Cycles: Support heat volume attribute

Similar to velocity, it was kind of supported by the mesh manager but
was missing a code in BlenderSession to get actual values.

In Cycles Heat is an attribute which goes from -1 to 1, where -1 is
the coldest ever temperature, 1 is the hottest ever one.

1 files changed, 59 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_smoke.c b/source/blender/makesrna/intern/rna_smoke.c
index ba3198a4843..9a31952b84b 100644
--- a/source/blender/makesrna/intern/rna_smoke.c
+++ b/source/blender/makesrna/intern/rna_smoke.c
@@ -191,6 +191,29 @@ static int rna_SmokeModifier_velocity_grid_get_length(PointerRNA *ptr, int lengt
 	return length[0];
 }
 
+static int rna_SmokeModifier_heat_grid_get_length(
+        PointerRNA *ptr,
+        int length[RNA_MAX_ARRAY_DIMENSION])
+{
+#ifdef WITH_SMOKE
+	SmokeDomainSettings *sds = (SmokeDomainSettings *)ptr->data;
+	float *heat = NULL;
+	int size = 0;
+
+	/* Heat data is always low-resolution. */
+	if (sds->fluid) {
+		size = sds->res[0] * sds->res[1] * sds->res[2];
+		heat = smoke_get_heat(sds->fluid);
+	}
+
+	length[0] = (heat) ? size : 0;
+#else
+	(void)ptr;
+	length[0] = 0;
+#endif
+	return length[0];
+}
+
 static void rna_SmokeModifier_density_grid_get(PointerRNA *ptr, float *values)
 {
 #ifdef WITH_SMOKE
@@ -293,6 +316,34 @@ static void rna_SmokeModifier_flame_grid_get(PointerRNA *ptr, float *values)
 #endif
 }
 
+static void rna_SmokeModifier_heat_grid_get(PointerRNA *ptr, float *values)
+{
+#ifdef WITH_SMOKE
+	SmokeDomainSettings *sds = (SmokeDomainSettings *)ptr->data;
+	int length[RNA_MAX_ARRAY_DIMENSION];
+	int size = rna_SmokeModifier_heat_grid_get_length(ptr, length);
+	float *heat;
+
+	BLI_rw_mutex_lock(sds->fluid_mutex, THREAD_LOCK_READ);
+
+	heat = smoke_get_heat(sds->fluid);
+
+	if (heat != NULL) {
+		/* scale heat values from -2.0-2.0 to -1.0-1.0. */
+		for (int i = 0; i < size; i++) {
+			values[i] = heat[i] * 0.5f;
+		}
+	}
+	else {
+		memset(values, 0, size * sizeof(float));
+	}
+
+	BLI_rw_mutex_unlock(sds->fluid_mutex);
+#else
+	UNUSED_VARS(ptr, values);
+#endif
+}
+
 static void rna_SmokeFlow_density_vgroup_get(PointerRNA *ptr, char *value)
 {
 	SmokeFlowSettings *flow = (SmokeFlowSettings *)ptr->data;
@@ -563,6 +614,14 @@ static void rna_def_smoke_domain_settings(BlenderRNA *brna)
 	RNA_def_property_float_funcs(prop, "rna_SmokeModifier_color_grid_get", NULL, NULL);
 	RNA_def_property_ui_text(prop, "Color Grid", "Smoke color grid");
 
+	prop = RNA_def_property(srna, "heat_grid", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_array(prop, 32);
+	RNA_def_property_flag(prop, PROP_DYNAMIC);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_dynamic_array_funcs(prop, "rna_SmokeModifier_heat_grid_get_length");
+	RNA_def_property_float_funcs(prop, "rna_SmokeModifier_heat_grid_get", NULL, NULL);
+	RNA_def_property_ui_text(prop, "Heat Grid", "Smoke heat grid");
+
 	prop = RNA_def_property(srna, "cell_size", PROP_FLOAT, PROP_XYZ); /* can change each frame when using adaptive domain */
 	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
 	RNA_def_property_ui_text(prop, "cell_size", "Cell Size");