Tessellation terrain

Desktop/CAVE2 terrain rendering using tessellation shaders.

Screenshots

Contact: Toan Nguyen (http://monash.edu/mivp)

References:

• DirectX 11 terrain tessellation
• Solid wireframe
• QT5 and OpenGL terrain tessellation example

Prerequisites

• OpenGL version >= 4.0

Omegalib module

Tested with Omegalib 13.1

Compile:

cd tessterrain
mkdir build
cd build
cmake ..
make

Run with python script:

import tessterrain

tt = tessterrain.initialize()
tt.initTerrain('vic_config.ini')

Functions which can be used in python script:

nextDisplayMode(n): change display mode.
displayInfo(): display information of terrains
toggleFog(): toggle fog in scene
setHeightScale(scale): set height scale for terrain

Standalone app

Tested with MacOS 10.12.4

cd tessterrain/app
mkdir build
cd build
cmake .. (or cmake .. -G Xcode to build XCode project)
make (or run build in XCode)

Run

./tessterrain [path/to/inifile.ini]

Keys

• 'n': go to next display mode
• 'i': print out camera information
• 't': toggle fog
• 'o': change overlay opacity

Configuration file (INI)

Example

[general]
terrains = 	s38_e141, s38_e142, s38_e143, s38_e144,
	        s39_e141, s39_e142, s39_e143, s39_e144,
sizeScale = 0.3, 0.3	; x, z
refPoint = -36.9998611, 140.9998611 ; lat, lon
preloadAll = 0          ; preload all terrrains
maxTerrainDisplay = 35  ; max terrains can be displayed
maxTerrainInMem = 40    ; max terrains can be stored in VRAM
numLoaderThreads = 4    ; number of threads to load texture images
bboxEnlargeFactor = 1	  ; enlarged bbox size += bboxEnlargeFactor*(bbox size)/2

; elevation data
terrainDir = terraindata/terrain
terrainFile = %s_1arc_v3_8.png 			; %s = terrain name defined in [terrains]

; texture (aerial image)
texture = 1
textureDir = terraindata/texture
textureFile = %s_1arc_v3_sat_crop.png

; overlay data
overlay = 0
overlayDir = terraindata/overlay/current
overlayFile = %s.png

; details
; geo position: tl.lat, tl.lon, br.lat, br.lon
[s35_e141]
pos = -33.9998611, 140.9998611, -35.0001389, 142.0001389
heightRange = 15, 144

[s35_e142]
pos = -33.9998611, 141.9998611, -35.0001389, 143.0001389
heightRange = 3, 135

...

Heightmap

Currently support heightmaps stored in a png file (red channel will be used) or a text file. Heightmaps can be generated from geotiff with scripts/dem2heightmap.py. The python script uses GDAL and numpy.