Play around with open boundaries

2 files changed, 23 insertions, 8 deletions

diff --git a/src/main.cc b/src/main.cc
index 99e9a73..5604f3d 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -25,7 +25,7 @@
 #include "timer.h"
 
 constexpr GLuint nX = 256;
-constexpr GLuint nY = 256;
+constexpr GLuint nY = 128;
 
 constexpr int lups = 50; // max lattice updates per second
 
@@ -53,11 +53,19 @@ int setupGeometry(int x, int y) {
 	if ( x == 0 || y == 0 || x == nX-1 || y == nY-1 ) {
 		return 0; // disable end of world
 	}
-	if (   ((x == 1 || x == nX-2) && (y > 0 && y < nY-1))
-		|| ((y == 1 || y == nY-2) && (x > 0 && x < nX-1)) ) {
+	if ( (x == 1 || x == nX-2) && (y > 0 && y < nY-1) ) {
+		if ( x == 1 && y > nY/4 && y < 3*nY/4 ) {
+			return 5; // inflow
+		}
+		if ( x == nX-2 && y > nY/4 && y < 3*nY/4 ) {
+			return 6; // outflow
+		}
+		return 2; // bounce back outer walls
+	}
+	if ( (y == 1 || y == nY-2) && (x > 0 && x < nX-1) ) {
 		return 2; // bounce back outer walls
 	}
-	return 1; // everything else shall be fluid
+	return 1; // everything else shall be bulk fluid
 }
 
 int renderWindow() {
@@ -68,7 +76,7 @@ int renderWindow() {
 		return -1;
 	}
 
-	float world_width  = 1.5*nX;
+	float world_width  = 1*nX;
 	float world_height = getWorldHeight(window.getWidth(), window.getHeight(), world_width);
 
 	glm::mat4 MVP = getMVP(world_width,  world_height);
diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index 0ddae7b..673a285 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -102,7 +102,7 @@ float equilibrium(float d, vec2 v, int i, int j) {
 /// Material number meaning (geometry is only changed by the interaction shader)
 
 bool isBulkFluidCell(int material) {
-	return material == 1 || material == 4;
+	return material == 1 || material == 4 || material == 5 || material == 6;
 }
 
 float getExternalMassInflux(int material) {
@@ -126,8 +126,15 @@ void main() {
 	const int material = getMaterial(x,y);
 
 	if ( isBulkFluidCell(material) ) {
-		const float d = max(density(x,y), getExternalMassInflux(material));
-		const vec2  v = velocity(x,y,d);
+		float d = max(density(x,y), getExternalMassInflux(material));
+		vec2  v = velocity(x,y,d);
+
+		if ( material == 5 ) {
+			v = vec2(0.1,0.0);
+		}
+		if ( material == 6 ) {
+			d = 1.0;
+		}
 
 		setFluid(x,y,v);