From 9ed8efcc53f54dce8ec34279e47df851693854ec Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 25 Feb 2019 21:29:03 +0100
Subject: Add cylinder and dampened inflow to open geometry

---
 src/main.cc                  | 19 ++++++++++++++-----
 src/shader/code/collide.glsl |  9 +++++----
 src/shader/code/vertex.glsl  |  2 +-
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/main.cc b/src/main.cc
index fb3bfd0..0b4df95 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -23,10 +23,10 @@
 
 #include "timer.h"
 
-constexpr GLuint nX = 256;
+constexpr GLuint nX = 512;
 constexpr GLuint nY = 128;
 
-constexpr int lups = 50; // max lattice updates per second
+constexpr int lups = 100; // max lattice updates per second
 
 float getWorldHeight(int window_width, int window_height, float world_width) {
 	return world_width / window_width * window_height;
@@ -64,10 +64,10 @@ int setupOpenGeometry(int x, int y) {
 		return 0; // disable end of world
 	}
 	if ( (x == 1 || x == nX-2) && (y > 0 && y < nY-1) ) {
-		if ( x == 1 && y > nY/4 && y < 3*nY/4 ) {
+		if ( x == 1 && y > 1 && y < nY-2 ) {
 			return 5; // inflow
 		}
-		if ( x == nX-2 && y > nY/4 && y < 3*nY/4 ) {
+		if ( x == nX-2 && y > 1 && y < nY-2 ) {
 			return 6; // outflow
 		}
 		return 2; // bounce back outer walls
@@ -75,6 +75,9 @@ int setupOpenGeometry(int x, int y) {
 	if ( (y == 1 || y == nY-2) && (x > 0 && x < nX-1) ) {
 		return 2; // bounce back outer walls
 	}
+	if ( (x-50)*(x-50) + (y-nY/2)*(y-nY/2) < 200 ) {
+		return 3; // bounce back cylinder
+	}
 	return 1; // everything else shall be bulk fluid
 }
 
@@ -86,7 +89,7 @@ int render(bool open_boundaries) {
 		return -1;
 	}
 
-	float world_width  = 1*nX;
+	float world_width  = 1.1*nX;
 	float world_height = getWorldHeight(window.getWidth(), window.getHeight(), world_width);
 
 	glm::mat4 MVP = getMVP(world_width,  world_height);
@@ -124,6 +127,8 @@ int render(bool open_boundaries) {
 
 	auto pause_key = window.getKeyWatcher(GLFW_KEY_SPACE);
 
+	GLuint iT = 0;
+
 	int prevMouseState = 0;
 	float prevLatticeMouseX;
 	float prevLatticeMouseY;
@@ -186,6 +191,10 @@ int render(bool open_boundaries) {
 				/// Perform collide & stream steps
 				{
 					auto guard = collide_shader->use();
+
+					collide_shader->setUniform("iT", iT);
+					iT += 1;
+
 					collide_shader->dispatch(nX, nY);
 				}
 
diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index 4efd7fb..230f02e 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -7,10 +7,11 @@ layout (std430, binding=1) buffer bufferCollide  { float collideCells[];  };
 layout (std430, binding=2) buffer bufferStream   { float streamCells[];   };
 layout (std430, binding=3) buffer bufferFluid    { float fluidCells[];    };
 
-/// LBM constants
-
 uniform uint nX;
 uniform uint nY;
+uniform uint iT;
+
+/// LBM constants
 
 const uint  q         = 9;
 const float weight[q] = float[](
@@ -19,7 +20,7 @@ const float weight[q] = float[](
 	1./36 , 1./9., 1./36.
 );
 
-const float tau   = 0.8;
+const float tau   = 0.6;
 const float omega = 1/tau;
 
 /// Vector utilities
@@ -142,7 +143,7 @@ void main() {
 
 	if ( isBulkFluidCell(material) ) {
 		if ( isInflowCell(material) ) {
-			v = vec2(0.1,0.0);
+			v = vec2(min(float(iT)*0.2/2000.0, 0.2), 0.0);
 		}
 		if ( isOutflowCell(material) ) {
 			d = 1.0;
diff --git a/src/shader/code/vertex.glsl b/src/shader/code/vertex.glsl
index e0ce9a8..67a5d80 100644
--- a/src/shader/code/vertex.glsl
+++ b/src/shader/code/vertex.glsl
@@ -10,7 +10,7 @@ out VS_OUT {
 uniform uint nX;
 uniform uint nY;
 
-const float displayAmplifier = 10.0;
+const float displayAmplifier = 4.0;
 
 float unit(float x) {
 	return 1.0/(1.0+exp(-x));
-- 
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