Cinder Frame Graph

Cinder Frame Graph is a block for libcinder that allows node-based image and video processing. It provides a number of nodes for loading images and videos to textures and processing with shaders. It has experimental support for OpenColorIO, a node for applying LUTs to texture sources, and a color grading node. It is also integrated with Cinder's vector types, making it easy to apply transformations to vectors and use them as inputs/outputs with other nodes.

Frame Graph also makes it easy to define your own node-based data-flow applications. It is based on libnodes, which provides a type-safe node architecture. New node classes can easily be defined to process any data type, whether text, JSON, or OpenCV matrices. While it works well with external libraries like OpenCV, direct support is currently omitted in the interest of reducing dependencies.

Getting Cinder Frame Graph

Frame Graph depends on libnodes and, optionally, libglvideo. To install Frame Graph and its dependencies, clone the Frame Graph repo into your Cinder/blocks directory:

cd Cinder/blocks
# on older versions of git, use --recursive instead of --recurse-submodules
git clone --recurse-submodules [email protected]:heisters/Cinder-FrameGraph

libglvideo support is not enabled by default. See below for details on how to use it.

A Brief Example

#include "cinder/FrameGraph.hpp"
#include "cinder/framegraph/LUTNode.hpp"

using namespace ci;
using namespace ci::app;
using namespace std;
using namespace frame_graph;
using namespace frame_graph::operators;

// Use a TextureINode to feed an image-based texture into the node graph
TextureINode n_image( loadImage( getOpenFilePath() ) );
// Use another TextureINode to load the LUT
TextureINode n_lutImage( getAssetPath( "luts/K_TONE_Kodachrome.png" ) );
// This will provide a texture to draw to the screen
TextureONode n_out;
// This applies the LUT to the input texture
LUTNode n_lut( getWindowSize() );

// connect the input image to the LUT applicator using the >> operator. When no
// inlet or outlet is specified, >> defaults to the first (index 0) outlet and
// inlet on the nodes.
n_image >>      n_lut >>            n_out;
// now feed the LUT itself into the LUT applicator's second inlet.
n_lutImage >>   n_lut.in< 1 >();

// Call update on the root nodes to propagate their messages through the graph.
n_image.update();
n_lutImage.update();

// TextureONode provides a coercion operator to bool, which exposes the
// underlying ci::gl::Texture2dRef's bool coercion operator.
if ( n_out ) {
    // TextureONode can also be implicity coerced to the underlying Texture2dRef
    gl::draw( n_out );
}

For more examples, see the examples folder and libnodes itself.

Building

Cinder Frame Graph uses CMake. It has a Cinder Block CMake config, you can see an example of its usage in the Color example project.

libglvideo support

To enable libglvideo support, set ENABLE_FRAMEGRAPH_LIBGLVIDEO in your CMakeLists.txt file before calling ci_make_app():

set(ENABLE_FRAMEGRAPH_LIBGLVIDEO ON CACHE BOOL "Enable FrameGraph libglvideo support")

Provided you have properly cloned Frame Graph's submodule dependencies, this will automatically find libglvideo, build it, and link it.

With libglvideo support enabled, you will need two nodes to read and decode a HAPQ video:

#include "cinder/framegraph/GLVideo.hpp"

// ...

// Create a glvideo context that will be shared by all movies. The number
// of worker threads depends on the number of available CPU cores and the
// number of videos you anticipate to need to decode simultaneously.
glvideo::Context::ref ctx = glvideo::Context::create( 4 /* worker threads */ );

// Create the movie control node
GLVideoINode movie( ctx, "path/to/a/hapq_video.mp4" );

// Create the YUV -> RGB decoding node
GLVideoHapQDecodeShaderIONode decoder( movie.getSize() );

// Create a texture output node
TextureONode out;

// Start the movie and loop it
movie.play().loop();

// Setup the node graph
movie >> decoder >> out;

// update the movie once per frame:
movie.update();

// draw the movie
if ( out ) gl::draw( out );

See the Color example project for a full example.

MIT License

Copyright (c) 2016-2017 Ian Heisters

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.