Drawing a Rotating 3D Cube with Delta Time using SDL3, GLM, GLAD, and OpenGL 3.3 Отрисовка вращающегося 3D-куба с дельта-таймом с помощью SDL3, GLM, GLAD и OpenGL 3.3

A step-by-step guide to rendering a colored 3D rotating cube with frame-rate independent animation using SDL3, GLM 3D matrix transformations, depth testing, and the GLAD loader library on Windows and Ubuntu. Пошаговое руководство по отрисовке цветного вращающегося 3D-куба с анимацией, независимой от частоты кадров, с использованием SDL3, 3D-трансформаций GLM, теста глубины и библиотеки-загрузчика GLAD под Windows и Ubuntu.

Before proceeding, make sure you have generated GLAD and installed the required libraries on your system using the appropriate guides: Перед продолжением убедитесь, что вы сгенерировали GLAD и установили необходимые библиотеки в вашей системе, следуя соответствующим инструкциям:

Step 1: Create Project Directory Шаг 1: Создание директории проекта

Create a workspace folder and a new directory for your 3D cube project: Создайте рабочую папку для проектов и новую директорию для вашего проекта 3D-куба:

Windows (Command Prompt / PowerShell)

mkdir C:\projects\draw-cube-sdl3-glm-glad-opengl-desktop
cd C:\projects\draw-cube-sdl3-glm-glad-opengl-desktop

Ubuntu (Terminal)

mkdir -p ~/projects/draw-cube-sdl3-glm-glad-opengl-desktop
cd ~/projects/draw-cube-sdl3-glm-glad-opengl-desktop

Step 2: Create Source Files (main.cpp & CMakeLists.txt) Шаг 2: Создание исходных файлов (main.cpp и CMakeLists.txt)

Create these files using Notepad / Sublime Text on Windows, or nano in Ubuntu terminal: Создайте эти файлы через Блокнот / Sublime Text в Windows или с помощью nano в терминале Ubuntu:

Windows (Terminal / Notepad)

notepad main.cpp
notepad CMakeLists.txt

Ubuntu (Terminal / Nano)

nano main.cpp
nano CMakeLists.txt

Quick Nano Commands (Ubuntu):Быстрые команды Nano (Ubuntu): Paste code with Right Mouse Button (RMB) → Press Ctrl + O and Enter to save → Press Ctrl + X to exit. Вставьте код правой кнопкой мыши (ПКМ) → Нажмите Ctrl + O и Enter для сохранения → Нажмите Ctrl + X для выхода.

Key Features in 3D Rendering with Delta TimeКлючевые особенности 3D-рендеринга с дельта-таймом
1. Depth Buffer: Enabled via glEnable(GL_DEPTH_TEST) and cleared with GL_DEPTH_BUFFER_BIT so back faces don't overlap front faces.
2. Delta Time: Uses SDL_GetTicksNS() to compute smooth frame delta in seconds, making rotation speed consistent regardless of GPU framerate. 1. Буфер глубины: Включается с помощью glEnable(GL_DEPTH_TEST) и очищается вместе с GL_DEPTH_BUFFER_BIT, чтобы задние грани не перекрывали передние.
2. Дельта-тайм: Использует SDL_GetTicksNS() для расчёта плавного шага времени в секундах, делая скорость вращения постоянной независимо от FPS.

1A. File Contents for main.cpp (Classic Loop) 1A. Содержимое файла main.cpp (Классический цикл)

#include <glad/glad.h> // Must be included before SDL headers
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

// Vertex Shader source code
const char* vertexShaderSource = R"(
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;

out vec3 ourColor;
uniform mat4 uMVP;

void main() {
    gl_Position = uMVP * vec4(aPos, 1.0);
    ourColor = aColor;
}
)";

// Fragment Shader source code
const char* fragmentShaderSource = R"(
#version 330 core
out vec4 FragColor;
in vec3 ourColor;

void main() {
    FragColor = vec4(ourColor, 1.0);
}
)";

GLuint createShaderProgram(const char* vertexSrc, const char* fragmentSrc) {
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexSrc, nullptr);
    glCompileShader(vertexShader);

    GLint success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(vertexShader, 512, nullptr, infoLog);
        SDL_Log("Vertex Shader Compilation Failed: %s", infoLog);
    }

    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentSrc, nullptr);
    glCompileShader(fragmentShader);

    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(fragmentShader, 512, nullptr, infoLog);
        SDL_Log("Fragment Shader Compilation Failed: %s", infoLog);
    }

    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, nullptr, infoLog);
        SDL_Log("Shader Program Link Failed: %s", infoLog);
    }

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    return shaderProgram;
}

int main(int argc, char* argv[]) {
    if (!SDL_Init(SDL_INIT_VIDEO)) {
        SDL_Log("SDL Initialization failed: %s", SDL_GetError());
        return -1;
    }

    // Configure OpenGL 3.3 Core Profile attributes
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

    SDL_Window* window = SDL_CreateWindow("SDL3 GLM GLAD OpenGL 3.3 Rotating Cube (Classic)", 800, 450, SDL_WINDOW_OPENGL);
    if (!window) {
        SDL_Log("Window creation failed: %s", SDL_GetError());
        SDL_Quit();
        return -1;
    }

    SDL_GLContext glContext = SDL_GL_CreateContext(window);
    if (!glContext) {
        SDL_Log("OpenGL context creation failed: %s", SDL_GetError());
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    SDL_GL_MakeCurrent(window, glContext);
    SDL_GL_SetSwapInterval(1); // Enable VSync

    // Initialize GLAD function pointers
    if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress)) {
        SDL_Log("Failed to initialize GLAD");
        SDL_GL_DestroyContext(glContext);
        SDL_DestroyWindow(window);
        SDL_Quit();
        return -1;
    }

    // Enable OpenGL Depth Testing
    glEnable(GL_DEPTH_TEST);

    GLuint shaderProgram = createShaderProgram(vertexShaderSource, fragmentShaderSource);

    // Cube Vertex Data (Positions + RGB Colors for 6 faces, 36 vertices)
    float vertices[] = {
        // Positions          // Colors
        // Front face (Reddish)
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
        -0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,

        // Back face (Greenish)
        -0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
        -0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,

        // Left face (Blueish)
        -0.5f,  0.5f,  0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.2f, 0.2f, 1.0f,

        // Right face (Yellowish)
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.2f,

        // Top face (Cyanish)
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,

        // Bottom face (Magentaish)
        -0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f
    };

    GLuint VAO, VBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // Position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // Color attribute
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    GLint mvpLoc = glGetUniformLocation(shaderProgram, "uMVP");

    glm::vec3 clearColorVec(0.1f, 0.12f, 0.15f);
    glm::mat4 projection = glm::perspective(glm::radians(45.0f), 800.0f / 450.0f, 0.1f, 100.0f);
    glm::mat4 view = glm::lookAt(glm::vec3(0.0f, 1.5f, 3.5f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));

    float rotationAngle = 0.0f;
    Uint64 lastTicks = SDL_GetTicksNS();

    bool running = true;
    while (running) {
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_EVENT_QUIT) {
                running = false;
            }
        }

        // Calculate Delta Time in seconds
        Uint64 currentTicks = SDL_GetTicksNS();
        float deltaTime = static_cast<float>(currentTicks - lastTicks) / 1e9f;
        lastTicks = currentTicks;

        // Rotate 60 degrees per second
        rotationAngle += 60.0f * deltaTime;
        if (rotationAngle >= 360.0f) {
            rotationAngle -= 360.0f;
        }

        // Model matrix transformation
        glm::mat4 model = glm::mat4(1.0f);
        model = glm::rotate(model, glm::radians(rotationAngle), glm::vec3(0.5f, 1.0f, 0.0f));

        glm::mat4 mvp = projection * view * model;

        // Clear Color and Depth Buffers
        glClearColor(clearColorVec.r, clearColorVec.g, clearColorVec.b, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Draw Cube
        glUseProgram(shaderProgram);
        glUniformMatrix4fv(mvpLoc, 1, GL_FALSE, glm::value_ptr(mvp));

        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        SDL_GL_SwapWindow(window);
    }

    // Cleanup resources
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteProgram(shaderProgram);

    SDL_GL_DestroyContext(glContext);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}

1B. File Contents for main.cpp (SDL3 Callbacks API) 1B. Содержимое файла main.cpp (SDL3 Callbacks API)

#define SDL_MAIN_USE_CALLBACKS 1
#include <glad/glad.h> // Must be included before SDL headers
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

// Vertex Shader source code
const char* vertexShaderSource = R"(
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;

out vec3 ourColor;
uniform mat4 uMVP;

void main() {
    gl_Position = uMVP * vec4(aPos, 1.0);
    ourColor = aColor;
}
)";

// Fragment Shader source code
const char* fragmentShaderSource = R"(
#version 330 core
out vec4 FragColor;
in vec3 ourColor;

void main() {
    FragColor = vec4(ourColor, 1.0);
}
)";

GLuint createShaderProgram(const char* vertexSrc, const char* fragmentSrc) {
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexSrc, nullptr);
    glCompileShader(vertexShader);

    GLint success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(vertexShader, 512, nullptr, infoLog);
        SDL_Log("Vertex Shader Compilation Failed: %s", infoLog);
    }

    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentSrc, nullptr);
    glCompileShader(fragmentShader);

    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(fragmentShader, 512, nullptr, infoLog);
        SDL_Log("Fragment Shader Compilation Failed: %s", infoLog);
    }

    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, nullptr, infoLog);
        SDL_Log("Shader Program Link Failed: %s", infoLog);
    }

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    return shaderProgram;
}

struct AppState {
    SDL_Window* window = nullptr;
    SDL_GLContext glContext = nullptr;
    GLuint shaderProgram = 0;
    GLuint VAO = 0;
    GLuint VBO = 0;
    GLint mvpLoc = -1;
    glm::mat4 projection = glm::mat4(1.0f);
    glm::mat4 view = glm::mat4(1.0f);
    float rotationAngle = 0.0f;
    Uint64 lastTicks = 0;
    glm::vec3 clearColorVec = glm::vec3(0.1f, 0.12f, 0.15f);
};

SDL_AppResult SDL_AppInit(void** appstate, int argc, char* argv[]) {
    if (!SDL_Init(SDL_INIT_VIDEO)) {
        SDL_Log("SDL Initialization failed: %s", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    // Set callback rate hint before window creation
    SDL_SetHint(SDL_HINT_MAIN_CALLBACK_RATE, "60");

    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1); // Enable MULTISAMPLE
    SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 8); // Can be 2, 4, 8 or 16

    // Configure OpenGL 3.3 Core Profile attributes
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);

    AppState* state = new AppState();
    *appstate = state;

    state->window = SDL_CreateWindow("SDL3 GLM GLAD OpenGL 3.3 Rotating Cube (Callbacks)", 800, 450, SDL_WINDOW_OPENGL);
    if (!state->window) {
        SDL_Log("Window creation failed: %s", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    state->glContext = SDL_GL_CreateContext(state->window);
    if (!state->glContext) {
        SDL_Log("OpenGL context creation failed: %s", SDL_GetError());
        return SDL_APP_FAILURE;
    }

    SDL_GL_MakeCurrent(state->window, state->glContext);
    SDL_GL_SetSwapInterval(1);

    if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress)) {
        SDL_Log("Failed to initialize GLAD");
        return SDL_APP_FAILURE;
    }

    glEnable(GL_DEPTH_TEST);

    state->shaderProgram = createShaderProgram(vertexShaderSource, fragmentShaderSource);

    float vertices[] = {
        // Front face (Reddish)
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
        -0.5f,  0.5f,  0.5f,  1.0f, 0.2f, 0.2f,
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 0.2f,

        // Back face (Greenish)
        -0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,
        -0.5f, -0.5f, -0.5f,  0.2f, 1.0f, 0.2f,

        // Left face (Blueish)
        -0.5f,  0.5f,  0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f, -0.5f,  0.5f,  0.2f, 0.2f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.2f, 0.2f, 1.0f,

        // Right face (Yellowish)
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.2f,
         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.2f,

        // Top face (Cyanish)
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,
        -0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,  0.2f, 1.0f, 1.0f,
         0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,
        -0.5f,  0.5f, -0.5f,  0.2f, 1.0f, 1.0f,

        // Bottom face (Magentaish)
        -0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
         0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
        -0.5f, -0.5f,  0.5f,  1.0f, 0.2f, 1.0f,
        -0.5f, -0.5f, -0.5f,  1.0f, 0.2f, 1.0f
    };

    glGenVertexArrays(1, &state->VAO);
    glGenBuffers(1, &state->VBO);

    glBindVertexArray(state->VAO);

    glBindBuffer(GL_ARRAY_BUFFER, state->VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    state->projection = glm::perspective(glm::radians(45.0f), 800.0f / 450.0f, 0.1f, 100.0f);
    state->view = glm::lookAt(glm::vec3(0.0f, 1.5f, 3.5f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 1.0f, 0.0f));
    state->mvpLoc = glGetUniformLocation(state->shaderProgram, "uMVP");
    state->lastTicks = SDL_GetTicksNS();

    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppEvent(void* appstate, SDL_Event* event) {
    if (event->type == SDL_EVENT_QUIT) {
        return SDL_APP_SUCCESS;
    }
    return SDL_APP_CONTINUE;
}

SDL_AppResult SDL_AppIterate(void* appstate) {
    auto* state = static_cast<AppState*>(appstate);

    Uint64 currentTicks = SDL_GetTicksNS();
    float deltaTime = static_cast<float>(currentTicks - state->lastTicks) / 1e9f;
    state->lastTicks = currentTicks;

    state->rotationAngle += 60.0f * deltaTime;
    if (state->rotationAngle >= 360.0f) {
        state->rotationAngle -= 360.0f;
    }

    glm::mat4 model = glm::mat4(1.0f);
    model = glm::rotate(model, glm::radians(state->rotationAngle), glm::vec3(0.5f, 1.0f, 0.0f));

    glm::mat4 mvp = state->projection * state->view * model;

    glClearColor(state->clearColorVec.r, state->clearColorVec.g, state->clearColorVec.b, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glUseProgram(state->shaderProgram);
    glUniformMatrix4fv(state->mvpLoc, 1, GL_FALSE, glm::value_ptr(mvp));

    glBindVertexArray(state->VAO);
    glDrawArrays(GL_TRIANGLES, 0, 36);

    SDL_GL_SwapWindow(state->window);

    return SDL_APP_CONTINUE;
}

void SDL_AppQuit(void* appstate, SDL_AppResult result) {
    if (appstate) {
        auto* state = static_cast<AppState*>(appstate);

        if (state->VAO) glDeleteVertexArrays(1, &state->VAO);
        if (state->VBO) glDeleteBuffers(1, &state->VBO);
        if (state->shaderProgram) glDeleteProgram(state->shaderProgram);

        if (state->glContext) {
            SDL_GL_DestroyContext(state->glContext);
        }
        if (state->window) {
            SDL_DestroyWindow(state->window);
        }
        delete state;
    }
    SDL_Quit();
}

2. File Contents for CMakeLists.txt 2. Содержимое файла CMakeLists.txt

cmake_minimum_required(VERSION 3.21)

# Default to Debug if CMAKE_BUILD_TYPE is not set via command line
if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE "Debug")
endif()

project(draw-cube-sdl3-glm-glad-opengl-desktop CXX C)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# -----------------------------------------------------------------------------
# Locate System OpenGL Package
# -----------------------------------------------------------------------------
find_package(OpenGL REQUIRED)

# -----------------------------------------------------------------------------
# Locate SDL3 Package via Custom Paths
# -----------------------------------------------------------------------------
if(WIN32)
    set(SDL3_DIR "C:/libs/sdl3-3.4.16-mingw/lib/cmake/SDL3")
else()
    set(SDL3_DIR "$ENV{HOME}/libs/sdl3-3.4.16-ubuntu/lib/cmake/SDL3")
endif()

find_package(SDL3 REQUIRED CONFIG)

# -----------------------------------------------------------------------------
# Set Include Path for Header-Only GLM Library
# -----------------------------------------------------------------------------
if(WIN32)
    set(GLM_INCLUDE_DIR "C:/libs/glm-1.0.3/glm")
else()
    set(GLM_INCLUDE_DIR "$ENV{HOME}/libs/glm-1.0.3")
endif()

# -----------------------------------------------------------------------------
# Set Path and Source for GLAD Loader
# -----------------------------------------------------------------------------
if(WIN32)
    set(GLAD_DIR "C:/libs/glad-0.1.36/opengl-3.3")
else()
    set(GLAD_DIR "$ENV{HOME}/libs/glad-0.1.36/opengl-3.3")
endif()

set(GLAD_INCLUDE_DIR "${GLAD_DIR}/include")
set(GLAD_SOURCE "${GLAD_DIR}/src/glad.c")

# -----------------------------------------------------------------------------
# Target Definition
# -----------------------------------------------------------------------------
set(PROJECT_SOURCES
    main.cpp
    ${GLAD_SOURCE}
)

add_executable(app ${PROJECT_SOURCES})

# Include GLM and GLAD headers
target_include_directories(app PRIVATE 
    ${GLM_INCLUDE_DIR}
    ${GLAD_INCLUDE_DIR}
)

# Link SDL3 statically and system OpenGL library
target_link_libraries(app PRIVATE SDL3::SDL3-static OpenGL::GL)

# -----------------------------------------------------------------------------
# Platform-Specific Compiler & Linker Flags
# -----------------------------------------------------------------------------
if(WIN32)
    target_compile_options(app PRIVATE -Os)
    target_link_options(app PRIVATE -static -s -static-libgcc)

    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        target_link_options(app PRIVATE -mconsole)
    else()
        target_link_options(app PRIVATE -mwindows)
    endif()
endif()

Step 3: Create Build & Execution Scripts Шаг 3: Создание скриптов сборки и запуска

Windows (MinGW / Batch Scripts)

config-exe.bat

cmake -G Ninja -S . -B dist/win

build-exe.bat

cmake --build dist/win

run-exe.bat

@echo off
.\dist\win\app.exe

Run the scripts sequentially in Command Prompt or PowerShell: Последовательно запустите скрипты в командной строке или PowerShell:

config-exe.bat
build-exe.bat
run-exe.bat

Ubuntu (Bash Scripts)

config-bin.sh

#!/usr/bin/env bash
set -e
cmake -G Ninja -S . -B dist/linux

build-bin.sh

#!/usr/bin/env bash
set -e
cmake --build dist/linux

run-bin.sh

#!/usr/bin/env bash
set -e
./dist/linux/app

Grant execute permissions on Ubuntu before running: Предоставьте права на выполнение в Ubuntu перед запуском:

chmod +x config-bin.sh build-bin.sh run-bin.sh
./config-bin.sh
./build-bin.sh
./run-bin.sh

Step 4: Expected Output Шаг 4: Ожидаемый результат

Upon running the application, a window will open displaying a smoothly rotating colored 3D cube rendered with OpenGL 3.3 depth testing and GLM perspective projection. После запуска приложения откроется окно с плавно вращающимся цветным 3D-кубом, отрисованным с помощью теста глубины OpenGL 3.3 и перспективной проекции GLM.

SDL3 GLM GLAD OpenGL 3.3 Rotating Cube (Classic)

or (if using the Callbacks API version): или (если используется версия с Callbacks API):

SDL3 GLM GLAD OpenGL 3.3 Rotating Cube (Callbacks)

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