R reloads the shaders.
• Pressing the spacebar pauses/resumes GLSL Playground.
• Esc or closing the program through traditional means exits the program.

TODO

• Learn more how OpenGL works (I'm a noob at this)
• Improve performance by optimizing code
• Add pause function that can be done by pressing the space bar
• Implement resolution factor as seen in GLSL Heroku
• Add ability to reload shader that can be done by pressing Shift + R
• Improve compatibility with GLSL Heroku and Shadertoy
• Add various geometry that can be used to test shaders on rather than simply rendering on the screen
• Add capability to read in multiple shaders, that can be navigated by pressing the cursor keys.

Why do this?

Hasn't GLSL Heroku/Shadertoy have given you what you need?

This is purely a learning experience, to allow me to learn more about OpenGL and GLSL. I'm inspired from others who produce vivid shaders which is breathtaking and breaks a whole new level of algorithmic arts. GLSL is a powerful language, and I think it deserves a native program to get more people interested in this field. I chose C++ in hopes of achieving better performance and removing the overhead required to render the website; however I'm skeptical that my program can run significantly faster than GLSL Heroku or Shadertoy.

License

This program is under BSD 2-Clause license.