1 Efficient rendering of terrain elevation model
3 start with some top level cells
9 views from google earth
11 image data + info viewing / illumination
16 [ ] seems - not important
17 [ ] when creating texture for region, don't up sample, select larger area
21 [X] selection of channels to display
22 [ ] more sensible sampling of elevation data
23 [ ] edges of box should interpolate
24 [X] inner vertices should be sensible
26 [X] basic linear interpolation
27 [X] spline interpolation
28 [X] gui to toggle {flat, unprocessed, corrected -> refined}
30 [ ] different colours for ridges and valleys
32 [X] focus extended altitude
33 [X] mouse click -> lon lat transformation
34 [ ] terrain grab while dragging
35 [X] selection of region
36 [ ] region image preview (full resolution)
38 [ ] in region, detect shadow areas
39 [ ] border and highlight in both views
46 16801 x 14921 - 250MB x1
49 downsample entire image to a reasonable size
50 1/8 x 1/8 = 1/64th size = ~10MB
51 or use the thumbnail in each image
52 when a portion of the image is desired in higher detail
53 reload portion of the image at full resolution
54 1/8 x 1/8 = 1/64th size of image
55 when a portion of the image is no longer being used
67 determine if we need to subdivide quality in this cell
68 if we're close, then we do
69 find distance from each corner
70 use distance[i] < max(dist(corner[i], corner[j]))*factor
71 if we should subdivide
72 renderCell on each of the 4 subdivisions
73 determine the quality at this level
74 find distance to center
75 apply magic function to find detail level
76 render the cell in this detail level