Polygon picking?

[EgonOlsen]

You can use the same collision detection approach that are using for picking to detect the height of the terrain simply by shooting a ray from above down to the terrain and calculate the intersection point. Alien Runner does this for example. That's what i would do with a terrain on the desktop. On Android, it might be a better idea to keep some simplified data structure storing the average height of a "tile" of the terrain and interpolate between those. It's not as accurate though, but should be much faster.

[paulscode]

I'm not sure the procedure you used to create your terrain, so this might not apply, but in my RobotBuilder project, I have the terrain built as a tiled grid with a height for each vertice.  I can accurately know the height at a given 2D coordinate on the map by interpolating between the two horizontal and two vertical vertices, as long as the remaining "catty-corner" vertice isn't completely different than the other three (which I've made sure of when I originally created the terrain).  I can provide some example code if that is hard to visualize from my description.

[Kaiidyn]

I used my heightmap2serialized object generator :p (current name terragen ) to create the terrain,
some example code would not hurt (I even prefer getting some )

Terragen download (source)

[Kaiidyn]

I still dont got this 'waling towards' a vector to work.
and have no clue on how to do this ..  would prefer an example ...

[Kaiidyn]

Finally figured it out.. Is is being done using Lerp

Code Select Expand

float speed = (0.5f * ticks);
float timeToGetThere = 1.0f / playerPos.distance(gotoPos) * speed;

playerPos = lerp(playerPos, gotoPos, timeToGetThere);
player.clearTranslation();
player.translate(playerPos);

Lerp function:

Code Select Expand

private SimpleVector lerp(SimpleVector start, SimpleVector end, double time){

float x = (float) (start.x + (end.x - start.x) * time);
float y = (float) (start.y + (end.y - start.y) * time);
float z = (float) (start.z + (end.z - start.z) * time);

return new SimpleVector(x, y, z);

}

What I still need though is to get the height based on terrain... at playerPos.x, playerPos.z

[Kaiidyn]

The direction vector in

Code Select Expand

this.terrain.calcMinDistance(SimpleVector.create(x,y,z), direction, 100);
to cast this down, should it be 0,1,0?

[EgonOlsen]

Yes.

[Kaiidyn]

wow, that was fast :p lol ok thanks


Got my getTerrainHeightAtXZ function finally working now

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public float getTerrainHeightAtXZ(float x, float y, float z){

direction = SimpleVector.create(0,1,0);
distance = this.terrain.calcMinDistance(SimpleVector.create(x,y,z), direction, 1000);

if(distance != Object3D.COLLISION_NONE){

collisionPoint = direction;
        collisionPoint.scalarMul( distance );
        collisionPoint.add( SimpleVector.create(x,y,z) );
        Log.d(collisionPoint.y + "");
        return collisionPoint.y;

}


return 0;
}

Thanks for all the help