New C++ dmnsn_camera* wrapper.

1 files changed, 80 insertions, 0 deletions

diff --git a/libdimension/cameras.c b/libdimension/cameras.c
new file mode 100644
index 0000000..c6dcf59
--- /dev/null
+++ b/libdimension/cameras.c
@@ -0,0 +1,80 @@
+/*************************************************************************
+ * Copyright (C) 2008 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"
+
+/*
+ * Perspective camera
+ */
+
+/* Perspective camera ray callback */
+static dmnsn_line dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
+                                                  const dmnsn_canvas *canvas,
+                                                  unsigned int x,
+                                                  unsigned int y);
+
+/* Create a new perspective camera.  Rays are aimed from the origin to a screen
+   located on the z = 1 frame, from (-0.5, -0.5) to (0.5, 0.5).  Rays are then
+   transformed by the matrix `trans'. */
+dmnsn_camera *
+dmnsn_new_perspective_camera(dmnsn_matrix trans)
+{
+  dmnsn_camera *camera = dmnsn_new_camera();
+  if (camera) {
+    camera->ray_fn = &dmnsn_perspective_camera_ray_fn;
+
+    camera->ptr = malloc(sizeof(dmnsn_matrix));
+    if (!camera->ptr) {
+      dmnsn_delete_camera(camera);
+      return NULL;
+    }
+    *((dmnsn_matrix*)camera->ptr) = trans;
+  }
+  return camera;
+}
+
+/* Delete a perspective camera */
+void
+dmnsn_delete_perspective_camera(dmnsn_camera *camera)
+{
+  if (camera) {
+    free(camera->ptr);
+    dmnsn_delete_camera(camera);
+  }
+}
+
+static dmnsn_line
+dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
+                                const dmnsn_canvas *canvas,
+                                unsigned int x, unsigned int y)
+{
+  dmnsn_matrix *trans = (dmnsn_matrix *)camera->ptr;
+  dmnsn_line l;
+
+  /* Rays originate at the origin, oddly enough */
+  l.x0 = dmnsn_vector_construct(0.0, 0.0, 0.0);
+
+  /* Aim at the z = 1 plane */
+  l.n.x = ((double)x)/(canvas->x - 1) - 0.5;
+  l.n.y = ((double)y)/(canvas->y - 1) - 0.5;
+  l.n.z = 1.0;
+
+  return dmnsn_matrix_line_mul(*trans, l);
+}