Particle System: move data creation into RNA update

Relying on evaluation to initialize data causes issues w/ 2.8.

3 files changed, 32 insertions, 20 deletions

diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index f09aa17ea92..8eee749ef70 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -304,6 +304,7 @@ bool psys_check_edited(struct ParticleSystem *psys);
 
 void psys_check_group_weights(struct ParticleSettings *part);
 int psys_uses_gravity(struct ParticleSimulationData *sim);
+void BKE_particlesettings_fluid_default_settings(struct ParticleSettings *part);
 
 /* free */
 void BKE_particlesettings_free(struct ParticleSettings *part);
diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 47e0994bb83..9eaebc2c55c 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -4140,7 +4140,7 @@ void psys_check_boid_data(ParticleSystem *psys)
 		}
 }
 
-static void fluid_default_settings(ParticleSettings *part)
+void BKE_particlesettings_fluid_default_settings(ParticleSettings *part)
 {
 	SPHFluidSettings *fluid = part->fluid;
 
@@ -4172,24 +4172,12 @@ static void psys_prepare_physics(ParticleSimulationData *sim)
 		sim->psys->flag &= ~PSYS_KEYED;
 	}
 
-	if (part->phystype == PART_PHYS_BOIDS && part->boids == NULL) {
-		BoidState *state;
-
-		part->boids = MEM_callocN(sizeof(BoidSettings), "Boid Settings");
-		boid_default_settings(part->boids);
-
-		state = boid_new_state(part->boids);
-		BLI_addtail(&state->rules, boid_new_rule(eBoidRuleType_Separate));
-		BLI_addtail(&state->rules, boid_new_rule(eBoidRuleType_Flock));
-
-		((BoidRule*)state->rules.first)->flag |= BOIDRULE_CURRENT;
-
-		state->flag |= BOIDSTATE_CURRENT;
-		BLI_addtail(&part->boids->states, state);
+	/* RNA Update must ensure this is true. */
+	if (part->phystype == PART_PHYS_BOIDS) {
+		BLI_assert(part->boids != NULL);
 	}
-	else if (part->phystype == PART_PHYS_FLUID && part->fluid == NULL) {
-		part->fluid = MEM_callocN(sizeof(SPHFluidSettings), "SPH Fluid Settings");
-		fluid_default_settings(part);
+	else if (part->phystype == PART_PHYS_FLUID) {
+		BLI_assert(part->fluid != NULL);
 	}
 
 	psys_check_boid_data(sim->psys);
diff --git a/source/blender/makesrna/intern/rna_particle.c b/source/blender/makesrna/intern/rna_particle.c
index f3828d8ddf2..5b0b718fc28 100644
--- a/source/blender/makesrna/intern/rna_particle.c
+++ b/source/blender/makesrna/intern/rna_particle.c
@@ -131,6 +131,7 @@ static const EnumPropertyItem part_hair_ren_as_items[] = {
 
 #include "BLI_math.h"
 
+#include "BKE_boids.h"
 #include "BKE_context.h"
 #include "BKE_cloth.h"
 #include "BKE_colortools.h"
@@ -679,9 +680,31 @@ static void rna_Particle_change_type(Main *bmain, Scene *scene, PointerRNA *ptr)
 	DAG_relations_tag_update(bmain);
 }
 
-static void rna_Particle_change_physics(Main *bmain, Scene *scene, PointerRNA *ptr)
+static void rna_Particle_change_physics_type(Main *bmain, Scene *scene, PointerRNA *ptr)
 {
 	particle_recalc(bmain, scene, ptr, PSYS_RECALC_RESET | PSYS_RECALC_PHYS);
+	
+	ParticleSettings *part = (ParticleSettings *)ptr->data;
+
+	if (part->phystype == PART_PHYS_BOIDS && part->boids == NULL) {
+		BoidState *state;
+
+		part->boids = MEM_callocN(sizeof(BoidSettings), "Boid Settings");
+		boid_default_settings(part->boids);
+
+		state = boid_new_state(part->boids);
+		BLI_addtail(&state->rules, boid_new_rule(eBoidRuleType_Separate));
+		BLI_addtail(&state->rules, boid_new_rule(eBoidRuleType_Flock));
+
+		((BoidRule*)state->rules.first)->flag |= BOIDRULE_CURRENT;
+
+		state->flag |= BOIDSTATE_CURRENT;
+		BLI_addtail(&part->boids->states, state);
+	}
+	else if (part->phystype == PART_PHYS_FLUID && part->fluid == NULL) {
+		part->fluid = MEM_callocN(sizeof(SPHFluidSettings), "SPH Fluid Settings");
+		BKE_particlesettings_fluid_default_settings(part);
+	}
 }
 
 static void rna_Particle_redo_child(Main *bmain, Scene *scene, PointerRNA *ptr)
@@ -2265,7 +2288,7 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_enum_items(prop, phys_type_items);
 	RNA_def_property_ui_text(prop, "Physics Type", "Particle physics type");
-	RNA_def_property_update(prop, 0, "rna_Particle_change_physics");
+	RNA_def_property_update(prop, 0, "rna_Particle_change_physics_type");
 
 	prop = RNA_def_property(srna, "rotation_mode", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "rotmode");