From 128d4058a4e0d37b7bef394ccde7277391e4ae0e Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@debian.org>
Date: Sun, 9 Aug 2015 18:28:26 +0200
Subject: [PATCH] Fix throwing grenades from moving platforms.

The train and obstacle collision code made a distinction between
horizontally moving entities (which covers bullets and lasers), and
vertically moving entities (falling items?), but didn't handle
diagonally moving entities correctly, like grenades.
---
 src/bullets.cpp   |  2 +-
 src/defs.h        |  6 ++++++
 src/entities.cpp  |  4 ++--
 src/obstacles.cpp | 12 ++++++++----
 src/trains.cpp    | 14 +++++++++-----
 5 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/src/bullets.cpp b/src/bullets.cpp
index 88e288c..fb84642 100644
--- a/src/bullets.cpp
+++ b/src/bullets.cpp
@@ -264,7 +264,7 @@ bool bulletHasCollided(Entity *bullet, float dx, float dy)
 	
 	checkSwitchContact(bullet);
 
-	if ((checkTrainContact(bullet, 0)) || (checkObstacleContact(bullet, 0)))
+	if ((checkTrainContact(bullet, DIR_XY)) || (checkObstacleContact(bullet, DIR_XY)))
 	{
 		if (bullet->flags & ENT_BOUNCES)
 			bounceBullet(bullet, dx, dy);
diff --git a/src/defs.h b/src/defs.h
index d358d3e..5c59832 100644
--- a/src/defs.h
+++ b/src/defs.h
@@ -378,6 +378,12 @@ enum {
 	PAK_TAGS
 };
 
+/* ######### miscellaneous ############## */
+
+#define DIR_X 1
+#define DIR_Y 2
+#define DIR_XY 3
+
 /* ############# debug ################## */
 
 #if DEBUG
diff --git a/src/entities.cpp b/src/entities.cpp
index 25ae954..4a48160 100644
--- a/src/entities.cpp
+++ b/src/entities.cpp
@@ -321,7 +321,7 @@ void moveEntity(Entity *ent)
 
 	if (ent->dx != 0)
 	{		
-		if ((checkBrickContactX(ent)) || (checkObstacleContact(ent, 0)) || (checkTrainContact(ent, 0)))
+		if ((checkBrickContactX(ent)) || (checkObstacleContact(ent, DIR_X)) || (checkTrainContact(ent, DIR_X)))
 		{
 			ent->dx = 0;
 		}
@@ -336,7 +336,7 @@ void moveEntity(Entity *ent)
 
 	if (ent->dy != 0)
 	{
-		if ((checkBrickContactY(ent)) || (checkObstacleContact(ent, 1)) || (checkTrainContact(ent, 1)))
+		if ((checkBrickContactY(ent)) || (checkObstacleContact(ent, DIR_Y)) || (checkTrainContact(ent, DIR_Y)))
 		{
 			if ((ent->flags & ENT_BOUNCES) && (ent->dy >= 3))
 			{
diff --git a/src/obstacles.cpp b/src/obstacles.cpp
index dc1ddfe..a919e52 100644
--- a/src/obstacles.cpp
+++ b/src/obstacles.cpp
@@ -57,18 +57,22 @@ bool checkObstacleContact(Entity *ent, int dir)
 			continue;
 		}
 			
-		if (dir == 0)
+		if (dir == DIR_X)
 		{
 			collision = Collision::collision(ent->x + ent->dx, ent->y, ent->width, ent->height - 1, obstacle->x, obstacle->y, obstacle->width, obstacle->height);
 		}
-		else
+		else if (dir == DIR_Y)
 		{
 			collision = Collision::collision(ent->x, ent->y + ent->dy, ent->width, ent->height - 1, obstacle->x, obstacle->y, obstacle->width, obstacle->height);
 		}
+		else
+		{
+			collision = Collision::collision(ent->x + ent->dx, ent->y + ent->dy, ent->width, ent->height - 1, obstacle->x, obstacle->y, obstacle->width, obstacle->height);
+		}
 
 		if (collision)
 		{
-			if (dir == 0)
+			if (dir & DIR_X)
 			{
 				if ((ent->y + ent->height == obstacle->y + obstacle->height) || ((ent->flags & ENT_BULLET) && (ent->owner == &player)))
 				{
@@ -79,7 +83,7 @@ bool checkObstacleContact(Entity *ent, int dir)
 				}
 			}
 
-			if (dir == 1)
+			if (dir & DIR_Y)
 			{
 				ent->falling = false;
 				ent->dy = 0;
diff --git a/src/trains.cpp b/src/trains.cpp
index 2c7585f..9853123 100644
--- a/src/trains.cpp
+++ b/src/trains.cpp
@@ -87,14 +87,14 @@ void trainBlockEntity(Entity *ent, const char *message, Train *train, int dir)
 	
 	if ((ent->flags & ENT_BULLET) && (!(ent->flags & ENT_BOUNCES)))
 	{
-		if (dir == 0)
+		if (dir & DIR_X)
 		{
 			if (ent->dx < 0) ent->x = train->x + train->sprite->image[0]->w;
 			if (ent->dx > 0) ent->x = train->x - ent->width;
 		}
 	}
 
-	if (dir == 1)
+	if (dir & DIR_Y)
 	{
 		if ((ent->dy >= 0) && (train->type >= TR_SLIDEDOOR))
 		{
@@ -122,14 +122,18 @@ bool checkTrainContact(Entity *ent, int dir)
 	{
 		train = (Train*)train->next;
 
-		if (dir == 0)
+		if (dir == DIR_X)
 		{
 			collision = (Collision::collision(ent->x + ent->dx, ent->y, ent->width, ent->height - 1, train->x, train->y, train->width, train->height));
 		}
-		else
+		else if (dir == DIR_Y)
 		{
 			collision = (Collision::collision(ent->x, ent->y + ent->dy, ent->width, ent->height - 1, train->x, train->y, train->width, train->height));
 		}
+		else
+		{
+			collision = (Collision::collision(ent->x + ent->dx, ent->y + ent->dy, ent->width, ent->height - 1, train->x, train->y, train->width, train->height));
+		}
 
 		if (collision)
 		{
@@ -185,7 +189,7 @@ bool checkTrainContact(Entity *ent, int dir)
 						openDoor(train);
 					}
 					
-					if (dir == 1)
+					if (dir & DIR_Y)
 					{
 						ent->dy = 0;
 						ent->falling = false;
-- 
2.39.5