From 057ea93beacf593c79e03b5179a94e2889f714c2 Mon Sep 17 00:00:00 2001
From: Jiaming Guo <jackguo523@gmail.com>
Date: Thu, 13 Jul 2017 15:33:32 -0500
Subject: [PATCH] add flow velocity vector field visualization feature replacing the former flow direction indicating method

---
 flow.h  | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 main.cu | 32 ++++++++++++++++++++++++--------
 2 files changed, 84 insertions(+), 9 deletions(-)

diff --git a/flow.h b/flow.h
index 7159085..83229e3 100644
--- a/flow.h
+++ b/flow.h
@@ -1076,6 +1076,64 @@ namespace stim {
 			glFlush();
 		}
 
+		// draw flow velocity field, glyph
+		void glyph(std::vector<unsigned char> color, GLint subdivision, T r = 4.0f) {
+			
+			// v1----v2-->v3
+			T k = 4.0f;							// quartering
+			stim::vec3<T> v1, v2, v3;			// three point
+			stim::vec3<T> d;					// direction vector
+			stim::circle<float> tmp_c;
+			std::vector<typename stim::vec3<float> > cp1(subdivision + 1);
+			std::vector<typename stim::vec3<float> > cp2(subdivision + 1);
+
+			for (unsigned i = 0; i < num_edge; i++) {				// for every edge
+				glColor3f((float)color[i * 3 + 0] / 255.0f, (float)color[i * 3 + 1] / 255.0f, (float)color[i * 3 + 2] / 255.0f);
+				for (unsigned j = 0; j < E[i].size() - 1; j++) {	// for every point on that edge
+
+					// consider the velocity valuence
+					if (v[i] > 0) {		// positive, from start point to end point
+						v1 = E[i][j];
+						v3 = E[i][j + 1];
+					}
+					else {				// negative, from end point to start point
+						v1 = E[i][j + 1];
+						v3 = E[i][j];
+					}
+					d = v3 - v1;
+					// place the arrow in the middel of one edge
+					v2 = v1 + (1.0f / k * 2.0f) * d;			// looks like =->=
+					v1 = v1 + (1.0f / k) * d;
+					v3 = v3 - (1.0f / k) * d;
+					d = d.norm();
+					tmp_c.rotate(d);
+
+					// render the cylinder part
+					stim::circle<T> c1(v1, r / 2, d, tmp_c.U);
+					cp1 = c1.glpoints(subdivision);
+					stim::circle<T> c2(v2, r / 2, d, tmp_c.U);
+					cp2 = c2.glpoints(subdivision);
+					
+					glBegin(GL_QUAD_STRIP);
+					for (unsigned k = 0; k < cp1.size(); k++) {
+						glVertex3f(cp1[k][0], cp1[k][1], cp1[k][2]);
+						glVertex3f(cp2[k][0], cp2[k][1], cp2[k][2]);
+					}
+					glEnd();
+
+					// render the cone part
+					stim::circle<T> c3(v2, r, d, tmp_c.U);
+					cp2 = c3.glpoints(subdivision);
+					glBegin(GL_TRIANGLE_FAN);
+					glVertex3f(v3[0], v3[1], v3[2]);
+					for (unsigned k = 0; k < cp2.size(); k++)
+						glVertex3f(cp2[k][0], cp2[k][1], cp2[k][2]);
+					glEnd();
+				}
+			}
+			glFlush();
+		}
+
 		// display the total volume flow rate
 		void display_flow_rate(T in, T out) {
 			
@@ -1609,7 +1667,8 @@ namespace stim {
 				width = (T)origin_l / (2 * n);										// updates
 				height = (desire_l - origin_l) / (2 * n);
 				
-				if (width < times * radius) {										// check feasibility
+				// there are cases that the fragment can not satisfy the requirement for width
+				if (width < times * radius || n == 0) {								// check feasibility
 					ratio = 0.0f;													// load
 					desire_l = tmp_d;
 					origin_l = tmp_l;
diff --git a/main.cu b/main.cu
index ec4bc9b..81da29b 100644
--- a/main.cu
+++ b/main.cu
@@ -84,7 +84,8 @@ bool render_direction = false;		// flag indicates rendering flow direction for o
 bool simulation = false;			// flag indicates simulation mode
 bool color_bound = false;			// flag indicates velocity color map bound
 bool to_select_pressure = false;	// flag indicates having selected a vertex to modify pressure
-bool mark_index = true;			// flag indicates marking the index near the vertex
+bool mark_index = true;				// flag indicates marking the index near the vertex
+bool flow_direction = false;		// flag indicates rendering glyph for flow velocity field
 unsigned pressure_index;			// the index of vertex that is clicked
 unsigned direction_index = -1;		// the index of edge that is pointed at
 unsigned index_index = -1;			// the index of the vertex
@@ -255,11 +256,18 @@ void glut_render() {
 	}
 	else {
 		flow.bounding_box();
-		flow.glSolidSphere(max_pressure, scale, subdivision);
-		if (mark_index)
-			flow.mark_vertex(scale);
-		//flow.glSolidCone(subdivision);
-		flow.glSolidCylinder(direction_index, color, scale, subdivision);
+		// render network
+		if (!flow_direction) {
+			flow.glSolidSphere(max_pressure, scale, subdivision);
+			if (mark_index)
+				flow.mark_vertex(scale);
+			//flow.glSolidCone(subdivision);
+			flow.glSolidCylinder(direction_index, color, scale, subdivision);
+		}
+		// render glyphs
+		else 
+			flow.glyph(color, subdivision);
+		
 		flow.glSolidCuboid(manufacture, length);
 		if (render_direction)
 			flow.glSolidCone(direction_index, scale, subdivision);
@@ -531,9 +539,9 @@ void glut_passive_motion(int x, int y) {
 
 	if (simulation || build_inlet_outlet && !mods) {
 		bool flag = flow.epsilon_edge((float)posX, (float)posY, (float)posZ, eps, direction_index);
-		if (flag)
+		if (flag && !flow_direction)
 			render_direction = true;
-		else {
+		else if (!flag && !flow_direction) {
 			if (render_direction)				// if the direction is displaying currently, do a short delay
 				Sleep(300);
 			render_direction = false;
@@ -844,6 +852,14 @@ void glut_keyboard(unsigned char key, int x, int y) {
 	case 's':
 		flow.save_network();
 		break;
+
+		// flow vector field visualization, Glyphs
+	case 'f':
+		if (flow_direction && !manufacture && (simulation || build_inlet_outlet))
+			flow_direction = false;
+		else if(!flow_direction && !manufacture && (simulation || build_inlet_outlet))
+			flow_direction = true;
+		break;
 	
 		// open/close index marks
 	case 'e':
--
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