path: root/src/demo.cpp

#include "demo.hpp"

#include "stb_image.h"

#include <SDL.h>
#include <SDL_opengl.h>
#include <cstdio>
#include <fud_c_file.hpp>
#include <fud_string.hpp>
#include <imgui/imgui.h>
#include <imgui/imgui_impl_opengl3.h>
#include <imgui/imgui_impl_sdl2.h>
#include <spdlog/spdlog.h>
#include <vector>

namespace bookworm {

// Simple helper function to load an image into a OpenGL texture with common settings
bool LoadTextureFromMemory(const void* data, size_t data_size, GLuint* out_texture, int* out_width, int* out_height)
{
    // Load from file
    int width = 0;
    int height = 0;
    int channelsInFile = 4;
    unsigned char*
        image_data = stbi_load_from_memory((const unsigned char*)data, (int)data_size, &width, &height, nullptr, 4);
    if (image_data == nullptr) {
        spdlog::error("Failed to get data from");
        return false;
    }

    spdlog::info("Got result: {} pixels per row of {} scanlines with {} channels", width, height, channelsInFile);

    // Create a OpenGL texture identifier
    GLuint image_texture;
    glGenTextures(1, &image_texture);
    glBindTexture(GL_TEXTURE_2D, image_texture);

    // Setup filtering parameters for display
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // Upload pixels into texture
    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image_data);
    stbi_image_free(image_data);

    *out_texture = image_texture;
    *out_width = width;
    *out_height = height;

    return true;
}

// Open and read a file, then forward to LoadTextureFromMemory()
bool LoadTextureFromFile(const fud::String& filename, GLuint* out_texture, int* out_width, int* out_height)
{
    fud::CBinaryFile inFile{filename, fud::CFileMode::ReadOnly};
    auto fileResult = inFile.open();
    using fud::FileStatus;
    if (fileResult == FileStatus::Error) {
        spdlog::error("can't open {}", filename.c_str());
        // return err(ImageError::FileError);
        return false;
    }

    auto fileSizeResult = inFile.size();
    if (fileSizeResult.isError()) {
        spdlog::error("bad file size {} {}", filename.c_str(), FileStatusToString(fileSizeResult.getError()));
        return false;
    }
    auto fileSize = fileSizeResult.getOkay();

    auto* filePtr = inFile.file();
    if (filePtr == nullptr) {
        spdlog::error("File associated with {} returned nullptr", filename.c_str());
        // return err(ImageError::FileError);
        return false;
    }

    std::vector<char> fileData{};
    fileData.resize(fileSize);

    auto readStatus = inFile.read(fileData.data(), fileSize, fileSize);
    if (readStatus != FileStatus::Success) {
        spdlog::error("bad read {} {}", filename.c_str(), FileStatusToString(readStatus));
        return false;
    }

    bool ret = LoadTextureFromMemory(fileData.data(), fileSize, out_texture, out_width, out_height);
    return ret;
}

int demo(const fud::String& m_filename)
{

    // Setup SDL
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0) {
        printf("Error: %s\n", SDL_GetError());
        return -1;
    }

    // Decide GL+GLSL versions
#if defined(IMGUI_IMPL_OPENGL_ES2)
    // GL ES 2.0 + GLSL 100
    const char* glsl_version = "#version 100";
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_ES);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
#elif defined(__APPLE__)
    // GL 3.2 Core + GLSL 150
    const char* glsl_version = "#version 150";
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
#else
    // GL 3.0 + GLSL 130
    const char* glsl_version = "#version 130";
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
#endif

    // From 2.0.18: Enable native IME.
#ifdef SDL_HINT_IME_SHOW_UI
    SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");
#endif

    // Create window with graphics context
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
    SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
    SDL_WindowFlags window_flags = (SDL_WindowFlags)(SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE |
                                                     SDL_WINDOW_ALLOW_HIGHDPI);
    SDL_Window* window = SDL_CreateWindow(
        "Dear ImGui SDL2+OpenGL3 example",
        SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED,
        1280,
        720,
        window_flags);
    if (window == nullptr) {
        printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
        return -1;
    }

    SDL_GLContext gl_context = SDL_GL_CreateContext(window);
    SDL_GL_MakeCurrent(window, gl_context);
    SDL_GL_SetSwapInterval(1); // Enable vsync

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;  // Enable Gamepad Controls

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    // ImGui::StyleColorsLight();

    // Setup Platform/Renderer backends
    ImGui_ImplSDL2_InitForOpenGL(window, gl_context);
    ImGui_ImplOpenGL3_Init(glsl_version);

    int my_image_width = 0;
    int my_image_height = 0;
    GLuint my_image_texture = 0;
    bool ret = LoadTextureFromFile(m_filename, &my_image_texture, &my_image_width, &my_image_height);
    IM_ASSERT(ret);

    // Load Fonts
    // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use
    // ImGui::PushFont()/PopFont() to select them.
    // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
    // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your
    // application (e.g. use an assertion, or display an error and quit).
    // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling
    // ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
    // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering.
    // - Read 'docs/FONTS.md' for more instructions and details.
    // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double
    // backslash \\ !
    // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See
    // Makefile.emscripten for details.
    // io.Fonts->AddFontDefault();
    // io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf", 18.0f);
    // io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
    // io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
    // io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
    // ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr,
    // io.Fonts->GetGlyphRangesJapanese()); IM_ASSERT(font != nullptr);

    // Our state
    bool show_demo_window = true;
    bool show_another_window = false;
    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

    // Main loop
    bool done = false;
#ifdef __EMSCRIPTEN__
    // For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the
    // imgui.ini file. You may manually call LoadIniSettingsFromMemory() to load settings from your own storage.
    io.IniFilename = nullptr;
    EMSCRIPTEN_MAINLOOP_BEGIN
#else
    while (!done)
#endif
    {
        // Poll and handle events (inputs, window resize, etc.)
        // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your
        // inputs.
        // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or
        // clear/overwrite your copy of the mouse data.
        // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or
        // clear/overwrite your copy of the keyboard data.
        // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those
        // two flags.
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            ImGui_ImplSDL2_ProcessEvent(&event);
            if (event.type == SDL_QUIT)
                done = true;
            if (event.type == SDL_WINDOWEVENT && event.window.event == SDL_WINDOWEVENT_CLOSE &&
                event.window.windowID == SDL_GetWindowID(window))
                done = true;
        }
        if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED) {
            SDL_Delay(10);
            continue;
        }

        // Start the Dear ImGui frame
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplSDL2_NewFrame();
        ImGui::NewFrame();

        // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code
        // to learn more about Dear ImGui!).
        if (show_demo_window)
            ImGui::ShowDemoWindow(&show_demo_window);

        // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
        {
            ImGui::Begin("OpenGL Texture Text");
            ImGui::Text("pointer = %x", my_image_texture);
            ImGui::Text("size = %d x %d", my_image_width, my_image_height);
            ImGui::Image(
                (void*)(intptr_t)my_image_texture,
                ImVec2(static_cast<float>(my_image_width), static_cast<float>(my_image_height)));
            ImGui::End();

            static float f = 0.0f;
            static int counter = 0;

            // Create a window called "Hello, world!" and append into it.
            ImGui::Begin("Hello, world!");

            // Display some text (you can use a format strings too)
            ImGui::Text("This is some useful text.");
            // Edit bools storing our window open/close state
            ImGui::Checkbox("Demo Window", &show_demo_window);
            ImGui::Checkbox("Another Window", &show_another_window);

            // Edit 1 float using a slider from 0.0f to 1.0f
            ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
            // Edit 3 floats representing a color
            ImGui::ColorEdit3("clear color", (float*)&clear_color);

            // Buttons return true when clicked (most widgets return true when edited/activated)
            if (ImGui::Button("Button"))
                counter++;
            ImGui::SameLine();
            ImGui::Text("counter = %d", counter);

            ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
            ImGui::End();
        }

        // 3. Show another simple window.
        if (show_another_window) {
            // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when
            // clicked)
            ImGui::Begin("Another Window", &show_another_window);
            ImGui::Text("Hello from another window!");
            if (ImGui::Button("Close Me"))
                show_another_window = false;
            ImGui::End();
        }

        // Rendering
        ImGui::Render();
        glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
        glClearColor(
            clear_color.x * clear_color.w,
            clear_color.y * clear_color.w,
            clear_color.z * clear_color.w,
            clear_color.w);
        glClear(GL_COLOR_BUFFER_BIT);
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
        SDL_GL_SwapWindow(window);
    }
#ifdef __EMSCRIPTEN__
    EMSCRIPTEN_MAINLOOP_END;
#endif

    // Cleanup
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplSDL2_Shutdown();
    ImGui::DestroyContext();

    SDL_GL_DeleteContext(gl_context);
    SDL_DestroyWindow(window);
    SDL_Quit();
    // return ImageResult::okay(image);

    return 0;
}

} // namespace bookworm