added comments

1 files changed, 66 insertions, 20 deletions

diff --git a/engine.c b/engine.c
index 19a7cf9..8acd11a 100644
--- a/engine.c
+++ b/engine.c
@@ -11,6 +11,7 @@
 

 float fps;

 

+// swap two floats

 void swap(float *a, float *b)

 {

 	float tmp = *a;

@@ -18,6 +19,7 @@ void swap(float *a, float *b)
 	*b = tmp;

 }

 

+// sort algorithm for sprites

 void combSort(int* order, float* dist, int amount)

 {

 	int gap = amount, i;

@@ -43,17 +45,21 @@ void combSort(int* order, float* dist, int amount)
 

 #define PI 3.141592653589793238464

 

+// perform a shoot

 static void pshoot()

 {

 	float xadd, yadd, x, y;

 	int c;

 	

+	// check for every sprite whether it is hit

 	for(c = 0; c < spritecnt; c++)

 	{

+		// but just enemies, packs shouldn't die

 		if(sprites[c].type == TYPE_ENEMY)

 		{

-			 x = player.x;

-			 y = player.y;

+			x = player.x;

+			y = player.y;

+			

 			if(Abs(x - sprites[c].x) > Abs(y - sprites[c].y))

 			{

 				xadd = sgn(sprites[c].x - x);

@@ -65,8 +71,9 @@ static void pshoot()
 				yadd = sgn(sprites[c].y - y);

 			}

 			

-			if(1/*TODOTODOTODOTODO*/)

+			if(1/*TODOTODOTODOTODO*/) // todo: implement something to check whether the player shoots in the right direction

 			{

+				// very simple raycasting

 				while(x < MAPSIZE && y < MAPSIZE && x >= 0 && y >= 0)

 				{

 					x += xadd;

@@ -74,6 +81,7 @@ static void pshoot()
 					

 					if((int)y == (int)sprites[c].y && (int)x == (int)sprites[c].x)

 					{

+						// if hit, reduce enemie's health or let it die

 						sprites[c].effect -= 5;

 						if(sprites[c].effect <= 0)

 						{

@@ -81,9 +89,11 @@ static void pshoot()
 							sprites = (struct st_sprite *) realloc(sprites, spritecnt-- * sizeof(struct st_sprite));

 							if(sprites == NULL)error();

 						}

+						// we hit an enemy, go back to the game

 						return;

 					}

 					

+					// if there is a wall, no chance, try again

 					if(solids[(int)(x + 0.5)][(int)(y + 0.5)] == SOLID)

 					{

 						break;

@@ -94,17 +104,22 @@ static void pshoot()
 	}

 }

 

+// this moves the player in the world

 void move()

 {

 	float oldDirX, oldPlaneX, moveSpeed = fps * 1.25, rotSpeed = fps / 1.25;

 	float newx = 0, newy = 0;

+	// update the key buffer

 	keyupdate();

+	

+	// I hope this is self-explaining

 	if(keydown(KEY_CTRL_DOWN) || keydown(KEY_CTRL_UP) || keydown(KEY_CTRL_LEFT) || keydown(KEY_CTRL_RIGHT))

 	{

 		if(keydown(KEY_CTRL_DOWN))

 		{

 				newy = player.y - (player.dirY * moveSpeed);

 				newx = player.x - (player.dirX * moveSpeed);

+				

 				if(newx >= 0 && newx < MAPSIZE)

 				if(solids[(int)newx][(int)player.y] != SOLID)

 				{

@@ -116,7 +131,7 @@ void move()
 				{

 					player.y = newy;

 				}

-				output = 2;

+				output = 2; // 2 means the player moved, so the gun has to move

 		}

 		if(keydown(KEY_CTRL_UP))

 		{

@@ -136,12 +151,15 @@ void move()
 		}

 		if(keydown(KEY_CTRL_RIGHT))

 		{

+				// rotate the plane

 				oldDirX = player.dirX;

 				player.dirX = player.dirX * cosf(-rotSpeed) - player.dirY * sinf(-rotSpeed);

 				player.dirY = oldDirX * sinf(-rotSpeed) + player.dirY * cosf(-rotSpeed);

 				oldPlaneX = player.planeX;

 				player.planeX = player.planeX * cosf(-rotSpeed) - player.planeY * sinf(-rotSpeed);

 				player.planeY = oldPlaneX * sinf(-rotSpeed) + player.planeY * cosf(-rotSpeed);

+				

+				// if the output is 2 (move gun), let it; ortherwise set to 1 (just update)

 				output = (output < 2)?1:2;

 		}

 		if(keydown(KEY_CTRL_LEFT))

@@ -152,8 +170,11 @@ void move()
 				oldPlaneX = player.planeX;

 				player.planeX = player.planeX * cosf(rotSpeed) - player.planeY * sinf(rotSpeed);

 				player.planeY = oldPlaneX * sinf(rotSpeed) + player.planeY * cosf(rotSpeed);

+				

 				output = (output < 2)?1:2;

 		}

+		

+		// if we hit a sprite

 		if(solids[(int)newx][(int)newy] == SPRITE)

 		{

 			int c;

@@ -161,14 +182,17 @@ void move()
 			{

 				if(sprites[c].type == TYPE_PACK && (int)sprites[c].x == (int)newx && (int)sprites[c].y == (int)newy)

 				{

+					// cool, it is a pack

 					solids[(int)newx][(int)newy] = UNSOLID;

 					player.health += sprites[c].effect;

 					

+					// delete it

 					sprites[c] = sprites[spritecnt];

 					sprites = (struct st_sprite *) realloc(sprites, spritecnt-- * sizeof(struct st_sprite));

 					if(sprites == NULL)error();

 					

 					output = 2;

+					// got it

 					status = packmsg;

 					statustimer = 0;

 					break;

@@ -180,6 +204,7 @@ void move()
 	{

 		if(keydown(KEY_CTRL_MENU))

 		{

+			// open game menu

 			openmenu();

 			output = (output < 2)?1:2;

 			return;

@@ -188,24 +213,27 @@ void move()
 	

 	if(keydown(KEY_CTRL_SHIFT))

 	{

-			switch(player.weapon)

-			{

-				case GUN:

-					pshoot();

-					break;

-				/*case KNIFE:

-					newy = player.y + player.dirY;

-					newx = player.x + player.dirX;

-					if(newx >= 0 && newx < MAPSIZE)

-						if(map[(int)(newx)][(int)(newy)] >= 10)

-						{enemies[map[(int)(newx)][(int)(newy)] - 10].health -= 15;}

-					break;*/

-			}

-			

-			output = 2;

+		// fire!

+		switch(player.weapon)

+		{

+			case GUN:

+				// perhaps an enemy was hit?

+				pshoot();

+				break;

+			/*case KNIFE: // todo: fix this for dynamical enemies

+				newy = player.y + player.dirY;

+				newx = player.x + player.dirX;

+				if(newx >= 0 && newx < MAPSIZE)

+					if(map[(int)(newx)][(int)(newy)] >= 10)

+					{enemies[map[(int)(newx)][(int)(newy)] - 10].health -= 15;}

+				break;*/

+		}

+		

+		output = 2;

 	}

 	if(keydown(KEY_CTRL_ALPHA))

 	{

+		// alpha opens a door

 		newy = player.y + player.dirY;

 		newx = player.x + player.dirX;

 		if(newx >= 0 && newx < MAPSIZE)

@@ -213,6 +241,7 @@ void move()
 			if(map[(int)(newx)][(int)(newy)] == DOOR)

 			{

 				map[(int)(newx)][(int)(newy)] = SPACE;

+				// now there is no wall any more, we can walk through

 				solids[(int)newx][(int)newy] = UNSOLID;

 			}

 		}

@@ -220,14 +249,18 @@ void move()
 	}

 	if(keydown(KEY_CTRL_OPTN))

 	{

+		// optn, change weapon

 		player.weapon += 1;

 		if(player.weapon == WEAPON_OVERFLOW)

 		player.weapon = GUN;

 	}

 }

 

+// this is the "core", most important part

+// rendering is done here

 void cast()

 {

+	// see Lode Vandevenne's tutorial for details

 	float cameraX,rayDirX, rayDirY, sideDistX, sideDistY, deltaDistX, deltaDistY, perpWallDist, wallX, floorXWall, floorYWall, distWall;

 	int mapX, mapY, lineHeight, hit, side, x, tex, y, black, floorTexX, floorTexY, actualheight, heightdiff;

 	int stepX, drawStart, drawEnd, stepY;

@@ -254,6 +287,7 @@ void cast()
 

 	for(x = 0; x < 128; x++)

 	{

+		// create a ray from player

 		mapX = player.x;

 		mapY = player.y;		

 

@@ -315,10 +349,12 @@ void cast()
 			{			

 				if(heights[mapX][mapY] == 0 || drawheight == FALSE)

 				{

+					// it is a normal wall or something

 					hit = TRUE;

 				}

 				else

 				{

+					// now it's going to be complicated, let's draw a wall with a different height than the others \o/

 					if (side == 0)

 						perpWallDist = Abs((mapX - player.x + (1 - stepX) / 2) / rayDirX);

 					else

@@ -336,9 +372,11 @@ void cast()
 					if(drawStart < 0) drawStart = 0;	

 					drawEnd = (actualheight == 0)?32 + (Abs((int)(64 / perpWallDist)) >> 1):actualheight;

 					if(drawEnd >= 64) drawEnd = 63;	

-						

+					

+					// draw the wall

 					vertical(x, tex , drawStart, drawEnd, map[mapX][mapY], side, Abs((32 + (Abs((int)(64 / perpWallDist)) >> 1)) - (32 - (Abs((int)(64 / perpWallDist)) >> 1))));

 					

+					// now, the floor and the ceiling

 					if(side == 0 && rayDirX > 0)

 					{

 						floorXWall = mapX;

@@ -380,6 +418,7 @@ void cast()
 							(*(vram +  (y << 4) + (x >> 3))) |= (128 >> (x & 7));

 						}

 					}

+					// continue casting, but draw it 'behind' the current wall

 					actualheight = drawStart;

 				}

 			}

@@ -387,6 +426,7 @@ void cast()
 						

 		if(hit == TRUE)

 		{

+			// if we hit a wall or something, draw it

 			if (side == 0)

 				perpWallDist = Abs((mapX - player.x + (1 - stepX) / 2) / rayDirX);

 			else

@@ -407,8 +447,10 @@ void cast()
 			drawEnd = (actualheight == 0)?(lineHeight >> 1) + 32:actualheight;

 			if(drawEnd >= 64) drawEnd = 63;

 			

+			// draw it to the display

 			vertical(x, tex , drawStart, drawEnd, map[mapX][mapY], side, (actualheight > 0)?((lineHeight >> 1) + 32) - (32 - (lineHeight >> 1)):0);

 			

+			// draw floor & ceiling

 			if(drawfloor == TRUE)

 			{

 				if(side == 0 && rayDirX > 0)

@@ -468,6 +510,7 @@ void cast()
 		}

 	}

 	

+	// here something wants to be fixed... The sprites appear strange when there is a wall lower than the others

 	#define uDiv 1

 	#define vDiv 1

 	#define vMove 0.0

@@ -524,6 +567,9 @@ void cast()
 	

 	free(spriteOrder);

 }

+

+// old casting algo, this is just a backup

+// there is nothing else below, you can skip this

 /*void cast()

 {

 	float cameraX,rayDirX, rayDirY, sideDistX, sideDistY, deltaDistX, deltaDistY, perpWallDist, wallX, floorXWall, floorYWall, distWall;