feat: add single-player support

- include an option for single-player support in the menu, with two players set as the default game mode
- enhance code readability by passing the global game state as an argument

include/display.h

@@ -3,6 +3,8 @@
 
 #include <GL/glut.h>
 
+#include "carrom.h"
+
 // display callback function used to redraw the scene
 void display(void);
 
@@ -16,18 +18,18 @@ void trigger(int value);
 void carromBoard(void);
 
 // display the current positions of the carrom coins
-void carromCoins(void);
+void carromCoins(struct GameState *gameState);
 
 // displaying the direction in which the striker must be struck
-void strikerDirection(void);
+void strikerDirection(struct GameState *gameState);
 
 // display the power reader that shows the force applied to the striker
-void powerReader(void);
+void powerReader(struct GameState *gameState);
 
 // display the scores obtained by either team during their individual turns
-void scoreBoard(void);
+void scoreBoard(struct BoardStatus *boardStatus);
 
 // display the team and player number while it is their turn
-void teamTurnPanel(void);
+void teamTurnPanel(struct BoardStatus *boardStatus);
 
 #endif

include/menu.h

@@ -6,8 +6,9 @@
 #define SUBMENU_NEW 1
 #define MENU_RESTART 2
 #define MENU_QUIT 3
-#define MENU_SUB_TWO_PLAYER_GAME 4
-#define MENU_SUB_FOUR_PLAYER_GAME 5
+#define MENU_SUB_SINGLE_PLAYER_GAME 4
+#define MENU_SUB_TWO_PLAYER_GAME 5
+#define MENU_SUB_FOUR_PLAYER_GAME 6
 
 // menu callback function for handling the user's selection from the menu
 void menu(int option);

include/physics.h

@@ -28,7 +28,7 @@
 #define RADIANS_PER_DEGREE 57.29577951308232087679
 
 // calculate the force at which the striker has to be struck
-void hitStriker(void);
+void hitStriker(struct GameState *gameState);
 
 // simulate the physical interactions between coins during a collision
 void coinCollision(int i, int j, struct Coin *coins);

src/display.c

@@ -10,11 +10,11 @@
 
 void display(void) {
 	carromBoard();
-	carromCoins();
-	strikerDirection();
-	powerReader();
-	scoreBoard();
-	teamTurnPanel();
+	carromCoins(state);
+	strikerDirection(state);
+	powerReader(state);
+	scoreBoard(start);
+	teamTurnPanel(start);
 	glFlush();
 	glutSwapBuffers();
 	glutPostRedisplay();
@@ -112,8 +112,8 @@ void carromBoard(void) {
 	}
 }
 
-void carromCoins(void) {
-	int i; struct Coin *coins = state->coins;
+void carromCoins(struct GameState *gameState) {
+	int i; struct Coin *coins = gameState->coins;
 	// place coins in their initial positions
 	for(i = 0; i < (MAX_COIN_COUNT - 2) / 2; i++) {
 		// if the coin is in the pot, color it black
@@ -161,11 +161,11 @@ void carromCoins(void) {
 	}
 }
 
-void strikerDirection(void) {
-	float theta = state->theta;
-	struct Coin *coins = state->coins;
+void strikerDirection(struct GameState *gameState) {
+	float theta = gameState->theta;
+	struct Coin *coins = gameState->coins;
 
-	if(state->strikerState == 1) {
+	if(gameState->strikerState == 1) {
 		float strikerX = BOARD_SCALING_FACTOR * coins[MAX_COIN_COUNT - 1].center.x;
 		float strikerY = BOARD_SCALING_FACTOR * coins[MAX_COIN_COUNT - 1].center.y;
 
@@ -180,8 +180,8 @@ void strikerDirection(void) {
 	}
 }
 
-void powerReader(void) {
-	int currentPower = state->currentPower;
+void powerReader(struct GameState *gameState) {
+	int currentPower = gameState->currentPower;
 	// 25% power
 	if(currentPower == POWER_READER_VARIATION) {
 		glColor3f(POWER_READER_ON_25);
@@ -215,7 +215,7 @@ void powerReader(void) {
 	glEnd();
 }
 
-void scoreBoard(void) {
+void scoreBoard(struct BoardStatus *boardStatus) {
 	int score;
 	float x = -1.03, y = 0;
 
@@ -228,11 +228,11 @@ void scoreBoard(void) {
 		glVertex2f(-1, 0.33);
 	glEnd();
 
-	if(start->currentTeam == 1) {
-		score = start->pointsTeamOne;
+	if(boardStatus->currentTeam == 1) {
+		score = boardStatus->pointsTeamOne;
 	}
 	else {
-		score = start->pointsTeamTwo;
+		score = boardStatus->pointsTeamTwo;
 	}
 
 	if(score == 0) {
@@ -250,7 +250,7 @@ void scoreBoard(void) {
 	drawStringAtPos(-1.385, -0.3, (const unsigned char *) "SCORE");
 }
 
-void teamTurnPanel(void) {
+void teamTurnPanel(struct BoardStatus *boardStatus) {
 	float x = 1.69, y = 0.77, digitX = 1.47, digitY = 0.5;
 
 	// render a background for the player number display
@@ -261,7 +261,7 @@ void teamTurnPanel(void) {
 		glVertex2f(x - 0.65, y - 0.59);
 		glVertex2f(x - 0.65, y);
 	glEnd();
-	drawDigit(start->turn + 1, digitX, digitY);
+	drawDigit(boardStatus->turn + 1, digitX, digitY);
 	drawStringAtPos(1.31, 0.2, (const unsigned char *) "PLAYER");
 
 	// render a background for the team number display
@@ -272,6 +272,6 @@ void teamTurnPanel(void) {
 		glVertex2f(x - 0.65, -(y - 0.53));
 		glVertex2f(x - 0.65, -(y + 0.06));
 	glEnd();
-	drawDigit(start->currentTeam, digitX, -digitY);
+	drawDigit(boardStatus->currentTeam, digitX, -digitY);
 	drawStringAtPos(1.33, -0.8, (const unsigned char *) "TEAM");
 }

src/input.c

@@ -26,7 +26,7 @@ void keyboard(unsigned char key, int x, int y) {
 				break;
 
 			case SPACE:
-				hitStriker();
+				hitStriker(state);
 				break;
 
 		}
@@ -43,7 +43,7 @@ void joystick(unsigned int buttonMask, int x, int y, int z) {
 			shiftStrikerRight(state, start);
 		}
 		if(buttonMask & GLUT_JOYSTICK_BUTTON_B) {
-			hitStriker();
+			hitStriker(state);
 		}
 		if(buttonMask & GLUT_JOYSTICK_BUTTON_D) {
 			increaseStrikerPower(state);

src/menu.c

@@ -7,9 +7,16 @@
 
 void menu(int option) {
     switch(option) {
+        case MENU_SUB_SINGLE_PLAYER_GAME:
+            // restart the game only if it is not a single-player game
+            if(state->numberOfPlayers > 0) {
+                restartGame(1);
+            }
+            break;
+
         case MENU_SUB_TWO_PLAYER_GAME:
             // restart the game only if it is not a two-player game
-            if(state->numberOfPlayers > 1) {
+            if(state->numberOfPlayers > 1 || state->numberOfPlayers == 0) {
                 restartGame(2);
             }
             break;
@@ -33,6 +40,7 @@ void menu(int option) {
 
 void createGameMenu(void) {
     int subMenuId = glutCreateMenu(menu);
+    glutAddMenuEntry("Single Player", MENU_SUB_SINGLE_PLAYER_GAME);
     glutAddMenuEntry("Two Players", MENU_SUB_TWO_PLAYER_GAME);
     glutAddMenuEntry("Four Players", MENU_SUB_FOUR_PLAYER_GAME);
     // create the main menu and attach the submenu

src/physics.c

@@ -4,12 +4,12 @@
 #include "context.h"
 #include "physics.h"
 
-void hitStriker(void) {
-	int currentPower = state->currentPower;
-	float theta = state->theta;
-	struct Coin *coins = state->coins;
+void hitStriker(struct GameState *gameState) {
+	int currentPower = gameState->currentPower;
+	float theta = gameState->theta;
+	struct Coin *coins = gameState->coins;
 	// update striker state to zero as it is in action
-	state->strikerState = 0;
+	gameState->strikerState = 0;
 	coins[MAX_COIN_COUNT - 1].velocity.x = currentPower * cos((theta / 360.0) * 2 * M_PI);
 	coins[MAX_COIN_COUNT - 1].velocity.y = currentPower * sin((theta / 360.0) * 2 * M_PI);
 }

src/rules.c

@@ -96,7 +96,10 @@ void finalize(struct GameState *gameState, struct BoardStatus *start, bool strik
 			- the player has not scored any points
 		*/
 		if(strikerState == false) {
-			if(numberOfPlayers < 3) {
+			if(numberOfPlayers == 0) {
+				turn = 0;
+			}
+			else if(numberOfPlayers < 3) {
 				turn = (turn + 2) % 4;
 				start->currentTeam = (int) (turn / 2) + 1;
 			}