Tidy up external influence implementation

2 files changed, 24 insertions, 19 deletions

diff --git a/src/main.cc b/src/main.cc
index 067af40..c19b32d 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -23,10 +23,10 @@
 
 #include "timer.h"
 
-constexpr GLuint nX = 256;
-constexpr GLuint nY = 256;
+constexpr GLuint nX = 512;
+constexpr GLuint nY = 512;
 
-constexpr int lups = 30; // max lattice updates per second
+constexpr int lups = 50; // max lattice updates per second
 
 float getWorldHeight(int window_width, int window_height, float world_width) {
 	return world_width / window_width * window_height;
@@ -56,7 +56,7 @@ int renderWindow() {
 		return -1;
 	}
 
-	float world_width  = 2*nX;
+	float world_width  = 1.5*nX;
 	float world_height = getWorldHeight(window.getWidth(), window.getHeight(), world_width);
 
 	glm::mat4 MVP = getMVP(world_width,  world_height);
@@ -123,13 +123,11 @@ int renderWindow() {
 					auto guard = collide_shader->use();
 
 					const auto m = window.getMouse();
-					collide_shader->setUniform("mouseClicked", std::get<0>(m));
-					collide_shader->setUniform("mouseX", int(
-						float(std::get<1>(m)) / window.getWidth() * world_width + nX/2-1
-					));
-					collide_shader->setUniform("mouseY", int(
-						float(std::get<2>(m)) / window.getHeight() * world_height + nY/2
-					));
+					const float latticeMouseX = float(std::get<1>(m)) / window.getWidth()  * world_width  + nX/2;
+					const float latticeMouseY = float(std::get<2>(m)) / window.getHeight() * world_height + nY/2;
+
+					collide_shader->setUniform("mouseState", std::get<0>(m));
+					collide_shader->setUniform("mousePos", latticeMouseX, latticeMouseY);
 
 					collide_shader->dispatch(nX, nY);
 				}
diff --git a/src/shader/code/collide.glsl b/src/shader/code/collide.glsl
index 2626c70..75bfd35 100644
--- a/src/shader/code/collide.glsl
+++ b/src/shader/code/collide.glsl
@@ -7,9 +7,10 @@ layout (std430, binding=1) buffer bufferCollide{ float collideCells[]; };
 layout (std430, binding=2) buffer bufferStream{  float streamCells[]; };
 layout (std430, binding=3) buffer bufferFluid{   float fluidCells[]; };
 
-uniform int mouseClicked;
-uniform int mouseX;
-uniform int mouseY;
+/// external influence
+
+uniform int  mouseState;
+uniform vec2 mousePos;
 
 /// LBM constants
 
@@ -97,6 +98,16 @@ vec2 velocity(uint x, uint y, float d) {
 	);
 }
 
+/// Determine external influence
+
+float getExternalPressureInflux(uint x, uint y) {
+	if ( mouseState == 1 && norm(vec2(x,y) - mousePos) < 4 ) {
+		return 1.5;
+	} else {
+		return 0.0;
+	}
+}
+
 /// Actual collide kernel
 
 void main() {
@@ -107,11 +118,7 @@ void main() {
 		return;
 	}
 
-	float d = density(x,y);
-	if ( mouseClicked == 1 && abs(x - mouseX) < 3 && abs(y - mouseY) < 3 ) {
-		d = 1.5;
-	}
-
+	const float d = max(getExternalPressureInflux(x,y), density(x,y));
 	const vec2  v = velocity(x,y,d);
 
 	setFluid(x,y,v,d);