Do some culling based on camera direction

src/wipeout/camera.c

@@ -21,10 +21,17 @@ void camera_init(camera_t *camera, section_t *section) {
 	camera->velocity = vec3(0, 0, 0);
 	camera->angle = vec3(0, 0, 0);
 	camera->angular_velocity = vec3(0, 0, 0);
-	camera->mat = mat4_identity();
 	camera->has_initial_section = false;
 }
 
+vec3_t camera_forward(camera_t *camera) {
+	float sx = sin(camera->angle.x);
+	float cx = cos(camera->angle.x);
+	float sy = sin(camera->angle.y);
+	float cy = cos(camera->angle.y);
+	return vec3(-(sy * cx), -sx, (cy * cx));
+}
+
 void camera_update(camera_t *camera, ship_t *ship, droid_t *droid) {
 	camera->last_position = camera->position;
 	(camera->update_func)(camera, ship, droid);

src/wipeout/camera.h

@@ -11,7 +11,6 @@ typedef struct camera_t {
 	vec3_t angular_velocity;
 	vec3_t last_position;
 	vec3_t real_velocity;
-	mat4_t mat;
 	section_t *section;
 	bool has_initial_section;
 	float update_timer;
@@ -19,6 +18,7 @@ typedef struct camera_t {
 } camera_t;
 
 void camera_init(camera_t *camera, section_t *section);
+vec3_t camera_forward(camera_t *camera);
 void camera_update(camera_t *camera, ship_t *ship, droid_t *droid);
 void camera_update_race_external(camera_t *, ship_t *camShip, droid_t *);
 void camera_update_race_internal(camera_t *, ship_t *camShip, droid_t *);

src/wipeout/object.c

@@ -68,13 +68,26 @@ Object *objects_load(char *name, texture_list_t tl) {
 		p += 4; // skeleton sub
 		p += 4; // skeleton next
 
+		object->radius = 0;
 		object->vertices = mem_bump(object->vertices_len * sizeof(vec3_t));
 		for (int i = 0; i < object->vertices_len; i++) {
 			object->vertices[i].x = get_i16(bytes, &p);
 			object->vertices[i].y = get_i16(bytes, &p);
 			object->vertices[i].z = get_i16(bytes, &p);
 			p += 2; // padding
+
+			if (abs(object->vertices[i].x) > object->radius) {
+				object->radius = abs(object->vertices[i].x);
 			}
+			if (abs(object->vertices[i].y) > object->radius) {
+				object->radius = abs(object->vertices[i].y);
+			}
+			if (abs(object->vertices[i].z) > object->radius) {
+				object->radius = abs(object->vertices[i].z);
+			}
+		}
+
+
 
 		object->normals = mem_bump(object->normals_len * sizeof(vec3_t));
 		for (int i = 0; i < object->normals_len; i++) {

src/wipeout/object.h

@@ -343,6 +343,7 @@ typedef struct Object {
 	vec3_t origin;
 	int32_t extent; // Flags for object characteristics
 	int16_t flags; // Next object in list
+	float radius;
 	struct Object *next; // Next object in list
 } Object;
 

src/wipeout/scene.c

@@ -123,21 +123,26 @@ void scene_draw(camera_t *camera) {
 	object_draw(sky_object, &sky_object->mat);
 	render_set_depth_write(true);
 
-	// Nearby objects
-	vec3_t cam_pos = camera->position;
-	Object *object = scene_objects;
-	float max_dist_sq = RENDER_FADEOUT_FAR * RENDER_FADEOUT_FAR;
-	while (object) {
-		vec3_t d = vec3_sub(cam_pos, object->origin);
-		float dist_sq = d.x * d.x + d.y * d.y + d.z * d.z;
+	// Objects
 
-		if (dist_sq < max_dist_sq) {
+	// Calculate the camera forward vector, so we can cull everything that's
+	// behind. Ideally we'd want to do a full frustum culling here. FIXME.
+	vec3_t cam_pos = camera->position;
+	vec3_t cam_dir = camera_forward(camera);
+	Object *object = scene_objects;
+	
+	while (object) {
+		vec3_t diff = vec3_sub(cam_pos, object->origin);
+		float cam_dot = vec3_dot(diff, cam_dir);
+		float dist_sq = vec3_dot(diff, diff);
+		if (
+			cam_dot < object->radius && 
+			dist_sq < (RENDER_FADEOUT_FAR * RENDER_FADEOUT_FAR)
+		) {
 			object_draw(object, &object->mat);
 		}
-		
 		object = object->next;
 	}
-
 }
 
 void scene_set_start_booms(int light_index) {

src/wipeout/track.c

@@ -261,15 +261,22 @@ void track_draw_section(section_t *section) {
 void track_draw(camera_t *camera) {	
 	render_set_model_mat(&mat4_identity());
 
-	float max_dist_sq = RENDER_FADEOUT_FAR * RENDER_FADEOUT_FAR;
+	// Calculate the camera forward vector, so we can cull everything that's
+	// behind. Ideally we'd want to do a full frustum culling here. FIXME.
 	vec3_t cam_pos = camera->position;
+	vec3_t cam_dir = camera_forward(camera);
 	
-	section_t *s = g.track.sections;
-	for(int32_t i = 0; i < g.track.section_count; ++i, ++s)
-	{
-		vec3_t d = vec3_sub(cam_pos, s->center);
-		float dist_sq = d.x * d.x + d.y * d.y + d.z * d.z;
-		if (dist_sq <  max_dist_sq) {
+	int drawn = 0;
+	int skipped = 0;
+	for(int32_t i = 0; i < g.track.section_count; i++) {
+		section_t *s = &g.track.sections[i];
+		vec3_t diff = vec3_sub(cam_pos, s->center);
+		float cam_dot = vec3_dot(diff, cam_dir);
+		float dist_sq = vec3_dot(diff, diff);
+		if (
+			cam_dot < 2048 && // FIXME: should use the bounding radius of the section
+			dist_sq < (RENDER_FADEOUT_FAR * RENDER_FADEOUT_FAR)
+		) {
 			track_draw_section(s);
 		}
 	}