RigidElasticSim/src/viewer/ColorbarPlugin.h

//
// Created by cflin on 4/8/23.
//

#ifndef RIGIDIPC_COLORBARPLUGIN_H
#define RIGIDIPC_COLORBARPLUGIN_H

#include <Eigen/Dense>
#include <igl/opengl/glfw/Viewer.h>
#include <igl/opengl/glfw/imgui/ImGuiMenu.h>

class ColorbarPlugin {
public:
     ColorbarPlugin() {
         // initialize
        Eigen::MatrixXd rgb;
        Eigen::MatrixXd f=Eigen::VectorXd::LinSpaced(100,0.0,1.0);
        for (size_t i = 0; i < igl::NUM_COLOR_MAP_TYPES; ++i) {
            GLuint id = 0;
            igl::colormap(static_cast<igl::ColorMapType>(i),f,0.0,1.0,rgb);
//            std::cout<<std::endl;
//            std::cout<<rgb<<std::endl;
            texture_from_colormap(rgb, id);
            colormaps_[i] = id;
        }
    }

// Draws a combo box for selecting the colormap
    int draw_colormap_combo() const {
        const char *items[]{
                "Inferno",
                "Jet",
                "Magma",
                "Parula",
                "Plasma",
                "Viridis",
        };
        static int selected_index = 5;
        static const char *current_item = items[selected_index];
        ImVec2 combo_pos = ImGui::GetCursorScreenPos();
        if (ImGui::BeginCombo("Colormap##combo", "")) {
            for (int n = 0; n < IM_ARRAYSIZE(items); ++n) {
                // You can store your selection however you want, outside or inside your objects
                bool is_selected = (current_item == items[n]);
                ImGui::PushID(n);
                if (ImGui::Selectable("", is_selected)) {
                    current_item = items[n];
                    selected_index = n;
                }
                ImGui::SameLine(0, 0);
                ImGui::Image(
                        reinterpret_cast<ImTextureID>(colormaps_[n]),
                        ImVec2(ImGui::GetTextLineHeight(), ImGui::GetTextLineHeight()),
                        ImVec2(0, 0), ImVec2(1, 1));
                ImGui::SameLine();
                ImGui::Text("%s", items[n]);
                if (is_selected) {
                    ImGui::SetItemDefaultFocus();
                }
                ImGui::PopID();
            }
            ImGui::EndCombo();
        }

        ImVec2 backup_pos = ImGui::GetCursorScreenPos();
        ImGuiStyle &style = ImGui::GetStyle();
        ImGui::SetCursorScreenPos(ImVec2(combo_pos.x + style.FramePadding.x, combo_pos.y + style.FramePadding.y));
        float h = ImGui::GetTextLineHeight();
        ImGui::Image(
                reinterpret_cast<ImTextureID>(colormaps_[selected_index]),
                ImVec2(h, h));
        ImGui::SameLine();
        ImGui::Text("%s", current_item);
        ImGui::SetCursorScreenPos(backup_pos);

        return selected_index;
    }

    void draw_colorbar(igl::ColorMapType cm, float xmin, float xmax,
                       const Eigen::Vector4f &background_color) const {
        ImVec4 color(0, 0, 0, 1);
        auto rgb = background_color;
        // http://stackoverflow.com/a/3943023/112731
        if (rgb[0] * 0.299 + rgb[1] * 0.587 + rgb[2] * 0.114 > 186) {
            color = ImVec4(1, 1, 1, 1);
        }
        float w = 20;
        float h = 100;
        ImGui::BeginGroup();
        ImGui::BeginGroup();
        ImGui::TextColored(color, "%.3g", xmin);
        ImGui::Dummy(ImVec2(0, h - 2 * ImGui::GetTextLineHeightWithSpacing()));
        ImGui::TextColored(color, "%.3g", xmax);
        ImGui::EndGroup();
        ImGui::SameLine();
        ImGui::Image(reinterpret_cast<ImTextureID>(colormaps_[cm]), ImVec2(w, h));
        ImGui::EndGroup();
    }

    static void texture_from_colormap(const Eigen::MatrixXd &rgb, GLuint &id) {
        int width = 1;
        int height = (int) rgb.rows();

        Eigen::Matrix<unsigned char, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor> cmap;
        if (rgb.maxCoeff() > 1.0) {
            cmap = rgb.cast<unsigned char>();
        } else {
            cmap = (rgb.array() * 255.f).cast<unsigned char>();
        }
        assert(cmap.cols() == 3);
        cmap.conservativeResize(cmap.rows(), 4);
        cmap.col(3).setConstant(255);

        if (id == 0) {
            glGenTextures(1, &id);
        }
        glBindTexture(GL_TEXTURE_2D, id);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexImage2D(
                GL_TEXTURE_2D, 0, GL_RGBA,
                width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, cmap.data());
        glGenerateMipmap(GL_TEXTURE_2D);
        glBindTexture(GL_TEXTURE_2D, 0);
    }

protected:
    std::array<GLuint, igl::NUM_COLOR_MAP_TYPES> colormaps_;
    igl::ColorMapType colormap_type_ = igl::COLOR_MAP_TYPE_VIRIDIS;
};


#endif //RIGIDIPC_COLORBARPLUGIN_H