Add CSG unions to libdimension.

4 files changed, 179 insertions, 0 deletions

diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am
index 4f427d0..2dda68c 100644
--- a/libdimension/Makefile.am
+++ b/libdimension/Makefile.am
@@ -26,6 +26,7 @@ nobase_include_HEADERS = dimension.h                                           \
                          dimension/cameras.h                                   \
                          dimension/canvas.h                                    \
                          dimension/color.h                                     \
+                         dimension/csg.h                                       \
                          dimension/error.h                                     \
                          dimension/finishes.h                                  \
                          dimension/geometry.h                                  \
@@ -52,6 +53,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS)                            \
                           canvas.c                                             \
                           color.c                                              \
                           cube.c                                               \
+                          csg.c                                                \
                           diffuse.c                                            \
                           dimension_impl.h                                     \
                           error.c                                              \
diff --git a/libdimension/csg.c b/libdimension/csg.c
new file mode 100644
index 0000000..5b3cf9a
--- /dev/null
+++ b/libdimension/csg.c
@@ -0,0 +1,143 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimension.h"
+#include <errno.h>
+
+static void
+dmnsn_csg_free_fn(void *ptr)
+{
+  dmnsn_object **params = ptr;
+  dmnsn_delete_object(params[1]);
+  dmnsn_delete_object(params[0]);
+  free(ptr);
+}
+
+/* Unions */
+
+static dmnsn_intersection *
+dmnsn_csg_union_intersection_fn(const dmnsn_object *csg, dmnsn_line line)
+{
+  const dmnsn_object **params = csg->ptr;
+
+  dmnsn_line line1 = dmnsn_matrix_line_mul(params[0]->trans_inv, line);
+  dmnsn_line line2 = dmnsn_matrix_line_mul(params[1]->trans_inv, line);
+  dmnsn_intersection *i1 = (*params[0]->intersection_fn)(params[0], line1);
+  dmnsn_intersection *i2 = (*params[1]->intersection_fn)(params[1], line2);
+
+  if (i1) {
+    /* Transform the intersection back to the observer's view */
+    i1->ray = line;
+    i1->normal = dmnsn_vector_normalize(
+      dmnsn_vector_sub(
+        dmnsn_matrix_vector_mul(params[0]->trans, i1->normal),
+        dmnsn_matrix_vector_mul(params[0]->trans, dmnsn_zero)
+      )
+    );
+
+    if (!i1->texture)
+      i1->texture = csg->texture;
+    if (!i1->interior)
+      i1->interior = csg->interior;
+  }
+
+  if (i2) {
+    i2->ray = line;
+    i2->normal = dmnsn_vector_normalize(
+      dmnsn_vector_sub(
+        dmnsn_matrix_vector_mul(params[1]->trans, i2->normal),
+        dmnsn_matrix_vector_mul(params[1]->trans, dmnsn_zero)
+      )
+    );
+
+    if (!i2->texture)
+      i2->texture = csg->texture;
+    if (!i2->interior)
+      i2->interior = csg->interior;
+  }
+
+  if (!i1)
+    return i2;
+  if (!i2)
+    return i1;
+
+  if (i1->t < i2->t) {
+    dmnsn_delete_intersection(i2);
+    return i1;
+  } else {
+    dmnsn_delete_intersection(i1);
+    return i2;
+  }
+}
+
+static bool
+dmnsn_csg_union_inside_fn(const dmnsn_object *csg, dmnsn_vector point)
+{
+  dmnsn_object **params = csg->ptr;
+  return (*params[0]->inside_fn)(params[0], point)
+      || (*params[1]->inside_fn)(params[1], point);
+}
+
+dmnsn_object *
+dmnsn_new_csg_union(dmnsn_object *A, dmnsn_object *B)
+{
+  if (A && B) {
+    A->trans_inv = dmnsn_matrix_inverse(A->trans);
+    B->trans_inv = dmnsn_matrix_inverse(B->trans);
+
+    dmnsn_object *csg = dmnsn_new_object();
+    if (csg) {
+      dmnsn_object **params = malloc(2*sizeof(dmnsn_object *));
+      if (!params) {
+        dmnsn_delete_object(csg);
+        dmnsn_delete_object(B);
+        dmnsn_delete_object(A);
+        errno = ENOMEM;
+        return NULL;
+      }
+
+      params[0] = A;
+      params[1] = B;
+
+      csg->ptr             = params;
+      csg->intersection_fn = &dmnsn_csg_union_intersection_fn;
+      csg->inside_fn       = &dmnsn_csg_union_inside_fn;
+      csg->free_fn         = &dmnsn_csg_free_fn;
+
+      dmnsn_bounding_box Abox
+        = dmnsn_matrix_bounding_box_mul(A->trans, A->bounding_box);
+      dmnsn_bounding_box Bbox
+        = dmnsn_matrix_bounding_box_mul(B->trans, B->bounding_box);
+      csg->bounding_box.min = dmnsn_vector_min(Abox.min, Bbox.min);
+      csg->bounding_box.max = dmnsn_vector_max(Abox.max, Bbox.max);
+
+      return csg;
+    } else {
+      dmnsn_delete_object(B);
+      dmnsn_delete_object(A);
+    }
+  } else if (A) {
+    dmnsn_delete_object(B);
+  } else if (B) {
+    dmnsn_delete_object(A);
+  }
+
+  return NULL;
+}
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index be0e9bb..e693841 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -74,6 +74,7 @@ typedef void dmnsn_free_fn(void *ptr);
 #include <dimension/interior.h>
 #include <dimension/object.h>
 #include <dimension/objects.h>
+#include <dimension/csg.h>
 #include <dimension/light.h>
 #include <dimension/lights.h>
 #include <dimension/camera.h>
diff --git a/libdimension/dimension/csg.h b/libdimension/dimension/csg.h
new file mode 100644
index 0000000..383efb4
--- /dev/null
+++ b/libdimension/dimension/csg.h
@@ -0,0 +1,33 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/*
+ * Constructive solid geometry
+ */
+
+#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_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);
+
+#endif /* DIMENSION_CSG_H */