Monthly Archives: August 2014

Length of a Day

First, the sun rises in the west on Venus, not the east.

Venus rotates slower than any other planet in our solar system… 243 days. That is actually longer than it takes for Venus to revolve around the sun (the Venus year is 225 days). The net result is a solar day that lasts about 116.75 Earth days.

Fortunately for the gameplay we aren’t tethered to the surface and we are suspended in a medium that is moving, on average, 200 km/h. That cuts the day down to about 192 hours or almost exactly 8 Earth days.

So that means that the “magic hour” lasts about 8 hours but then we are in complete darkness for almost 4 days!

Venus Level 7 Data

Preliminary tests at almost 19 km above the surface.  The plate is about 148.5 km square.


Level 7 data is essentially a Mercator map that is 131072 x 65536 pixels. That comes out to 3.447 pixel per km.

The equatorial circumference is 38,026 km with no oblateneess – Venus rotates so slowly that it doesn’t bulge at the equator!

Display Tests Day 6

Finally got it!  It was a combination of OpenGL row-major vs. column-major and a lesser known difference between projection matrices (DirectX screen-space origin is top-left, OpenGL is bottom-left).

8-5-2014 11-50-57 AM

8-5-2014 11-48-28 AM

8-5-2014 11-57-44 AM

Such a relief for me – I have literally not been sleeping well … my dreams incorporate concatenations, negative signs, etc.  I actually read this lecture a while back but I didn’t focus on the differences between OpenGL and DirectX because I didn’t actually have a solution for either platform until very recently.

Display Tests Day 4

2014-08-02_10-02-04The latest work… working past some of the column-major vs. row-major matrix ordering and differences between left-hand and right-hand coordinate systems – brings back memories.

Wired up the Motion Control Unit (MCU) which does the start-up and shut-down sequences for me automatically and currently mimics the joystick motion.

I also got asynchronous email support wired up and fixed a couple glaring issues with multiple game controllers.  Still working out issues with the door device (processing multiple requests for open and close simultaneously).