1 files changed, 324 insertions, 0 deletions
diff --git a/src/demo.cpp b/src/demo.cpp
new file mode 100644
index 0000000..c571006
--- /dev/null
+++ b/src/demo.cpp
@@ -0,0 +1,324 @@
+#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