Tutorial 00.2: System Interface (SDL2)

If you want to use SDL2 instead of GLFW to create a system interface, use this class instead:

Complete Source Code:

Main.cpp

#include "Main.h"

#include "System_SDL2.h"

#include "Renderer_OpenGL.h"

int main(int argc, char* argv[])

{

//System_GLFW& system = System_GLFW::Instance();

System_SDL2& system = System_SDL2::Instance();

return Main::Instance(&system).MainLoop();

}

// ...

System_SDL2.h

#pragma once

#include "System.h"

#include <GL/glew.h>

#include <SDL2/SDL.h>

class System_SDL2 : public System

{

public:

// singelton

static System_SDL2& Instance(unsigned int width = 0, unsigned int height = 0);

virtual ~System_SDL2();

// update 1 frame

virtual void Update();

// window

virtual void SwapBuffers() const;

virtual bool IsCloseRequested() const;

virtual void SetWindowTitle(const std::string& name);

private:

virtual void SetupInputMap();

SDL_Window* m_window{ nullptr };

SDL_GLContext m_context;

bool m_close{ false };

System_SDL2(unsigned int width, unsigned int height);

// NOT ALLOWED TO BE COPIED OR ASSIGNED TO

System_SDL2(const System_SDL2& other) = delete;

System_SDL2& operator=(const System_SDL2& other) = delete;

};

System_SDL2.cpp

#include "System_SDL2.h"

#include <iostream>

InputState sdl_events_catched_globally;

System_SDL2::System_SDL2(unsigned int width, unsigned int height)

{

SDL_Init(SDL_INIT_EVERYTHING);

if (width == 0 || height == 0)

{

width = 1200;

height = 900;

}

unsigned int flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE;

m_window = SDL_CreateWindow("OpenGL", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, flags);

m_context = SDL_GL_CreateContext(m_window);

SDL_GL_MakeCurrent(m_window, m_context);

// initialize GLEW

if (glewInit() != GLEW_OK)

exit(EXIT_FAILURE);

// map SDL keys and mouse buttons to indices

SetupInputMap();

// initial values

Update();

}

System_SDL2 & System_SDL2::Instance(unsigned int width, unsigned int height)

{

static System_SDL2 instance(width, height);

return instance;

}

System_SDL2::~System_SDL2()

{

SDL_GL_DeleteContext(m_context);

SDL_DestroyWindow(m_window);

SDL_Quit();

}

void System_SDL2::Update()

{

// window

SDL_GetWindowPosition(m_window, &m_windowpos.x, &m_windowpos.y);

SDL_GetWindowSize(m_window, &m_windowsize.x, &m_windowsize.y);

// process events

SDL_Event e;

while (SDL_PollEvent(&e))

{

switch (e.type)

{

case SDL_QUIT:

m_close = true;

break;

case SDL_WINDOWEVENT:

if (e.window.windowID == SDL_GetWindowID(m_window))

{

switch (e.window.event)

{

case SDL_WINDOWEVENT_SIZE_CHANGED:

//std::cout << "window resized to " << e.window.data1 << " x " << e.window.data2 << std::endl;

break;

default:

break;

}

}

break;

case SDL_MOUSEMOTION:

sdl_events_catched_globally.cursor.position.x = e.motion.x;

sdl_events_catched_globally.cursor.position.y = m_windowsize.y - e.motion.y;

break;

case SDL_MOUSEBUTTONUP:

sdl_events_catched_globally.cursor.button[m_mousebuttonindex[e.button.button]] = false;

break;

case SDL_MOUSEBUTTONDOWN:

sdl_events_catched_globally.cursor.button[m_mousebuttonindex[e.button.button]] = true;

break;

case SDL_MOUSEWHEEL:

sdl_events_catched_globally.cursor.scroll = e.wheel.y;

break;

case SDL_KEYUP:

sdl_events_catched_globally.keyboard.key[m_keyindex[e.key.keysym.sym]] = false;

break;

case SDL_KEYDOWN:

sdl_events_catched_globally.keyboard.key[m_keyindex[e.key.keysym.sym]] = true;

break;

default:

break;

}

}

// input

m_previous = m_current;

m_current = sdl_events_catched_globally;

// reset scroll event

sdl_events_catched_globally.cursor.scroll = 0;

}

void System_SDL2::SwapBuffers() const

{

SDL_GL_SwapWindow(m_window);

}

bool System_SDL2::IsCloseRequested() const

{

return m_close;

}

void System_SDL2::SetWindowTitle(const std::string & name)

{

SDL_SetWindowTitle(m_window, name.c_str());

}

void System_SDL2::SetupInputMap()

{

m_keyindex[SDLK_SPACE] = KEY_SPACE;

//m_keyindex[...] = KEY_APOSTROPHE;

m_keyindex[SDLK_COMMA] = KEY_COMMA;

m_keyindex[SDLK_MINUS] = KEY_MINUS;

m_keyindex[SDLK_PERIOD] = KEY_PERIOD;

m_keyindex[SDLK_SLASH] = KEY_SLASH;

m_keyindex[SDLK_0] = KEY_0;

m_keyindex[SDLK_1] = KEY_1;

m_keyindex[SDLK_2] = KEY_2;

m_keyindex[SDLK_3] = KEY_3;

m_keyindex[SDLK_4] = KEY_4;

m_keyindex[SDLK_5] = KEY_5;

m_keyindex[SDLK_6] = KEY_6;

m_keyindex[SDLK_7] = KEY_7;

m_keyindex[SDLK_8] = KEY_8;

m_keyindex[SDLK_9] = KEY_9;

m_keyindex[SDLK_SEMICOLON] = KEY_SEMICOLON;

m_keyindex[SDLK_EQUALS] = KEY_EQUAL;

m_keyindex[SDLK_a] = KEY_A;

m_keyindex[SDLK_b] = KEY_B;

m_keyindex[SDLK_c] = KEY_C;

m_keyindex[SDLK_d] = KEY_D;

m_keyindex[SDLK_e] = KEY_E;

m_keyindex[SDLK_f] = KEY_F;

m_keyindex[SDLK_g] = KEY_G;

m_keyindex[SDLK_h] = KEY_H;

m_keyindex[SDLK_i] = KEY_I;

m_keyindex[SDLK_j] = KEY_J;

m_keyindex[SDLK_k] = KEY_K;

m_keyindex[SDLK_l] = KEY_L;

m_keyindex[SDLK_m] = KEY_M;

m_keyindex[SDLK_n] = KEY_N;

m_keyindex[SDLK_o] = KEY_O;

m_keyindex[SDLK_p] = KEY_P;

m_keyindex[SDLK_q] = KEY_Q;

m_keyindex[SDLK_r] = KEY_R;

m_keyindex[SDLK_s] = KEY_S;

m_keyindex[SDLK_t] = KEY_T;

m_keyindex[SDLK_u] = KEY_U;

m_keyindex[SDLK_v] = KEY_V;

m_keyindex[SDLK_w] = KEY_W;

m_keyindex[SDLK_x] = KEY_X;

m_keyindex[SDLK_y] = KEY_Y;

m_keyindex[SDLK_z] = KEY_Z;

m_keyindex[SDLK_LEFTBRACKET] = KEY_LEFT_BRACKET;

m_keyindex[SDLK_BACKSLASH] = KEY_BACKSLASH;

m_keyindex[SDLK_RIGHTBRACKET] = KEY_RIGHT_BRACKET;

//m_keyindex[...] = KEY_GRAVE_ACCENT;

//m_keyindex[...] = KEY_WORLD_1;

//m_keyindex[...] = KEY_WORLD_2;

/* Function keys */

m_keyindex[SDLK_ESCAPE] = KEY_ESCAPE;

//m_keyindex[...] = KEY_ENTER;

m_keyindex[SDLK_TAB] = KEY_TAB;

m_keyindex[SDLK_BACKSPACE] = KEY_BACKSPACE;

m_keyindex[SDLK_INSERT] = KEY_INSERT;

m_keyindex[SDLK_DELETE] = KEY_DELETE;

m_keyindex[SDLK_RIGHT] = KEY_RIGHT;

m_keyindex[SDLK_LEFT] = KEY_LEFT;

m_keyindex[SDLK_DOWN] = KEY_DOWN;

m_keyindex[SDLK_UP] = KEY_UP;

m_keyindex[SDLK_PAGEUP] = KEY_PAGE_UP;

m_keyindex[SDLK_PAGEDOWN] = KEY_PAGE_DOWN;

m_keyindex[SDLK_HOME] = KEY_HOME;

m_keyindex[SDLK_END] = KEY_END;

m_keyindex[SDLK_CAPSLOCK] = KEY_CAPS_LOCK;

m_keyindex[SDLK_SCROLLLOCK] = KEY_SCROLL_LOCK;

//m_keyindex[...] = KEY_NUM_LOCK;

m_keyindex[SDLK_PRINTSCREEN] = KEY_PRINT_SCREEN;

m_keyindex[SDLK_PAUSE] = KEY_PAUSE;

m_keyindex[SDLK_F1] = KEY_F1;

m_keyindex[SDLK_F2] = KEY_F2;

m_keyindex[SDLK_F3] = KEY_F3;

m_keyindex[SDLK_F4] = KEY_F4;

m_keyindex[SDLK_F5] = KEY_F5;

m_keyindex[SDLK_F6] = KEY_F6;

m_keyindex[SDLK_F7] = KEY_F7;

m_keyindex[SDLK_F8] = KEY_F8;

m_keyindex[SDLK_F9] = KEY_F9;

m_keyindex[SDLK_F10] = KEY_F10;

m_keyindex[SDLK_F11] = KEY_F11;

m_keyindex[SDLK_F12] = KEY_F12;

m_keyindex[SDLK_F13] = KEY_F13;

m_keyindex[SDLK_F14] = KEY_F14;

m_keyindex[SDLK_F15] = KEY_F15;

m_keyindex[SDLK_F16] = KEY_F16;

m_keyindex[SDLK_F17] = KEY_F17;

m_keyindex[SDLK_F18] = KEY_F18;

m_keyindex[SDLK_F19] = KEY_F19;

m_keyindex[SDLK_F20] = KEY_F20;

m_keyindex[SDLK_F21] = KEY_F21;

m_keyindex[SDLK_F22] = KEY_F22;

m_keyindex[SDLK_F23] = KEY_F23;

m_keyindex[SDLK_F24] = KEY_F24;

//m_keyindex[...] = KEY_F25;

m_keyindex[SDLK_KP_0] = KEY_KP_0;

m_keyindex[SDLK_KP_1] = KEY_KP_1;

m_keyindex[SDLK_KP_2] = KEY_KP_2;

m_keyindex[SDLK_KP_3] = KEY_KP_3;

m_keyindex[SDLK_KP_4] = KEY_KP_4;

m_keyindex[SDLK_KP_5] = KEY_KP_5;

m_keyindex[SDLK_KP_6] = KEY_KP_6;

m_keyindex[SDLK_KP_7] = KEY_KP_7;

m_keyindex[SDLK_KP_8] = KEY_KP_8;

m_keyindex[SDLK_KP_9] = KEY_KP_9;

m_keyindex[SDLK_KP_DECIMAL] = KEY_KP_DECIMAL;

m_keyindex[SDLK_KP_DIVIDE] = KEY_KP_DIVIDE;

m_keyindex[SDLK_KP_MULTIPLY] = KEY_KP_MULTIPLY;

m_keyindex[SDLK_KP_MINUS] = KEY_KP_SUBTRACT;

m_keyindex[SDLK_KP_PLUS] = KEY_KP_ADD;

m_keyindex[SDLK_KP_ENTER] = KEY_KP_ENTER;

m_keyindex[SDLK_KP_EQUALS] = KEY_KP_EQUAL;

m_keyindex[SDLK_LSHIFT] = KEY_LEFT_SHIFT;

m_keyindex[SDLK_LCTRL] = KEY_LEFT_CONTROL;

m_keyindex[SDLK_LALT] = KEY_LEFT_ALT;

m_keyindex[SDLK_LGUI] = KEY_LEFT_SUPER;

m_keyindex[SDLK_RSHIFT] = KEY_RIGHT_SHIFT;

m_keyindex[SDLK_RCTRL] = KEY_RIGHT_CONTROL;

m_keyindex[SDLK_RALT] = KEY_RIGHT_ALT;

m_keyindex[SDLK_RGUI] = KEY_RIGHT_SUPER;

//m_keyindex[...] = KEY_MENU;

//m_keyindex[...] = KEY_LAST;

//m_mousebuttonindex[...] = MOUSE_BUTTON_LAST;

m_mousebuttonindex[SDL_BUTTON_LEFT] = MOUSE_BUTTON_LEFT;

m_mousebuttonindex[SDL_BUTTON_RIGHT] = MOUSE_BUTTON_RIGHT;

m_mousebuttonindex[SDL_BUTTON_MIDDLE] = MOUSE_BUTTON_MIDDLE;

//m_mousebuttonindex[...] = MOUSE_BUTTON_4;

//m_mousebuttonindex[...] = MOUSE_BUTTON_5;

//m_mousebuttonindex[...] = MOUSE_BUTTON_6;

//m_mousebuttonindex[...] = MOUSE_BUTTON_7;

//m_mousebuttonindex[...] = MOUSE_BUTTON_8;

}