Small camera fix

camera.h

@@ -13,20 +13,39 @@ class Camera
         /* Camera constructor */
         Camera()
         {
-            eyePos = Vec3(0.0f, 0.0f, -20.0f);
-            centerPos = Vec3(0.0f, 0.0f, -10.0f);
+            eyePos = Vec3(0.0f, 0.0f, -1.0f);
+            centerPos = Vec3(0.0f, 0.0f, 0.0f);
             upVector = Vec3(0.0f, 1.0f, 0.0f);
         }
 
         /* Update the camera to look at the correct position with correct orientation */
         void updateCamera()
         {
+            this->calculateUp();
             gluLookAt(
                 eyePos.x, eyePos.y, eyePos.z,
                 centerPos.x, centerPos.y, centerPos.z,
                 upVector.x, upVector.y, upVector.z
             );
         }
+
+        /* Compute the current up vector */
+        void calculateUp()
+        {
+            float l = eyePos.length();
+            Vec3 v = Vec3(eyePos.x/l, eyePos.y/l, eyePos.z/l);
+            Vec3 up = Vec3(0.0f, 1.0f, 0.0f);
+
+            Vec3 s = Vec3(
+                v.y * up.z - v.z * up.y,
+                v.z * up.x - v.x * up.z,
+                v.x * up.y - v.y * up.x
+            );
+
+            upVector.x = s.y * v.z - s.z * v.y;
+            upVector.y = s.z * v.x - s.x * v.z;
+            upVector.z = s.x * v.y - s.y * v.x;
+        }
 };
 
 class Light

main.cpp

@@ -32,23 +32,26 @@ void display()
 {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glMatrixMode(GL_MODELVIEW);
-    glLoadIdentity();
-    glClearColor(0.0, 0.0, 0.0, 0.0);
-    glRotatef(angle, 0.0f, 1.0f, 0.0f);
 
+    glClearColor(0.0, 0.0, 0.0, 0.0);
+
+    glLoadIdentity();
     c.updateCamera();
+    glTranslatef(0, -0.5, 1);
+    glRotatef(angle, 0.0f, 1.0f, 0.0f);
+    glScalef(0.05, 0.05, 0.05);
 
     glBegin(GL_TRIANGLES);
         unsigned int size = m.getVertexList().size();
+        glColor3f(1.0, 0.0, 0.0);
         for (unsigned int i = 0; i < size; i++)
         {
             Vec3 v = m.getVertexList()[i];
-            glColor3f(0.0, 1.0, ((float)i)/size);
             glVertex3f(v.x, v.y, v.z);
         }
     glEnd();
     glutSwapBuffers();
-    angle += 0.9;
+    angle += 0.2;
 }
 
 

res/ex.obj

@@ -1,8 +1,8 @@
 v -0.5 0   -0
 v  0   0.5 -0
 v  0.5 0   -0
-v  1   0   -0
-v  1   1   -0
-v  0   1   -0
+v  0   0   -1
+v  0   1   -1
+v  0   1   0
 f  1   2   3
 f  4   5   6