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392 lines (341 loc) · 7.77 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 <GL/glew.h>
#include "Texture.h"
#include "VertexArray.h"
#include "Shader.h"
#include <algorithm>
#include "Actor.h"
#include "SpriteComponent.h"
#include "Actor.h"
#include "Ship.h"
#include "Asteroid.h"
#include "Random.h"
#include "InputSystem.h"
Game::Game()
:mWindow(nullptr)
,mSpriteShader(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;
}
// Set OpenGL attributes
// Use the core OpenGL profile
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
// Specify version 3.3
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
// Request a color buffer with 8-bits per RGBA channel
SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
// Enable double buffering
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
// Force OpenGL to use hardware acceleration
SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
mWindow = SDL_CreateWindow("Game Programming in C++ (Chapter 5)", 100, 100,
1024, 768, SDL_WINDOW_OPENGL);
if (!mWindow)
{
SDL_Log("Failed to create window: %s", SDL_GetError());
return false;
}
// Initialize input system
mInputSystem = new InputSystem();
if (!mInputSystem->Initialize())
{
SDL_Log("Failed to initialize input system");
return false;
}
// Create an OpenGL context
mContext = SDL_GL_CreateContext(mWindow);
// Initialize GLEW
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK)
{
SDL_Log("Failed to initialize GLEW.");
return false;
}
// On some platforms, GLEW will emit a benign error code,
// so clear it
glGetError();
// Make sure we can create/compile shaders
if (!LoadShaders())
{
SDL_Log("Failed to load shaders.");
return false;
}
// Create quad for drawing sprites
CreateSpriteVerts();
LoadData();
mTicksCount = SDL_GetTicks();
return true;
}
void Game::RunLoop()
{
while (mIsRunning)
{
ProcessInput();
UpdateGame();
GenerateOutput();
}
}
void Game::ProcessInput()
{
mInputSystem->PrepareForUpdate();
SDL_Event event;
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_QUIT:
mIsRunning = false;
break;
}
}
mInputSystem->Update();
const InputState& state = mInputSystem->GetState();
if (state.Keyboard.GetKeyState(SDL_SCANCODE_ESCAPE)
== EReleased)
{
mIsRunning = false;
}
mUpdatingActors = true;
for (auto actor : mActors)
{
actor->ProcessInput(state);
}
mUpdatingActors = false;
}
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)
{
pending->ComputeWorldTransform();
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()
{
// Set the clear color to grey
glClearColor(0.86f, 0.86f, 0.86f, 1.0f);
// Clear the color buffer
glClear(GL_COLOR_BUFFER_BIT);
// Draw all sprite components
// Enable alpha blending on the color buffer
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// Set shader/vao as active
mSpriteShader->SetActive();
mSpriteVerts->SetActive();
for (auto sprite : mSprites)
{
sprite->Draw(mSpriteShader);
}
// Swap the buffers
SDL_GL_SwapWindow(mWindow);
}
bool Game::LoadShaders()
{
mSpriteShader = new Shader();
if (!mSpriteShader->Load("Shaders/Sprite.vert", "Shaders/Sprite.frag"))
{
return false;
}
mSpriteShader->SetActive();
// Set the view-projection matrix
Matrix4 viewProj = Matrix4::CreateSimpleViewProj(1024.f, 768.f);
mSpriteShader->SetMatrixUniform("uViewProj", viewProj);
return true;
}
void Game::CreateSpriteVerts()
{
float vertices[] = {
-0.5f, 0.5f, 0.f, 0.f, 0.f, // top left
0.5f, 0.5f, 0.f, 1.f, 0.f, // top right
0.5f, -0.5f, 0.f, 1.f, 1.f, // bottom right
-0.5f, -0.5f, 0.f, 0.f, 1.f // bottom left
};
unsigned int indices[] = {
0, 1, 2,
2, 3, 0
};
mSpriteVerts = new VertexArray(vertices, 4, indices, 6);
}
void Game::LoadData()
{
// Create player's ship
mShip = new Ship(this);
mShip->SetRotation(Math::PiOver2);
// Create asteroids
const int numAsteroids = 20;
for (int i = 0; i < numAsteroids; i++)
{
new Asteroid(this);
}
}
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)
{
i.second->Unload();
delete i.second;
}
mTextures.clear();
}
Texture* Game::GetTexture(const std::string& fileName)
{
Texture* tex = nullptr;
auto iter = mTextures.find(fileName);
if (iter != mTextures.end())
{
tex = iter->second;
}
else
{
tex = new Texture();
if (tex->Load(fileName))
{
mTextures.emplace(fileName, tex);
}
else
{
delete tex;
tex = nullptr;
}
}
return tex;
}
void Game::AddAsteroid(Asteroid* ast)
{
mAsteroids.emplace_back(ast);
}
void Game::RemoveAsteroid(Asteroid* ast)
{
auto iter = std::find(mAsteroids.begin(),
mAsteroids.end(), ast);
if (iter != mAsteroids.end())
{
mAsteroids.erase(iter);
}
}
void Game::Shutdown()
{
UnloadData();
mInputSystem->Shutdown();
delete mInputSystem;
delete mSpriteVerts;
mSpriteShader->Unload();
delete mSpriteShader;
SDL_GL_DeleteContext(mContext);
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)
{
auto iter = std::find(mSprites.begin(), mSprites.end(), sprite);
mSprites.erase(iter);
}