Pass callback function with custom arguments to glfwSetKeyCallback()? - c++

Question

I have a GLWindow class which is a wrapper for OpenGL. This class declares data types enum class that are the arguments of the callback function:
enum class Modifier
{
NoModifier = 0,
Shift = 1,
Control = 2,
Alt = 4,
Super = 8,
};
enum class Action
{
Release = 0,
Press = 1,
Repeat = 2,
};
enum class ButtonCode
{
Button_0 = 0,
//... repeats all buttons codes from the glfw header
};
enum class KeyCode
{
UNKNOWN = -1,
Space = 32,
//.... repeats all key codes from the glfw header
};
Pointers to be passed to glfwSetKeyCallback as second parameter to std::function:
using KeyCallback = std::function<void(GLFWwindow* window, int key, int scancode, int action, int mode)>;
using CursorPosCallback = std::function<void(double, double)>;
using MouseCallback = std::function<void(ButtonCode, Action, Modifier, double, double)>;
using ScrollCallback = std::function<void(double, double)>;
On assignment, I have to declare a callback function in Main.cpp and through the GLWindow class pass a pointer to this function to glfwSetKeyCallback as the second parameter
Main.cpp:
void onKeyCallback(KeyCode key, Action action, Modifier mods)
{
std::cout << "Key: " << glfwGetKeyName(key, 0) << " is pressed." << std::endl;
}
int main()
{
...
GLWindow window("myWindow", 640, 480);
window.setKeyCallback(onKeyCallback);
...
}
And GLWindow.cpp:
void GLWindow::setKeyCallback(const KeyCallback& callback)
{
glfwSetKeyCallback(handle, ?????????);
}
Just in case, I provide the complete program code:
Window.h:
#include <glad/glad.h>
#include <glfw\glfw3.h>
#include <functional>
#include <string>
#include <iostream>
enum class Modifier
{
NoModifier = 0,
Shift = 1,
Control = 2,
Alt = 4,
Super = 8,
};
enum class Action
{
Release = 0,
Press = 1,
Repeat = 2,
};
enum class ButtonCode
{
Button_0 = 0,
//... repeats all buttons codes from the glfw header
};
enum class KeyCode
{
UNKNOWN = -1,
Space = 32,
//.... repeats all key codes from the glfw header
};
class GLWindow
{
public:
using KeyCallback = std::function<void(GLFWwindow* window, int key, int scancode, int action, int mode)>;
using CursorPosCallback = std::function<void(double, double)>;
using MouseCallback = std::function<void(ButtonCode, Action, Modifier, double, double)>;
using ScrollCallback = std::function<void(double, double)>;
GLWindow(const std::string& title, uint32_t width, uint32_t height);
~GLWindow();
uint32_t getWidth() const;
uint32_t getHeight() const;
void setKeyCallback(const KeyCallback& callback);
void setCursorPosCallback(const CursorPosCallback& callback);
void setMouseCallback(const MouseCallback& callback);
void setScrollCallback(const ScrollCallback& callback);
GLFWwindow* getGLFWHandle() const;
private:
GLFWwindow* handle;
// TODO
};
Window.cpp:
#include <glfw\glfw3.h>
#include "GLWindow.h"
GLWindow::GLWindow(const std::string& title, uint32_t width, uint32_t height)
{
handle = glfwCreateWindow(width, height, title.data(), nullptr, nullptr);
glfwMakeContextCurrent(handle);
static bool initGLAD = false;
if (!initGLAD)
{
initGLAD = true;
gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
}
glfwSetWindowUserPointer(handle, this);
glfwSetKeyCallback(handle,/* implementation details */);
glfwSetMouseButtonCallback(handle, /* implementation details */);
glfwSetCursorPosCallback(handle, /* implementation details */);
glfwSetScrollCallback(handle, /* implementation details */);
}
GLWindow::~GLWindow()
{
}
uint32_t GLWindow::getWidth() const
{
return uint32_t();
}
uint32_t GLWindow::getHeight() const
{
return uint32_t();
}
void GLWindow::setKeyCallback(const KeyCallback& callback)
{
glfwSetKeyCallback(handle, ?????????);
}
void GLWindow::setCursorPosCallback(const CursorPosCallback& callback)
{
}
void GLWindow::setMouseCallback(const MouseCallback& callback)
{
}
void GLWindow::setScrollCallback(const ScrollCallback& callback)
{
}
GLFWwindow* GLWindow::getGLFWHandle() const
{
return nullptr;
}
Main.cpp:
#include <glfw\glfw3.h>
#include "GLWindow.h"
void onKeyCallback(KeyCode key, Action action, Modifier mods)
{
std::cout << "Key: " << glfwGetKeyName(key, 0) << " is pressed." << std::endl;
}
int main()
{
glfwInit();
GLWindow window("myWindow", 640, 480);
window.setKeyCallback(onKeyCallback);
while (glfwWindowShouldClose(window.getGLFWHandle())
{
glfwSwapBuffers(window.getGLFWHandle());
glfwWaitEvents();
}
glfwTerminate();
return 0;
}