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https://git.code.sf.net/p/quake/quakeforge
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72f7fcea47
Based on the article (https://developer.nvidia.com/content/depth-precision-visualized), this should give nice precision behavior, and removes the need to worry about large maps getting clipped. If I'm doing my math correctly, despite being reversed, near precision is still crazy high. And (thanks to the reversed depth) about a quarter of a unit (for near clip of 4) out at 1M unit distance.
88 lines
1.8 KiB
C
88 lines
1.8 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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#include <math.h>
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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_x, float fov_y)
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{
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float neard;
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neard = r_nearclip;
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proj[0] = (vec4f_t) { 1 / fov_x, 0, 0, 0 };
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proj[1] = (vec4f_t) { 0, 1 / fov_y, 0, 0 };
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proj[2] = (vec4f_t) { 0, 0, 0, 1 };
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proj[3] = (vec4f_t) { 0, 0, neard, 0 };
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}
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void
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QFV_PerspectiveCos (mat4f_t proj, float fov)
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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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float t = sqrt ((1 - fov) / fov);
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QFV_PerspectiveTan (proj, t, t);
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}
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