1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
#include <algorithm>
#include <cmath>
#include "api/LoopTimer.h"
#include "manager/ComponentManager.h"
#include "manager/Mediator.h"
#include "AISystem.h"
using namespace crepe;
void AISystem::update() {
const Mediator & mediator = this->mediator;
ComponentManager & mgr = mediator.component_manager;
LoopTimer & timer = mediator.timer;
RefVector<AI> ai_components = mgr.get_components_by_type<AI>();
//TODO: Use fixed loop dt (this is not available at master at the moment)
double dt = timer.get_delta_time();
// Loop through all AI components
for (AI & ai : ai_components) {
if (!ai.active) {
continue;
}
RefVector<Rigidbody> rigidbodies
= mgr.get_components_by_id<Rigidbody>(ai.game_object_id);
if (rigidbodies.empty()) {
throw std::runtime_error(
"AI component must be attached to a GameObject with a Rigidbody component");
}
Rigidbody & rigidbody = rigidbodies.front().get();
if (!rigidbody.active) {
continue;
}
if (rigidbody.data.mass <= 0) {
throw std::runtime_error("Mass must be greater than 0");
}
// Calculate the force to apply to the entity
vec2 force = this->calculate(ai, rigidbody);
// Calculate the acceleration (using the above calculated force)
vec2 acceleration = force / rigidbody.data.mass;
// Finally, update Rigidbody's velocity
rigidbody.data.linear_velocity += acceleration * dt;
}
}
vec2 AISystem::calculate(AI & ai, const Rigidbody & rigidbody) {
const Mediator & mediator = this->mediator;
ComponentManager & mgr = mediator.component_manager;
RefVector<Transform> transforms = mgr.get_components_by_id<Transform>(ai.game_object_id);
Transform & transform = transforms.front().get();
vec2 force;
// Run all the behaviors that are on, and stop if the force gets too high
if (ai.on(AI::BehaviorTypeMask::FLEE)) {
vec2 force_to_add = this->flee(ai, rigidbody, transform);
if (!this->accumulate_force(ai, force, force_to_add)) {
return force;
}
}
if (ai.on(AI::BehaviorTypeMask::ARRIVE)) {
vec2 force_to_add = this->arrive(ai, rigidbody, transform);
if (!this->accumulate_force(ai, force, force_to_add)) {
return force;
}
}
if (ai.on(AI::BehaviorTypeMask::SEEK)) {
vec2 force_to_add = this->seek(ai, rigidbody, transform);
if (!this->accumulate_force(ai, force, force_to_add)) {
return force;
}
}
if (ai.on(AI::BehaviorTypeMask::PATH_FOLLOW)) {
vec2 force_to_add = this->path_follow(ai, rigidbody, transform);
if (!this->accumulate_force(ai, force, force_to_add)) {
return force;
}
}
return force;
}
bool AISystem::accumulate_force(const AI & ai, vec2 & running_total, vec2 & force_to_add) {
float magnitude = running_total.length();
float magnitude_remaining = ai.max_force - magnitude;
if (magnitude_remaining <= 0.0f) {
// If the force is already at/above the max force, return false
return false;
}
float magnitude_to_add = force_to_add.length();
if (magnitude_to_add < magnitude_remaining) {
// If the force to add is less than the remaining force, add it
running_total += force_to_add;
} else {
// If the force to add is greater than the remaining force, add a fraction of it
force_to_add.normalize();
running_total += force_to_add * magnitude_remaining;
}
return true;
}
vec2 AISystem::seek(const AI & ai, const Rigidbody & rigidbody,
const Transform & transform) const {
// Calculate the desired velocity
vec2 desired_velocity = ai.seek_target - transform.position;
desired_velocity.normalize();
desired_velocity *= rigidbody.data.max_linear_velocity;
return desired_velocity - rigidbody.data.linear_velocity;
}
vec2 AISystem::flee(const AI & ai, const Rigidbody & rigidbody,
const Transform & transform) const {
// Calculate the desired velocity if the entity is within the panic distance
vec2 desired_velocity = transform.position - ai.flee_target;
if (desired_velocity.length_squared() > ai.square_flee_panic_distance) {
return vec2{0, 0};
}
desired_velocity.normalize();
desired_velocity *= rigidbody.data.max_linear_velocity;
return desired_velocity - rigidbody.data.linear_velocity;
}
vec2 AISystem::arrive(const AI & ai, const Rigidbody & rigidbody,
const Transform & transform) const {
// Calculate the desired velocity (taking into account the deceleration rate)
vec2 to_target = ai.arrive_target - transform.position;
float distance = to_target.length();
if (distance > 0.0f) {
if (ai.arrive_deceleration <= 0.0f) {
throw std::runtime_error("Deceleration rate must be greater than 0");
}
float speed = distance / ai.arrive_deceleration;
speed = std::min(speed, rigidbody.data.max_linear_velocity.length());
vec2 desired_velocity = to_target * (speed / distance);
return desired_velocity - rigidbody.data.linear_velocity;
}
return vec2{0, 0};
}
vec2 AISystem::path_follow(AI & ai, const Rigidbody & rigidbody, const Transform & transform) {
if (ai.path.empty()) {
return vec2{0, 0};
}
// Get the target node
vec2 target = ai.path.at(ai.path_index);
// Calculate the force to apply to the entity
vec2 to_target = target - transform.position;
if (to_target.length_squared() > ai.path_node_distance * ai.path_node_distance) {
// If the entity is not close enough to the target node, seek it
ai.seek_target = target;
ai.arrive_target = target;
} else {
// If the entity is close enough to the target node, move to the next node
ai.path_index++;
if (ai.path_index >= ai.path.size()) {
if (ai.path_loop) {
// If the path is looping, reset the path index
ai.path_index = 0;
} else {
// If the path is not looping, arrive at the last node
ai.path_index = ai.path.size() - 1;
return this->arrive(ai, rigidbody, transform);
}
}
}
// Seek the target node
return this->seek(ai, rigidbody, transform);
}
|