119 lines
4.6 KiB
C
119 lines
4.6 KiB
C
/**
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* Behavior for bhvBird. These are the birds in the castle grounds
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* that fly away and scatter when Mario comes near them. There are
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* 2 types of birds; spawner birds and spawned birds. Spawner birds
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* are loaded by the level, and are inactive until Mario comes within
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* 2000 units of them, when they spawn 6 spawned birds and start flying.
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* Spawned birds are only spawned by a spawner bird, and start flying
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* immediately after spawning.
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*/
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/**
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* If the object is a spawned bird, start flying; if it's a spawner bird,
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* spawn spawned birds if Mario comes within 2000 units of it.
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*/
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static void bird_act_inactive(void) {
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// Start flying if the object is a spawned bird or if it's a spawner bird
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// and Mario is within 2000 units.
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if (o->oBehParams2ndByte == BIRD_BP_SPAWNED || o->oDistanceToMario < 2000.0f) {
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// If the object is a spawner bird, play the sound of birds flying away,
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// and spawn 6 spawned birds (which will start flying on the next frame).
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if (o->oBehParams2ndByte != BIRD_BP_SPAWNED) {
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s32 i;
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cur_obj_play_sound_2(SOUND_GENERAL_BIRDS_FLY_AWAY);
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for (i = 0; i < 6; i++) {
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spawn_object(o, MODEL_BIRDS, bhvBird);
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}
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// The spawner bird's home acts as its target location.
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o->oHomeX = -20.0f;
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o->oHomeZ = -3990.0f;
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}
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// Start flying
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o->oAction = BIRD_ACT_FLY;
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// Start with a random yaw, and a random pitch from 1000 to 5000.
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// Positive pitch is downwards.
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o->oMoveAnglePitch = 5000 - (s32)(4000.0f * random_float());
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o->oMoveAngleYaw = random_u16();
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o->oBirdSpeed = 40.0f;
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cur_obj_unhide();
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}
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}
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/**
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* Make the bird fly.
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* The bird flies laterally towards a target; (-20, -3990) if it's a spawner bird,
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* and the parent spawner bird if it's a spawned bird.
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*/
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static void bird_act_fly(void) {
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UNUSED s32 unused;
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f32 distance;
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// Compute forward velocity and vertical velocity from oBirdSpeed and pitch
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obj_compute_vel_from_move_pitch(o->oBirdSpeed);
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// If the bird's parent is higher than 8000 units, despawn the bird.
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// A spawned bird's parent is its spawner bird. A spawner bird's parent
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// is itself. In other words, when a group of birds has its spawner bird
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// fly past Y=8000, they will all despawn simultaneously. Otherwise, fly.
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if (o->parentObj->oPosY > 8000.0f) {
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obj_mark_for_deletion(o);
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} else {
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// If the bird is a spawner bird, fly towards its home; otherwise,
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// fly towards the bird's spawner bird.
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if (o->oBehParams2ndByte != BIRD_BP_SPAWNED) {
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distance = cur_obj_lateral_dist_to_home();
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// The spawner bird will start with its downwards (positive) pitch
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// and will continuously decrease its pitch (i.e. make itself face more upwards)
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// until it reaches its home, at which point it will face directly up.
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// This is done by making its target pitch the arctangent of its distance
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// to its home and its position - 10,000 (which is always negative).
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o->oBirdTargetPitch = atan2s(distance, o->oPosY - 10000.0f);
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o->oBirdTargetYaw = cur_obj_angle_to_home();
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} else {
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distance = lateral_dist_between_objects(o, o->parentObj);
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// The bird's target pitch will face directly to its spawner bird.
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o->oBirdTargetPitch = atan2s(distance, o->oPosY - o->parentObj->oPosY);
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o->oBirdTargetYaw = obj_angle_to_object(o, o->parentObj);
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// The bird goes faster the farther it is from its spawner bird so it can catch up.
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o->oBirdSpeed = 0.04f * dist_between_objects(o, o->parentObj) + 20.0f;
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}
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// Approach to match the bird's target yaw and pitch.
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obj_move_pitch_approach(o->oBirdTargetPitch, 140);
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cur_obj_rotate_yaw_toward(o->oBirdTargetYaw, 800);
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obj_roll_to_match_yaw_turn(o->oBirdTargetYaw, 0x3000, 600);
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}
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// The bird has no gravity, so this function only
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// moves the bird using its forward velocity.
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// Even if it did have gravity, it would only act as
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// a constant added to its Y position every frame since
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// its Y velocity is reset every frame by
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// obj_compute_vel_from_move_pitch.
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cur_obj_move_using_fvel_and_gravity();
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}
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/**
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* Update function for bhvBird.
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*/
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void bhv_bird_update(void) {
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switch (o->oAction) {
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case BIRD_ACT_INACTIVE:
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bird_act_inactive();
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break;
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case BIRD_ACT_FLY:
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bird_act_fly();
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break;
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}
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}
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