Added a basic client which tracks the second ship through UDP

Spacewar-Client.c

@@ -0,0 +1,228 @@
+// SDL Experiment 15, Barra Ó Catháin.
+// ===================================
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_image.h>
+#include <SDL2/SDL_timer.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+// A 2D vector:
+typedef struct xyVector
+{
+	double xComponent;
+	double yComponent;
+} xyVector;
+
+// A struct storing the needed data to draw a ship:
+typedef struct ship
+{
+	SDL_Rect rectangle;
+	xyVector position;
+	xyVector velocity;
+	xyVector gravity;
+	int number;
+} ship;
+
+// Get the angle between vectors:
+static inline double angleBetweenVectors(xyVector * vectorA, xyVector * vectorB)
+{
+	double dotProduct = (vectorA->xComponent * vectorB->xComponent) + (vectorA->yComponent * vectorB->yComponent);
+	double determinant = (vectorA->xComponent * vectorB->yComponent) - (vectorA->yComponent * vectorB->xComponent);
+
+	return atan2(dotProduct, determinant) / 0.01745329;
+}
+
+void DrawCircle(SDL_Renderer * renderer, int32_t centreX, int32_t centreY, int32_t radius)
+{
+	const int32_t diameter = (radius * 2);
+
+	int32_t x = (radius - 1); 
+	int32_t y = 0;
+	int32_t tx = 1;
+	int32_t ty = 1;
+	int32_t error = (tx - diameter);
+
+	while (x >= y)
+	{
+		//  Each of the following renders an octant of the circle
+		SDL_RenderDrawPoint(renderer, centreX + x, centreY - y);
+		SDL_RenderDrawPoint(renderer, centreX + x, centreY + y);
+		SDL_RenderDrawPoint(renderer, centreX - x, centreY - y);
+		SDL_RenderDrawPoint(renderer, centreX - x, centreY + y);
+		SDL_RenderDrawPoint(renderer, centreX + y, centreY - x);
+		SDL_RenderDrawPoint(renderer, centreX + y, centreY + x);
+		SDL_RenderDrawPoint(renderer, centreX - y, centreY - x);
+		SDL_RenderDrawPoint(renderer, centreX - y, centreY + x);
+
+		if (error <= 0)
+		{
+			++y;
+			error += ty;
+			ty += 2;
+		}
+
+		if (error > 0)
+		{
+			--x;
+			tx += 2;
+			error += (tx - diameter);
+		}
+	}
+}
+
+int main(int argc, char ** argv)
+{
+	SDL_Event event;
+	bool quit = false;
+	int width = 0, height = 0;
+	uint32_t rendererFlags = SDL_RENDERER_ACCELERATED;
+	uint64_t thisFrameTime = SDL_GetPerformanceCounter(), lastFrameTime = 0;
+	long positionX = 512, positionY = 512, starPositionX = 0, starPositionY = 0;
+	xyVector positionVector = {512, 512}, velocityVector = {1, 0}, gravityVector = {0, 0},
+		engineVector = {0.04, 0}, upVector = {0, 0.1}, starPosition = {0, 0};
+
+    // Create the socket:
+	int socketFileDesc = socket(AF_INET, SOCK_DGRAM, 0);
+	if (socketFileDesc < 0)
+	{
+		fprintf(stderr, "\tSocket Creation is:\t\033[33;40mRED.\033[0m Aborting launch.\n");
+		exit(0);
+	}
+	printf("\tSocket Creation is:\t\033[32;40mGREEN.\033[0m\n");
+
+	// Make the socket timeout:
+	struct timeval read_timeout;
+	read_timeout.tv_sec = 0;
+	read_timeout.tv_usec = 10;
+	setsockopt(socketFileDesc, SOL_SOCKET, SO_RCVTIMEO, &read_timeout, sizeof read_timeout);
+	
+	// Create and fill the information needed to bind to the socket:
+	struct sockaddr_in serverAddress;
+	memset(&serverAddress, 0, sizeof(serverAddress));
+	serverAddress.sin_family = AF_INET; // IPv4
+	serverAddress.sin_addr.s_addr = INADDR_ANY;
+	serverAddress.sin_port = htons(12000);
+
+	// Bind to the socket:
+	if (bind(socketFileDesc, (const struct sockaddr *)&serverAddress, sizeof(serverAddress)) < 0)
+    {
+        perror("bind failed");
+        exit(EXIT_FAILURE);
+    }
+
+	// Get the initial
+	ship shipA;
+	ship shipB;
+	
+	// Initialize the SDL library, video, sound, and input:
+	if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
+	{
+		printf("SDL Initialization Error: %s\n", SDL_GetError());
+	}
+
+	// Initialize image loading:
+	IMG_Init(IMG_INIT_PNG);
+	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2");
+
+	// Create an SDL window and rendering context in that window:
+	SDL_Window * window = SDL_CreateWindow("SDL_TEST", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 700, 700, 0);
+	SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags);
+	SDL_SetWindowTitle(window, "Spacewar!");
+	
+	// Load in all of our textures:
+	SDL_Texture * idleTexture, * acceleratingTexture, * clockwiseTexture, * anticlockwiseTexture, * currentTexture,
+	    * acceleratingTexture2;
+	
+	idleTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Idle.png");
+	clockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Clockwise.png");
+	acceleratingTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Accelerating.png");
+	anticlockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Anticlockwise.png");
+	acceleratingTexture2 = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Accelerating-Frame-2.png");
+
+	// Enable resizing the window:
+	SDL_SetWindowResizable(window, SDL_TRUE);
+	ship Temp;
+	bool shipAUpdated, shipBUpdated;
+	while (!quit)
+	{
+		while(!(shipAUpdated && shipBUpdated))
+		{
+			// Receive data from the socket:
+			recvfrom(socketFileDesc, &Temp, sizeof(ship), 0, NULL, NULL);
+			if(Temp.number == 0)
+			{
+				shipA = Temp;
+				shipAUpdated = true;
+			}
+			if(Temp.number == 1)
+			{
+				shipB = Temp;
+				shipBUpdated = true;
+			}
+		}
+		
+		// Check if the user wants to quit:
+		while (SDL_PollEvent(&event))
+        {
+            switch (event.type)
+            {
+				case SDL_QUIT:
+				{
+					quit = true;
+					break;
+				}
+				default:
+				{
+					break;
+				}
+            }
+        }
+
+        // Store the window's current width and height:
+		SDL_GetWindowSize(window, &width, &height);
+
+		// Set the texture to idle:
+		currentTexture = idleTexture;
+		
+		// Calculate the position of the sprites:
+		shipB.rectangle.x = (width/2) - 16 - (shipB.velocity.xComponent * 15);
+		shipB.rectangle.y = (height/2) - 16 - (shipB.velocity.yComponent * 15);
+
+		shipA.rectangle.x = (long)((((shipA.position.xComponent - shipB.position.xComponent) - 32) + width/2) - (shipB.velocity.xComponent * 15));
+		shipA.rectangle.y = (long)((((shipA.position.yComponent - shipB.position.yComponent) - 32) + height/2) - (shipB.velocity.yComponent * 15));
+		
+		// Set the colour to black:
+		SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+
+		// Clear the screen, filling it with black:
+		SDL_RenderClear(renderer);
+
+		// Draw the ship:
+		SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipA.rectangle,
+						 angleBetweenVectors(&shipA.velocity, &upVector) + 90, NULL, 0);
+		SDL_RenderCopyEx(renderer, currentTexture, NULL, &shipB.rectangle,
+						 angleBetweenVectors(&shipB.velocity, &upVector) + 90, NULL, 0);
+		
+		// Set the colour to yellow:
+		SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
+
+		// Draw a circle as the star:
+		DrawCircle(renderer, (long)(starPositionX - shipB.position.xComponent) + width/2  - (shipB.velocity.xComponent * 15),
+				   (long)(starPositionY - shipB.position.yComponent) + height/2  - (shipB.velocity.yComponent * 15), 50);
+
+		// Present the rendered graphics:
+		SDL_RenderPresent(renderer);
+		shipAUpdated = false;
+		shipBUpdated = false;
+	}
+	return 0;
+}
+// ========================================================================================================
+// Local Variables:
+// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-15-Client.c -lSDL2_image -lm -o 'Spacewar Client!'"
+// End:

Spacewar.c

@@ -1,4 +1,4 @@
-// SDL Experiment 14, Barra Ó Catháin.
+// SDL Experiment 15, Barra Ó Catháin.
 // ===================================
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_image.h>
@@ -6,6 +6,10 @@
 #include <math.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
 
 // A 2D vector:
 typedef struct xyVector
@@ -21,6 +25,7 @@ typedef struct ship
 	xyVector position;
 	xyVector velocity;
 	xyVector gravity;
+	int number;
 } ship;
 
 // Calculate the vector from point A to point B:
@@ -133,11 +138,11 @@ void calculateGravity(xyVector * starPosition, ship * shipUnderGravity)
 	{
 		if(gravityMagnitude >= 116)
 		{
-			gravityAcceleration = 0.67 * (50000 / (pow(gravityMagnitude, 2)));
+			gravityAcceleration = pow(2, (2500 / (pow(gravityMagnitude, 2)))) / 10;
 		}
 		else
 		{
-			gravityAcceleration = 1;
+			gravityAcceleration = pow(2, (2500 / (pow(gravityMagnitude, 2)))) / 5;
 		}
 	}
 	else
@@ -155,7 +160,7 @@ void calculateGravity(xyVector * starPosition, ship * shipUnderGravity)
 }
 
 // Create a ship with the given parameters:
-ship createShip(int width, int height, double positionX, double positionY, double velocityX, double velocityY)
+ship createShip(int width, int height, double positionX, double positionY, double velocityX, double velocityY, int number)
 {
 	ship newShip;
 	newShip.rectangle.w = width;
@@ -166,6 +171,7 @@ ship createShip(int width, int height, double positionX, double positionY, doubl
 	newShip.velocity.yComponent = velocityY;
 	newShip.gravity.xComponent = 0;
 	newShip.gravity.yComponent = 0;
+	newShip.number = number;
 	return newShip;
 }
 
@@ -179,11 +185,26 @@ int main(int argc, char ** argv)
 	double deltaTime = 0, gravityMagnitude = 0, gravityAcceleration = 0, frameAccumulator = 0;	
 	bool quit = false, rotatingClockwise = false, rotatingAnticlockwise = false, accelerating = false;
 	xyVector positionVector = {512, 512}, velocityVector = {1, 0}, gravityVector = {0, 0},
-		engineVector = {0.04, 0}, upVector = {0, 0.1}, starPosition = {0, 0};
+		engineVector = {0.08, 0}, upVector = {0, 0.1}, starPosition = {0, 0};
+
+	// Create the socket:
+	int socketFileDesc = socket(AF_INET, SOCK_DGRAM, 0);
+	if (socketFileDesc < 0)
+	{
+		fprintf(stderr, "\tSocket Creation is:\t\033[33;40mRED.\033[0m Aborting launch.\n");
+		exit(0);
+	}
+	printf("\tSocket Creation is:\t\033[32;40mGREEN.\033[0m\n");
+
+	// Create and fill the information needed to bind to the socket:
+	struct sockaddr_in serverAddress;
+	serverAddress.sin_family = AF_INET; // IPv4
+	serverAddress.sin_addr.s_addr = inet_addr("127.0.0.1");
+	serverAddress.sin_port = htons(12000);
 
 	// Get the initial
-	ship shipA = createShip(32, 32, 512, 512, 1, 0);
+	ship shipA = createShip(32, 32, 512, 512, 1, 0, 0);
-	ship shipB = createShip(32, 32, -512, -512, 0, 1);
+	ship shipB = createShip(32, 32, -512, -512, 0, 1, 1);
 	
 	// Initialize the SDL library, video, sound, and input:
 	if (SDL_Init(SDL_INIT_EVERYTHING) != 0)
@@ -204,11 +225,11 @@ int main(int argc, char ** argv)
 	SDL_Texture * idleTexture, * acceleratingTexture, * clockwiseTexture, * anticlockwiseTexture, * currentTexture,
 	    * acceleratingTexture2;
 	
-	idleTexture = IMG_LoadTexture(renderer, "./Experiment-14-Images/Ship-Idle.png");
+	idleTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Idle.png");
-	clockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-14-Images/Ship-Clockwise.png");
+	clockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Clockwise.png");
-	acceleratingTexture = IMG_LoadTexture(renderer, "./Experiment-14-Images/Ship-Accelerating.png");
+	acceleratingTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Accelerating.png");
-	anticlockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-14-Images/Ship-Anticlockwise.png");
+	anticlockwiseTexture = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Anticlockwise.png");
-	acceleratingTexture2 = IMG_LoadTexture(renderer, "./Experiment-14-Images/Ship-Accelerating-Frame-2.png");
+	acceleratingTexture2 = IMG_LoadTexture(renderer, "./Experiment-15-Images/Ship-Accelerating-Frame-2.png");
 
 	// Enable resizing the window:
 	SDL_SetWindowResizable(window, SDL_TRUE);
@@ -415,10 +436,13 @@ int main(int argc, char ** argv)
 
 		// Present the rendered graphics:
 		SDL_RenderPresent(renderer);
+
+		sendto(socketFileDesc, &shipA, sizeof(ship), 0, (const struct sockaddr *)&serverAddress, sizeof(serverAddress));
+		sendto(socketFileDesc, &shipB, sizeof(ship), 0, (const struct sockaddr *)&serverAddress, sizeof(serverAddress));
 	}
 	return 0;
 }
 // ========================================================================================================
 // Local Variables:
-// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-14.c -lSDL2_image -lm -o 'Spacewar!'"
+// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-15.c -lSDL2_image -lm -o 'Spacewar!'"
 // End: