ProjectileSpawnSystem Class

System that spawns projectiles for entities with active ShootComponents. More...

Declaration

class helios::engine::mechanics::combat::systems::ProjectileSpawnSystem { ... }

Public Member Typedefs Index

using	EngineRoleTag = helios::engine::common::tags::SystemRole

Public Constructors Index

	ProjectileSpawnSystem (const helios::engine::runtime::spawn::types::SpawnProfileId &spawnProfileId)
	Constructs a ProjectileSpawnSystem with the specified spawn profile. More...

Public Member Functions Index

void	update (helios::engine::runtime::world::UpdateContext &updateContext) noexcept
	Processes all shooting entities and spawns projectiles. More...

Private Member Attributes Index

const helios::engine::runtime::spawn::types::SpawnProfileId	spawnProfileId_
	The spawn profile ID used for projectile creation. More...

Description

System that spawns projectiles for entities with active ShootComponents.

ProjectileSpawnSystem iterates all entities that have a ShootComponent, Aim2DComponent, and TranslationStateComponent. When a ShootComponent has non-zero intensity and the aim component has a valid frequency, the system calculates how many projectiles to spawn based on accumulated time and cooldown.

## Fire Rate Mechanics

The system implements an intensity-based fire rate: 1. Accumulates `deltaTime * intensity` into the cooldown timer 2. When timer >= cooldownDelta, spawns `floor(timer / cooldownDelta)` projectiles 3. Reduces timer by spawned amount, preserving fractional remainder

This allows continuous fire with variable intensity affecting the effective rate.

## Spawn Context

Each SpawnCommand includes an EmitterContext containing:

• **position:** Current translation from TranslationStateComponent
• **velocity:** sourceVelocity + (aimDirection * projectileSpeed)

Example setup: ```cpp auto projectileSpawnSystem = std::make_unique<ProjectileSpawnSystem>( SpawnProfileId{1} // ID of the projectile spawn profile ); mainPhase.addPass().add(std::move(projectileSpawnSystem)); ```

info

Entities must have ShootComponent, Aim2DComponent, and TranslationStateComponent to be processed.

See Also

ShootComponent

See Also

Aim2DComponent

See Also

SpawnCommand

See Also

EmitterContext

Definition at line 73 of file ProjectileSpawnSystem.ixx.

Public Member Typedefs

EngineRoleTag

using helios::engine::mechanics::combat::systems::ProjectileSpawnSystem::EngineRoleTag = helios::engine::common::tags::SystemRole

Definition at line 86 of file ProjectileSpawnSystem.ixx.

86 using EngineRoleTag = helios::engine::common::tags::SystemRole;

Public Constructors

ProjectileSpawnSystem()

helios::engine::mechanics::combat::systems::ProjectileSpawnSystem::ProjectileSpawnSystem (const helios::engine::runtime::spawn::types::SpawnProfileId & spawnProfileId)

inline explicit

Constructs a ProjectileSpawnSystem with the specified spawn profile.

Parameters

spawnProfileId

The ID of the spawn profile to use for projectiles.

Definition at line 93 of file ProjectileSpawnSystem.ixx.

93 explicit ProjectileSpawnSystem(

94 const helios::engine::runtime::spawn::types::SpawnProfileId& spawnProfileId

95 ) :

96 spawnProfileId_(spawnProfileId)

97 {}

Public Member Functions

update()

void helios::engine::mechanics::combat::systems::ProjectileSpawnSystem::update (helios::engine::runtime::world::UpdateContext & updateContext)

inline noexcept

Processes all shooting entities and spawns projectiles.

For each entity with ShootComponent, Aim2DComponent, and TranslationStateComponent:

1. Skips if aim frequency or intensity are near zero 2. Accumulates `deltaTime * intensity` into the cooldown timer 3. If timer < cooldownDelta, updates timer and continues 4. Calculates projectile count as `floor(timer / cooldownDelta)` 5. Reduces timer by `count * cooldownDelta` 6. Enqueues SpawnCommands with EmitterContext for each projectile

Parameters

updateContext

The current frame's update context.

Definition at line 114 of file ProjectileSpawnSystem.ixx.

114 void update(helios::engine::runtime::world::UpdateContext& updateContext) noexcept {

115

116 for (auto [entity, tsc, ac, sc, active] : updateContext.view<

117 helios::engine::modules::spatial::transform::components::TranslationStateComponent,

118 helios::engine::mechanics::combat::components::Aim2DComponent,

119 helios::engine::mechanics::combat::components::ShootComponent,

120 helios::engine::mechanics::lifecycle::components::Active

121 >().whereEnabled()) {

122

123

124 const float intensity = sc->intensity();

125 const float cooldown = sc->cooldownDelta();

126

127 float timer = sc->cooldownTimer();

128

129 // only process for meaningful values

130 assert(cooldown > helios::math::EPSILON_LENGTH && "Unexpected cooldownDelta");

131 if (ac->frequency() <= helios::math::EPSILON_LENGTH ||

132 intensity <= helios::math::EPSILON_LENGTH) {

133 continue;

134 };

135

136 const float delta = updateContext.deltaTime();

137

138 // update the timer to accumulate frame times * intensity.

139 // will be updated in this frame if projectiles spawned,

140 timer += delta * intensity;

141

142 if (timer < cooldown) {

143 sc->setCooldownTimer(timer);

144 continue;

145 }

146

147 const unsigned int amount = static_cast<unsigned int>(timer / cooldown);

148

149 // reduce timer by the product of projectiles and cooldown,

150 // which leaves a fractional part that did not add a whole projectile

151 // to this frame

152 sc->setCooldownTimer(timer - (amount * cooldown));

153

154 const auto aimDirection = ac->direction().toVec3();

155 assert(aimDirection.isNormalized() && "Unexpected aimDirection.length()");

156

157 for (unsigned int i = 0; i < amount; i++) {

158 updateContext.queueCommand<

159 helios::engine::runtime::spawn::commands::SpawnCommand

160 >(

161 spawnProfileId_,

162 SpawnContext{

163 EmitterContext{

164 tsc->translation(),

165 sc->sourceVelocity() + (aimDirection * sc->projectileSpeed()),

166 entity.entityHandle()

167 }

168 }

169 );

170 }

171 }

172 }

Reference helios::math::EPSILON_LENGTH.

Private Member Attributes

spawnProfileId_

const helios::engine::runtime::spawn::types::SpawnProfileId helios::engine::mechanics::combat::systems::ProjectileSpawnSystem::spawnProfileId_

The spawn profile ID used for projectile creation.

References a SpawnProfile in the spawn system that defines how projectiles are placed and initialized.

Definition at line 81 of file ProjectileSpawnSystem.ixx.

81 const helios::engine::runtime::spawn::types::SpawnProfileId spawnProfileId_;

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The documentation for this class was generated from the following file:

• ProjectileSpawnSystem.ixx

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