Add Paddle/Ball collision detection.

Signed-off-by: Matt Turner <mattst88@gmail.com>

6 files changed, 122 insertions, 118 deletions

diff --git a/ball.c b/ball.c
index e5a0c4e..f5f9876 100644
--- a/ball.c
+++ b/ball.c
@@ -1,31 +1,23 @@
 #include "SDL.h"
 #include "SDL_opengl.h"
 
+#include "glpong3d.h"
 #include "ball.h"
 
-typedef struct {
-	Coord_t coord;
-	GLfloat w, h;
-	GLfloat r, g, b;
-	GLfloat xv, yv, zv;
-	GLfloat rotate;
-} Ball_t;
-
-static Ball_t ball;
 static GLuint ball_texture;
 
 void
-GLPong_BallDraw(void) {
+GLPong_BallDraw(const Ball_t * ball) {
 	glLoadIdentity();
 	glBindTexture(GL_TEXTURE_2D, ball_texture);
 	glEnable(GL_TEXTURE_2D);
-	glColor3f(ball.r, ball.g, ball.b);
-	glTranslatef(ball.coord.x, ball.coord.y, ball.coord.z);
+	glColor3f(ball->r, ball->g, ball->b);
+	glTranslatef(ball->x, ball->y, ball->z);
 	glBegin(GL_QUADS);
-		glTexCoord2f(0.0f, 1.0f); glVertex2f(ball.w, ball.h);	/* Lower Left */
-		glTexCoord2f(1.0f, 1.0f); glVertex2f(0.0f, ball.h);		/* Lower Right */
-		glTexCoord2f(1.0f, 0.0f); glVertex2f(0.0f, 0.0f);			/* Upper Right */
-		glTexCoord2f(0.0f, 0.0f); glVertex2f(ball.w, 0.0f);		/* Upper Left */
+		glTexCoord2f(0.0f, 1.0f); glVertex2f(ball->w, ball->h);	/* Lower Left */
+		glTexCoord2f(1.0f, 1.0f); glVertex2f(0.0f, ball->h);	/* Lower Right */
+		glTexCoord2f(1.0f, 0.0f); glVertex2f(0.0f, 0.0f);		/* Upper Right */
+		glTexCoord2f(0.0f, 0.0f); glVertex2f(ball->w, 0.0f);	/* Upper Left */
 	glEnd();
 	glDisable(GL_TEXTURE_2D);
 
@@ -33,80 +25,80 @@ GLPong_BallDraw(void) {
 	/* Lower Left */
 	glLoadIdentity();
 	glColor3f(1.0f, 0.0f, 0.0f);
-	glTranslatef(ball.coord.x, ball.coord.y, ball.coord.z);
+	glTranslatef(ball->x, ball->y, ball->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 
 	/* Lower Right */
 	glLoadIdentity();
-	glTranslatef(ball.coord.x + ball.w, ball.coord.y, ball.coord.z);
+	glTranslatef(ball->x + ball->w, ball->y, ball->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	
 	/* Top Right */
 	glLoadIdentity();
-	glTranslatef(ball.coord.x + ball.w, ball.coord.y + ball.h, ball.coord.z);
+	glTranslatef(ball->x + ball->w, ball->y + ball->h, ball->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	/* Top Left */
 	glLoadIdentity();
-	glTranslatef(ball.coord.x, ball.coord.y + ball.h, ball.coord.z);
+	glTranslatef(ball->x, ball->y + ball->h, ball->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 #endif
 	
 	glLoadIdentity();
-	glTranslatef(0.0f, 0.0f, ball.coord.z);
+	glTranslatef(0.0f, 0.0f, ball->z);
 	glCallList(box);
 }
 
 void
-GLPong_BallInit(GLuint texture) {
-	ball.w = 0.5f;
-	ball.h = 0.5f;
-	ball.coord.x = -(ball.w / 2);
-	ball.coord.y = -(ball.h / 2);
-	ball.coord.z = GLPONG_FRONT_Z;
-	ball.r = 1.0f;
-	ball.g = 0.0f;
-	ball.b = 0.0f;
-	ball.xv = 0.02f;
-	ball.yv = 0.01f;
-	ball.zv = -0.05f;
+GLPong_BallInit(Ball_t * ball, GLuint texture) {
+	ball->w = 0.5f;
+	ball->h = 0.5f;
+	ball->x = -(ball->w / 2);
+	ball->y = -(ball->h / 2);
+	ball->z = GLPONG_FRONT_Z;
+	ball->r = 1.0f;
+	ball->g = 0.0f;
+	ball->b = 0.0f;
+	ball->xv = 0.02f;
+	ball->yv = 0.01f;
+	ball->zv = -0.05f;
 
 	ball_texture = texture;
 }
 
 void
-GLPong_BallMove(void) {
-	ball.coord.x += ball.xv;
-	if (ball.coord.x > 1.0f) {
-		ball.coord.x = 1.0f;
-		ball.xv = -ball.xv;
-	} else if (ball.coord.x  + ball.w < -1.0f) {
-		ball.coord.x = -1.0f - ball.w;
-		ball.xv = -ball.xv;
+GLPong_BallMove(Ball_t * ball) {
+	ball->x += ball->xv;
+	if (ball->x > 1.0f) {
+		ball->x = 1.0f;
+		ball->xv = -ball->xv;
+	} else if (ball->x  + ball->w < -1.0f) {
+		ball->x = -1.0f - ball->w;
+		ball->xv = -ball->xv;
 	}
 
-	ball.coord.y += ball.yv;
-	if (ball.coord.y > 0.5f) {
-		ball.coord.y = 0.5f;
-		ball.yv = -ball.yv;
-	} else if (ball.coord.y + ball.h < -0.5f) {
-		ball.coord.y = -0.5f - ball.h;
-		ball.yv = -ball.yv;
+	ball->y += ball->yv;
+	if (ball->y > 0.5f) {
+		ball->y = 0.5f;
+		ball->yv = -ball->yv;
+	} else if (ball->y + ball->h < -0.5f) {
+		ball->y = -0.5f - ball->h;
+		ball->yv = -ball->yv;
 	}
 
-	ball.coord.z += ball.zv;
-	if (ball.coord.z < GLPONG_BACK_Z) {
-		ball.coord.z = GLPONG_BACK_Z;
-		ball.zv = -ball.zv;
-	} else if (ball.coord.z > GLPONG_FRONT_Z) {
-		ball.coord.z = GLPONG_FRONT_Z;
-		ball.zv = -ball.zv;
+	ball->z += ball->zv;
+	if (ball->z < GLPONG_BACK_Z) {
+		ball->z = GLPONG_BACK_Z;
+		ball->zv = -ball->zv;
+	} else if (ball->z > GLPONG_FRONT_Z) {
+		ball->z = GLPONG_FRONT_Z;
+		ball->zv = -ball->zv;
 	}
 }
diff --git a/ball.h b/ball.h
index bf3e849..fcda649 100644
--- a/ball.h
+++ b/ball.h
@@ -4,10 +4,16 @@
 #include "SDL.h"
 #include "SDL_opengl.h"
 
-#include "glpong3d.h"
+typedef struct {
+	GLfloat x, y, z;
+	GLfloat w, h;
+	GLfloat r, g, b;
+	GLfloat xv, yv, zv;
+	GLfloat rotate;
+} Ball_t;
 
-void GLPong_BallDraw(void);
-void GLPong_BallInit(GLuint texture);
-void GLPong_BallMove(void);
+void GLPong_BallDraw(const Ball_t * ball);
+void GLPong_BallInit(Ball_t * ball, GLuint texture);
+void GLPong_BallMove(Ball_t * ball);
 
 #endif
diff --git a/glpong3d.c b/glpong3d.c
index 60d720b..2fd98f6 100644
--- a/glpong3d.c
+++ b/glpong3d.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 
 #include "SDL.h"
 #include "SDL_opengl.h"
@@ -15,13 +16,15 @@
 
 static int  GLPong_Init(GLPong_t * GLPong);
 static int  GLPong_HandleEvents(void);
-static void GLPong_Draw(void);
+static void GLPong_Draw(const GLPong_t * GLPong);
+static bool GLPong_Collide(const Ball_t * ball, const Paddle_t * paddle);
 static void GLPong_CleanUp(void);
-static void GLPong_Move(void);
+static void GLPong_Move(GLPong_t * GLPong);
 static void SDL_GL_GetMouseState(GLfloat * x, GLfloat * y);
 static GLuint SDL_GL_SurfaceToTexture(SDL_Surface * surface);
 
 int main(int argc, char * argv[]) {
+	GLPong_t GLPong;
 	unsigned int frames = 0;
 	int done = 0;
 	int action;
@@ -45,12 +48,12 @@ int main(int argc, char * argv[]) {
 				break;
 		}
 
-		GLPong_Move();
+		GLPong_Move(&GLPong);
 
 		/* begin drawing */
 		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-		GLPong_Draw();
+		GLPong_Draw(&GLPong);
 
 		frames++;
 		if (frames == 30) {
@@ -137,7 +140,7 @@ GLPong_Init(GLPong_t * GLPong) {
 	
 	/*temp = IMG_Load("ball.png");*/ /* disabled since it's already loaded for the icon */
 	texture = SDL_GL_SurfaceToTexture(temp);
-	GLPong_BallInit(texture);
+	GLPong_BallInit(&GLPong->ball, texture);
 	SDL_FreeSurface(temp);
 
 	temp = IMG_Load("paddle-skyos.png");
@@ -194,16 +197,28 @@ GLPong_HandleEvents(void) {
 }
 
 static void
-GLPong_Move(void) {
+GLPong_Move(GLPong_t * GLPong) {
 	GLfloat x, y;
 
 	SDL_GL_GetMouseState(&x, &y);
-	GLPong_PaddleMove(&GLPong.front_paddle, x, y);
+	GLPong_PaddleMove(&GLPong->front_paddle, x, y);
 
-	GLPong_BallMove();
+	GLPong_BallMove(&GLPong->ball);
+
+	if (GLPong_Collide(&GLPong->ball, &GLPong->front_paddle)
+		|| GLPong_Collide(&GLPong->ball, &GLPong->back_paddle)) {
+		if (GLPong->ball.zv < 0) {
+			GLPong->ball.zv -= 0.005f;
+		} else {
+			GLPong->ball.zv += 0.005f;
+		}
+#ifdef DEBUG
+		printf("Collision: x: %.3f, y: %.2f, z: %.2f\n", GLPong->ball.x, GLPong->ball.y, GLPong->ball.z);
+#endif
+	}
 }
 
-void GLPong_Draw(void) {
+void GLPong_Draw(const GLPong_t * GLPong) {
 	float count;
 
 	glColor3f(0.0f, 1.0f, 0.0f);
@@ -235,29 +250,23 @@ void GLPong_Draw(void) {
 		glVertex3f(-1.5f,  1.0f, GLPONG_BACK_Z);
 	glEnd();
 	
-	GLPong_PaddleDraw(&GLPong.back_paddle);
+	GLPong_PaddleDraw(&GLPong->back_paddle);
 
-	GLPong_BallDraw();
+	GLPong_BallDraw(&GLPong->ball);
 
-	GLPong_PaddleDraw(&GLPong.front_paddle);
+	GLPong_PaddleDraw(&GLPong->front_paddle);
 }
 
-#if 0
-void GLPong_Collide(Ball_t * ball, const Paddle_t * paddle) {
-	if (ball->coord.z == paddle->coord.z) {
-		if (ball->coord.x + ball->w < paddle->coord.x) return; 				/* if ball is left of paddle */
-		if (ball->coord.x > paddle->coord.x + paddle->w) return;				/* if ball is right of paddle */
-		if (ball->coord.y > paddle->coord.y + paddle->h) return;				/* if ball is above paddle */
-		if (ball->coord.y + ball->h < paddle->coord.y) return;				/* if ball is below paddle */
-		if (ball->zv < 0) {
-			ball->zv -= 0.005f;
-		} else {
-			ball->zv += 0.005f;
-		}
-		printf("x: %.3f, y: %.2f, z: %.2f\n", ball->coord.x, ball->coord.y, ball->coord.z);
+bool GLPong_Collide(const Ball_t * ball, const Paddle_t * paddle) {
+	if (ball->z == paddle->z) {
+		if (ball->x + ball->w < paddle->x) return false; 				/* if ball is left of paddle */
+		if (ball->x > paddle->x + paddle->w) return false;				/* if ball is right of paddle */
+		if (ball->y > paddle->y + paddle->h) return false;				/* if ball is above paddle */
+		if (ball->y + ball->h < paddle->y) return false;				/* if ball is below paddle */
+		return true;
 	}
+	return false;
 }
-#endif
 
 void GLPong_CleanUp(void) {
 
diff --git a/glpong3d.h b/glpong3d.h
index 13615db..1952131 100644
--- a/glpong3d.h
+++ b/glpong3d.h
@@ -4,6 +4,9 @@
 #include "SDL.h"
 #include "SDL_opengl.h"
 
+#include "ball.h"
+#include "paddle.h"
+
 #define GLPONG_WIDTH	800.0f
 #define GLPONG_HEIGHT	600.0f
 
@@ -26,22 +29,11 @@
 #endif
 
 typedef struct {
-	GLfloat x, y, z;
-} Coord_t;
-
-typedef struct {
-	Coord_t coord;
-	GLfloat w, h;
-	GLfloat r, g, b;
-} Paddle_t;
-
-typedef struct {
 	Paddle_t front_paddle;
 	Paddle_t back_paddle;
+	Ball_t ball;
 } GLPong_t;
 
-GLPong_t GLPong;
-
 GLuint box;
 
 #endif
diff --git a/paddle.c b/paddle.c
index 7dcb2f2..4c4c9f0 100644
--- a/paddle.c
+++ b/paddle.c
@@ -14,7 +14,7 @@ GLPong_PaddleDraw(const Paddle_t * paddle) {
 	glBindTexture(GL_TEXTURE_2D, paddle_texture);
 	glEnable(GL_TEXTURE_2D);
 	glColor3f(paddle->r, paddle->g, paddle->b);
-	glTranslatef(paddle->coord.x + (paddle->w / 2), paddle->coord.y + (paddle->h / 2), paddle->coord.z);
+	glTranslatef(paddle->x + (paddle->w / 2), paddle->y + (paddle->h / 2), paddle->z);
 	glBegin(GL_QUADS);
 		glTexCoord2f(0.168f, 1.0f); glVertex2f(paddle->w / 2, paddle->h / 2);	/* Upper Right */
 		glTexCoord2f(0.832f, 1.0f); glVertex2f(-paddle->w / 2, paddle->h / 2);	/* Upper Left  */
@@ -27,33 +27,33 @@ GLPong_PaddleDraw(const Paddle_t * paddle) {
 	/* Lower Left */
 	glLoadIdentity();
 	glColor3f(0.0f, 0.0f, 1.0f);
-	glTranslatef(paddle->coord.x, paddle->coord.y, paddle->coord.z);
+	glTranslatef(paddle->x, paddle->y, paddle->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	/* Lower Right */
 	glLoadIdentity();
 	glColor3f(1.0f, 0.0f, 0.0f);
-	glTranslatef(paddle->coord.x + paddle->w, paddle->coord.y, paddle->coord.z);
+	glTranslatef(paddle->x + paddle->w, paddle->y, paddle->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	/* Top Right */
 	glLoadIdentity();
-	glTranslatef(paddle->coord.x + paddle->w, paddle->coord.y + paddle->h, paddle->coord.z);
+	glTranslatef(paddle->x + paddle->w, paddle->y + paddle->h, paddle->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	/* Top Left */
 	glLoadIdentity();
-	glTranslatef(paddle->coord.x, paddle->coord.y + paddle->h, paddle->coord.z);
+	glTranslatef(paddle->x, paddle->y + paddle->h, paddle->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
 	/* Center */
 	glLoadIdentity();
 	glColor3f(0.0f, 1.0f, 0.0f);
-	glTranslatef(paddle->coord.x + paddle->w / 2.0f, paddle->coord.y + paddle->h / 2.0f, paddle->coord.z);
+	glTranslatef(paddle->x + paddle->w / 2.0f, paddle->y + paddle->h / 2.0f, paddle->z);
 	glBegin(GL_POINTS);
 		glVertex3f(0.0f, 0.0f, 0.0f);
 	glEnd();
@@ -64,9 +64,9 @@ void
 GLPong_PaddleInit(Paddle_t * paddle, GLfloat z, GLuint texture) {
 	paddle->w = 0.66f;
 	paddle->h = 0.5f;
-	paddle->coord.x = paddle->w / 2.0f;
-	paddle->coord.y = paddle->h / 2.0f;
-	paddle->coord.z = z;
+	paddle->x = paddle->w / 2.0f;
+	paddle->y = paddle->h / 2.0f;
+	paddle->z = z;
 	paddle->r = 1.0f;
 	paddle->g = 1.0f;
 	paddle->b = 1.0f;
@@ -76,8 +76,8 @@ GLPong_PaddleInit(Paddle_t * paddle, GLfloat z, GLuint texture) {
 
 void
 GLPong_PaddleMove(Paddle_t * paddle, GLfloat x, GLfloat y) {
-	GLfloat old_x = paddle->coord.x;
-	GLfloat old_y = paddle->coord.y;
+	GLfloat old_x = paddle->x;
+	GLfloat old_y = paddle->y;
 	GLfloat mouse_x;
 	GLfloat mouse_y;
 
@@ -96,29 +96,30 @@ GLPong_PaddleMove(Paddle_t * paddle, GLfloat x, GLfloat y) {
 
 	mouse_x = x - (paddle->w / 2.0f);
 	mouse_y = -(y + (paddle->h / 2.0f));
-	printf("(mouse_x, mouse_y) = (%.3f, %.3f)\n", mouse_x, mouse_y);
 
+#ifdef DEBUG
+	printf("(mouse_x, mouse_y) = (%.3f, %.3f)\n", mouse_x, mouse_y);
 	printf("x diff is %f\n", fabs(mouse_x - old_x));
+	printf("y diff is %f\n", fabs(mouse_y - old_y));
+#endif
 
 	if (fabs(mouse_x - old_x) > 0.33f / 2.0f) {
 		if (mouse_x > old_x) {
-			paddle->coord.x += 0.33f / 2.0f;
+			paddle->x += 0.33f / 2.0f;
 		} else {
-			paddle->coord.x -= 0.33f / 2.0f;
+			paddle->x -= 0.33f / 2.0f;
 		}
 	} else {
-		paddle->coord.x = mouse_x;
+		paddle->x = mouse_x;
 	}
 
-	printf("y diff is %f\n", fabs(mouse_y - old_y));
-
 	if (fabs(mouse_y - old_y) > 0.25f / 2.0f) {
 		if (mouse_y > old_y) {
-			paddle->coord.y += 0.25f / 2.0f;
+			paddle->y += 0.25f / 2.0f;
 		} else {
-			paddle->coord.y -= 0.25f / 2.0f;
+			paddle->y -= 0.25f / 2.0f;
 		}
 	} else {
-		paddle->coord.y = mouse_y;
+		paddle->y = mouse_y;
 	}
 }
diff --git a/paddle.h b/paddle.h
index 14b7ed8..61962e7 100644
--- a/paddle.h
+++ b/paddle.h
@@ -4,7 +4,11 @@
 #include "SDL.h"
 #include "SDL_opengl.h"
 
-#include "glpong3d.h"
+typedef struct {
+	GLfloat x, y, z;
+	GLfloat w, h;
+	GLfloat r, g, b;
+} Paddle_t;
 
 void GLPong_PaddleDraw(const Paddle_t * paddle);
 void GLPong_PaddleInit(Paddle_t * paddle, GLfloat z, GLuint texture);