SkigenPlot

Hardware-accelerated C++ plotting for scientific and ML visualization.

Overview

SkigenPlot is the visualization component of the Skigen ecosystem. It renders 2D and 3D scientific data through Qt's RHI abstraction layer, mapping directly to Vulkan, Metal, or Direct3D 12 without intermediate software rasterization.

The library accepts Eigen expression templates natively — any Eigen::MatrixBase<Derived> is a valid input with zero-copy semantics for contiguous data. Dynamic vertex buffers sustain 60 Hz+ update rates at 1M+ data points, suitable for real-time telemetry, EEG streams, and simulation output.

Example

#include <skigen/plot/plotview.h>
#include <Eigen/Core>
#include <QApplication>
#include <numbers>

int main(int argc, char* argv[]) {
    QApplication app(argc, argv);

    Eigen::VectorXf x = Eigen::VectorXf::LinSpaced(500, 0.f,
        4.f * std::numbers::pi_v<float>);
    Eigen::VectorXf y = x.array().sin();

    Skigen::Plot::PlotView view;
    view.plot(x, y);
    view.setLineColor({0.2f, 0.8f, 0.4f, 1.0f});
    view.resize(800, 500);
    view.show();

    return app.exec();
}

Plot Types

Type	Dimension	Input
Line plot	2D	VectorXf x, y
Scatter plot	2D	VectorXf x, y
Scrolling telemetry	2D	Streaming VectorXf
Point cloud	3D	MatrixXf (N x 3)
Surface mesh	3D	Vertices (N x 3) + indices (M x 3)

Requirements

Dependency	Version
C++	C++23 (GCC >= 13, Clang >= 17, MSVC >= 19.38)
Eigen 3	>= 3.4
Qt 6	>= 6.7 (Core, Gui, Widgets, ShaderTools)
CMake	>= 3.20

Building

git clone https://github.com/skigen-project/skigen-plot.git
cd skigen-plot
cmake -B build -DSKIGENPLOT_BUILD_TESTS=ON -DSKIGENPLOT_BUILD_EXAMPLES=ON
cmake --build build
ctest --test-dir build

Eigen is discovered from the system or from a sibling ../eigen directory.

CMake Integration

# As a subdirectory
add_subdirectory(skigen-plot)
target_link_libraries(my_app PRIVATE SkigenPlot::SkigenPlot)

# As an installed package
find_package(SkigenPlot REQUIRED)
target_link_libraries(my_app PRIVATE SkigenPlot::SkigenPlot)

Architecture

All rendering passes through QRhiWidget, which maps directly to the platform's native GPU API. Public headers forward-declare QRhi types; the <rhi/qrhi.h> include is confined to .cpp files.

User Code -> PlotView API -> Vertex Buffer Upload -> QRhi Pipeline -> Vulkan / Metal / D3D12
                 ^
         core.h: BoundingBox, Camera3D, Projections

Project Structure

include/skigen/plot/
  core.h          BoundingBox2D/3D, Camera3D, projections, normalization
  plotview.h      PlotView widget: plot(), scatter(), pointCloud(), mesh()
  export.h        Shared library export macros

src/
  core.cpp        Projection and camera matrix implementations
  plotview.cpp    QRhi pipeline, shader loading, GPU buffer management
  shaders/        GLSL 440 vertex/fragment shaders (compiled to .qsb)

tests/            Headless math tests
examples/         Line, scatter, point cloud, and mesh examples
doc/              API registry, guide pages

Documentation

Integrated into the Skigen Project website under the Plot navigation entry.

License

MIT