Terrain Rendering

[Elfinitiy]

Ok so I followed this tutorial http://irrlicht.sourceforge.net/docu/example012.html
and my question is

Code: Select all

camera->setPosition(core::vector3df(2700*2,255*2,2600*2));

How did we get these values ?

[Radikalizm]

Does it matter?
Those are just camera coordinates, they were probably picked at random, maybe these coordinates put you in the middle of the terrain or something

Don't dig too deep into that kind of stuff

[Elfinitiy]

I know that they put me in the middle.
But how to calculate the middle of the terrain ?

[Acki]

But how to calculate the middle of the terrain ?

trial and error !?
move camera around and print camera's position !?
calculate from terrain's position and size !?

[Elfinitiy]

But how to calculate the middle of the terrain ?

trial and error !?
move camera around and print camera's position !?
calculate from terrain's position and size !?

Thants pretty much the first thing that comes to mind.
But its kinda hard to position in the right spot.

[blAaarg]

"Trial and error?" I hate that!

"calculate from terrain's position and size !?"

Interesting! Hmm, let's see if I get this right or should I go to sleep...

from the API:

scale,: The scale factor for the terrain. If you're using a heightmap of size 129x129 and would like your terrain to be 12900x12900 in game units, then use a scale factor of ( core::vector ( 100.0f, 100.0f, 100.0f ). If you use a Y scaling factor of 0.0f, then your terrain will be flat.

The heightmap being used is "terrain-heightmap.bmp" which is 256x256. and we scale it by 40 units in the X, Z direction,

// add terrain scene node
scene::ITerrainSceneNode* terrain = smgr->addTerrainSceneNode(
"../../media/terrain-heightmap.bmp",
0, // parent node
-1, // node id
core::vector3df(0.f, 0.f, 0.f), // position
core::vector3df(0.f, 0.f, 0.f), // rotation
core::vector3df(40.f, 4.4f, 40.f), // scale <--here!
video::SColor ( 255, 255, 255, 255 ), // vertexColor
5, // maxLOD
scene::ETPS_17, // patchSize
4 // smoothFactor
);

So the terrain scene node is a bit over 10,000x10,000 units?

Then the camera gets set to a position of:

camera->setPosition(core::vector3df(2700*2,255*2,2600*2));

which would be like x=5400, z=5200 (in reduced terms) which is approximately the middle.

Then, of course, there's the Y value.

Hopefully, I got that right and it's helpful.

[Elfinitiy]

Great Answer.
Thank you very much,this is what i needed.