Move OpenGL backend classes from tests/OpenGL to engine/

- Relocated OpenGLDevice, OpenGLShader, OpenGLBuffer, OpenGLVertexArray, OpenGLTexture to engine/
- Updated engine/CMakeLists.txt to include OpenGL backend source files
- Updated tests/OpenGL/CMakeLists.txt to use engine backend
- Added OpenGLTexture class implementation

engine/src/RHI/OpenGL/OpenGLBuffer.cpp

@@ -0,0 +1,61 @@
+#define GLFW_INCLUDE_NONE
+#include "XCEngine/RHI/OpenGL/OpenGLBuffer.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+namespace XCEngine {
+namespace RHI {
+
+OpenGLBuffer::OpenGLBuffer()
+    : m_buffer(0)
+    , m_size(0)
+    , m_isIndexBuffer(false) {
+}
+
+OpenGLBuffer::~OpenGLBuffer() {
+    Shutdown();
+}
+
+bool OpenGLBuffer::InitializeVertexBuffer(const void* data, size_t size) {
+    glGenBuffers(1, &m_buffer);
+    glBindBuffer(GL_ARRAY_BUFFER, m_buffer);
+    glBufferData(GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW);
+    m_size = size;
+    m_isIndexBuffer = false;
+    return true;
+}
+
+bool OpenGLBuffer::InitializeIndexBuffer(const void* data, size_t size) {
+    glGenBuffers(1, &m_buffer);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_buffer);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, size, data, GL_STATIC_DRAW);
+    m_size = size;
+    m_isIndexBuffer = true;
+    return true;
+}
+
+void OpenGLBuffer::Shutdown() {
+    if (m_buffer) {
+        glDeleteBuffers(1, &m_buffer);
+        m_buffer = 0;
+    }
+}
+
+void OpenGLBuffer::Bind() const {
+    if (m_isIndexBuffer) {
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_buffer);
+    } else {
+        glBindBuffer(GL_ARRAY_BUFFER, m_buffer);
+    }
+}
+
+void OpenGLBuffer::Unbind() const {
+    if (m_isIndexBuffer) {
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+    } else {
+        glBindBuffer(GL_ARRAY_BUFFER, 0);
+    }
+}
+
+} // namespace RHI
+} // namespace XCEngine

engine/src/RHI/OpenGL/OpenGLDevice.cpp

@@ -0,0 +1,95 @@
+#define GLFW_INCLUDE_NONE
+#include "XCEngine/RHI/OpenGL/OpenGLDevice.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+namespace XCEngine {
+namespace RHI {
+
+OpenGLDevice::OpenGLDevice()
+    : m_window(nullptr)
+    , m_initialized(false)
+    , m_ownsWindow(false) {
+}
+
+OpenGLDevice::~OpenGLDevice() {
+    Shutdown();
+}
+
+bool OpenGLDevice::CreateRenderWindow(int width, int height, const char* title, bool enableDebug) {
+    if (m_initialized) {
+        return true;
+    }
+
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+    m_window = glfwCreateWindow(width, height, title, nullptr, nullptr);
+    if (!m_window) {
+        return false;
+    }
+
+    m_ownsWindow = true;
+    return InitializeWithExistingWindow(m_window);
+}
+
+bool OpenGLDevice::InitializeWithExistingWindow(GLFWwindow* window) {
+    if (m_initialized) {
+        return true;
+    }
+
+    m_window = window;
+    if (!m_window) {
+        return false;
+    }
+
+    glfwMakeContextCurrent(m_window);
+
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+        return false;
+    }
+
+    m_deviceInfo.vendor = reinterpret_cast<const char*>(glGetString(GL_VENDOR));
+    m_deviceInfo.renderer = reinterpret_cast<const char*>(glGetString(GL_RENDERER));
+    m_deviceInfo.version = reinterpret_cast<const char*>(glGetString(GL_VERSION));
+    
+    glGetIntegerv(GL_MAJOR_VERSION, &m_deviceInfo.majorVersion);
+    glGetIntegerv(GL_MINOR_VERSION, &m_deviceInfo.minorVersion);
+
+    m_initialized = true;
+    return true;
+}
+
+void OpenGLDevice::Shutdown() {
+    if (m_ownsWindow && m_window) {
+        glfwDestroyWindow(m_window);
+    }
+    m_window = nullptr;
+    m_initialized = false;
+    m_ownsWindow = false;
+}
+
+void OpenGLDevice::SwapBuffers() {
+    if (m_window) {
+        glfwSwapBuffers(m_window);
+    }
+}
+
+bool OpenGLDevice::PollEvents() {
+    glfwPollEvents();
+    return !glfwWindowShouldClose(m_window);
+}
+
+void OpenGLDevice::SetShouldClose(bool shouldClose) {
+    if (m_window) {
+        glfwSetWindowShouldClose(m_window, shouldClose ? GLFW_TRUE : GLFW_FALSE);
+    }
+}
+
+bool OpenGLDevice::ShouldClose() const {
+    return m_window && glfwWindowShouldClose(m_window) == GLFW_TRUE;
+}
+
+} // namespace RHI
+} // namespace XCEngine

engine/src/RHI/OpenGL/OpenGLShader.cpp

@@ -0,0 +1,130 @@
+#define GLFW_INCLUDE_NONE
+#include "XCEngine/RHI/OpenGL/OpenGLShader.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+
+namespace XCEngine {
+namespace RHI {
+
+OpenGLShader::OpenGLShader()
+    : m_program(0) {
+}
+
+OpenGLShader::~OpenGLShader() {
+    Shutdown();
+}
+
+bool OpenGLShader::CompileFromFile(const char* vertexPath, const char* fragmentPath) {
+    std::string vertexCode, fragmentCode;
+    std::ifstream vShaderFile(vertexPath), fShaderFile(fragmentPath);
+    
+    if (!vShaderFile.is_open() || !fShaderFile.is_open()) {
+        return false;
+    }
+    
+    std::stringstream vShaderStream, fShaderStream;
+    vShaderStream << vShaderFile.rdbuf();
+    fShaderStream << fShaderFile.rdbuf();
+    vShaderFile.close();
+    fShaderFile.close();
+    
+    vertexCode = vShaderStream.str();
+    fragmentCode = fShaderStream.str();
+    
+    return Compile(vertexCode.c_str(), fragmentCode.c_str());
+}
+
+bool OpenGLShader::Compile(const char* vertexSource, const char* fragmentSource) {
+    unsigned int vertex, fragment;
+    
+    vertex = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertex, 1, &vertexSource, NULL);
+    glCompileShader(vertex);
+    if (!CheckCompileErrors(vertex, "VERTEX")) {
+        return false;
+    }
+    
+    fragment = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragment, 1, &fragmentSource, NULL);
+    glCompileShader(fragment);
+    if (!CheckCompileErrors(fragment, "FRAGMENT")) {
+        return false;
+    }
+    
+    m_program = glCreateProgram();
+    glAttachShader(m_program, vertex);
+    glAttachShader(m_program, fragment);
+    glLinkProgram(m_program);
+    
+    if (!CheckLinkErrors(m_program)) {
+        return false;
+    }
+    
+    glDeleteShader(vertex);
+    glDeleteShader(fragment);
+    
+    return true;
+}
+
+void OpenGLShader::Shutdown() {
+    if (m_program) {
+        glDeleteProgram(m_program);
+        m_program = 0;
+    }
+}
+
+void OpenGLShader::Use() const {
+    glUseProgram(m_program);
+}
+
+void OpenGLShader::SetInt(const std::string& name, int value) const {
+    glUniform1i(glGetUniformLocation(m_program, name.c_str()), value);
+}
+
+void OpenGLShader::SetFloat(const std::string& name, float value) const {
+    glUniform1f(glGetUniformLocation(m_program, name.c_str()), value);
+}
+
+void OpenGLShader::SetVec3(const std::string& name, float x, float y, float z) const {
+    glUniform3f(glGetUniformLocation(m_program, name.c_str()), x, y, z);
+}
+
+void OpenGLShader::SetVec3(const std::string& name, const float* values) const {
+    glUniform3fv(glGetUniformLocation(m_program, name.c_str()), 1, values);
+}
+
+void OpenGLShader::SetMat4(const std::string& name, const float* value) const {
+    glUniformMatrix4fv(glGetUniformLocation(m_program, name.c_str()), 1, GL_FALSE, value);
+}
+
+bool OpenGLShader::CheckCompileErrors(unsigned int shader, const char* type) {
+    int success;
+    char infoLog[1024];
+    
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        glGetShaderInfoLog(shader, 1024, NULL, infoLog);
+        std::cout << "ERROR::SHADER_COMPILATION_ERROR: " << type << "\n" << infoLog << std::endl;
+        return false;
+    }
+    return true;
+}
+
+bool OpenGLShader::CheckLinkErrors(unsigned int program) {
+    int success;
+    char infoLog[1024];
+    
+    glGetProgramiv(program, GL_LINK_STATUS, &success);
+    if (!success) {
+        glGetProgramInfoLog(program, 1024, NULL, infoLog);
+        std::cout << "ERROR::PROGRAM_LINKING_ERROR\n" << infoLog << std::endl;
+        return false;
+    }
+    return true;
+}
+
+} // namespace RHI
+} // namespace XCEngine

engine/src/RHI/OpenGL/OpenGLTexture.cpp

@@ -0,0 +1,79 @@
+#define GLFW_INCLUDE_NONE
+#include "XCEngine/RHI/OpenGL/OpenGLTexture.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <stb_image.h>
+#include <iostream>
+
+namespace XCEngine {
+namespace RHI {
+
+OpenGLTexture::OpenGLTexture()
+    : m_texture(0)
+    , m_width(0)
+    , m_height(0)
+    , m_channels(0) {
+}
+
+OpenGLTexture::~OpenGLTexture() {
+    Shutdown();
+}
+
+bool OpenGLTexture::Initialize2D(int width, int height, int channels, const void* data, bool generateMipmap) {
+    glGenTextures(1, &m_texture);
+    glBindTexture(GL_TEXTURE_2D, m_texture);
+    
+    GLenum format = (channels == 4) ? GL_RGBA : GL_RGB;
+    glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
+    
+    if (generateMipmap) {
+        glGenerateMipmap(GL_TEXTURE_2D);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    } else {
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    }
+    
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+    
+    m_width = width;
+    m_height = height;
+    m_channels = channels;
+    
+    glBindTexture(GL_TEXTURE_2D, 0);
+    return true;
+}
+
+bool OpenGLTexture::LoadFromFile(const char* path, bool flipVertical) {
+    stbi_set_flip_vertically_on_load(flipVertical ? 1 : 0);
+    
+    unsigned char* data = stbi_load(path, &m_width, &m_height, &m_channels, 0);
+    if (!data) {
+        std::cout << "Failed to load texture: " << path << std::endl;
+        return false;
+    }
+    
+    bool result = Initialize2D(m_width, m_height, m_channels, data, true);
+    stbi_image_free(data);
+    return result;
+}
+
+void OpenGLTexture::Shutdown() {
+    if (m_texture) {
+        glDeleteTextures(1, &m_texture);
+        m_texture = 0;
+    }
+}
+
+void OpenGLTexture::Bind(int slot) const {
+    glActiveTexture(GL_TEXTURE0 + slot);
+    glBindTexture(GL_TEXTURE_2D, m_texture);
+}
+
+void OpenGLTexture::Unbind() const {
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+} // namespace RHI
+} // namespace XCEngine

engine/src/RHI/OpenGL/OpenGLVertexArray.cpp

@@ -0,0 +1,60 @@
+#define GLFW_INCLUDE_NONE
+#include "XCEngine/RHI/OpenGL/OpenGLVertexArray.h"
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+namespace XCEngine {
+namespace RHI {
+
+OpenGLVertexArray::OpenGLVertexArray()
+    : m_vao(0)
+    , m_indexBuffer(0)
+    , m_indexCount(0)
+    , m_vertexBufferCount(0) {
+}
+
+OpenGLVertexArray::~OpenGLVertexArray() {
+    Shutdown();
+}
+
+bool OpenGLVertexArray::Initialize() {
+    glGenVertexArrays(1, &m_vao);
+    return true;
+}
+
+void OpenGLVertexArray::AddVertexBuffer(unsigned int buffer, const VertexAttribute& attribute) {
+    glBindVertexArray(m_vao);
+    glBindBuffer(GL_ARRAY_BUFFER, buffer);
+    glEnableVertexAttribArray(attribute.index);
+    glVertexAttribPointer(attribute.index, attribute.count, attribute.type, 
+        attribute.normalized ? GL_TRUE : GL_FALSE, 
+        attribute.stride, (void*)attribute.offset);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindVertexArray(0);
+    m_vertexBufferCount++;
+}
+
+void OpenGLVertexArray::SetIndexBuffer(unsigned int buffer, unsigned int type) {
+    glBindVertexArray(m_vao);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
+    glBindVertexArray(0);
+    m_indexBuffer = buffer;
+}
+
+void OpenGLVertexArray::Shutdown() {
+    if (m_vao) {
+        glDeleteVertexArrays(1, &m_vao);
+        m_vao = 0;
+    }
+}
+
+void OpenGLVertexArray::Bind() const {
+    glBindVertexArray(m_vao);
+}
+
+void OpenGLVertexArray::Unbind() const {
+    glBindVertexArray(0);
+}
+
+} // namespace RHI
+} // namespace XCEngine