Improvise interactive wall drawing

Internal wall cells need to be disabled to prevent delayed propagation
of the reflected populations.

This is just quickly thrown together - both the visual drawing and the backend's
material handling remain to be improved.

1 files changed, 11 insertions, 4 deletions

diff --git a/src/shader/code/stream.glsl b/src/shader/code/stream.glsl
index 345127d..a8aec1d 100644
--- a/src/shader/code/stream.glsl
+++ b/src/shader/code/stream.glsl
@@ -3,8 +3,9 @@ static const std::string STREAM_SHADER_CODE = R"(
 
 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=1) buffer bufferCollide  { float collideCells[];  };
+layout (std430, binding=2) buffer bufferStream   { float streamCells[];   };
+layout (std430, binding=4) buffer bufferGeometry { int   materialCells[]; };
 
 /// LBM constants
 
@@ -33,6 +34,10 @@ void set(uint x, uint y, int i, int j, float v) {
 	streamCells[indexOfLatticeCell(x,y) + indexOfDirection(i,j)] = v;
 }
 
+int getMaterial(uint x, uint y) {
+	return materialCells[nX*y + x];
+}
+
 /// Domain description
 
 bool isEndOfWorld(uint x, uint y) {
@@ -63,11 +68,13 @@ void main() {
 		return;
 	}
 
-	if ( isEndOfWorld(x,y) ) {
+	const int material = getMaterial(x,y);
+
+	if ( material == 0 ) {
 		return;
 	}
 
-	if ( isOuterWall(x,y) ) {
+	if ( material == 2 ) {
 		bounceBack(x,y);
 	}