imgui_bezier.hpp

Go to the documentation of this file.

#pragma once
 
#define IMGUI_DEFINE_MATH_OPERATORS
#include <imgui.h>
#include <imgui_internal.h>
#include <time.h>
 
namespace ImGui
{
template <int steps>
auto bezier_table(ImVec2 P[], ImVec2 results[]) -> void
{
    static float C[(steps + 1) * 4], *K = nullptr;
    if (!K)
    {
        K = C;
        for (unsigned step = 0; step <= steps; ++step)
        {
            auto t          = static_cast<float>(step) / static_cast<float>(steps);
            C[step * 4 + 0] = (1 - t) * (1 - t) * (1 - t); // * P0
            C[step * 4 + 1] = 3 * (1 - t) * (1 - t) * t;   // * P1
            C[step * 4 + 2] = 3 * (1 - t) * t * t;         // * P2
            C[step * 4 + 3] = t * t * t;                   // * P3
        }
    }
    for (unsigned step = 0; step <= steps; ++step)
    {
        ImVec2 point = {
                K[step * 4 + 0] * P[0].x + K[step * 4 + 1] * P[1].x + K[step * 4 + 2] * P[2].x + K[step * 4 + 3] * P[3].
                x,
                K[step * 4 + 0] * P[0].y + K[step * 4 + 1] * P[1].y + K[step * 4 + 2] * P[2].y + K[step * 4 + 3] * P[3].
                y};
        results[step] = point;
    }
}
 
auto BezierValue(float dt01, float P[4]) -> float;
 
auto Bezier(const char* label, float P[5]) -> int;
 
// void ShowBezierDemo() {
//    { static float v[5] = { 0.950f, 0.050f, 0.795f, 0.035f };
//    Bezier("easeInExpo", v); }
//}
} // namespace ImGui