Shader Playground

Create shaders easily !

Same use as https://shadertoy.com, but for desktop environment.

Created using C++ 17, OpenGL 4.6, GLFW 3.3.8, GLEW 2.2.0 for debug and GLEW 2.1.0 for release, and GLM 0.9.9.

IDE used : Visual Studio 2022, CMake project. Available on Windows, Linux and MacOS.

How to use

All further paths are relative to the binary's folder (where the executable is).

When running the program inside Visual Studio 2022 or the executable, you have a terminal waiting for your input.
It explains you everything you need to know.

1. Write a fragment shader (.glsl) in a res/shaders/ folder.
2. Run the application.
3. Enter the name of your fragment shader, without the path and without the extension.
   1. For example, if you created res/shaders/fractals/mandelbrot.glsl, write fractals/mandelbrot to the prompter.
4. Enjoy your shader.

Type "quit" or "exit" to terminate the program.

Some helpful commands while running :

• Esc : hide the window to return to the prompter, to load a new shader. You do not need to qui the application to load a newly created shader.

• F5 : Hot-reload the shader that is currently running, without closing the window. It makes easy-to-develop.

• F8 : Toggle FPS limit (screen refresh rate). It is enabled by default.

• F9 : Reset runtime variables (zoom, position, ...).

• F11 : Toggle fullscreen (windowed fullscreen borderless). It does not hide the taskbar of your OS.

• The 4 arrow keys : move the camera.

• The I and D keys : respectivly increment and decrement a uniform variable.

• The LShift and LControl keys : respectivly zoom in and zoom out. It will zoom to the center of the camera.

• The Tab key : switch mode (3 available modes).

• The Space, RShift, RControl, RAlt, LAlt keys : each of those have a boolean pressed state (true while pressed, false otherwise).

• The [0-9] keys : each of those have a toggle boolean state.

Development

Your fragment shaders are included in the main fragment shader code. So, you don't have to specify the #version. The version used is 460 core. You can put the line to help the linter, but it will be ignored when compiling your shader. You also don't need to declare neither the main function and the in/out/uniform variables.
Your fragment must be located in the res/shaders/ folder.
You can use the #include <path/to/chunk> directive to include other .glsl files, making it easy to factorize your code and make it more reusable. Do not specify the extension while including. It will search in the res/shaders/ folder. Your fragment shader file must contain a vec3 mainImage() function, which will be called by the main() fragment shader function at runtime. You must assign a color to the predefined vec4 FragColor variable to set the pixel's color.

No circular dependencies can happen, because this directive is handled only in the .frag files, and only .glsl can be included.

Note : Remember to setup your project's paths correctly to GLFW, GLEW and GLM with the config.cmake file !

Global variables

In your shaders, you can access various variables. Here's the list :

• FragCoord: a vec2 with current pixel coordinates, between 0 and the window's resolution.
• MVP: a mat4, the model-view-projection matrix.
• M: a mat4, the model matrix.
• V: a mat4, the view matrix.
• P: a mat4, the projection matrix.
• ivMouse: a vec2, the current mouse position in the window.
• fvCenter: a vec2, the center of the camera. See below for further explanations.
• uvResolution: a vec2, the size of the window, and thus of the surface to which the shader will render.
• fTime: a float, the total time elapsed, in seconds.
• fDelta: a float, the delta time that is the duration between the last frame and the current.
• fRatio: a float, the ratio of the window, thus the surface (width/height).
• fZoom: a float, the current level of zoom. See below for further explanations.
• iIncrement : an integer that can be incremented or decremented by user input.
• iMode : an integer that switchs between 0, 1 and 2 by user input.
• vbFlags : an array of 10 booleans that can be toggled by user input.
• vbMousePressed : an array of 3 booleans that are true while the mouse buttons are pressed. 0 = left, 1 = middle and 2 = right.
• vbKeyPressed : an array of 4 special keys that are true while the keys are pressed. 0 = Space, 1 = LAlt, 2 = RShift, 3 = RControl.

The zoom and center uniforms

User can zoom pressing Shift, and unzoom pressing Control.
It will zoom lerping to the mouse position (center of the window if the mouse is outside).

The zoom and center uniforms are updated consequently.

More informations

• BUG : boolean flags and special keys are having a buffer overflow.
• ENCHANCEMENT : the zoom is not changing depending the time passed but depending frame count.

Most of the code is on App.cpp and is not that well organized neither commented. It could be splitted and improved, but this is a simple project and like this there is less complexity and better performances.

Author

NoxFly

License

This project is under the GPL-3.0 license.