refactor: split into static libraries and restructure scenes

- Create cbt_opengl static library for OpenGL abstraction
- Create cbt_scene static library for base scene class
- Create scenes_cube static library for cube scene
- Move scene base to cbt/ (utility), scenes to root scenes/
- Link libraries in dependency chain: cuber -> scenes -> cbt_scene -> cbt_opengl

CMakeLists.txt

@@ -18,8 +18,8 @@ find_package(glad REQUIRED)
 find_package(asio REQUIRED)
 find_package(glm REQUIRED)
 
-# Target setup
+# OpenGL abstraction library
-add_executable(cuber "cuber.cpp"
+add_library(cbt_opengl STATIC
     "cbt/opengl/context.cpp"
     "cbt/opengl/buffer.cpp"
     "cbt/opengl/texture.cpp"
@@ -27,8 +27,36 @@ add_executable(cuber "cuber.cpp"
     "cbt/opengl/shader.cpp"
     "cbt/opengl/vao.cpp"
 )
+target_include_directories(cbt_opengl PRIVATE ".")
+target_compile_features(cbt_opengl PRIVATE cxx_std_23)
+target_compile_options(cbt_opengl PRIVATE ${BASE_OPTIONS})
+target_compile_definitions(cbt_opengl PRIVATE ${BASE_DEFINITIONS})
+target_link_libraries(cbt_opengl PUBLIC fmt::fmt glfw::glfw glad::glad)
+
+# Scene base library
+add_library(cbt_scene STATIC
+    "cbt/scene.cpp"
+)
+target_include_directories(cbt_scene PRIVATE ".")
+target_compile_features(cbt_scene PRIVATE cxx_std_23)
+target_compile_options(cbt_scene PRIVATE ${BASE_OPTIONS})
+target_compile_definitions(cbt_scene PRIVATE ${BASE_DEFINITIONS})
+target_link_libraries(cbt_scene PUBLIC cbt_opengl)
+
+# Application scenes
+add_library(scenes_cube STATIC
+    "scenes/cube.cpp"
+)
+target_include_directories(scenes_cube PRIVATE ".")
+target_compile_features(scenes_cube PRIVATE cxx_std_23)
+target_compile_options(scenes_cube PRIVATE ${BASE_OPTIONS})
+target_compile_definitions(scenes_cube PRIVATE ${BASE_DEFINITIONS})
+target_link_libraries(scenes_cube PUBLIC cbt_scene glm::glm)
+
+# Main executable
+add_executable(cuber "cuber.cpp")
 target_include_directories(cuber PRIVATE ".")
 target_compile_features(cuber PRIVATE cxx_std_23)
 target_compile_options(cuber PRIVATE ${BASE_OPTIONS})
 target_compile_definitions(cuber PRIVATE ${BASE_DEFINITIONS})
-target_link_libraries(cuber PRIVATE fmt::fmt glfw::glfw glad::glad asio::asio glm::glm ${BASE_LIBRARIES})
+target_link_libraries(cuber PRIVATE cbt_scene scenes_cube asio::asio ${BASE_LIBRARIES})

cbt/scene.cpp

@@ -0,0 +1,13 @@
+#include "cbt/scene.hpp"
+
+namespace cbt {
+
+auto scene::init() -> bool {
+    return true;
+}
+
+auto scene::update(float) -> void {}
+
+auto scene::render() -> void {}
+
+}

cbt/scene.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <chrono>
+
+namespace cbt {
+
+class scene {
+public:
+    virtual ~scene() = default;
+
+    virtual auto init() -> bool;
+    virtual auto update(float delta_time) -> void;
+    virtual auto render() -> void;
+};
+
+}

cuber.cpp

@@ -2,18 +2,11 @@
 #include "GLFW/glfw3.h"
 
 #include "cbt/opengl/context.hpp"
-#include "cbt/opengl/shader.hpp"
+#include "scenes/cube.hpp"
-#include "cbt/opengl/buffer.hpp"
-#include "cbt/opengl/vao.hpp"
 
-#include <chrono>
+#include <csignal>
 
 #include <asio.hpp>
-#include <glm/glm.hpp>
-#include <glm/gtc/matrix_transform.hpp>
-#include <glm/gtc/type_ptr.hpp>
-
-#include "glad/glad.h"
 
 auto main(int, char const*[]) -> int {
     auto ctx = cbt::opengl::context("cuber", 1280, 720);
@@ -22,106 +15,11 @@ auto main(int, char const*[]) -> int {
         return 1;
     }
 
-    // compile shader
+    auto scn = cbt::scenes::cube();
-    auto prog = cbt::opengl::shader();
+    if (!scn.init()) {
-
-    char const* vert_src = R"glsl(
-        #version 410 core
-        layout(location = 0) in vec3 a_pos;
-        layout(location = 1) in vec3 a_color;
-        uniform mat4 u_model;
-        uniform mat4 u_view;
-        uniform mat4 u_proj;
-        out vec3 v_color;
-        void main() {
-            gl_Position = u_proj * u_view * u_model * vec4(a_pos, 1.0);
-            v_color = a_color;
-        }
-    )glsl";
-
-    char const* frag_src = R"glsl(
-        #version 410 core
-        in vec3 v_color;
-        out vec4 frag_color;
-        void main() {
-            frag_color = vec4(v_color, 1.0);
-        }
-    )glsl";
-
-    if (!prog.compile_vertex(vert_src) || !prog.compile_fragment(frag_src) || !prog.link()) {
         return 1;
     }
 
-    // cube vertices: 6 faces, 2 triangles per face, 3 verts each = 36 vertices
-    // each vertex: x, y, z, r, g, b
-    std::array<float, 36 * 6> vertices = {
-        // front face (cyan)
-         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-        -0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
-
-        // back face (magenta)
-         0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-        -0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-         0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
-
-        // top face (yellow)
-         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
-        -0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
-         0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
-
-        // bottom face (white)
-         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
-        -0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
-        -0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
-         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
-        -0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
-         0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
-
-        // right face (lime)
-         0.5f, -0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
-         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
-         0.5f, -0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
-         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
-         0.5f,  0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
-
-        // left face (orange)
-        -0.5f, -0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
-        -0.5f, -0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
-        -0.5f,  0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
-        -0.5f, -0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
-        -0.5f,  0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
-        -0.5f,  0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
-    };
-
-    auto vbo = cbt::opengl::buffer(cbt::opengl::buffer_type::vertex);
-    vbo.upload(vertices.data(), vertices.size() * sizeof(float));
-
-    // bind VAO and configure vertex attributes
-    auto vao = cbt::opengl::vao();
-    vao.bind();
-    vbo.bind();
-    glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), nullptr);
-    glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float),
-                         reinterpret_cast<void*>(3 * sizeof(float)));
-    vbo.unbind();
-    vao.unbind();
-
-    // enable depth testing
-    glEnable(GL_DEPTH_TEST);
-
     // signal handling
     asio::io_context io;
     asio::signal_set signals(io, SIGINT, SIGTERM);
@@ -137,7 +35,7 @@ auto main(int, char const*[]) -> int {
     };
 
     // render loop
-    auto start = std::chrono::steady_clock::now();
+    auto prev = std::chrono::steady_clock::now();
 
     while (!ctx.should_close()) {
         process_signals();
@@ -147,26 +45,11 @@ auto main(int, char const*[]) -> int {
         }
 
         auto now = std::chrono::steady_clock::now();
-        auto elapsed = std::chrono::duration<float>(now - start).count();
+        auto dt = std::chrono::duration<float>(now - prev).count();
+        prev = now;
 
-        glClearColor(0.15f, 0.15f, 0.2f, 1.0f);
+        scn.update(dt);
-        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+        scn.render();
-
-        // compute MVP matrices
-        auto aspect = 1280.0f / 720.0f;
-        auto proj = glm::perspective(glm::radians(45.0f), aspect, 0.1f, 100.0f);
-        auto view = glm::translate(glm::mat4{1.0f}, glm::vec3{0.0f, 0.0f, -3.0f});
-        auto model = glm::rotate(glm::mat4{1.0f}, elapsed, glm::vec3{1.0f, 0.5f, 0.3f});
-
-        prog.use();
-        glUniformMatrix4fv(glGetUniformLocation(prog.id(), "u_proj"), 1, GL_FALSE, glm::value_ptr(proj));
-        glUniformMatrix4fv(glGetUniformLocation(prog.id(), "u_view"), 1, GL_FALSE, glm::value_ptr(view));
-        glUniformMatrix4fv(glGetUniformLocation(prog.id(), "u_model"), 1, GL_FALSE, glm::value_ptr(model));
-
-        vao.bind();
-        glDrawArrays(GL_TRIANGLES, 0, 36);
-        vao.unbind();
-        prog.unuse();
 
         ctx.swap_buffers();
         ctx.poll_events();

scenes/cube.cpp

@@ -0,0 +1,149 @@
+#include "scenes/cube.hpp"
+
+#include <array>
+
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+#include "glad/glad.h"
+
+namespace cbt::scenes {
+
+cube::cube() {
+    m_start = std::chrono::steady_clock::now();
+}
+
+auto cube::init() -> bool {
+    if (!build_shader()) {
+        return false;
+    }
+    build_mesh();
+    glEnable(GL_DEPTH_TEST);
+    return true;
+}
+
+auto cube::update(float) -> void {}
+
+auto cube::render() -> void {
+    auto now = std::chrono::steady_clock::now();
+    auto elapsed = std::chrono::duration<float>(now - m_start).count();
+
+    glClearColor(0.15f, 0.15f, 0.2f, 1.0f);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    auto aspect = 1280.0f / 720.0f;
+    auto proj = glm::perspective(glm::radians(45.0f), aspect, 0.1f, 100.0f);
+    auto view = glm::translate(glm::mat4{1.0f}, glm::vec3{0.0f, 0.0f, -3.0f});
+    auto model = glm::rotate(glm::mat4{1.0f}, elapsed, glm::vec3{1.0f, 0.5f, 0.3f});
+
+    m_prog.use();
+    glUniformMatrix4fv(m_loc_proj, 1, GL_FALSE, glm::value_ptr(proj));
+    glUniformMatrix4fv(m_loc_view, 1, GL_FALSE, glm::value_ptr(view));
+    glUniformMatrix4fv(m_loc_model, 1, GL_FALSE, glm::value_ptr(model));
+
+    m_vao.bind();
+    glDrawArrays(GL_TRIANGLES, 0, 36);
+    m_vao.unbind();
+    m_prog.unuse();
+}
+
+auto cube::build_mesh() -> void {
+    std::array<float, 36 * 6> vertices = {
+        // front face (cyan)
+         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 1.0f,
+
+        // back face (magenta)
+         0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+        -0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+         0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 0.0f, 1.0f,
+
+        // top face (yellow)
+         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 0.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f,
+
+        // bottom face (white)
+         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
+        -0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
+         0.5f, -0.5f, -0.5f,  1.0f, 1.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
+         0.5f, -0.5f,  0.5f,  1.0f, 1.0f, 1.0f,
+
+        // right face (lime)
+         0.5f, -0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
+         0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
+         0.5f, -0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  0.0f, 1.0f, 0.0f,
+         0.5f,  0.5f, -0.5f,  0.0f, 1.0f, 0.0f,
+
+        // left face (orange)
+        -0.5f, -0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
+        -0.5f, -0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
+        -0.5f, -0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  1.0f, 0.5f, 0.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 0.5f, 0.0f,
+    };
+
+    m_vbo.upload(vertices.data(), vertices.size() * sizeof(float));
+
+    m_vao.bind();
+    m_vbo.bind();
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), nullptr);
+    glEnableVertexAttribArray(1);
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float),
+                         reinterpret_cast<void*>(3 * sizeof(float)));
+    m_vbo.unbind();
+    m_vao.unbind();
+}
+
+auto cube::build_shader() -> bool {
+    char const* vert_src = R"glsl(
+        #version 410 core
+        layout(location = 0) in vec3 a_pos;
+        layout(location = 1) in vec3 a_color;
+        uniform mat4 u_model;
+        uniform mat4 u_view;
+        uniform mat4 u_proj;
+        out vec3 v_color;
+        void main() {
+            gl_Position = u_proj * u_view * u_model * vec4(a_pos, 1.0);
+            v_color = a_color;
+        }
+    )glsl";
+
+    char const* frag_src = R"glsl(
+        #version 410 core
+        in vec3 v_color;
+        out vec4 frag_color;
+        void main() {
+            frag_color = vec4(v_color, 1.0);
+        }
+    )glsl";
+
+    if (!m_prog.compile_vertex(vert_src) || !m_prog.compile_fragment(frag_src) || !m_prog.link()) {
+        return false;
+    }
+
+    m_loc_proj = glGetUniformLocation(m_prog.id(), "u_proj");
+    m_loc_view = glGetUniformLocation(m_prog.id(), "u_view");
+    m_loc_model = glGetUniformLocation(m_prog.id(), "u_model");
+
+    return true;
+}
+
+}

scenes/cube.hpp

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "cbt/scene.hpp"
+
+#include "cbt/opengl/shader.hpp"
+#include "cbt/opengl/buffer.hpp"
+#include "cbt/opengl/vao.hpp"
+
+#include <glm/glm.hpp>
+
+namespace cbt::scenes {
+
+class cube final : public scene {
+    opengl::shader m_prog;
+    opengl::buffer m_vbo;
+    opengl::vao m_vao;
+
+    GLint m_loc_proj = -1;
+    GLint m_loc_view = -1;
+    GLint m_loc_model = -1;
+
+    std::chrono::steady_clock::time_point m_start;
+
+    auto build_mesh() -> void;
+    auto build_shader() -> bool;
+
+public:
+    cube();
+    auto init() -> bool override;
+    auto update(float delta_time) -> void override;
+    auto render() -> void override;
+};
+
+}