Two fixes for domain boundary conditions.

* Domain vertical velocity was accelerating over time. This issue has been in trunk since smoke was first introduced, but was especially troublesome for fire simulations due to higher temperatures and therefore higher buoyancy lift.
* Domain sides were partly considered obstacles regardless of the active "Border Collisions" setting. Now all boundaries behave identically. This should be especially useful when using new gsoc features like domain rotation or changing gravity direction.

2 files changed, 3 insertions, 39 deletions

diff --git a/intern/smoke/intern/FLUID_3D.cpp b/intern/smoke/intern/FLUID_3D.cpp
index 3e56f6a36e5..3b775e84e96 100644
--- a/intern/smoke/intern/FLUID_3D.cpp
+++ b/intern/smoke/intern/FLUID_3D.cpp
@@ -149,9 +149,6 @@ FLUID_3D::FLUID_3D(int *res, float dx, float dtdef, int init_heat, int init_fire
 	_domainBcRight	= _domainBcLeft;
 
 	_colloPrev = 1;	// default value
-
-	setBorderObstacles(); // walls
-
 }
 
 void FLUID_3D::initHeat()
@@ -1455,14 +1452,9 @@ void FLUID_3D::advectMacCormackBegin(int zBegin, int zEnd)
 {
 	Vec3Int res = Vec3Int(_xRes,_yRes,_zRes);
 
-	if(!_domainBcLeft) copyBorderX(_xVelocityOld, res, zBegin, zEnd);
-	else setZeroX(_xVelocityOld, res, zBegin, zEnd);
-
-	if(!_domainBcFront) copyBorderY(_yVelocityOld, res, zBegin, zEnd);
-	else setZeroY(_yVelocityOld, res, zBegin, zEnd); 
-
-	if(!_domainBcTop) copyBorderZ(_zVelocityOld, res, zBegin, zEnd);
-	else setZeroZ(_zVelocityOld, res, zBegin, zEnd);
+	setZeroX(_xVelocityOld, res, zBegin, zEnd);
+	setZeroY(_yVelocityOld, res, zBegin, zEnd);
+	setZeroZ(_zVelocityOld, res, zBegin, zEnd);
 }
 
 //////////////////////////////////////////////////////////////////////
diff --git a/intern/smoke/intern/FLUID_3D_STATIC.cpp b/intern/smoke/intern/FLUID_3D_STATIC.cpp
index c7a0ddcd04c..ac485ad983a 100644
--- a/intern/smoke/intern/FLUID_3D_STATIC.cpp
+++ b/intern/smoke/intern/FLUID_3D_STATIC.cpp
@@ -92,18 +92,10 @@ void FLUID_3D::setNeumannX(float* field, Vec3Int res, int zBegin, int zEnd)
 			// left slab
 			index = y * res[0] + z * slabSize;
 			field[index] = field[index + 2];
-			/* only allow outwards flux */
-			if(field[index]>0.) field[index] = 0.;
-			index += 1;
-			if(field[index]>0.) field[index] = 0.;
 
 			// right slab
 			index = y * res[0] + z * slabSize + res[0] - 1;
 			field[index] = field[index - 2];
-			/* only allow outwards flux */
-			if(field[index]<0.) field[index] = 0.;
-			index -= 1;
-			if(field[index]<0.) field[index] = 0.;
 		}
  }
 
@@ -120,18 +112,10 @@ void FLUID_3D::setNeumannY(float* field, Vec3Int res, int zBegin, int zEnd)
 			// front slab
 			index = x + z * slabSize;
 			field[index] = field[index + 2 * res[0]];
-			/* only allow outwards flux */
-			if(field[index]>0.) field[index] = 0.;
-			index += res[0];
-			if(field[index]>0.) field[index] = 0.;
 
 			// back slab
 			index = x + z * slabSize + slabSize - res[0];
 			field[index] = field[index - 2 * res[0]];
-			/* only allow outwards flux */
-			if(field[index]<0.) field[index] = 0.;
-			index -= res[0];
-			if(field[index]<0.) field[index] = 0.;
 		}
 }
 
@@ -152,14 +136,6 @@ void FLUID_3D::setNeumannZ(float* field, Vec3Int res, int zBegin, int zEnd)
 				// front slab
 				index = x + y * res[0];
 				field[index] = field[index + 2 * slabSize];
-				/* only allow outwards flux */
-
-				// DG: Disable this for z-axis.
-				// The problem is that smoke somehow gets sucked in again
-				// from the TOP slab when this is enabled
-				// if(field[index]>0.) field[index] = 0.;
-				// index += slabSize;
-				// if(field[index]>0.) field[index] = 0.;
 			}
 	}
 
@@ -170,10 +146,6 @@ void FLUID_3D::setNeumannZ(float* field, Vec3Int res, int zBegin, int zEnd)
 				// back slab
 				index = x + y * res[0] + cellsslab;
 				field[index] = field[index - 2 * slabSize];
-				/* only allow outwards flux */
-				if(field[index]<0.) field[index] = 0.;
-				index -= slabSize;
-				if(field[index]<0.) field[index] = 0.;
 			}
 	}