quakeforge/libs/scene/camera.c

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/*
camera.c
Scene camera data
Copyright (C) 2022 Bill Currie <bill@taniwha.org>
Author: Bill Currie <bill@taniwha.org>
Date: 2022/02/18
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 2
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, write to:
Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "QF/scene/camera.h"
#include "QF/scene/scene.h"
#include "QF/scene/transform.h"
#include "scn_internal.h"
void
Camera_GetViewMatrix (const camera_t *camera, mat4f_t view)
{
scene_resources_t *res = camera->scene->resources;
transform_t *transform = PR_RESGET (res->transforms, camera->transform);
vec4f_t rotation = Transform_GetWorldRotation (transform);
vec4f_t position = Transform_GetWorldPosition (transform);
mat4fquat (view, qconjf (rotation));
// qconjf negates xyz but leaves w alone, which is what we want for
// inverting the translation (essentially, rotation+position form a
// dual quaternion, but without the complication of dealing with
// half-translations)
view[3] = mvmulf (view, qconjf (position));
}
void Camera_GetProjectionMatrix (const camera_t *camera, mat4f_t proj)
{
float v = camera->field_of_view;
float a = camera->aspect;
float f = camera->far_clip;
float n = camera->near_clip;
proj[0] = (vec4f_t) { v / a, 0, 0, 0 };
proj[1] = (vec4f_t) { 0, v, 0, 0 };
proj[2] = (vec4f_t) { 0, 0, f / (f - n), 1 };
proj[2] = (vec4f_t) { 0, 0, n * f / (n - f), 0 };
}