I have a trimesh object. I want to know the Camera Distance, Elevation and Azimuth Angle for this trimesh object. How can I get this ? Is there a function I can use to get these three metrics or is there a formula I can use?
I have tried to google quite a bit but could not find anything relevant.
Related
Considering the camera is not tilted, it is easy to get the distance. However, can you refer a source where camera is tilted at some angle on y axis. By tilt i mean pitch. Also the camera is not looking directly at the object.
I have data from a 2D laser range finder, in the form of 360-elements float arrays, each element representing a distance for an angle. So for example, if the 10th element of the array is the value 2.5 that means that at 10 degrees angle, the distance to an obstacle is 2.5 meters.
Given these points expressed in polar coordinates (angle, distance), what's the best way of creating a PointCloud instance? I see PointCloud is a templated class, so it depends on the type of PointT it contains. Reviewing these types, it seems they are all in cartesian coordinates (x, y, z), sometimes with added info on top. But I couldn't find any native polar coordinate point type. Am I missing it? Is it expected the transformation from whatever coordinates to cartesian to be done outside the library?
Transforming polar to cartesian is straightforward, I just want to know if there's a native, probably more efficient way of doing it within the PCL library (maybe keeping it in polar avoiding conversions altogether, etc.)
Thanks!
As far as known, there is no native way to represent a point in polar coordinates.But Why don't you create your own PointType?
Here is the help doc:https://pcl.readthedocs.io/projects/tutorials/en/latest/adding_custom_ptype.html#adding-custom-ptype
First off, I am not sure if this is the right place so I apologize if this belongs elsewhere - please let me know if it does. I am currently doing some prototyping with this in VB so that's why I come here first.
My Goal
I am trying to make a program to be able to log different types of information for a video game that I play. I would like to be able to map out the entire game with my program and add locations for mobs, resources, etc.
What I have
The in game map can be downloaded so I have literally just stuck this in as a background image on the form (just for now). The map that I get downloaded though is not exactly as the map appears in the game though since the game will add extra water around everything when scrolling around. This makes it a bit tricky to match up where the origin for the map is in game compared to where it would be on the downloaded map.
The nice thing though is that while I am in the game I can print my current coordinates to the screen. So I thought that maybe I can somehow use this to get the right calculation for the rest of the points on the map.
Here is an example image I will refer to now:
In the above map you will see a dotted bounding box. This is an invisible box in the game where once you move your mouse out of the longitude and latitude points will no longer show. This is what I refer to above when I mean I can't find the exact point of origin for the in game map.
You will also see 2 points: A and B. In the game there are teleporters. This is what I would use to get the most accurate position possible. I am thinking I can find the position (in game) of point A and point B and then somehow calculate that into a conversion for my mouse drag event in VB.
In VB the screen starts at top-left and is 0,0. I did already try to get the 2 points like this and just add or subtract the number to the x and y pixel position of the mouse, but it didn't quite line up right.
So with all this information does anyone know if it is possible to write a lon/lat conversion to pixels based on this kind of data?
I appreciate any thoughts and suggestions and if you need any clarification of any information I have posted please let me know and I will be happy to expand on it. I am really hoping I can get this solved!
Thanks!
EDIT:
I also want to mention I am not sure if there is an exact pixel to lat/lon point for the in game map. I.e. the in game map could be 1 pixel = 100 latitude or something. So I might also need to figure out what that conversion number is?
Some clarifications about conversion between the pixel location to 'latitude and longitude'.
First the map in your game is in a geometry coordinate system, which means everything lies in 2D and you can measure the distance between two points by calculate the pixel position.
But when we talk about longitude and latitude, we are actually talking about a geography coordinate system, which is a '3D' model of the sphere oabout the surface of the earth. All the maps on earth are abstracted from 3D to 2D through one step called projection. Like google maps or your GPS. In this projection process, the 3D model converted to 2D model but there is always some part of the map will be tortured, so that same distance in pixels on a map could be different in length in reality.
So if you don't care about the accuracy then you can consider the geometry point as geography point. Otherwise, you need to implement some GIS library to handle the geodesic distance and calculate the geography point based on the projection coordinate system.
I have a flat pan and using kinetic v1.
I want to receive the angle of the pan using kinetic camera.
for eg: If I put the angle in 45 degrees so kinetic will read the closet or exact angle it placed.
is this possible or any solutions ?
Thanks.
I don't know exactly how the data comes back in Kinect V1 but I believe this methodology should work for you.
First: You have to assume that the Kinect is your level of reference, if it is necessary to get the pans angle relative to the ground then make sure the Kinect is level with the ground.
Second: Separate the pan data from all other data. This should be straight forward, the pan should be the closets object so transmit the closest measurements into 3D coordinate points (array of x,y,z).
Third: Assuming you wish for horizontal angle find the highest and lowest grounds of data and average their depth from the camera. Then save both those depths and the vertical distance they are away from each other.
Fourth: Now you can essentially do the math for a triangle. Given you know the width of the pan(saves steps to know the objects size otherwise you have to estimate that too) you can solve for a triangle with sides a: distance to point 1, side b: distance to point 2, side c: size of pan and finding the angle of where points a and c or b and c meet will give you the horizontal angle of the pan relative to the Kinect.
Fifth: For verification your measurements came back correct you can then use the angle you found to calculate the width of the pan given the angle and distance of the top and bottom most points.
Needless to say, you need to make sure that your understanding of trig is solid for this task.
I have a vector which points from my camera to an object I want to point to, so I want to make a quaternion which rotates the camera so that it points to that vector. So i do this (using glm)
glm::quat rotation=glm::angleAxis(0.0f,vector);
If i understand that function correctly in the case of a vector of, for example, (0.0f,0.0f,-1.0f), the camera should point forward in the depth axis, and with no roll. But i don't know why, in that case it creates this quaternion:
x:-0
y:-0
z:-0
w:1
wich does nothing, and the x,y,z values only differ from 0 if the angle parameter passed to angleAxis() is different from 0. Why does this happen? if i pass angle 0, shouldn't it simply create a rotation with only yaw and pitch, and no roll?
Already go the answer: (on the gameDev forum, from the user clb)
No, your understanding is off. Angle-axis rotation generates rotation about the given axis, by the given angle. If you don't specify an angle, you'll always get identity back. This is because rotation a zero angle, be it about any axis, of course does not rotate at all.
What you are thinking about is the LookAt rotation. I am not sure what the function signature in glm is, but I'm sure they have a similar function. Use a LookAt rotation to orient one direction vector to face towards another vector.