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Copy pathGame.cpp
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278 lines (242 loc) · 5.37 KB
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// ----------------------------------------------------------------
// From Game Programming in C++ by Sanjay Madhav
// Copyright (C) 2017 Sanjay Madhav. All rights reserved.
//
// Released under the BSD License
// See LICENSE in root directory for full details.
// ----------------------------------------------------------------
#include "Game.h"
#include "SDL/SDL_image.h"
#include <algorithm>
#include "Actor.h"
#include "SpriteComponent.h"
#include "Ship.h"
Game::Game()
:mWindow(nullptr)
,mRenderer(nullptr)
,mIsRunning(true)
,mUpdatingActors(false)
{
}
bool Game::Initialize()
{
if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO) != 0)
{
SDL_Log("Unable to initialize SDL: %s", SDL_GetError());
return false;
}
mWindow = SDL_CreateWindow("Game Programming in C++ (Chapter 3)", 100, 100, 1024, 768, 0);
if (!mWindow)
{
SDL_Log("Failed to create window: %s", SDL_GetError());
return false;
}
mRenderer = SDL_CreateRenderer(mWindow, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
if (!mRenderer)
{
SDL_Log("Failed to create renderer: %s", SDL_GetError());
return false;
}
if (IMG_Init(IMG_INIT_PNG) == 0)
{
SDL_Log("Unable to initialize SDL_image: %s", SDL_GetError());
return false;
}
LoadData();
mTicksCount = SDL_GetTicks();
return true;
}
void Game::RunLoop()
{
while (mIsRunning)
{
ProcessInput();
UpdateGame();
GenerateOutput();
}
}
void Game::ProcessInput()
{
SDL_Event event;
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_QUIT:
mIsRunning = false;
break;
}
}
const Uint8* state = SDL_GetKeyboardState(NULL);
if (state[SDL_SCANCODE_ESCAPE])
{
mIsRunning = false;
}
// Process ship input
mShip->ProcessKeyboard(state);
}
void Game::UpdateGame()
{
// Compute delta time
// Wait until 16ms has elapsed since last frame
while (!SDL_TICKS_PASSED(SDL_GetTicks(), mTicksCount + 16))
;
float deltaTime = (SDL_GetTicks() - mTicksCount) / 1000.0f;
if (deltaTime > 0.05f)
{
deltaTime = 0.05f;
}
mTicksCount = SDL_GetTicks();
// Update all actors
mUpdatingActors = true;
for (auto actor : mActors)
{
actor->Update(deltaTime);
}
mUpdatingActors = false;
// Move any pending actors to mActors
for (auto pending : mPendingActors)
{
mActors.emplace_back(pending);
}
mPendingActors.clear();
// Add any dead actors to a temp vector
std::vector<Actor*> deadActors;
for (auto actor : mActors)
{
if (actor->GetState() == Actor::EDead)
{
deadActors.emplace_back(actor);
}
}
// Delete dead actors (which removes them from mActors)
for (auto actor : deadActors)
{
delete actor;
}
}
void Game::GenerateOutput()
{
SDL_SetRenderDrawColor(mRenderer, 0, 0, 0, 255);
SDL_RenderClear(mRenderer);
// Draw all sprite components
for (auto sprite : mSprites)
{
sprite->Draw(mRenderer);
}
SDL_RenderPresent(mRenderer);
}
void Game::LoadData()
{
// Create player's ship
mShip = new Ship(this);
mShip->SetPosition(Vector2(100.0f, 384.0f));
}
void Game::UnloadData()
{
// Delete actors
// Because ~Actor calls RemoveActor, have to use a different style loop
while (!mActors.empty())
{
delete mActors.back();
}
// Destroy textures
for (auto i : mTextures)
{
SDL_DestroyTexture(i.second);
}
mTextures.clear();
}
SDL_Texture* Game::GetTexture(const std::string& fileName)
{
SDL_Texture* tex = nullptr;
// Is the texture already in the map?
auto iter = mTextures.find(fileName);
if (iter != mTextures.end())
{
tex = iter->second;
}
else
{
// Load from file
SDL_Surface* surf = IMG_Load(fileName.c_str());
if (!surf)
{
SDL_Log("Failed to load texture file %s", fileName.c_str());
return nullptr;
}
// Create texture from surface
tex = SDL_CreateTextureFromSurface(mRenderer, surf);
SDL_FreeSurface(surf);
if (!tex)
{
SDL_Log("Failed to convert surface to texture for %s", fileName.c_str());
return nullptr;
}
mTextures.emplace(fileName.c_str(), tex);
}
return tex;
}
void Game::Shutdown()
{
UnloadData();
IMG_Quit();
SDL_DestroyRenderer(mRenderer);
SDL_DestroyWindow(mWindow);
SDL_Quit();
}
void Game::AddActor(Actor* actor)
{
// If we're updating actors, need to add to pending
if (mUpdatingActors)
{
mPendingActors.emplace_back(actor);
}
else
{
mActors.emplace_back(actor);
}
}
void Game::RemoveActor(Actor* actor)
{
// Is it in pending actors?
auto iter = std::find(mPendingActors.begin(), mPendingActors.end(), actor);
if (iter != mPendingActors.end())
{
// Swap to end of vector and pop off (avoid erase copies)
std::iter_swap(iter, mPendingActors.end() - 1);
mPendingActors.pop_back();
}
// Is it in actors?
iter = std::find(mActors.begin(), mActors.end(), actor);
if (iter != mActors.end())
{
// Swap to end of vector and pop off (avoid erase copies)
std::iter_swap(iter, mActors.end() - 1);
mActors.pop_back();
}
}
void Game::AddSprite(SpriteComponent* sprite)
{
// Find the insertion point in the sorted vector
// (The first element with a higher draw order than me)
int myDrawOrder = sprite->GetDrawOrder();
auto iter = mSprites.begin();
for ( ;
iter != mSprites.end();
++iter)
{
if (myDrawOrder < (*iter)->GetDrawOrder())
{
break;
}
}
// Inserts element before position of iterator
mSprites.insert(iter, sprite);
}
void Game::RemoveSprite(SpriteComponent* sprite)
{
// (We can't swap because it ruins ordering)
auto iter = std::find(mSprites.begin(), mSprites.end(), sprite);
mSprites.erase(iter);
}