I'm french so sorry for my english.
I'm currently making a splitscreen 2D game with LWJGL.
I'm using the openAL API which is given with LWJGL. Everything seems to works perfectly. Well, too perfectly to be honest : because I'm making a splitscreen game and because I can't have 2 listener sharing the same context, I want to get rid of the left/right panning.
Sound attenuation work well. I change the position of sound depending on the closest player.
The listener doesn't change, always at (0,0,0). The sound position is (soundPosition - closestPlayerPosition).
So how do I get rid of the surround thing ? I want to keep sound attenuation over distance, of course.
I could simply put the sound on the Z-axis depending on the distance but this seem a bit silly (I have to compute the distance every time I have to update a sound position).
Thanks !
When you calculate the sound's position (soundPosition - closestPlayerPosition) take the length of the vector returned by that and then put that sound directly down the z axis that distance away from the player.
Example:
soundPosition = (1.4,0,1.4)
closestPlayerPosition = (0,0,0)
soundDirection = soundPosition - closestPlayerPosition = (1.4,0,1.4)
soundDistance = soundDirection.Length()
And finally, the final position of your sound:
finalSoundPosition = (0,0,soundDistance) = (0,0,2)
Edit: I didn't notice you already suggested this. To be honest I think this is fine, and its the only way to solve your problem beyond rewriting stuff internal to openAL
Related
I have a list of points in the field (like upper_goal_point/ left_upper_outer_corner, etc.
I know their corresponding coordinates in destination image - so I can calculate the homography:
h, status = cv2.findHomography(pts_src, pts_dst)
I also have blue points in the upper corner line (look at image above), which I only know that their destination's y coordinates are 0 (because they are in the upper line), but I don't know where exactly they lay in that line.
Can I use those blue points in order to improve the homography?
P.S.
You can see that the upper corner line in the homography is not horizontal line, it's diagonal, which of course is not correct:
Actually it possible to use line correspondence in find homography.
https://www.researchgate.net/publication/220845575_Combining_Line_and_Point_Correspondences_for_Homography_Estimation
Several years ago we implement this approach in one project. During simplification all math we come up with simple trick. We transform every line a*x + b*y + c = 0 to point (a/c, b/c)
// *** Don't copy paste this code, read below! ***//
Point2f convertPointsToHomogeneousLine(Point2f p1, Point2f p2) {
Point3f p1h(p1.x, p1.y, 1);
Point3f p2h(p2.x, p2.y, 1);
Point3f lineHomo(p1h.y*p2h.z - p1h.z*p2h.y,
p1h.z*p2h.x - p1h.x*p2h.z,
p1h.x*p2h.y - p1h.y*p2h.x);
Point2f lineHomoNorm(lineHomo.x / lineHomo.z,
lineHomo.y / lineHomo.z);
return lineHomoNorm;
}
And pass this points inside. As I remember I also dig inside OpenCV implementation of findHomography and insert this lines somewhere inside to solve step. Inside OpenCV there some normalization applied to points before pass to solve step. So you need to skip this step for this kind of points.
We do not use it in production. User need to calibrate camera manually by providing lines and points on the image and in meter system. It has too complicated interface and bad stability. But in your case I think it can work better. If you will automatically find lines and correspondence.
P.S. Please note that in paper they use some normalization technique.
It will improve stability. We faced with stability problem, do not
solved it in our journey.
I'm working on a program in Godot using Gdscript, and I ran into a problem when trying to use the Transform.translated(Vector3) function. My code is supposed to move a bone to (0,0,0) by translating it by its current coordinates but with negative sign. Example: (1,2,3) would be translated by (-1,-2,-3) so it would end up at (0,0,0). For some reason when I do this, the end position of the bone is not (0,0,0), but some other coordinate. In the Godot documents, it says the .translated function is "relative to the transform's basis vectors", so maybe that's why? Also if there is a better way to change a bones position than using the Transform.translated(Vector3) function that would be helpful too. Thanks!
My Code:
bonePose = skel.get_bone_global_pose(bone)
var globalBonePose = skel.to_global(bonePose.origin)
translateVector = -globalBonePose
var newPose = bonePose.translated(translateVector)
skel.set_bone_pose(bone, newPose)
Code Output / Results:
bonePose (the original position of the bone) is around (-0.82,0.49,0.50)
translateVector (the amount the bone will be translated) is around (0.82,-0.49,-0.50)
newPose (the final position of the bone -- should be [0,0,0]) is around (0.82,-0.66,-0.46). Even when I call skel.to_global(newPose.origin) to see the global coordinates, it's (-0.76,0.44,0.42), which is not (0,0,0)
In Godot a Transform is composed of a basis (a Basis) and an origin (a Vector3). Where the origin handles the translation part of the transform, and the Basis the rest.
A Basis is the set of vectors that define the coordinate system. There is a vector that defines the x axis, another for the y axis, and another for the z axis. And this is the way Godot will encode rotation and scaling transformations.
When the documentation says "relative to the transform's basis vectors" it means the Basis will be applied to the vector you pass in. Thus, in your case, you are getting a translation on the local space of the bone. Which implies that if the bone is rotated or scaled (or something like that), that will affect the translation.
If you don't want to deal with rotation, scaling, et.al. I suggest you work with the origin of the Transform instead.
If you have a Transform and you want another that is otherwise equal but located at (0, 0, 0), you do this:
var new_transform = Transform(transform.basis, Vector.ZERO)
Or replace Vector.ZERO with whatever origin you want to give the new transform.
I also need to remind you that get_bone_global_pose and set_bone_pose do not operate on the same thing. On one hand set_bone_pose is relative to the parent bone, on the other get_bone_global_pose is relative to the Skeleton. Thus, I suggest you use set_bone_global_pose_override instead.
The final piece you need is the opposite of Spatial.to_global. Because setting the pose like as follows…
bonePose = skel.get_bone_global_pose(bone)
var newPose = Transform(bonePose.basis, Vector.ZERO)
skel.set_bone_global_pose_override(bone, newPose, 1.0)
… Would place it at the origin of the Skeleton.
Well, the opposite of Spatial.to_global is Spatial.to_local, and you would use it like this:
bonePose = skel.get_bone_global_pose(bone)
var newPose = Transform(bonePose.basis, skel.to_local(Vector.ZERO))
skel.set_bone_global_pose_override(bone, newPose, 1.0)
Here skel.to_local(Vector.ZERO) should give the origin of the world relative to the Skeleton. And given that set_bone_global_pose_override wants a Transform relative to the Skeleton, the result should be that the bone is placed at the origin of the world. With its rotation and scaling preserved.
Recently I have been working on making a game with Haskell, and we have been using the library Gloss in order to complete the graphic part. To make a game with Gloss, as you probably know, you have to use Graphics.Gloss.Interface.Pure.Game (or IO game, that's not the main thing to focus here). My doubt is simple. As they say on their description of this module : "Pressing ESC will still abort the program, but you don't get automatic pan and zoom controls like with displayInWindow.". I have been trying to build those two effects but with no sucess. I made an accumulator in my state, called v, that gets the value of 1 when 'reactEvent (EventKey (MouseButton WheelUp) Down _ _) ((px,py),p,mapas,i,players,b,c,d,v) = ((px,py),p,mapas,i,players,b,c,d,1)' and then the function that makes the picture appear would turn it back to 0 after applying the effect needed, creating a cicle. What's the mistake in my logic?
Edit : Added the prints, that's what I am trying to get to work. Also, if anyone has a clue on how to make different camera angles, I would also appreciate some help.
https://imgur.com/3PAqO2x
https://imgur.com/jk93lzQ
I am in the process of learning LWJGL and also OpenGL. I have done the tutorials on quads, and also succesfully drawn polygons on a display. I am trying to draw lines using the same methods, but the lines are not created, or they are made invisible, possibly with a pixel width of 0? I have googled for an answer or a tutorial, but so far all of them seems to claim that I am doing the right thing. my method is as follows:
private void drawLine(Point point, Joint Point2) {
GL11.glColor3f(0.0f, 1.0f, 0.2f);
GL11.glBegin(GL11.GL_LINE);
GL11.glVertex2d(point.getX(), point.getY());
GL11.glVertex2d(point2.getX(), point2.getY());
GL11.glEnd();
}
I also tried to put this one in the middle, but no effect.
GL11.glLineWidth(3.8f);
As stated in the comments, The answer was that GL11.GL_LINE is not accepted as a constant in this case. GL11.LINE_STRIP however works like a charm.
I've already know how to dark-down a CCSprite object by:
sprite.color = ccc3(x, x, x); // x is a value less then 255
(As far as i know, it should be a direct mapping of openGL functions, so its easy to achieve.)
But when it comes to light-up, my current solution is adding another mask sprite (same shape but all in white), changing its blendFunc to { GL_SRC_ALPHA, GL_ONE } and overlaying it onto the target. Besides all the codes added, there should be a mask image for each need-to-light-up one.
Is there a way to do light-up as easily as dark-down?
However, not as easy as setColor, in Cocos2d 2.x, with OpenGL ES 2.0 support, you can achieve this by using custom shaders. You can get started here:
http://www.raywenderlich.com/10862/how-to-create-cool-effects-with-custom-shaders-in-opengl-es-2-0-and-cocos2d-2-x
You may also try inverting the sprite's darker color to get a lighter one.