Function PathBezierCubicCurveToCasteljau

tutorials/common/imgui/imgui_draw.cpp:1237–1260

Closely mimics ImBezierCubicClosestPointCasteljau() in imgui.cpp

// Closely mimics ImBezierCubicClosestPointCasteljau() in imgui.cpp
static void PathBezierCubicCurveToCasteljau(ImVector<ImVec2>* path, float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, float tess_tol, int level)
{
    float dx = x4 - x1;
    float dy = y4 - y1;
    float d2 = (x2 - x4) * dy - (y2 - y4) * dx;
    float d3 = (x3 - x4) * dy - (y3 - y4) * dx;
    d2 = (d2 >= 0) ? d2 : -d2;
    d3 = (d3 >= 0) ? d3 : -d3;
    if ((d2 + d3) * (d2 + d3) < tess_tol * (dx * dx + dy * dy))
    {
        path->push_back(ImVec2(x4, y4));
    }
    else if (level < 10)
    {
        float x12 = (x1 + x2) * 0.5f, y12 = (y1 + y2) * 0.5f;
        float x23 = (x2 + x3) * 0.5f, y23 = (y2 + y3) * 0.5f;
        float x34 = (x3 + x4) * 0.5f, y34 = (y3 + y4) * 0.5f;
        float x123 = (x12 + x23) * 0.5f, y123 = (y12 + y23) * 0.5f;
        float x234 = (x23 + x34) * 0.5f, y234 = (y23 + y34) * 0.5f;
        float x1234 = (x123 + x234) * 0.5f, y1234 = (y123 + y234) * 0.5f;
        PathBezierCubicCurveToCasteljau(path, x1, y1, x12, y12, x123, y123, x1234, y1234, tess_tol, level + 1);
        PathBezierCubicCurveToCasteljau(path, x1234, y1234, x234, y234, x34, y34, x4, y4, tess_tol, level + 1);
    }
}

static void PathBezierQuadraticCurveToCasteljau(ImVector<ImVec2>* path, float x1, float y1, float x2, float y2, float x3, float y3, float tess_tol, int level)
{