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-rw-r--r--libdimension/perspective.c86
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diff --git a/libdimension/perspective.c b/libdimension/perspective.c
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+/*************************************************************************
+ * Copyright (C) 2009 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,
+ double x, double 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 camera's transformation matrix. */
+dmnsn_camera *
+dmnsn_new_perspective_camera()
+{
+ dmnsn_matrix *ptr;
+ dmnsn_camera *camera = dmnsn_new_camera();
+ if (camera) {
+ /* Allocate room for the transformation matrix */
+ ptr = malloc(sizeof(dmnsn_matrix));
+ if (!ptr) {
+ dmnsn_delete_camera(camera);
+ return NULL;
+ }
+ *ptr = dmnsn_identity_matrix();
+
+ camera->ray_fn = &dmnsn_perspective_camera_ray_fn;
+ camera->free_fn = &free;
+ camera->ptr = ptr;
+ }
+ return camera;
+}
+
+/* Get the transformation matrix */
+dmnsn_matrix
+dmnsn_get_perspective_camera_trans(const dmnsn_camera *camera)
+{
+ dmnsn_matrix *trans = camera->ptr;
+ return *trans;
+}
+
+/* Set the transformation matrix */
+void
+dmnsn_set_perspective_camera_trans(dmnsn_camera *camera, dmnsn_matrix T)
+{
+ dmnsn_matrix *trans = camera->ptr;
+ *trans = T;
+}
+
+/* Perspective camera ray callback */
+static dmnsn_line
+dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
+ double x, double y)
+{
+ dmnsn_matrix *trans = camera->ptr;
+ dmnsn_line l;
+
+ /* Rays originate at the origin, oddly enough */
+ l.x0 = dmnsn_new_vector(0.0, 0.0, 0.0);
+
+ /* Aim at the z = 1 plane */
+ l.n = dmnsn_new_vector(x - 0.5, y - 0.5, 1.0);
+
+ return dmnsn_matrix_line_mul(*trans, l);
+}