From 389da8159978571e8156ff7692bc595d957e846e Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sat, 23 Feb 2019 16:10:08 +0100
Subject: Store material in fluid buffer and improve visualization

Replaces the density value which is actually not that useful for visualization.

Encoding integer values as floats by casting and comparing them using
exact floating point comparison is not very safe but works out for now.
---
 src/shader/code/collide.glsl | 36 ++++++++++++++----------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

(limited to 'src/shader/code/collide.glsl')

diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index 182f5bd..3f4e2c5 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -6,7 +6,6 @@ layout (local_size_x = 1, local_size_y = 1) in;
 layout (std430, binding=1) buffer bufferCollide  { float collideCells[];  };
 layout (std430, binding=2) buffer bufferStream   { float streamCells[];   };
 layout (std430, binding=3) buffer bufferFluid    { float fluidCells[];    };
-layout (std430, binding=4) buffer bufferGeometry { int   materialCells[]; };
 
 /// external influence
 
@@ -70,29 +69,22 @@ void set(uint x, uint y, int i, int j, float v) {
 	collideCells[indexOfLatticeCell(x,y) + indexOfDirection(i,j)] = v;
 }
 
-void setFluid(uint x, uint y, vec2 v, float d) {
+void setFluid(uint x, uint y, vec2 v) {
 	const uint idx = indexOfFluidVertex(x, y);
 	fluidCells[idx + 0] = v.x;
 	fluidCells[idx + 1] = v.y;
-	fluidCells[idx + 2] = d;
 }
 
 int getMaterial(uint x, uint y) {
-	return materialCells[nX*y + x];
+	const uint idx = indexOfFluidVertex(x, y);
+	return int(fluidCells[idx + 2]);
 }
 
 void setMaterial(uint x, uint y, int m) {
-	materialCells[nX*y + x] = m;
-}
-
-void disableFluid(uint x, uint y) {
 	const uint idx = indexOfFluidVertex(x, y);
-	fluidCells[idx + 0] = 0.0;
-	fluidCells[idx + 1] = 0.0;
-	fluidCells[idx + 2] = -2.0;
+	fluidCells[idx + 2] = m;
 }
 
-
 /// Moments
 
 float density(uint x, uint y) {
@@ -125,7 +117,7 @@ void disableWallInterior(uint x, uint y) {
 	for ( int i = -1; i <= 1; ++i ) {
 		for ( int j = -1; j <= 1; ++j ) {
 			const int material = getMaterial(x+i,y+j);
-			if ( material  == 0 || material == 2 ) {
+			if ( material  == 0 || material == 2 || material == 3 ) {
 				++wallNeighbors;
 			}
 		}
@@ -139,7 +131,7 @@ void disableWallInterior(uint x, uint y) {
 /// Determine external influence
 
 float getExternalPressureInflux(uint x, uint y) {
-	if ( mouseState == 1 && norm(vec2(x,y) - mousePos) < 3 ) {
+	if ( mouseState == 1 && norm(vec2(x,y) - mousePos) < 2 ) {
 		return 1.5;
 	} else {
 		return 0.0;
@@ -147,7 +139,7 @@ float getExternalPressureInflux(uint x, uint y) {
 }
 
 bool isWallRequestedAt(uint x, uint y) {
-	if ( mouseState == 2 && norm(vec2(x,y) - mousePos) < 3 ) {
+	if ( mouseState == 2 && norm(vec2(x,y) - mousePos) < 2 ) {
 		return true;
 	} else {
 		return false;
@@ -164,14 +156,14 @@ void main() {
 		return;
 	}
 
-	if ( isWallRequestedAt(x,y) ) {
-		setMaterial(x,y,2);
-		disableFluid(x,y);
-	}
-
 	const int material = getMaterial(x,y);
 
-	if ( material == 2 ) { // wall
+	if ( isWallRequestedAt(x,y) && material == 1 ) {
+		setMaterial(x,y,3);
+		return;
+	}
+
+	if ( material == 3 ) { // manually added wall
 		disableWallInterior(x,y);
 	}
 
@@ -179,7 +171,7 @@ void main() {
 		const float d = max(getExternalPressureInflux(x,y), density(x,y));
 		const vec2  v = velocity(x,y,d);
 
-		setFluid(x,y,v,d);
+		setFluid(x,y,v);
 
 		for ( int i = -1; i <= 1; ++i ) {
 			for ( int j = -1; j <= 1; ++j ) {
-- 
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