From 444591b1b4dcd7ea0fa37b6db29ac20d4722a72c Mon Sep 17 00:00:00 2001
From: Alexander Schmidt <alex@treefish.org>
Date: Fri, 15 Jul 2016 14:19:20 +0200
Subject: [PATCH] Implemented view mouse control

---
 seamulator.cpp | 103 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 87 insertions(+), 16 deletions(-)

diff --git a/seamulator.cpp b/seamulator.cpp
index 15b731b..92567f8 100644
--- a/seamulator.cpp
+++ b/seamulator.cpp
@@ -1,4 +1,5 @@
 #include <ctime>
+#include <cmath>
 
 #include <GL/glut.h>
 
@@ -11,6 +12,44 @@ const double LATTICE_UNIT = 1;
 SeaPtr sea;
 WaterSurfacePtr surface;
 
+struct
+{
+  float lookRadius = LATTICE_SIZE*LATTICE_UNIT*1.5;
+  float lookAz = 0;
+  float lookAlt = M_PI/4;
+  float fstMouseAngle[2], oldLookAz, oldLookAlt;
+} view;
+
+void glDisplayFunc();
+void glReshapeFunc(int width, int height);
+void glMouseFunc(int button, int state, int x, int y);
+void glMotionFunc(int x, int y);
+
+int main(int argc, char** argv)
+{
+  std::srand(std::time(0));
+
+  surface = std::make_shared<WaterSurface>(LATTICE_SIZE, LATTICE_UNIT);
+  sea = std::make_shared<Sea>(surface);
+
+  glutInit(&argc, argv);
+  glutInitDisplayMode(GLUT_DOUBLE);
+  glutInitWindowSize(300, 300);
+  glutInitWindowPosition(100, 100);
+  glutCreateWindow("seamulator");
+
+  glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
+  glutDisplayFunc(glDisplayFunc);
+  glutReshapeFunc(glReshapeFunc);
+  glutMouseFunc(glMouseFunc);
+  glutMotionFunc(glMotionFunc);
+
+  glutMainLoop();
+
+  return 0;
+}
+
 void glDisplayFunc()
 {
   glMatrixMode(GL_MODELVIEW);
@@ -26,34 +65,66 @@ void glDisplayFunc()
   glutPostRedisplay();
 }
 
-void glReshapeFunc(int width, int height)
+void updateView(int width, int height)
 {
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
+
   gluPerspective(50.0, ((float)width/(float)height), 0, 1000.0);
   glViewport(0, 0, width, height);
-  gluLookAt(0,-10,10, 0,0,0, 0,1,0);
+
+  float eyePos[3];
+  eyePos[0] = view.lookRadius*cos(view.lookAlt)*sin(view.lookAz);
+  eyePos[1] = view.lookRadius*cos(view.lookAlt)*cos(view.lookAz);
+  eyePos[2] = view.lookRadius*sin(view.lookAlt);
+
+  gluLookAt(eyePos[0], eyePos[1], eyePos[2],
+	    0, 0, 0,
+	    0, 0, 1);
 }
 
-int main(int argc, char** argv)
+void updateView()
 {
-  std::srand(std::time(0));
+  updateView(glutGet(GLUT_WINDOW_WIDTH), glutGet(GLUT_WINDOW_HEIGHT));
+}
 
-  surface = std::make_shared<WaterSurface>(LATTICE_SIZE, LATTICE_UNIT);
-  sea = std::make_shared<Sea>(surface);
+void glReshapeFunc(int width, int height)
+{
+  updateView(width, height);
+}
 
-  glutInit(&argc, argv);
-  glutInitDisplayMode(GLUT_DOUBLE);
-  glutInitWindowSize(300, 300);
-  glutInitWindowPosition(100, 100);
-  glutCreateWindow("seamulator");
+void glMouseFunc(int button, int state, int x, int y)
+{
+  if (button == 3 && state == 0)
+    {
+      view.lookRadius += view.lookRadius*0.1;
+      updateView();
+    }
+
+  else if (button == 4 && state == 0)
+    {
+      view.lookRadius -= view.lookRadius*0.1;
+      updateView();
+    }
+
+  else if (button == 0 && state == 0) {
+    view.fstMouseAngle[0] = x;
+    view.fstMouseAngle[1] = y;
+    view.oldLookAz = view.lookAz;
+    view.oldLookAlt = view.lookAlt;
+  }
 
-  glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+}
 
-  glutDisplayFunc(glDisplayFunc);
-  glutReshapeFunc(glReshapeFunc);
+void glMotionFunc(int x, int y)
+{
+  view.lookAlt = fmod(view.oldLookAlt +
+		 (float)((y-view.fstMouseAngle[1])*2*M_PI/glutGet(GLUT_WINDOW_HEIGHT)),
+		 (float)(2*M_PI));
 
-  glutMainLoop();
+  view.lookAz = fmod(view.oldLookAz +
+		(float)((x-view.fstMouseAngle[0])*2*M_PI/glutGet(GLUT_WINDOW_WIDTH)),
+		(float)(2*M_PI));
 
-  return 0;
+  updateView();
 }
-- 
2.39.5