meemknight.PikaEngine/Pika/thirdparty/imgui-docking/imgui/imgui_spinner.h

#pragma once
#include "imgui_internal.h"
#include <cmath>

//https://github.com/ocornut/imgui/issues/1901

namespace ImGui
{

    bool inline BufferingBar(const char *label, float value, const ImVec2 &size_arg,
        const ImU32 &bg_col = ImGui::GetColorU32(ImGuiCol_FrameBg),
        const ImU32 &fg_col = ImGui::GetColorU32(ImGuiCol_PlotHistogram))
    {
        ImGuiWindow *window = GetCurrentWindow();
        if (window->SkipItems)
            return false;

        ImGuiContext &g = *GImGui;
        const ImGuiStyle &style = g.Style;
        const ImGuiID id = window->GetID(label);

        ImVec2 pos = window->DC.CursorPos;
        ImVec2 size = size_arg;
        size.x -= style.FramePadding.x * 2;

        const ImRect bb(pos, ImVec2(pos.x + size.x, pos.y + size.y));
        ItemSize(bb, style.FramePadding.y);
        if (!ItemAdd(bb, id))
            return false;

        // Render
        const float circleStart = size.x * 0.7f;
        const float circleEnd = size.x;
        const float circleWidth = circleEnd - circleStart;

        window->DrawList->AddRectFilled(bb.Min, ImVec2(pos.x + circleStart, bb.Max.y), bg_col);
        window->DrawList->AddRectFilled(bb.Min, ImVec2(pos.x + circleStart * value, bb.Max.y), fg_col);

        const float t = g.Time;
        const float r = size.y / 2;
        const float speed = 1.5f;

        const float a = speed * 0;
        const float b = speed * 0.333f;
        const float c = speed * 0.666f;

        const float o1 = (circleWidth + r) * (t + a - speed * (int)((t + a) / speed)) / speed;
        const float o2 = (circleWidth + r) * (t + b - speed * (int)((t + b) / speed)) / speed;
        const float o3 = (circleWidth + r) * (t + c - speed * (int)((t + c) / speed)) / speed;

        window->DrawList->AddCircleFilled(ImVec2(pos.x + circleEnd - o1, bb.Min.y + r), r, bg_col);
        window->DrawList->AddCircleFilled(ImVec2(pos.x + circleEnd - o2, bb.Min.y + r), r, bg_col);
        window->DrawList->AddCircleFilled(ImVec2(pos.x + circleEnd - o3, bb.Min.y + r), r, bg_col);
    }

    bool inline Spinner(const char *label, float radius, int thickness, const ImU32 &color =
        ImGui::GetColorU32(ImGuiCol_PlotHistogram))
    {
        ImGuiWindow *window = GetCurrentWindow();
        if (window->SkipItems)
            return false;

        ImGuiContext &g = *GImGui;
        const ImGuiStyle &style = g.Style;
        const ImGuiID id = window->GetID(label);

        ImVec2 pos = window->DC.CursorPos;
        ImVec2 size((radius) * 2, (radius + style.FramePadding.y) * 2);

        const ImRect bb(pos, ImVec2(pos.x + size.x, pos.y + size.y));
        ItemSize(bb, style.FramePadding.y);
        if (!ItemAdd(bb, id))
            return false;

        // Render
        window->DrawList->PathClear();

        int num_segments = 30;
        int start = std::abs(ImSin(g.Time * 1.8f) * (num_segments - 5));

        const float a_min = IM_PI * 2.0f * ((float)start) / (float)num_segments;
        const float a_max = IM_PI * 2.0f * ((float)num_segments - 3) / (float)num_segments;

        const ImVec2 centre = ImVec2(pos.x + radius, pos.y + radius + style.FramePadding.y);

        for (int i = 0; i < num_segments; i++)
        {
            const float a = a_min + ((float)i / (float)num_segments) * (a_max - a_min);
            window->DrawList->PathLineTo(ImVec2(centre.x + ImCos(a + g.Time * 8) * radius,
                centre.y + ImSin(a + g.Time * 8) * radius));
        }

        window->DrawList->PathStroke(color, false, thickness);
    }

    //todo refactor colors
    void inline LoadingIndicatorCircle(const char *label, const float indicator_radius,
        const int circle_count, const float speed,
        const ImU32 &bg_col = ImGui::GetColorU32(ImGuiCol_FrameBg),
        const ImU32 &fg_col = ImGui::GetColorU32(ImGuiCol_PlotHistogram)
        )
    {
        ImGuiWindow *window = GetCurrentWindow();
        if (window->SkipItems)
        {
            return;
        }

        ImGuiContext &g = *GImGui;
        const ImGuiID id = window->GetID(label);

        auto style = ImGui::GetStyle();

        const ImVec2 pos = window->DC.CursorPos;
        const float circle_radius = indicator_radius / 10.0f;
        const ImRect bb(pos, ImVec2(pos.x + indicator_radius * 2.0f,
            pos.y + indicator_radius * 2.0f));
        ItemSize(bb, style.FramePadding.y);
        if (!ItemAdd(bb, id))
        {
            return;
        }
        const float t = g.Time;
        const auto degree_offset = 2.0f * IM_PI / circle_count;
        for (int i = 0; i < circle_count; ++i)
        {
            const auto x = indicator_radius * std::sin(degree_offset * i);
            const auto y = indicator_radius * std::cos(degree_offset * i);
            const auto growth = std::max(0.0f, std::sin(t * speed - i * degree_offset));

            auto main_color = ColorConvertU32ToFloat4(fg_col);
            auto backdrop_color = ColorConvertU32ToFloat4(bg_col);

            ImVec4 color;
            color.x = main_color.x * growth + backdrop_color.x * (1.0f - growth);
            color.y = main_color.y * growth + backdrop_color.y * (1.0f - growth);
            color.z = main_color.z * growth + backdrop_color.z * (1.0f - growth);
            color.w = 1.0f;
            window->DrawList->AddCircleFilled(ImVec2(pos.x + indicator_radius + x,
                pos.y + indicator_radius - y),
                circle_radius + growth * circle_radius,
                GetColorU32(color));
        }
    }

}