Add some chase view Improvements (#3571)

* improve chase view cam

* fix comment

* comment description of acceleration

Author: Baezon

code/physics/physics.cpp

@@ -58,17 +58,11 @@ void physics_init( physics_info * pi )
 	pi->max_vel.xyz.z = 100.0f;		//forward
 	pi->max_rear_vel = 100.0f;	//backward -- controlled seperately
 
-	pi->max_rotvel.xyz.x = 2.0f;		//pitch
-	pi->max_rotvel.xyz.y = 1.0f;		//heading
-	pi->max_rotvel.xyz.z = 2.0f;		//bank
+	pi->max_rotvel = vm_vec_new(2.0f, 1.0f, 2.0f);
 
-	pi->prev_ramp_vel.xyz.x = 0.0f;
-	pi->prev_ramp_vel.xyz.y = 0.0f;
-	pi->prev_ramp_vel.xyz.z = 0.0f;
+	vm_vec_zero(&pi->prev_ramp_vel);
 
-	pi->desired_vel.xyz.x = 0.0f;
-	pi->desired_vel.xyz.y = 0.0f;
-	pi->desired_vel.xyz.z = 0.0f;
+	vm_vec_zero(&pi->desired_vel);
 
 	pi->slide_accel_time_const=pi->side_slip_time_const;	// slide using max_vel.xyz.x & .xyz.y
 	pi->slide_decel_time_const=pi->side_slip_time_const;	// slide using max_vel.xyz.x & .xyz.y
@@ -87,6 +81,7 @@ void physics_init( physics_info * pi )
 
 	pi->ai_desired_orient = vmd_zero_matrix; // Asteroth - initialize to the "invalid" orientation, which will be ignored by physics unless set otherwise
 
+	vm_vec_zero(&pi->acceleration);
 }
 
 
@@ -281,6 +276,8 @@ void physics_sim_vel(vec3d * position, physics_info * pi, float sim_time, matrix
 	vec3d local_v_out;		// velocity in local coords following this frame
 	vec3d damp;
 
+	vec3d old_vel = pi->vel;
+
 	//	Maybe clear the reduced_damp flag.
 	//	This fixes the problem of the player getting near-instantaneous acceleration under unknown circumstances.
 	//	The larger problem is probably that PF_USE_VEL is getting stuck set.
@@ -373,6 +370,10 @@ void physics_sim_vel(vec3d * position, physics_info * pi, float sim_time, matrix
 	// update world velocity
 	vm_vec_unrotate(&pi->vel, &local_v_out, orient);
 
+	// update acceleration
+	vm_vec_sub(&pi->acceleration, &pi->vel, &old_vel);
+	vm_vec_scale(&pi->acceleration, 1 / sim_time);
+
 	if (special_warp_in) {
 		vm_vec_rotate(&pi->prev_ramp_vel, &pi->vel, orient);
 	}

code/physics/physics.h

@@ -100,6 +100,7 @@ typedef struct physics_info {
 
 	matrix ai_desired_orient;   // Asteroth - This is only set to something other than the zero matrix if Framerate_independent_turning is enabled, and 
 								// only by the AI after calls to angular_move. It is read and then zeroed out for the rest of the frame by physics_sim_rot
+	vec3d acceleration;		// this is only the current trend of velocity in m/s^2, does NOT determine future velocity
 } physics_info;
 
 // control info override flags

code/ship/ship.cpp

@@ -1048,6 +1048,9 @@ void ship_info::clone(const ship_info& other)
 	closeup_pos_targetbox = other.closeup_pos_targetbox;
 	closeup_zoom_targetbox = other.closeup_zoom_targetbox;
 
+	chase_view_offset = other.chase_view_offset;
+	chase_view_rigidity = other.chase_view_rigidity;
+
 	allowed_weapons = other.allowed_weapons;
 
 	restricted_loadout_flag = other.restricted_loadout_flag;
@@ -1359,6 +1362,9 @@ void ship_info::move(ship_info&& other)
 	std::swap(closeup_pos_targetbox, other.closeup_pos_targetbox);
 	closeup_zoom_targetbox = other.closeup_zoom_targetbox;
 
+	std::swap(chase_view_offset, other.chase_view_offset);
+	chase_view_rigidity = other.chase_view_rigidity;
+
 	std::swap(allowed_weapons, other.allowed_weapons);
 
 	std::swap(restricted_loadout_flag, other.restricted_loadout_flag);
@@ -1775,6 +1781,9 @@ ship_info::ship_info()
 	vm_vec_zero(&closeup_pos_targetbox);
 	closeup_zoom_targetbox = 0.5f;
 
+	vm_vec_zero(&chase_view_offset);
+	chase_view_rigidity = 5.0f;
+
 	allowed_weapons.clear();
 
 	restricted_loadout_flag.clear();
@@ -4096,6 +4105,18 @@ static void parse_ship_values(ship_info* sip, const bool is_template, const bool
 		stuff_vec3d(&sip->topdown_offset);
 	}
 
+	if (optional_string("$Chase View Offset:"))	{
+		stuff_vec3d(&sip->chase_view_offset);
+	}
+
+	if (optional_string("$Chase View Rigidity:")) {
+		stuff_float(&sip->chase_view_rigidity);
+		if (sip->chase_view_rigidity <= 0) {
+			Warning(LOCATION, "Ship \'%s\' must have a Chase View Rigidity greater than 0.", sip->name);
+			sip->chase_view_rigidity = 5.0f;
+		}
+	}
+
 	if (optional_string("$Shield_icon:")) {
 		stuff_string(name_tmp, F_NAME, sizeof(name_tmp));
 		hud_shield_assign_info(sip, name_tmp);

code/ship/ship.h

@@ -1247,6 +1247,9 @@ class ship_info
 	vec3d	closeup_pos_targetbox;			// position for camera when using ship in closeup view for hud target monitor
 	float	closeup_zoom_targetbox;			// zoom when using ship in closeup view for hud target monitor
 
+	vec3d	chase_view_offset;				// special offset for chase view
+	float	chase_view_rigidity;			// how 'floaty' this ship is when viewed in chase view
+
 	allowed_weapon_bank allowed_weapons;	// specifies which weapons can be loaded out by the
 											// player during weapons loadout.
 

freespace2/freespace.cpp

@@ -2955,7 +2955,7 @@ camid game_render_frame_setup()
 
 	vec3d	eye_pos;
 	matrix	eye_orient = vmd_identity_matrix;
-	vec3d	tmp_dir;
+	vec3d	eye_vec;
 
 	static int last_Viewer_mode = 0;
 	static int last_Game_mode = 0;
@@ -2975,6 +2975,7 @@ camid game_render_frame_setup()
 
 	// This code is supposed to detect camera "cuts"... like going between
 	// different views.
+	bool camera_cut = false;
 	if ( (last_Viewer_mode != Viewer_mode)
 		|| (last_Game_mode != Game_mode)
 		|| (fov_changed)
@@ -2985,7 +2986,8 @@ camid game_render_frame_setup()
 		last_FOV = main_cam->get_fov();
 
 		// Camera moved.  Tell stars & debris to not do blurring.
-		stars_camera_cut();		
+		stars_camera_cut();	
+		camera_cut = true;
 	}
 
 	say_view_target();
@@ -3022,8 +3024,8 @@ camid game_render_frame_setup()
 				//	View target from player ship.
 				Viewer_obj = nullptr;
 				eye_pos = Player_obj->pos;
-				vm_vec_normalized_dir(&tmp_dir, &Objects[Player_ai->target_objnum].pos, &eye_pos);
-				vm_vector_2_matrix(&eye_orient, &tmp_dir, nullptr, nullptr);
+				vm_vec_normalized_dir(&eye_vec, &Objects[Player_ai->target_objnum].pos, &eye_pos);
+				vm_vector_2_matrix(&eye_orient, &eye_vec, nullptr, nullptr);
 				//rtn_cid = ship_get_followtarget_eye( Player_obj );
 			}
 		} else {
@@ -3054,9 +3056,9 @@ camid game_render_frame_setup()
 
 			eye_pos = Dead_camera_pos;
 
-			vm_vec_normalized_dir(&tmp_dir, &Player_obj->pos, &eye_pos);
+			vm_vec_normalized_dir(&eye_vec, &Player_obj->pos, &eye_pos);
 
-			vm_vector_2_matrix(&eye_orient, &tmp_dir, nullptr, nullptr);
+			vm_vector_2_matrix(&eye_orient, &eye_vec, nullptr, nullptr);
 			Viewer_obj = nullptr;
 		}
 	} 
@@ -3101,50 +3103,58 @@ camid game_render_frame_setup()
 
 				vm_vec_scale_add(&eye_pos, &Viewer_obj->pos, &tm.vec.fvec, Viewer_external_info.current_distance);
 
-				vm_vec_sub(&tmp_dir, &Viewer_obj->pos, &eye_pos);
-				vm_vec_normalize(&tmp_dir);
-				vm_vector_2_matrix(&eye_orient, &tmp_dir, &Viewer_obj->orient.vec.uvec, nullptr);
+				vm_vec_sub(&eye_vec, &Viewer_obj->pos, &eye_pos);
+				vm_vec_normalize(&eye_vec);
+				vm_vector_2_matrix(&eye_orient, &eye_vec, &Viewer_obj->orient.vec.uvec, nullptr);
 				Viewer_obj = nullptr;
 
 				//	Modify the orientation based on head orientation.
 				compute_slew_matrix(&eye_orient, &Viewer_slew_angles);
 
 			} else if ( Viewer_mode & VM_CHASE ) {
-				vec3d	move_dir;
 				vec3d aim_pt;
-				
-				if ( Viewer_obj->phys_info.speed < 62.5f )
-					move_dir = Viewer_obj->phys_info.vel;
-				else {
-					move_dir = Viewer_obj->phys_info.vel;
-					vm_vec_scale(&move_dir, (62.5f/Viewer_obj->phys_info.speed));
-				}
 
 				vec3d tmp_up;
 				matrix eyemat;
 				ship_get_eye(&tmp_up, &eyemat, Viewer_obj, false, false);
 
-				//create a better 3rd person view if this is the player ship
-				if (Viewer_obj==Player_obj)
-				{
-					//get a point 1000m forward of ship
-					vm_vec_copy_scale(&aim_pt,&Viewer_obj->orient.vec.fvec,1000.0f);
-					vm_vec_add2(&aim_pt,&Viewer_obj->pos);
-
-					vm_vec_scale_add(&eye_pos, &Viewer_obj->pos, &move_dir, -0.02f * Viewer_obj->radius);
-					vm_vec_scale_add2(&eye_pos, &eyemat.vec.fvec, -2.125f * Viewer_obj->radius - Viewer_chase_info.distance);
-					vm_vec_scale_add2(&eye_pos, &eyemat.vec.uvec, 0.625f * Viewer_obj->radius + 0.35f * Viewer_chase_info.distance);
-					vm_vec_sub(&tmp_dir, &aim_pt, &eye_pos);
-					vm_vec_normalize(&tmp_dir);
-				}
-				else
-				{
-					vm_vec_scale_add(&eye_pos, &Viewer_obj->pos, &move_dir, -0.02f * Viewer_obj->radius);
-					vm_vec_scale_add2(&eye_pos, &eyemat.vec.fvec, -2.5f * Viewer_obj->radius - Viewer_chase_info.distance);
-					vm_vec_scale_add2(&eye_pos, &eyemat.vec.uvec, 0.75f * Viewer_obj->radius + 0.35f * Viewer_chase_info.distance);
-					vm_vec_sub(&tmp_dir, &Viewer_obj->pos, &eye_pos);
-					vm_vec_normalize(&tmp_dir);
+				eye_pos = Viewer_obj->pos;
+
+				//get a point far in front of the ship to point the camera at
+				vm_vec_copy_scale(&aim_pt,&Viewer_obj->orient.vec.fvec, Viewer_obj->radius * 100.0f);
+				vm_vec_add2(&aim_pt,&Viewer_obj->pos);
+
+				vec3d chase_view_offset = Ship_info[Ships[Viewer_obj->instance].ship_info_index].chase_view_offset;
+				if (IS_VEC_NULL(&chase_view_offset)) {
+					if (Viewer_obj == Player_obj)
+						chase_view_offset = vm_vec_new(0.0f, 0.625f * Viewer_obj->radius, -2.125f * Viewer_obj->radius);
+					else
+						chase_view_offset = vm_vec_new(0.0f, 0.75f * Viewer_obj->radius, -2.5f * Viewer_obj->radius);
 				}
+
+				//position the camera based on the offset and external camera distance
+				vec3d rotated_chase_view_offset;
+				vm_vec_unrotate(&rotated_chase_view_offset, &chase_view_offset, &Viewer_obj->orient);
+				vm_vec_add2(&eye_pos, &rotated_chase_view_offset);
+				vm_vec_scale_add2(&eye_pos, &eyemat.vec.fvec, -Viewer_chase_info.distance);
+				vm_vec_scale_add2(&eye_pos, &eyemat.vec.uvec, 0.35f * Viewer_chase_info.distance);
+
+				vec3d old_pos;
+				main_cam->get_info(&old_pos, nullptr);
+				if (camera_cut)
+					old_pos = eye_pos;
+
+				// "push" the camera backwards in the direction of its old position based on acceleration to to make it 
+				// feel like the camera is trying to keep up with the ship (based on the rigidity value)
+				vec3d velocity_comp = Viewer_obj->phys_info.vel;
+				vm_vec_scale_add2(&velocity_comp, &Viewer_obj->phys_info.acceleration, (-5.0f / (vm_vec_mag(&Viewer_obj->phys_info.rotvel) * 2.0f + 1)) * flFrametime);
+				vm_vec_scale_add2(&old_pos, &velocity_comp, flFrametime);
+				vec3d eye_mov = eye_pos - old_pos;
+				eye_mov *= exp(-Ship_info[Ships[Viewer_obj->instance].ship_info_index].chase_view_rigidity * flFrametime);
+				eye_pos -= eye_mov;
+
+				vm_vec_sub(&eye_vec, &aim_pt, &eye_pos);
+				vm_vec_normalize(&eye_vec);
 
 				// JAS: I added the following code because if you slew up using
 				// Descent-style physics, tmp_dir and Viewer_obj->orient.vec.uvec are
@@ -3155,7 +3165,7 @@ camid game_render_frame_setup()
 				tmp_up = eyemat.vec.uvec;
 				vm_vec_scale_add2( &tmp_up, &eyemat.vec.rvec, 0.00001f );
 
-				vm_vector_2_matrix(&eye_orient, &tmp_dir, &tmp_up, nullptr);
+				vm_vector_2_matrix(&eye_orient, &eye_vec, &tmp_up, nullptr);
 				Viewer_obj = nullptr;
 
 				//	Modify the orientation based on head orientation.
@@ -3167,9 +3177,9 @@ camid game_render_frame_setup()
 
 					vec3d warp_pos = Player_obj->pos;
 					shipp->warpout_effect->getWarpPosition(&warp_pos);
-					vm_vec_sub(&tmp_dir, &warp_pos, &eye_pos);
-					vm_vec_normalize(&tmp_dir);
-					vm_vector_2_matrix(&eye_orient, &tmp_dir, &Player_obj->orient.vec.uvec, nullptr);
+					vm_vec_sub(&eye_vec, &warp_pos, &eye_pos);
+					vm_vec_normalize(&eye_vec);
+					vm_vector_2_matrix(&eye_orient, &eye_vec, &Player_obj->orient.vec.uvec, nullptr);
 					Viewer_obj = nullptr;
 			} else if (Viewer_mode & VM_TOPDOWN) {
 					angles rot_angles = { PI_2, 0.0f, 0.0f };