Code changes

chalonverse · chalonverse · commit a52d0fe900a4 · 2017-11-12T22:44:35.000-08:00
diff --git a/Chapter01/Game.cpp b/Chapter01/Game.cpp
@@ -24,7 +24,7 @@ Game::Game()
 bool Game::Initialize()
 {
 	// Initialize SDL
-	int sdlResult = SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO);
+	int sdlResult = SDL_Init(SDL_INIT_VIDEO);
 	if (sdlResult != 0)
 	{
 		SDL_Log("Unable to initialize SDL: %s", SDL_GetError());
@@ -47,7 +47,7 @@ bool Game::Initialize()
 		return false;
 	}
 	
-	// Create SDL renderer
+	//// Create SDL renderer
 	mRenderer = SDL_CreateRenderer(
 		mWindow, // Window to create renderer for
 		-1,		 // Usually -1
@@ -59,7 +59,7 @@ bool Game::Initialize()
 		SDL_Log("Failed to create renderer: %s", SDL_GetError());
 		return false;
 	}
-	
+	//
 	mPaddlePos.x = 10.0f;
 	mPaddlePos.y = 768.0f/2.0f;
 	mBallPos.x = 1024.0f/2.0f;
@@ -82,25 +82,26 @@ void Game::RunLoop()
 void Game::ProcessInput()
 {
 	SDL_Event event;
-	// Use poll event to figure out if user
-	// is trying to quit
 	while (SDL_PollEvent(&event))
 	{
 		switch (event.type)
 		{
+			// If we get an SDL_QUIT event, end loop
 			case SDL_QUIT:
 				mIsRunning = false;
 				break;
 		}
 	}
 	
 	// Get state of keyboard
-	const Uint8 *state = SDL_GetKeyboardState(NULL);
+	const Uint8* state = SDL_GetKeyboardState(NULL);
+	// If escape is pressed, also end loop
 	if (state[SDL_SCANCODE_ESCAPE])
 	{
 		mIsRunning = false;
 	}
 	
+	// Update paddle direction based on W/S keys
 	mPaddleDir = 0;
 	if (state[SDL_SCANCODE_W])
 	{
@@ -114,7 +115,6 @@ void Game::ProcessInput()
 
 void Game::UpdateGame()
 {
-	// Compute delta time
 	// Wait until 16ms has elapsed since last frame
 	while (!SDL_TICKS_PASSED(SDL_GetTicks(), mTicksCount + 16))
 		;
@@ -136,6 +136,7 @@ void Game::UpdateGame()
 	if (mPaddleDir != 0)
 	{
 		mPaddlePos.y += mPaddleDir * 300.0f * deltaTime;
+		// Make sure paddle doesn't move off screen!
 		if (mPaddlePos.y < (paddleH/2.0f + thickness))
 		{
 			mPaddlePos.y = paddleH/2.0f + thickness;
@@ -158,7 +159,6 @@ void Game::UpdateGame()
 		&& mBallVel.x < 0.0f)
 	{
 		mBallVel.x *= -1.0f;
-		mBallPos.x = 26.0f;
 	}
 	// Did the ball go off the screen? (if so, end game)
 	else if (mBallPos.x <= 0.0f)
@@ -169,35 +169,35 @@ void Game::UpdateGame()
 	else if (mBallPos.x >= (1024.0f - thickness) && mBallVel.x > 0.0f)
 	{
 		mBallVel.x *= -1.0f;
-		mBallPos.x = 1024.0f - thickness;
 	}
 	
 	// Did the ball collide with the top wall?
 	if (mBallPos.y <= thickness && mBallVel.y < 0.0f)
 	{
 		mBallVel.y *= -1;
-		mBallPos.y = thickness;
 	}
-	// Did the ball collide with the right wall?
+	// Did the ball collide with the bottom wall?
 	else if (mBallPos.y >= (768 - thickness) &&
 		mBallVel.y > 0.0f)
 	{
 		mBallVel.y *= -1;
-		mBallPos.y = 768 - thickness;
 	}
 }
 
 void Game::GenerateOutput()
 {
+	// Set draw color to blue
 	SDL_SetRenderDrawColor(
 		mRenderer,
 		0,		// R
 		0,		// G 
 		255,	// B
 		255		// A
 	);
-	SDL_RenderClear(mRenderer);
 	
+	// Clear back buffer
+	SDL_RenderClear(mRenderer);
+
 	// Draw walls
 	SDL_SetRenderDrawColor(mRenderer, 255, 255, 255, 255);
 	
@@ -231,14 +231,15 @@ void Game::GenerateOutput()
 	SDL_RenderFillRect(mRenderer, &paddle);
 	
 	// Draw ball
-	SDL_Rect ball{
+	SDL_Rect ball{	
 		static_cast<int>(mBallPos.x - thickness/2),
 		static_cast<int>(mBallPos.y - thickness/2),
 		thickness,
 		thickness
 	};
 	SDL_RenderFillRect(mRenderer, &ball);
 	
+	// Swap front buffer and back buffer
 	SDL_RenderPresent(mRenderer);
 }
 
diff --git a/Chapter01/Game.h b/Chapter01/Game.h
@@ -40,7 +40,7 @@ class Game
 	SDL_Renderer* mRenderer;
 	// Number of ticks since start of game
 	Uint32 mTicksCount;
-	// Game is still running
+	// Game should continue to run
 	bool mIsRunning;
 	
 	// Pong specific

Original file line number	Diff line number	Diff line change
`@@ -24,7 +24,7 @@ Game::Game()`
`24`	`24`	`bool Game::Initialize()`
`25`	`25`	`{`
`26`	`26`	`// Initialize SDL`
`27`		`- int sdlResult = SDL_Init(SDL_INIT_VIDEO \| SDL_INIT_AUDIO);`
	`27`	`+ int sdlResult = SDL_Init(SDL_INIT_VIDEO);`
`28`	`28`	`if (sdlResult != 0)`
`29`	`29`	`{`
`30`	`30`	`SDL_Log("Unable to initialize SDL: %s", SDL_GetError());`
`@@ -47,7 +47,7 @@ bool Game::Initialize()`
`47`	`47`	`return false;`
`48`	`48`	`}`
`49`	`49`
`50`		`- // Create SDL renderer`
	`50`	`+ //// Create SDL renderer`
`51`	`51`	`mRenderer = SDL_CreateRenderer(`
`52`	`52`	`mWindow, // Window to create renderer for`
`53`	`53`	`-1, // Usually -1`
`@@ -59,7 +59,7 @@ bool Game::Initialize()`
`59`	`59`	`SDL_Log("Failed to create renderer: %s", SDL_GetError());`
`60`	`60`	`return false;`
`61`	`61`	`}`
`62`		`-`
	`62`	`+ //`
`63`	`63`	`mPaddlePos.x = 10.0f;`
`64`	`64`	`mPaddlePos.y = 768.0f/2.0f;`
`65`	`65`	`mBallPos.x = 1024.0f/2.0f;`
`@@ -82,25 +82,26 @@ void Game::RunLoop()`
`82`	`82`	`void Game::ProcessInput()`
`83`	`83`	`{`
`84`	`84`	`SDL_Event event;`
`85`		`- // Use poll event to figure out if user`
`86`		`- // is trying to quit`
`87`	`85`	`while (SDL_PollEvent(&event))`
`88`	`86`	`{`
`89`	`87`	`switch (event.type)`
`90`	`88`	`{`
	`89`	`+ // If we get an SDL_QUIT event, end loop`
`91`	`90`	`case SDL_QUIT:`
`92`	`91`	`mIsRunning = false;`
`93`	`92`	`break;`
`94`	`93`	`}`
`95`	`94`	`}`
`96`	`95`
`97`	`96`	`// Get state of keyboard`
`98`		`- const Uint8 *state = SDL_GetKeyboardState(NULL);`
	`97`	`+ const Uint8* state = SDL_GetKeyboardState(NULL);`
	`98`	`+ // If escape is pressed, also end loop`
`99`	`99`	`if (state[SDL_SCANCODE_ESCAPE])`
`100`	`100`	`{`
`101`	`101`	`mIsRunning = false;`
`102`	`102`	`}`
`103`	`103`
	`104`	`+ // Update paddle direction based on W/S keys`
`104`	`105`	`mPaddleDir = 0;`
`105`	`106`	`if (state[SDL_SCANCODE_W])`
`106`	`107`	`{`
`@@ -114,7 +115,6 @@ void Game::ProcessInput()`
`114`	`115`
`115`	`116`	`void Game::UpdateGame()`
`116`	`117`	`{`
`117`		`- // Compute delta time`
`118`	`118`	`// Wait until 16ms has elapsed since last frame`
`119`	`119`	`while (!SDL_TICKS_PASSED(SDL_GetTicks(), mTicksCount + 16))`
`120`	`120`	`;`
`@@ -136,6 +136,7 @@ void Game::UpdateGame()`
`136`	`136`	`if (mPaddleDir != 0)`
`137`	`137`	`{`
`138`	`138`	`mPaddlePos.y += mPaddleDir * 300.0f * deltaTime;`
	`139`	`+ // Make sure paddle doesn't move off screen!`
`139`	`140`	`if (mPaddlePos.y < (paddleH/2.0f + thickness))`
`140`	`141`	`{`
`141`	`142`	`mPaddlePos.y = paddleH/2.0f + thickness;`
`@@ -158,7 +159,6 @@ void Game::UpdateGame()`
`158`	`159`	`&& mBallVel.x < 0.0f)`
`159`	`160`	`{`
`160`	`161`	`mBallVel.x *= -1.0f;`
`161`		`- mBallPos.x = 26.0f;`
`162`	`162`	`}`
`163`	`163`	`// Did the ball go off the screen? (if so, end game)`
`164`	`164`	`else if (mBallPos.x <= 0.0f)`
`@@ -169,35 +169,35 @@ void Game::UpdateGame()`
`169`	`169`	`else if (mBallPos.x >= (1024.0f - thickness) && mBallVel.x > 0.0f)`
`170`	`170`	`{`
`171`	`171`	`mBallVel.x *= -1.0f;`
`172`		`- mBallPos.x = 1024.0f - thickness;`
`173`	`172`	`}`
`174`	`173`
`175`	`174`	`// Did the ball collide with the top wall?`
`176`	`175`	`if (mBallPos.y <= thickness && mBallVel.y < 0.0f)`
`177`	`176`	`{`
`178`	`177`	`mBallVel.y *= -1;`
`179`		`- mBallPos.y = thickness;`
`180`	`178`	`}`
`181`		`- // Did the ball collide with the right wall?`
	`179`	`+ // Did the ball collide with the bottom wall?`
`182`	`180`	`else if (mBallPos.y >= (768 - thickness) &&`
`183`	`181`	`mBallVel.y > 0.0f)`
`184`	`182`	`{`
`185`	`183`	`mBallVel.y *= -1;`
`186`		`- mBallPos.y = 768 - thickness;`
`187`	`184`	`}`
`188`	`185`	`}`
`189`	`186`
`190`	`187`	`void Game::GenerateOutput()`
`191`	`188`	`{`
	`189`	`+ // Set draw color to blue`
`192`	`190`	`SDL_SetRenderDrawColor(`
`193`	`191`	`mRenderer,`
`194`	`192`	`0, // R`
`195`	`193`	`0, // G`
`196`	`194`	`255, // B`
`197`	`195`	`255 // A`
`198`	`196`	`);`
`199`		`- SDL_RenderClear(mRenderer);`
`200`	`197`
	`198`	`+ // Clear back buffer`
	`199`	`+ SDL_RenderClear(mRenderer);`
	`200`	`+`
`201`	`201`	`// Draw walls`
`202`	`202`	`SDL_SetRenderDrawColor(mRenderer, 255, 255, 255, 255);`
`203`	`203`
`@@ -231,14 +231,15 @@ void Game::GenerateOutput()`
`231`	`231`	`SDL_RenderFillRect(mRenderer, &paddle);`
`232`	`232`
`233`	`233`	`// Draw ball`
`234`		`- SDL_Rect ball{`
	`234`	`+ SDL_Rect ball{`
`235`	`235`	`static_cast<int>(mBallPos.x - thickness/2),`
`236`	`236`	`static_cast<int>(mBallPos.y - thickness/2),`
`237`	`237`	`thickness,`
`238`	`238`	`thickness`
`239`	`239`	`};`
`240`	`240`	`SDL_RenderFillRect(mRenderer, &ball);`
`241`	`241`
	`242`	`+ // Swap front buffer and back buffer`
`242`	`243`	`SDL_RenderPresent(mRenderer);`
`243`	`244`	`}`
`244`	`245`