@@ -25,61 +25,175 @@ inline static float expf_s(float arg)
2525 return expf (clamp_tpl (arg, -80 .0f , 80 .0f ));
2626}
2727
28+ AABB UnprojectAABB2D (const AABB& aabb, const CCamera& camera)
29+ {
30+ Vec3 results[4 ];
31+ camera.Unproject (Vec3 (aabb.min .x , aabb.min .y , 1 ), results[0 ]);
32+ camera.Unproject (Vec3 (aabb.max .x , aabb.min .y , 1 ), results[1 ]);
33+ camera.Unproject (Vec3 (aabb.max .x , aabb.max .y , 1 ), results[2 ]);
34+ camera.Unproject (Vec3 (aabb.min .x , aabb.max .y , 1 ), results[3 ]);
35+
36+ AABB newAABB (AABB::RESET);
37+ newAABB.Add (results[0 ]);
38+ newAABB.Add (results[1 ]);
39+ newAABB.Add (results[2 ]);
40+ newAABB.Add (results[3 ]);
41+ return newAABB;
42+ }
43+
44+ AABB GetProjectedQuadFromAABB (const AABB& aabb, const CCamera& camera)
45+ {
46+ // Get all 8 points of the AABB
47+
48+ Vec3 aabbPoints[] =
49+ {
50+ Vec3 (aabb.max .x , aabb.max .y , aabb.max .z ),
51+ Vec3 (aabb.max .x , aabb.min .y , aabb.max .z ),
52+ Vec3 (aabb.min .x , aabb.min .y , aabb.max .z ),
53+ Vec3 (aabb.min .x , aabb.max .y , aabb.max .z ),
54+ Vec3 (aabb.max .x , aabb.max .y , aabb.min .z ),
55+ Vec3 (aabb.max .x , aabb.min .y , aabb.min .z ),
56+ Vec3 (aabb.min .x , aabb.min .y , aabb.min .z ),
57+ Vec3 (aabb.min .x , aabb.max .y , aabb.min .z ),
58+ };
59+ const int numAABBPoints = AZ_ARRAY_SIZE (aabbPoints);
60+
61+ AZ_Assert (numAABBPoints==8 ," you should have 8 points in the aabb"
62+
63+ // Project each AABB point and construct another AABB.
64+ AABB quadResult (AABB::RESET);
65+ for (int i = 0 ; i < numAABBPoints; ++i)
66+ {
67+ Vec3 projectedPoint;
68+ camera.Project (aabbPoints[i], projectedPoint);
69+ quadResult.Add (projectedPoint);
70+ }
71+ return quadResult;
72+ }
73+
74+
75+ // To know if aabb are aligned with camera, we test if projected quads overlap.
76+ bool CFogVolumeRenderNode::OverlapProjectedAABB (const AABB& aabb0, const AABB& aabb1, const CCamera& camera)
77+ {
78+ // quads are AABB2D.
79+ AABB quad0 = GetProjectedQuadFromAABB (aabb0, camera);
80+ AABB quad1 = GetProjectedQuadFromAABB (aabb1, camera);
81+ bool bOverlap = Overlap::AABB_AABB2D (quad0, quad1);
82+ return bOverlap;
83+ }
84+
85+ void AverageFogVolume (SFogVolumeData& fogVolData, const CFogVolumeRenderNode* pFogVol)
86+ {
87+ AABB& avgAABBoxOut = fogVolData.avgAABBox ;
88+ avgAABBoxOut.Add (pFogVol->GetBBox ());
89+
90+ // ratio is used to approximate fog volumes contribution depending of the importance of their size.
91+ float ratio = pFogVol->GetBBox ().GetRadius () / avgAABBoxOut.GetRadius ();
92+ fogVolData.m_heightFallOffBasePoint = Lerp (fogVolData.m_heightFallOffBasePoint ,pFogVol->GetHeightFallOffBasePoint (), ratio);
93+ fogVolData.m_heightFallOffDirScaled = Lerp (fogVolData.m_heightFallOffDirScaled ,pFogVol->GetHeightFallOffDirScaled (), ratio);
94+ fogVolData.m_densityOffset = Lerp (fogVolData.m_densityOffset , pFogVol->GetDensityoffset (), ratio);
95+ fogVolData.m_globalDensity = Lerp (fogVolData.m_globalDensity , pFogVol->GetGlobalDensity (), ratio);
96+ fogVolData.m_volumeType |= pFogVol->GetVolumeType ();
97+ }
2898
2999// /////////////////////////////////////////////////////////////////////////////
100+ // TraceFogVolumes :
101+ // if object intersects/is aligned with fog volumes then register these fog volumes,
102+ // check if object is in front of the fog volume and compute average color.
103+ // if highVertexShadingQuality average fog volume box.
30104// /////////////////////////////////////////////////////////////////////////////
31- void CFogVolumeRenderNode::TraceFogVolumes (const Vec3& worldPos, ColorF& fogColor, const SRenderingPassInfo& passInfo)
105+ void CFogVolumeRenderNode::TraceFogVolumes (const Vec3& objPosition, const AABB& objAABB, SFogVolumeData& fogVolData, const SRenderingPassInfo& passInfo, bool fogVolumeShadingQuality )
32106{
33107 FUNCTION_PROFILER_3DENGINE;
34108 PrefetchLine (&s_tracableFogVolumeArea, 0 );
35109
36110 // init default result
37111 ColorF localFogColor = ColorF (0 .0f , 0 .0f , 0 .0f , 0 .0f );
38112
39-
113+ // We will "accumulate" fog volumes contribution the same way that fog color.
114+
40115 // trace is needed when volumetric fog is off.
41116 if (GetCVars ()->e_Fog && GetCVars ()->e_FogVolumes && (GetCVars ()->e_VolumetricFog == 0 ))
42117 {
118+ const Vec3 worldPos = objPosition;
119+
43120 // init view ray
44121 Vec3 camPos (s_tracableFogVolumeArea.GetCenter ());
45- Lineseg lineseg (camPos, worldPos );
122+ Lineseg lineseg (camPos, objPosition );
46123
47124#ifdef _DEBUG
48125 const SCachedFogVolume* prev (0 );
49126#endif
50-
127+
51128 // loop over all traceable fog volumes
52129 CachedFogVolumes::const_iterator itEnd (s_cachedFogVolumes.end ());
53130 for (CachedFogVolumes::const_iterator it (s_cachedFogVolumes.begin ()); it != itEnd; ++it)
54131 {
55132 // get current fog volume
56133 const CFogVolumeRenderNode* pFogVol ((*it).m_pFogVol );
57-
134+
135+ bool isAligned = false ;
136+ bool isFrontOfBoxCenter = false ;
58137 // only trace visible fog volumes
59138 if (!(pFogVol->GetRndFlags () & ERF_HIDDEN))
60139 {
140+ bool projectedAABBIntersect = false ;
141+ bool isInside = Overlap::Point_AABB (objPosition, pFogVol->m_WSBBox );
142+
143+ if (fogVolumeShadingQuality)
144+ {
145+ projectedAABBIntersect = OverlapProjectedAABB (pFogVol->m_WSBBox , objAABB, passInfo.GetCamera ());
146+ isInside = isInside || Overlap::AABB_AABB (objAABB, pFogVol->m_WSBBox );
147+ }
148+
61149 // check if view ray intersects with bounding box of current fog volume
62- if (Overlap::Lineseg_AABB (lineseg, pFogVol->m_WSBBox ))
150+ isAligned = Overlap::Lineseg_AABB (lineseg, pFogVol->m_WSBBox );
151+ if (projectedAABBIntersect || isAligned)
63152 {
64153 // compute contribution of current fog volume
65- ColorF color;
66- if (0 == pFogVol->m_volumeType )
154+ ColorF color (0 ,0 ,0 );
155+
156+ // Get distance camera to fog volume.
157+ const CCamera& cam (passInfo.GetCamera ());
158+ Vec3 cameraToObject (objPosition - cam.GetPosition ());
159+ Vec3 cameraToFogVolume (pFogVol->m_WSBBox .GetCenter () - cam.GetPosition ());
160+ isFrontOfBoxCenter = (cameraToFogVolume.GetLengthSquared () > cameraToObject.GetLengthSquared ());
161+ // if particle is in front of the box center and not inside the box, then do not accumulate fog color.
162+ if (isFrontOfBoxCenter && !isInside)
163+ {
164+ continue ;
165+ }
166+
167+ if (fogVolumeShadingQuality)
67168 {
68- pFogVol->GetVolumetricFogColorEllipsoid (worldPos, passInfo, color);
169+ // Accumulate this fogVolData
170+ AverageFogVolume (fogVolData, pFogVol);
171+ color = pFogVol->GetFogColor ();
69172 }
70173 else
71174 {
72- pFogVol->GetVolumetricFogColorBox (worldPos, passInfo, color);
175+ if (0 == pFogVol->m_volumeType )
176+ {
177+ pFogVol->GetVolumetricFogColorEllipsoid (worldPos, passInfo, color);
178+ }
179+ else
180+ {
181+ pFogVol->GetVolumetricFogColorBox (worldPos, passInfo, color);
182+ }
183+
184+ color.a = 1 .0f - color.a ; // 0 = transparent, 1 = opaque
73185 }
74-
75- color. a = 1 . 0f - color. a ; // 0 = transparent, 1 = opaque
76-
186+
187+
188+
77189 // blend fog colors
78190 localFogColor.r = Lerp (localFogColor.r , color.r , color.a );
79191 localFogColor.g = Lerp (localFogColor.g , color.g , color.a );
80192 localFogColor.b = Lerp (localFogColor.b , color.b , color.a );
81193 localFogColor.a = Lerp (localFogColor.a , 1 .0f , color.a );
194+
82195 }
196+
83197 }
84198
85199#ifdef _DEBUG
@@ -100,8 +214,7 @@ void CFogVolumeRenderNode::TraceFogVolumes(const Vec3& worldPos, ColorF& fogColo
100214 }
101215
102216 localFogColor.a = 1 .0f - localFogColor.a ;
103-
104- fogColor = localFogColor;
217+ fogVolData.fogColor = localFogColor;
105218}
106219
107220// /////////////////////////////////////////////////////////////////////////////
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