From de8a9632a6859010cc9d9bb4bcff721d640cdbd5 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Mon, 14 Jun 2010 19:22:33 -0600
Subject: Bulk-load CSG unions.

The old way made O(n) PR-trees for no particular reason.
---
 dimension/realize.c          | 40 +++++++++++++++++++++++++++++++++-------
 libdimension/csg.c           |  9 ++++++---
 libdimension/dimension/csg.h |  2 +-
 3 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/dimension/realize.c b/dimension/realize.c
index 711090b..e558c5b 100644
--- a/dimension/realize.c
+++ b/dimension/realize.c
@@ -854,6 +854,39 @@ dmnsn_realize_plane(dmnsn_astnode astnode)
   return plane;
 }
 
+/* Bulk-load a union */
+static dmnsn_object *
+dmnsn_realize_union(dmnsn_astnode astnode, dmnsn_array *lights)
+{
+  dmnsn_assert(astnode.type == DMNSN_AST_UNION, "Expected a union.");
+
+  dmnsn_astnode objects, modifiers;
+  dmnsn_array_get(astnode.children, 0, &objects);
+  dmnsn_array_get(astnode.children, 1, &modifiers);
+
+  dmnsn_array *children = dmnsn_new_array(sizeof(dmnsn_object *));
+  DMNSN_ARRAY_FOREACH (dmnsn_astnode *, onode, objects.children) {
+    if (onode->type == DMNSN_AST_LIGHT_SOURCE) {
+      dmnsn_light *light = dmnsn_realize_light_source(*onode);
+      dmnsn_realize_light_source_modifiers(modifiers, light);
+      dmnsn_array_push(lights, &light);
+    } else {
+      dmnsn_object *object = dmnsn_realize_object(*onode, lights);
+      if (object)
+        dmnsn_array_push(children, &object);
+    }
+  }
+
+  dmnsn_object *csg = NULL;
+  if (dmnsn_array_size(children) > 0) {
+    csg = dmnsn_new_csg_union(children);
+    dmnsn_realize_object_modifiers(modifiers, csg);
+  }
+
+  dmnsn_delete_array(children);
+  return csg;
+}
+
 typedef dmnsn_object *dmnsn_csg_object_fn(dmnsn_object *a, dmnsn_object *b);
 
 /* Generalized CSG realizer */
@@ -900,13 +933,6 @@ dmnsn_realize_csg(dmnsn_astnode astnode, dmnsn_array *lights,
   return csg;
 }
 
-static dmnsn_object *
-dmnsn_realize_union(dmnsn_astnode astnode, dmnsn_array *lights)
-{
-  dmnsn_assert(astnode.type == DMNSN_AST_UNION, "Expected a union.");
-  return dmnsn_realize_csg(astnode, lights, &dmnsn_new_csg_union);
-}
-
 static dmnsn_object *
 dmnsn_realize_intersection(dmnsn_astnode astnode, dmnsn_array *lights)
 {
diff --git a/libdimension/csg.c b/libdimension/csg.c
index 02c4d37..b48c2fa 100644
--- a/libdimension/csg.c
+++ b/libdimension/csg.c
@@ -76,13 +76,16 @@ dmnsn_csg_union_free_fn(void *ptr)
   dmnsn_delete_prtree(ptr);
 }
 
+/* Bulk-load a union */
 dmnsn_object *
-dmnsn_new_csg_union(dmnsn_object *A, dmnsn_object *B)
+dmnsn_new_csg_union(dmnsn_array *objects)
 {
   dmnsn_object *csg = dmnsn_new_object();
 
-  dmnsn_array_push(csg->children, &A);
-  dmnsn_array_push(csg->children, &B);
+  DMNSN_ARRAY_FOREACH (dmnsn_object **, object, objects) {
+    dmnsn_array_push(csg->children, object);
+  }
+
   csg->intersection_fn = &dmnsn_csg_union_intersection_fn;
   csg->inside_fn       = &dmnsn_csg_union_inside_fn;
   csg->init_fn         = &dmnsn_csg_union_init_fn;
diff --git a/libdimension/dimension/csg.h b/libdimension/dimension/csg.h
index 383efb4..176467a 100644
--- a/libdimension/dimension/csg.h
+++ b/libdimension/dimension/csg.h
@@ -25,7 +25,7 @@
 #ifndef DIMENSION_CSG_H
 #define DIMENSION_CSG_H
 
-dmnsn_object *dmnsn_new_csg_union(dmnsn_object *A, dmnsn_object *B);
+dmnsn_object *dmnsn_new_csg_union(dmnsn_array *objects);
 dmnsn_object *dmnsn_new_csg_intersection(dmnsn_object *A, dmnsn_object *B);
 dmnsn_object *dmnsn_new_csg_difference(dmnsn_object *A, dmnsn_object *B);
 dmnsn_object *dmnsn_new_csg_merge(dmnsn_object *A, dmnsn_object *B);
-- 
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