Subdivision fixes

First part of collision detection (needs work, commented out)
Wireframe mode ('w' to enter, 'e' to exit)
Spotlighting


git-svn-id: svn://cook.msm.cam.ac.uk:745/thrust3d/thrust3d@35 84d2e878-0bd5-11dd-ad15-13eda11d74c5

1 files changed, 127 insertions, 2 deletions

diff --git a/src/physics.c b/src/physics.c
index 0bcbae7..0c33e63 100644
--- a/src/physics.c
+++ b/src/physics.c
@@ -39,8 +39,130 @@
 /* Conversion factor between friction and 'yawthrust' */
 #define TORQUE 3
 
+static int physics_will_collide_face(GLfloat sx, GLfloat sy, GLfloat sz, GLfloat vx, GLfloat vy, GLfloat vz,
+					GLfloat nx, GLfloat ny, GLfloat nz, GLfloat *fvert, int nfvert, Uint32 dt) {
+
+	GLfloat px, py, pz;
+	GLfloat t1, t2, b;
+	int t;
+	
+	/* Range test */
+	px = fvert[3*0 + 0];
+	py = fvert[3*0 + 1];
+	pz = fvert[3*0 + 2];
+	
+	t1 = px*nx + py*ny + pz*nz;
+	t2 = sx*nx + sy*ny + sz*nz;
+	b = vx*nx + vy*ny + vz*nz;
+	if ( b == 0 ) return 0;		/* Collision happens infinitely far in the future */
+	t = (t1 - t2) / b;
+	
+//	printf("Testing vertex %8f %8f %8f, velocity %8f %8f %8f against face %8f %8f %8f\n",
+//			sx, sy, sz, vx, vy, vz, px, py, pz);
+//	printf("Collision happens at t + %i\n", t);
+//	exit(0);
+	
+	/* If the vertex is exactly on the plane, then moving away from the plane is OK */
+	if ( (t == 0) && (b > 0) ) return 0;
+	
+	if ( t < 0 ) return 0;		/* Collided in the past */
+	if ( t > dt ) return 0;		/* Not going to collide this step */
+	
+	/* Boundary test */
+	
+	
+	return 1;
+	
+}
+
+/* Return non-zero if 'obj' will collide with 'other' with 'dt' milliseconds */
+static int physics_will_collide(ModelInstance *obj, ModelInstance *other, Uint32 dt) {
+
+	int i;
+	
+	const GLfloat vx = obj->vx;
+	const GLfloat vy = obj->vy;
+	const GLfloat vz = obj->vz;
+	
+	/* Consider all the primitives in 'obj' */
+	for ( i=0; i<obj->model->num_primitives; i++ ) {
+		
+		int j;
+		
+		/* Consider all the vertices in this primitive */
+		for ( j=0; j<obj->model->primitives[i]->num_vertices; j++ ) {
+		
+			int a;
+			const GLfloat sx = obj->x + obj->model->primitives[i]->vertices[3*j+0];
+			const GLfloat sy = obj->y + obj->model->primitives[i]->vertices[3*j+1];
+			const GLfloat sz = obj->z + obj->model->primitives[i]->vertices[3*j+2];
+			
+			/* Consider all the primitives in 'other' */
+			for ( a=0; a<other->model->num_primitives; a++ ) {
+			
+				const GLfloat nx = other->model->primitives[a]->normals[0];
+				const GLfloat ny = other->model->primitives[a]->normals[1];
+				const GLfloat nz = other->model->primitives[a]->normals[2];
+				
+				switch ( other->model->primitives[a]->type ) {
+				
+					case PRIMITIVE_QUADS : {
+						
+						int f;
+						
+						/* Faces are quads */
+						for ( f=0; f<other->model->primitives[a]->num_vertices/4; f++ ) {
+						
+							GLfloat face[3*4];
+							int q;
+							
+							for ( q=0; q<4; q++ ) {
+								face[3*q + 0] = other->x + other->model->primitives[a]->vertices[4*(f+q) + 0];
+								face[3*q + 1] = other->y + other->model->primitives[a]->vertices[4*(f+q) + 1];
+								face[3*q + 2] = other->z + other->model->primitives[a]->vertices[4*(f+q) + 2];
+							}
+							
+							if ( physics_will_collide_face(sx, sy, sz, vx, vy, vz, nx, ny, nz,
+											face, 4, dt) != 0 ) {
+									return 1;	/* Don't waste time looking anywhere else */
+							}
+						}
+						break;
+					}
+				
+				}
+			
+			}
+			
+		}
+	}
+
+	return 0;
+	
+}
+
 /* Called once for each object which isn't just "scenery" */
-static void physics_process(ModelInstance *obj, Uint32 dt) {
+static void physics_process(ModelInstance *obj, Uint32 dt, Room **rooms, int num_rooms) {
+	
+	int i;
+	
+	#if 0
+	/* Consider all the currently relevant rooms */
+	for ( i=0; i<num_rooms; i++ ) {
+		int j;
+		/* Consider all the objects in this room */
+		for ( j=0; j<rooms[i]->num_objects; j++ ) {
+			if ( physics_will_collide(obj, rooms[i]->objects[j], dt) ) {
+				/* Stop the object in its tracks and return */
+				obj->vx = 0.0;
+				obj->vy = 0.0;
+				obj->vz = 0.0;
+				obj->yawspeed = 0.0;
+				return;
+			}
+		}
+	}
+	#endif
 	
 	/* Air friction */
 	if ( obj->vx > 0.0 ) {
@@ -115,7 +237,10 @@ void physics_step(Game *game, Uint32 t) {
 	if ( game->turn_right ) {
 		game->lander->yawspeed += YAWTHRUST *dt;	/* +ve yaw is "right" */
 	}
-	physics_process(game->lander, dt);
+	
+	/* The number of rooms to consider for physics purposes can probably be further reduced */
+	physics_process(game->lander, dt, game->rooms, game->num_rooms);
+	
 	game_check_handoff(game);
 	
 	game->tlast = t;