glslViewer

Live-coding tool that renders GLSL Fragment shaders and update them every time they change and runs directly from the console of your RaspberryPi or MacOS. It handles for you the injection of sub-programs, textures and other uniforms such as time, resolution and mouse position.

Installing in RaspberryPi

Install FreeImage libraries, download the code, compile and install.

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install libfreeimage-dev
cd ~ 
git clone http://github.com/patriciogonzalezvivo/glslViewer
cd glslViewer
make
make install

Installing in Mac OSX

brew update
brew upgrade
brew install freeimage 
brew tap homebrew/versions
brew install glfw3 pkg-config
cd ~ 
git clone http://github.com/patriciogonzalezvivo/glslViewer
cd glslViewer
make
make install

Use

Run the app:

glslViewer test.frag

If you set alpha value to 0.3 (glFragColor.a = 0.3;) you can se through the console and from another terminal edit your shader with you favorite editor:

vim test.frag

In the test fragment shader we have hook it up to the X mouse position so you can take a look while you work on it.

Or you can login remotely using ssh to your raspberryPi and live-code with your favorite editor:

ssh [email protected]
vim test.frag

Pre-Define Uniforms

Shaders are cross compatible with the webGL shaders from ShaderToy for that the following uniforms are pre-define and can be add to the shader with the -u argument

• u_time (float) or iGlobalTime (float) : shader playback time (in seconds)

• u_resolution (vec2) or iResolution (vec3): viewport resolution (in pixels)

• u_mouse (vec2) or iMouse (vec4): mouse pixel coords (xy: pos, zw: buttons)

• v_texcoord (vec2): UV of the billboard ( normalized )

Dynamic uniforms: textures

You can load any image suported by FreeImage libraries, tehy will be load automatically and asign a uniform name acording to the order they are pass as arguments: u_tex0, u_tex1, etc. Together with that a resolution vec2 uniform will be pass to: u_tex0Resolution, u_tex1Resolution, etc.

glslViewer test.frag test.png

Also you can name texture uniforms as you want by assigning it to an argument before the image file For example, the uniform sampled2D iChannel; and uniform vec2 iChannelResolution; is defined in this way:

glslViewer test.frag -iChannel test.png

Others arguments

Beside for texture uniforms other arguments can be add to glslViewer to change it setup.

• -x [pixels] set the X position of the billboard on the screen

• -y [pixels] set the Y position of the billboard on the screen

• -w [pixels] or --width [pixels] set the width of the billboard

• -h [pixels] or --height [pixels] set the height of the billboard

• -s [seconds] exit app after a specific amount of seconds

• -o [filename] save the viewport to a image file before exit

• -d or --dither dither the image before exit

• -u add pre-defined uniforms to the top of the shader so that you can run ShaderToy shader directly.

• --squared to set a squared billboard

• -l or --live-coding to draw a 500x500 billboard on the top right corner of the screen that let you see the code and the shader at the same time

Inject other files

You can include other GLSL code using a traditional #include “file.glsl” macro. Note: included files are not under watch so changes will not take effect until the main file is save.

Authors

• Patricio Gonzalez Vivo

• Karim Naaji.