PixieLib 0.2.0

PixieLib

Primitives and math for C++ and C#, with one vocabulary and one memory layout. A PxRect made in C# crosses P/Invoke and arrives in C++ as a pxRect, with no conversion.

• Points, sizes, rectangles, regions, paddings, and RGBA and HSL colors, in double, float and int.
• Vectors, segments and matrices, with the 2D transforms and the 3D projections. In C++ they are GLM's; C# follows GLM's formulas, in the same order, so both sides give the same bits.
• In C++ only: events with the shape of C#'s (+=, -=, and subscriptions that end on their own).

A point is a position and a vector a displacement: point - point is a vector, a point or a rectangle moves by a vector, and a 3x3 matrix applies its translation to a point. What depends on where the origin is, as point + point or point * 2, does not compile.

It is not an engine: no window, rendering, input or assets, and no dependency on a UI framework. The C# package is fully managed and calls no native code.

C#

dotnet add package PixieLib

For .NET 10 and .NET Framework 4.8.1. A name without a suffix is double; f is float and i is int (PxPoint, PxPointf, PxPointi).

using PixieLib;

var screen = new PxRect(0, 0, 640, 480);
bool inside = screen.Contains(new PxPoint(100, 50));     // true
var orange = new PxColorRgba(255, 128, 0);                // alpha last, 255 by default
var turn = PxMat3.Rotate(PxMat3.Identity, Math.PI / 2);  // 2D transforms on a 3x3 matrix
PxVec3 moved = turn * new PxVec3(1, 0, 1);                // the vector is a column: M * v
PxVec2 step = new PxPoint(4, 6) - new PxPoint(1, 2);     // (3, 4): point - point is a vector
double length = new PxSegment(new PxPoint(1, 2), new PxPoint(4, 6)).Length();  // 5

C++

C++20 and CMake 3.20. The CMake project is in cpp/:

include(FetchContent)
FetchContent_Declare(pixielib
    GIT_REPOSITORY https://github.com/Sakamoto0110/PixieLib.git
    GIT_TAG v0.2.0
    SOURCE_SUBDIR cpp)
FetchContent_MakeAvailable(pixielib)

target_link_libraries(engine PRIVATE pixie::pixie pixie::events pixie::math)

• pixie::pixie: the primitives, only headers.
• pixie::events: the events, only headers.
• pixie::math: the vectors and matrices. It brings GLM 1.0.3; PIXIE_SYSTEM_GLM=ON takes GLM from find_package instead, and PIXIE_MATH=OFF leaves the math (and GLM) out.

#include <pixie/pxRect.hpp>
#include <pixie/events/pxEvent.hpp>
#include <pixie/math/pxMat.hpp>

class Button {
public:
    pxEvent<Button, Button&> Click;  // only Button can raise it
    void Press() { Click(*this); }
};

void Example() {
    pxRect screen(0, 0, 640, 480);
    bool inside = screen.Contains(pxPoint(100, 50));  // true

    Button button;
    pxSubscription s = button.Click.Subscribe([](Button&) { /* ... */ });
    button.Press();

    pxMat4 projection = pxOrtho2D(640.0, 480.0);  // 2D keeps Y down
}

The same bits on both sides

The layout and the rules both sides follow are in docs/layout.md. The math gives the same bits in C++ and C# when the C++ compiler does not fuse a multiply and an add into one instruction: GCC and Clang need -ffp-contract=off, and MSVC does not fuse with its default /fp:precise. GLM compiled by MSVC adds the dot product of a vec4 in sequence instead of in pairs, so there the last bit of a few vec4 and mat4 operations can differ.

Documentation

• ROADMAP.md: what PixieLib is and is not, who uses it, and where it is going.
• TODO.md: promoted work. TASKLIST.md: its task breakdowns.
• DEPENDENCIES.md: every dependency and its status.
• docs/: the documentation index, the module references, the development guide, the proposals, and the archive, where the decisions behind the library are kept with their reasons.

License

MIT, in LICENSE.