Collision response - make it possible to land

git-svn-id: svn://cook.msm.cam.ac.uk:745/thrust3d/thrust3d@52 84d2e878-0bd5-11dd-ad15-13eda11d74c5

3 files changed, 16 insertions, 8 deletions

diff --git a/src/model.c b/src/model.c
index 30bc289..d182f32 100644
--- a/src/model.c
+++ b/src/model.c
@@ -478,6 +478,7 @@ ModelInstance *model_instance_new(ModelContext *ctx, const char *name, RenderCon
 	instance->vz = 0.0;
 	instance->yaw = 0.0;
 	instance->yawspeed = 0.0;
+	instance->landed = 0.0;
 	
 	return instance;
 
diff --git a/src/physics.c b/src/physics.c
index 1277f62..120caff 100644
--- a/src/physics.c
+++ b/src/physics.c
@@ -141,7 +141,7 @@ int physics_will_collide_face(GLfloat sx, GLfloat sy, GLfloat sz, GLfloat vx, GL
 }
 
 /* Return non-zero if 'obj' will collide with 'other' with 'dt' milliseconds */
-static int physics_will_collide(ModelInstance *obj, ModelInstance *other, Uint32 dt) {
+static int physics_check_collide(ModelInstance *obj, ModelInstance *other, Uint32 dt) {
 
 	int i;
 	
@@ -190,6 +190,15 @@ static int physics_will_collide(ModelInstance *obj, ModelInstance *other, Uint32
 							if ( physics_will_collide_face(sx, sy, sz, vx, vy, vz, nx, ny, nz,
 											face, 4, dt, other) != 0 ) {
 									//printf("collides with %s/%p\n", other->model->name, other);
+									if ( (nx == 0.0) && (ny == 0.0) && ( nz == 1.0) ) {
+										obj->vz = 0.0;
+										obj->landed = 1;
+									} else {
+										obj->vx = -obj->vx;
+										obj->vy = -obj->vy;
+										obj->vz = -obj->vz;
+										obj->yawspeed = 0.0;
+									}
 									return 1;	/* Don't waste time looking anywhere else */
 							}
 						}
@@ -219,12 +228,7 @@ static void physics_process(ModelInstance *obj, Uint32 dt, Game *game) {
 		/* Consider all the objects in this room */
 		int j;
 		for ( j=0; j<room->num_objects; j++ ) {
-			if ( physics_will_collide(obj, room->objects[j], dt) ) {
-				/* Stop the object in its tracks and return */
-				obj->vx = -obj->vx;
-				obj->vy = -obj->vy;
-				obj->vz = -obj->vz;
-				obj->yawspeed = 0.0;
+			if ( physics_check_collide(obj, room->objects[j], dt) ) {
 				return;
 			}
 		}
@@ -264,7 +268,7 @@ static void physics_process(ModelInstance *obj, Uint32 dt, Game *game) {
 	}
 	
 	/* Gravity */
-	if ( obj->attribs & OBJ_GRAVITY ) obj->vz -= GRAVITY * dt;
+	if ( (obj->attribs & OBJ_GRAVITY) && (!obj->landed) ) obj->vz -= GRAVITY * dt;
 	
 	/* Take a step */
 	obj->x += obj->vx * dt;
@@ -288,6 +292,7 @@ void physics_step(Game *game, Uint32 t) {
 		if ( game->fuel > 0.0 ) {
 			game->lander->vz += THRUST * dt;
 			game->fuel -= 0.0002;
+			game->lander->landed = 0;
 		}
 	}
 	if ( game->forward ) {
diff --git a/src/types.h b/src/types.h
index c70c9bb..71e8de7 100644
--- a/src/types.h
+++ b/src/types.h
@@ -101,6 +101,8 @@ typedef struct {
 	float yaw;
 	float yawspeed;
 	
+	int landed;
+	
 } ModelInstance;
 
 typedef struct {