quakeforge/libs/video/renderer/vulkan/projection.c
Bill Currie 562f3c2fe2 [vulkan] Add tan and cos perspective projection
The tan and cos versions allow specifying the fov directly from the tan
or cos of the half angle, useful for dealing with lights.
2021-04-29 19:27:01 +09:00

97 lines
2.1 KiB
C

/*
proejct.c
Vulkan projection matrices
Copyright (C) 2021 Bill Currie <bill@taniwha.org>
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
#ifdef HAVE_MATH_H
# include <math.h>
#endif
#include "QF/cvar.h"
#include "QF/Vulkan/projection.h"
#include "r_internal.h"
void
QFV_Orthographic (mat4f_t proj, float xmin, float xmax, float ymin, float ymax,
float znear, float zfar)
{
proj[0] = (vec4f_t) {
2 / (xmax - xmin),
0,
0,
0
};
proj[1] = (vec4f_t) {
0,
2 / (ymax - ymin),
0,
0
};
proj[2] = (vec4f_t) {
0,
0,
1 / (znear - zfar),
0
};
proj[3] = (vec4f_t) {
-(xmax + xmin) / (xmax - xmin),
-(ymax + ymin) / (ymax - ymin),
znear / (znear - zfar),
1,
};
}
void
QFV_PerspectiveTan (mat4f_t proj, float fov, float aspect)
{
float f = 1 / fov;
float neard, fard;
neard = r_nearclip->value;
fard = r_farclip->value;
proj[0] = (vec4f_t) { f / aspect, 0, 0, 0 };
proj[1] = (vec4f_t) { 0, -f, 0, 0 };
proj[2] = (vec4f_t) { 0, 0, fard / (neard - fard), -1 };
proj[3] = (vec4f_t) { 0, 0, (neard * fard) / (neard - fard), 0 };
}
void
QFV_PerspectiveCos (mat4f_t proj, float fov, float aspect)
{
// square first for auto-abs (no support for > 180 degree fov)
fov = fov * fov;
QFV_PerspectiveTan (proj, sqrt ((1 - fov) / fov), aspect);
}
void
QFV_Perspective (mat4f_t proj, float fov, float aspect)
{
QFV_PerspectiveTan (proj, tan (fov * M_PI / 360), aspect);
}