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https://git.code.sf.net/p/quake/quakeforge
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e67ec84db9
While both matrices had positive determinants in the first place, I find the projection matrix easier to understand without all the negatives, and having quake-x/vulkan-z positively parallel in the z-up matrix makes that a lot easier to think about.
97 lines
2.1 KiB
C
97 lines
2.1 KiB
C
/*
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proejct.c
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Vulkan projection matrices
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Copyright (C) 2021 Bill Currie <bill@taniwha.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_MATH_H
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# include <math.h>
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#endif
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#include "QF/cvar.h"
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#include "QF/Vulkan/projection.h"
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#include "r_internal.h"
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void
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QFV_Orthographic (mat4f_t proj, float xmin, float xmax, float ymin, float ymax,
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float znear, float zfar)
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{
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proj[0] = (vec4f_t) {
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2 / (xmax - xmin),
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0,
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0,
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0
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};
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proj[1] = (vec4f_t) {
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0,
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2 / (ymax - ymin),
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0,
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0
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};
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proj[2] = (vec4f_t) {
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0,
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0,
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1 / (znear - zfar),
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0
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};
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proj[3] = (vec4f_t) {
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-(xmax + xmin) / (xmax - xmin),
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-(ymax + ymin) / (ymax - ymin),
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znear / (znear - zfar),
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1,
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};
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}
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void
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QFV_PerspectiveTan (mat4f_t proj, float fov, float aspect)
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{
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float f = 1 / fov;
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float neard, fard;
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neard = r_nearclip->value;
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fard = r_farclip->value;
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proj[0] = (vec4f_t) { f / aspect, 0, 0, 0 };
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proj[1] = (vec4f_t) { 0, f, 0, 0 };
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proj[2] = (vec4f_t) { 0, 0, fard / (fard - neard), 1 };
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proj[3] = (vec4f_t) { 0, 0, (neard * fard) / (neard - fard), 0 };
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}
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void
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QFV_PerspectiveCos (mat4f_t proj, float fov, float aspect)
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{
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// square first for auto-abs (no support for > 180 degree fov)
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fov = fov * fov;
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QFV_PerspectiveTan (proj, sqrt ((1 - fov) / fov), aspect);
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}
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void
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QFV_Perspective (mat4f_t proj, float fov, float aspect)
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{
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QFV_PerspectiveTan (proj, tan (fov * M_PI / 360), aspect);
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}
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