medfall

commit 74d047d7eae558d25746bbe24a8c66c83f63587f
parent da1a6c3c7d1b656fd243c8ec479bbc029046c353
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Mon Aug 21 21:01:03 +0300

Much improved player physics. Walking up hills works now, walking down is a bit rubbish

Diffstat:
hm.cc
 | 
91
++++++++++++++++++++++++++++++++++++++++++++++---------------------------------
1 file changed, 53 insertions(+), 38 deletions(-)
diff --git a/hm.cc b/hm.cc
@@ -229,55 +229,73 @@ GAME_FRAME( game_frame ) {
 	while( remaining_t > 0 && spins < 5 ) {
 		spins++;
 		if( game->on_ground ) {
-			v3 start = game->pos + v3( 0, 0, 0.001f );
-			v3 end = start + game->velocity * remaining_t;
+			const float step_height = 0.1f;
 
-			float t;
-			float step_t = FLT_MAX;
-			v3 normal, step_normal;
+			v3 low_start = game->pos;
+			v3 low_end = low_start + game->velocity * remaining_t;
 
-			const float step_height = 0.1f;
-			v3 step_start = game->pos + v3( 0, 0, step_height );
+			v3 high_start = game->pos + v3( 0, 0, step_height );
+			v3 high_end = high_start + game->velocity * remaining_t;
 
-			bool hit = segment_vs_terrain( &game->tm, start, end, &t, &normal );
-			bool step_hit = false;
+			float low_t;
+			float high_t;
+			v3 low_normal, high_normal;
 
-			bool step_up_hit = segment_vs_terrain( &game->tm, start, step_start, NULL, NULL );
+			bool low_hit = segment_vs_terrain( &game->tm, low_start, low_end, &low_t, &low_normal );
+			bool high_hit = false;
+
+			bool step_up_hit = segment_vs_terrain( &game->tm, low_start, high_start, NULL, NULL );
 			if( !step_up_hit ) {
-				v3 step_end = step_start + game->velocity * remaining_t;
-				step_hit = segment_vs_terrain( &game->tm, step_start, step_end, &step_t, &step_normal );
+				high_hit = segment_vs_terrain( &game->tm, high_start, high_end, &high_t, &high_normal );
 			}
 
-			if( step_t > t ) {
-				v3 step_intersection = step_start + game->velocity * remaining_t * min( 1.0f, step_t );
-				v3 step_down = step_intersection - v3( 0, 0, step_height );
+			v3 step_down_start;
+			float step_down_distance;
+			bool should_step_down = false;
 
-				float step_down_t;
-				bool step_down_hit = segment_vs_terrain( &game->tm, step_intersection, step_down, &step_down_t, &step_normal );
-				if( !step_down_hit ) {
-					step_t = 1.0f;
-					game->on_ground = false;
+			if( high_t > low_t ) {
+				if( high_hit ) {
+					game->pos = high_start + game->velocity * high_t * remaining_t;
+					remaining_t = ( 1.0f - high_t ) * remaining_t;
+				}
+				else {
+					step_down_start = high_end;
+					step_down_distance = step_height * 2;
+					should_step_down = true;
+					remaining_t = 0;
 				}
-			}
-
-			if( hit ) {
-				game->pos = start + game->velocity * t * remaining_t + v3( 0, 0, 0.001f );
-				remaining_t = ( 1.0f - t ) * remaining_t;
 			}
 			else {
-				v3 down_end = end - v3( 0, 0, 0.2f );
-				float down_t;
-				bool down_hit = segment_vs_terrain( &game->tm, end, down_end, &down_t, NULL );
-				if( !down_hit ) {
-					game->on_ground = false;
-					down_t = 1;
+				if( low_hit ) {
+					game->pos = low_start + game->velocity * low_t * remaining_t;
+					remaining_t = ( 1.0f - low_t ) * remaining_t;
 				}
-				game->pos = lerp( end, down_t, down_end ) + v3( 0, 0, 0.001f );
-				// TODO: probably not right
-				remaining_t = 0;
+				else {
+					step_down_start = low_end;
+					step_down_distance = step_height;
+					should_step_down = true;
+					remaining_t = 0;
+				}
+			}
+
+			if( should_step_down ) {
+				float step_down_t;
+				v3 step_down_end = step_down_start - v3( 0, 0, step_down_distance );
+
+				bool step_down_hit = segment_vs_terrain( &game->tm, step_down_start, step_down_end, &step_down_t, NULL );
+
+				game->pos = lerp( step_down_start, step_down_t, step_down_end );
+				game->on_ground = step_down_hit;
+			}
+
+			if( game->on_ground ) {
+				// move up 1mm so float imprecision doesn't make us fall through the world
+				game->pos.z += 0.001f;
 			}
 		}
-		else {
+
+		if( !game->on_ground ) {
+			// TODO: rk4 integration
 			const float gravity = -30.0f;
 			game->velocity += v3( 0, 0, gravity ) * remaining_t;
 
@@ -307,9 +325,6 @@ GAME_FRAME( game_frame ) {
 	game->pos.z += dt * dz * speed;
 #endif
 
-	// game->pos.z = terrain_height( &game->tm, game->pos ) + 1.8f;
-	// game->pos.z += dz * 50.0f * dt;
-
 	terrain_update( &game->tm, game->pos );
 
 	v3 eye_pos = game->pos + v3( 0, 0, EYE_HEIGHT );