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/*************************************************************************
* 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_matrix *ptr;
dmnsn_camera *camera = dmnsn_new_camera();
if (camera) {
camera->ray_fn = &dmnsn_perspective_camera_ray_fn;
/* Allocate room for the transformation matrix */
ptr = malloc(sizeof(dmnsn_matrix));
if (!ptr) {
dmnsn_delete_camera(camera);
return NULL;
}
*ptr = trans;
camera->ptr = ptr;
}
return camera;
}
/* Delete a perspective camera */
void
dmnsn_delete_perspective_camera(dmnsn_camera *camera)
{
if (camera) {
free(camera->ptr);
dmnsn_delete_camera(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,
const dmnsn_canvas *canvas,
unsigned int x, unsigned int y)
{
dmnsn_matrix *trans = 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);
}
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