Adding a New Component

This skill guides you through adding a new component (class, system, or module) to the Vulkan Display Engine.

When to use this skill

•Creating a new engine system or subsystem
•Adding a new public API class
•Implementing a new renderer, manager, or utility class
•Extending the engine with new functionality
•Adding internal implementation classes

Component Structure

VDE follows a clear structure for code organization:

•Public API headers: include/vde/ - Headers exposed to users
•Implementation files: src/ - Core implementation code
•API implementation: src/api/ - Game-facing API implementations
•Tests: tests/ - Unit tests for components

Steps to Add a Component

1. Create the Header File

Add your header to include/vde/ComponentName.h:

cpp

#pragma once

#include <vulkan/vulkan.h>
// Other necessary includes

namespace vde {

/**
 * @brief Brief description of the component
 * 
 * Detailed description explaining the purpose,
 * usage patterns, and key responsibilities.
 */
class ComponentName {
public:
    ComponentName();
    ~ComponentName();
    
    // Public methods with Doxygen documentation
    
private:
    // Private members with m_ prefix
};

} // namespace vde

2. Create the Implementation File

Add your implementation to src/ComponentName.cpp:

cpp

#include <vde/ComponentName.h>

// Include order:
// 1. Corresponding header (already included)
// 2. Other vde headers: <vde/...>
// 3. Third-party headers
// 4. Standard library headers

namespace vde {

ComponentName::ComponentName() {
    // Implementation
}

ComponentName::~ComponentName() {
    // Cleanup
}

} // namespace vde

3. Register in CMake

Add both files to the root CMakeLists.txt:

cmake

# Add to VDE_PUBLIC_HEADERS
set(VDE_PUBLIC_HEADERS
    # ... existing headers ...
    include/vde/ComponentName.h
)

# Add to VDE_SOURCES
set(VDE_SOURCES
    # ... existing sources ...
    src/ComponentName.cpp
)

4. Make it Accessible

If the component is part of the public API, add it to include/vde/Core.h:

cpp

// Core VDE includes
#include <vde/ComponentName.h>

This allows users to include everything with #include <vde/Core.h>.

5. Create Unit Tests

Add test coverage in tests/ComponentName_test.cpp:

cpp

/**
 * @file ComponentName_test.cpp
 * @brief Unit tests for ComponentName
 */

#include <gtest/gtest.h>
#include <vde/ComponentName.h>
// Other necessary includes

namespace vde::test {

class ComponentNameTest : public ::testing::Test {
protected:
    void SetUp() override {
        // Test setup
    }
    
    void TearDown() override {
        // Test cleanup
    }
};

TEST_F(ComponentNameTest, DescriptiveTestName) {
    // Test implementation
    EXPECT_TRUE(true);
}

} // namespace vde::test

See the create-tests skill for detailed testing guidelines.

6. Register Tests in CMake

Add the test file to tests/CMakeLists.txt:

cmake

set(VDE_TEST_SOURCES
    # ... existing tests ...
    ComponentName_test.cpp
)

Naming Conventions

Follow these conventions from conventions.md:

•Classes: PascalCase (e.g., ComponentName, RenderManager)
•Functions/Methods: camelCase (e.g., initialize(), createBuffer())
•Constants: UPPER_SNAKE_CASE or kPrefix (e.g., MAX_FRAMES, kDefaultSize)
•Member variables: m_ prefix (e.g., m_device, m_bufferSize)
•Namespace: vde:: for all engine code

Best Practices

•One class per file: Keep headers and implementations focused
•RAII for resources: Use constructors/destructors for Vulkan resource management
•Document public APIs: Use Doxygen-style comments with @brief, @param, @return, @throws
•Error handling: Throw std::runtime_error for unrecoverable issues; return values for recoverable cases
•Include guards: Use #pragma once in all headers
•Test early: Create basic tests alongside the component to verify functionality
•Follow conventions: Match the style and patterns of existing engine code

Example: Adding a BufferManager

Header (include/vde/BufferManager.h):

cpp

#pragma once

#include <vulkan/vulkan.h>
#include <memory>
#include <vector>

namespace vde {

/**
 * @brief Manages Vulkan buffer allocation and lifetime
 * 
 * Provides RAII-based buffer management with automatic
 * cleanup and tracking of buffer resources.
 */
class BufferManager {
public:
    BufferManager(VkDevice device, VkPhysicalDevice physicalDevice);
    ~BufferManager();
    
    /**
     * @brief Creates a new buffer with the specified properties
     * @param size Size of the buffer in bytes
     * @param usage Buffer usage flags
     * @param properties Memory property flags
     * @return Unique pointer to the created buffer
     * @throws std::runtime_error if buffer creation fails
     */
    std::unique_ptr<Buffer> createBuffer(
        VkDeviceSize size,
        VkBufferUsageFlags usage,
        VkMemoryPropertyFlags properties
    );
    
private:
    VkDevice m_device;
    VkPhysicalDevice m_physicalDevice;
    std::vector<VkBuffer> m_buffers;
    std::vector<VkDeviceMemory> m_memories;
};

} // namespace vde

Implementation (src/BufferManager.cpp):

cpp

#include <vde/BufferManager.h>
#include <vde/BufferUtils.h>

#include <stdexcept>

namespace vde {

BufferManager::BufferManager(VkDevice device, VkPhysicalDevice physicalDevice)
    : m_device(device)
    , m_physicalDevice(physicalDevice) {
}

BufferManager::~BufferManager() {
    // RAII cleanup
    for (size_t i = 0; i < m_buffers.size(); ++i) {
        vkDestroyBuffer(m_device, m_buffers[i], nullptr);
        vkFreeMemory(m_device, m_memories[i], nullptr);
    }
}

std::unique_ptr<Buffer> BufferManager::createBuffer(
    VkDeviceSize size,
    VkBufferUsageFlags usage,
    VkMemoryPropertyFlags properties
) {
    VkBuffer buffer;
    VkDeviceMemory memory;
    
    BufferUtils::createBuffer(size, usage, properties, buffer, memory);
    
    m_buffers.push_back(buffer);
    m_memories.push_back(memory);
    
    return std::make_unique<Buffer>(buffer, memory, size);
}

} // namespace vde

Tests (tests/BufferManager_test.cpp):

cpp

#include <gtest/gtest.h>
#include <vde/BufferManager.h>

namespace vde::test {

TEST(BufferManagerTest, CreateBufferSucceeds) {
    // Test implementation
    EXPECT_TRUE(true);
}

} // namespace vde::test

Verification

After adding a component:

•Build succeeds: cmake --build build --config Debug
•Tests pass: ./scripts/build-and-test.ps1 -NoBuild
•No warnings: Check compiler output for warnings
•Documentation clear: Review Doxygen comments for clarity
•Follows conventions: Verify naming and style match project standards

See build-tool-workflows for build and test commands.