Increase camera angle to 60 degrees

Using the 30 degree viewing angle looks reasonable realistic,
but is difficult to use since it requires much more panning.

Derivation of FOV_DIST for a 1600x1200 monitor
with a vertical viewing angle of 60 degrees:

        ---  +.
         |   | '-.     angle
  height |   |    '-./
  (px)   |   |      /'-.
         |   +------|---+ (o) eye
         |   |      \ .-'
         |   |     .-'
         |   |  .-'
        ---  +-'

             |----------|
               FOV_DIST (px)

  height   = 1200 px
  angle    =   60 deg
  fov_dist = cot(angle/2)*(height/2) = ~1039.23

Derivation of angle for window of a given height:

  angle    = atan((height/2)/FOV_DIST)*2

diff --git a/src/grits-opengl.c b/src/grits-opengl.c
index 5bf1710b9f172d1f0b55e6b6e7979e58d4eac401..1b2cce95e362c4fc6c08978f298a3b27b61e2b35 100644 (file)
--- a/src/grits-opengl.c
+++ b/src/grits-opengl.c
@@ -67,7 +67,7 @@ static void _set_visuals(GritsOpenGL *opengl)
 
        double width  = GTK_WIDGET(opengl)->allocation.width;
        double height = GTK_WIDGET(opengl)->allocation.height;
-       double ang    = atan(height/FOV_DIST);
+       double ang    = atan((height/2)/FOV_DIST)*2;
        double atmos  = 100000;
        double near   = MAX(elev*0.75 - atmos, 50); // View 100km of atmosphere
        double far    = elev + 2*EARTH_R + atmos;   // on both sides of the earth

diff --git a/src/grits-util.h b/src/grits-util.h
index 8e7a2fd075d46c365a56a0bb679577a9cfc53bdb..9a22ab519e06c08163d63c89944269500332cd66 100644 (file)
--- a/src/grits-util.h
+++ b/src/grits-util.h
@@ -180,7 +180,7 @@ void grits_bounds_set_bounds(GritsBounds *bounds,
  *
  * Used by GritsOpenGL to set up the drawing window
  */
-#define FOV_DIST   2078.46
+#define FOV_DIST   (1039.23)
 
 /**
  * MPPX:

diff --git a/src/grits-viewer.c b/src/grits-viewer.c
index b4b672a62e6f814473dc36a79a98ded4d2238a9d..f7d70e9fa427836d79f054f0950e156226d1e60a 100644 (file)
--- a/src/grits-viewer.c
+++ b/src/grits-viewer.c
@@ -163,11 +163,11 @@ static gboolean on_motion_notify(GritsViewer *viewer, GdkEventMotion *event, gpo
        gdouble lat, lon, elev, scale, rx, ry, rz;
        grits_viewer_get_location(GRITS_VIEWER(viewer), &lat, &lon, &elev);
        grits_viewer_get_rotation(GRITS_VIEWER(viewer), &rx,  &ry,  &rz);
-       scale = (elev/EARTH_R/40) * (sin(deg2rad(ABS(rx)))*4+1);
+       scale = (elev/EARTH_R/14.1) * (sin(deg2rad(ABS(rx)))*4+1);
        switch (viewer->drag_mode) {
-       case GRITS_DRAG_PAN:  grits_viewer_pan(viewer, -y*scale, x*scale, 0); break;
+       case GRITS_DRAG_PAN:  grits_viewer_pan(viewer, -y*scale*0.782, x*scale, 0); break;
        case GRITS_DRAG_ZOOM: grits_viewer_zoom(viewer, pow(2, -y/500)); break;
-       case GRITS_DRAG_TILT: grits_viewer_rotate(viewer, y/30, 0, x/20); break;
+       case GRITS_DRAG_TILT: grits_viewer_rotate(viewer, y/10, 0, x/10); break;
        }
        viewer->drag_x = event->x;
        viewer->drag_y = event->y;
@@ -587,7 +587,7 @@ static void grits_viewer_init(GritsViewer *viewer)
        viewer->time        = time(NULL);
        viewer->location[0] = 40;
        viewer->location[1] = -100;
-       viewer->location[2] = 4*EARTH_R;
+       viewer->location[2] = EARTH_R;
        viewer->rotation[0] = 0;
        viewer->rotation[1] = 0;
        viewer->rotation[2] = 0;