add input (#7090)

Author: Kestrellius

code/particle/ParticleEffect.h

@@ -333,6 +333,10 @@ class ParticleEffect {
 			 modular_curves_submember_input<&particle::max_life>,
 			 ModularCurvesMathOperators::division>{}},
 		std::pair {"Radius", modular_curves_submember_input<&particle::radius>{}},
+		std::pair {"Apparent Size", modular_curves_math_input<
+			modular_curves_functional_input<&getPixelSize>,
+			modular_curves_global_submember_input<gr_screen, &screen::max_w>,
+			ModularCurvesMathOperators::division>{}},
 		std::pair {"Velocity", modular_curves_submember_input<&particle::velocity, &vm_vec_mag_quick>{}},
 		std::pair {"Parent Object Hitpoints", modular_curves_submember_input<&particle::attached_objnum, &Objects, &object::hull_strength>{}},
 		std::pair {"Parent Ship Hitpoints Fraction", modular_curves_math_input<

code/particle/particle.cpp

@@ -194,6 +194,24 @@ namespace particle
 		return {new_particle_ptr};
 	}
 
+	float getPixelSize(const particle& subject_particle) {
+		vec3d pos;
+
+		if (subject_particle.attached_objnum < 0) {
+			pos = subject_particle.pos;
+		} else {
+			pos = subject_particle.pos + Objects[subject_particle.attached_objnum].pos;
+		}
+
+		float distance_to_eye = vm_vec_dist(&Eye_position, &pos);
+
+		return convert_distance_and_diameter_to_pixel_size(
+			distance_to_eye,
+			subject_particle.radius * 2.f,
+			g3_get_hfov(Eye_fov),
+			gr_screen.max_w);
+	}
+
 	/**
 	 * @brief Moves a single particle
 	 * @param frametime The length of the current frame

code/particle/particle.h

@@ -116,6 +116,8 @@ namespace particle
 	 * @return A weak reference to the particle
 	 */
 	WeakParticlePtr createPersistent(particle&& new_particle);
+
+	float getPixelSize(const particle& subject_particle);
 }
 
 #endif // _PARTICLE_H

code/utils/modular_curves.h

@@ -249,8 +249,7 @@ struct modular_curves_global_submember_input {
 };
 
 template<auto grabber_fnc>
-struct modular_curves_functional_input {
-  private:
+struct modular_curves_functional_input {  private:
 	template<int tuple_idx, typename input_type>
 	static inline auto grab_from_tuple(const input_type& input) {
 		if constexpr(tuple_idx < 0)