src/client/shadows/dynamicshadows.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2021 Liso <anlismon@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include <cmath>
  21
  22 #include "client/shadows/dynamicshadows.h"
  23 #include "client/client.h"
  24 #include "client/clientenvironment.h"
  25 #include "client/clientmap.h"
  26 #include "client/camera.h"
  27
  28 using m4f = core::matrix4;
  29
  30 void DirectionalLight::createSplitMatrices(const Camera *cam)
  31 {
  32         v3f newCenter;
  33         v3f look = cam->getDirection();
  34
  35         // camera view tangents
  36         float tanFovY = tanf(cam->getFovY() * 0.5f);
  37         float tanFovX = tanf(cam->getFovX() * 0.5f);
  38
  39         // adjusted frustum boundaries
  40         float sfNear = future_frustum.zNear;
  41         float sfFar = adjustDist(future_frustum.zFar, cam->getFovY());
  42
  43         // adjusted camera positions
  44         v3f cam_pos_world = cam->getPosition();
  45         v3f cam_pos_scene = v3f(cam_pos_world.X - cam->getOffset().X * BS,
  46                         cam_pos_world.Y - cam->getOffset().Y * BS,
  47                         cam_pos_world.Z - cam->getOffset().Z * BS);
  48         cam_pos_scene += look * sfNear;
  49         cam_pos_world += look * sfNear;
  50
  51         // center point of light frustum
  52         v3f center_scene = cam_pos_scene + look * 0.35 * (sfFar - sfNear);
  53         v3f center_world = cam_pos_world + look * 0.35 * (sfFar - sfNear);
  54
  55         // Create a vector to the frustum far corner
  56         const v3f &viewUp = cam->getCameraNode()->getUpVector();
  57         v3f viewRight = look.crossProduct(viewUp);
  58
  59         v3f farCorner = (look + viewRight * tanFovX + viewUp * tanFovY).normalize();
  60         // Compute the frustumBoundingSphere radius
  61         v3f boundVec = (cam_pos_scene + farCorner * sfFar) - center_scene;
  62         float radius = boundVec.getLength();
  63         float length = radius * 3.0f;
  64         v3f eye_displacement = direction * length;
  65
  66         // we must compute the viewmat with the position - the camera offset
  67         // but the future_frustum position must be the actual world position
  68         v3f eye = center_scene - eye_displacement;
  69         future_frustum.player = cam_pos_scene;
  70         future_frustum.position = center_world - eye_displacement;
  71         future_frustum.length = length;
  72         future_frustum.radius = radius;
  73         future_frustum.ViewMat.buildCameraLookAtMatrixLH(eye, center_scene, v3f(0.0f, 1.0f, 0.0f));
  74         future_frustum.ProjOrthMat.buildProjectionMatrixOrthoLH(radius, radius,
  75                         0.0f, length, false);
  76         future_frustum.camera_offset = cam->getOffset();
  77 }
  78
  79 DirectionalLight::DirectionalLight(const u32 shadowMapResolution,
  80                 const v3f &position, video::SColorf lightColor,
  81                 f32 farValue) :
  82                 diffuseColor(lightColor),
  83                 farPlane(farValue), mapRes(shadowMapResolution), pos(position)
  84 {}
  85
  86 void DirectionalLight::update_frustum(const Camera *cam, Client *client, bool force)
  87 {
  88         if (dirty && !force)
  89                 return;
  90
  91         float zNear = cam->getCameraNode()->getNearValue();
  92         float zFar = getMaxFarValue();
  93         if (!client->getEnv().getClientMap().getControl().range_all)
  94                 zFar = MYMIN(zFar, client->getEnv().getClientMap().getControl().wanted_range * BS);
  95
  96         ///////////////////////////////////
  97         // update splits near and fars
  98         future_frustum.zNear = zNear;
  99         future_frustum.zFar = zFar;
 100
 101         // update shadow frustum
 102         createSplitMatrices(cam);
 103         // get the draw list for shadows
 104         client->getEnv().getClientMap().updateDrawListShadow(
 105                         getPosition(), getDirection(), future_frustum.radius, future_frustum.length);
 106         should_update_map_shadow = true;
 107         dirty = true;
 108
 109         // when camera offset changes, adjust the current frustum view matrix to avoid flicker
 110         v3s16 cam_offset = cam->getOffset();
 111         if (cam_offset != shadow_frustum.camera_offset) {
 112                 v3f rotated_offset;
 113                 shadow_frustum.ViewMat.rotateVect(rotated_offset, intToFloat(cam_offset - shadow_frustum.camera_offset, BS));
 114                 shadow_frustum.ViewMat.setTranslation(shadow_frustum.ViewMat.getTranslation() + rotated_offset);
 115                 shadow_frustum.player += intToFloat(shadow_frustum.camera_offset - cam->getOffset(), BS);
 116                 shadow_frustum.camera_offset = cam_offset;
 117         }
 118 }
 119
 120 void DirectionalLight::commitFrustum()
 121 {
 122         if (!dirty)
 123                 return;
 124
 125         shadow_frustum = future_frustum;
 126         dirty = false;
 127 }
 128
 129 void DirectionalLight::setDirection(v3f dir)
 130 {
 131         direction = -dir;
 132         direction.normalize();
 133 }
 134
 135 v3f DirectionalLight::getPosition() const
 136 {
 137         return shadow_frustum.position;
 138 }
 139
 140 v3f DirectionalLight::getPlayerPos() const
 141 {
 142         return shadow_frustum.player;
 143 }
 144
 145 v3f DirectionalLight::getFuturePlayerPos() const
 146 {
 147         return future_frustum.player;
 148 }
 149
 150 const m4f &DirectionalLight::getViewMatrix() const
 151 {
 152         return shadow_frustum.ViewMat;
 153 }
 154
 155 const m4f &DirectionalLight::getProjectionMatrix() const
 156 {
 157         return shadow_frustum.ProjOrthMat;
 158 }
 159
 160 const m4f &DirectionalLight::getFutureViewMatrix() const
 161 {
 162         return future_frustum.ViewMat;
 163 }
 164
 165 const m4f &DirectionalLight::getFutureProjectionMatrix() const
 166 {
 167         return future_frustum.ProjOrthMat;
 168 }
 169
 170 m4f DirectionalLight::getViewProjMatrix()
 171 {
 172         return shadow_frustum.ProjOrthMat * shadow_frustum.ViewMat;
 173 }