Add GritsVolume for 3D volume rendering

[grits] / src / objects / marching.h

diff --git a/src/objects/marching.h b/src/objects/marching.h
new file mode 100644 (file)
index 0000000..98ee729
--- /dev/null
+++ b/src/objects/marching.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2002 Jamie Zawinski <jwz@jwz.org>
+ * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
+ *
+ * Marching cubes implementation based on code from from the xscreensaver
+ * package.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __VOLUME_H__
+#define __VOLUME_H__
+
+#include <glib.h>
+
+/* VolCoord */
+typedef struct {
+       double x, y, z;
+} VolCoord;
+
+/* VolPoint */
+typedef struct {
+       VolCoord c;     /* Coordinate of the point */
+       double   value; /* Function value at point */
+} VolPoint;
+
+/* VolVertex */
+typedef struct {
+       VolCoord c;    /* Coordinate of the vertex */
+       gint     tris; /* Count of associated triangles */
+       VolCoord norm; /* Vertex normal */
+} VolVertex;
+
+/* VolTriangle */
+typedef struct {
+       VolVertex *v[3]; /* Vertices */
+       VolCoord   norm; /* Surface normal */
+} VolTriangle;
+
+/* VolCell */
+typedef struct {
+       VolPoint  *corner[8]; /* Corners */
+       VolVertex *edge[12];  /* Points along the edges (for caching) */
+} VolCell;
+
+/* VolGrid */
+typedef struct {
+       int xs, ys, zs; /* Dimensions of points */
+       gpointer data;  /* 3-D grid of points */
+} VolGrid;
+
+/* Find triangles on an isosurface that pass through the cell */
+GList *march_one_cube(VolCell *cell, double level);
+
+/* Find triangles along an isosurface in a grid of points */
+GList *marching_cubes(VolGrid *grid, double level);
+
+/* Free/unref data for triangle */
+void vol_triangle_free(VolTriangle *tri);
+
+/* Grid functions */
+static inline VolPoint *vol_grid_get(VolGrid *grid, int x, int y, int z)
+{
+       VolPoint (*points)[grid->ys][grid->zs] = grid->data;
+       return &points[x][y][z];
+}
+VolGrid *vol_grid_new(int xs, int ys, int zs);
+void vol_grid_free(VolGrid *grid);
+
+
+#endif