I put 180 planes around camera in each 2 degree.The count of plane show in view is deal due to the degree of planes is deal.
How to change the view of camera in ARKit to make the count of plane less than normal?
You cannot change the view of the camera as it is tightly coupled to physical camera of your device. What you could do is create a shader which will add a section plane.
To reduce the RGB view produced by ARCamera use SKCropNode from SpriteKit framework:
class SKCropNode: SKNode
Apple documentation says about it the following:
SKCropNode masks pixels drawn by its children so that only some pixels are seen
Related
I have successfully implemented shadow maps in my engine but the problem is the shadow map doesn't cover the whole scene. If I make the shadowmap large shadow quality will drop. So I'm trying make my shadows move with camera. I can do this if I can calculate the 8 world space positions of camera frustum vertices.
So how can I calculate world space positions of camera frustum vertices ? I'm working with Directx if it changes the way how it's calculated.
Thanks.
The frustum (near plane, far plane, fov) is in view space so multiplying it with an inverse view matrix will move it into world space. If you use DirectXMath (which I recommend) you can utilize the bounding frustum object. An example code might look something like this:
DirectX::BoundingFrustum frustum;
DirectX::BoundingFrustum::CreateFromMatrix(frustum, camera.getProjectionMatrix());
DirectX::XMMATRIX inverseViewMatrix = DirectX::XMMatrixInverse(nullptr, camera.getViewMatrix());
frustum.Transform(frustum, inverseViewMatrix);
BoundingFrustum docs: https://msdn.microsoft.com/en-us/library/windows/desktop/microsoft.directx_sdk.directxmath.boundingfrustum(v=vs.85).aspx
If your frustum is big and you have to view a large area (e.g. outdoor scene) then even a large moving shadow map might not be enough (or it takes a huge amount of memory). One technique to solve this is called cascaded shadow maps (CSM). In CSM more precise shadow maps are rendered close to the camera and less precise shadows are rendered in the distance where the low quality is not visible anyway. Here is a CSM tutorial in case you are interested: https://msdn.microsoft.com/en-us/library/windows/desktop/ee416307(v=vs.85).aspx
content
first i have a 360 (equirectangular) image viewer by applying the image as a texture onto a sphere with the scenekit camera at the center.
then i enter a "drawing mode" where i can use my finger to draw on a transparent UIView
when i'm done, i take the drawing and apply it to my sphere as an annotation
problem (with video example)
the problem is in this 3rd step, the scale isn't saved correctly.
https://www.dropbox.com/s/a2l3vvx92sa3cgh/drawing_defect_trimmed_480p.mp4?dl=0
temporary solution
i was able to add a magic number to the expected scale which lessens the scaling problem, but it is still a little bit off and obviously suboptimal from a technical perspective.
e.g. “scale_used = expected_scale + magic_constant”
implementation details
I am projecting a UIView in front of a Scene Kit camera at some custom
distance in the Scene Kit world and trying to make it so the new
Scene Kit node will have exactly the same visual size.
the approach is to calculate the perspective projection of the item,
located in the world at drawingContentItem.distance using camera
zNear - “(screenHeight * distance / Float(zNear))”.
Then we assume that size of visible world of scene kit is from -1000
to 1000; and the view angle is 60 degrees; and calculate the ratio of
scene Kit near plane view to UIView - “(sceneScreenHeight /
nearPlaneHeightInWorlCoordinates)”.
that gives us the finalHeight of drawing in the world coordinates and
we use this to calculate the scale.
But it seems that there is some mistake in the formula and it causes
the need for the magical number. :(
i have a question about achieving an effect like on a lunar eclipse. The effect should look like in the first seconds of this gif. So just like a black shadow which goes over the circle. The ideal situation would be a function where i can passed a parameter in percentage to get this amount as a shadow on the circle:
The problem which i am facing is that my background is an gradient. So it's not possible to have a black circle which moves over the moon to get the effect.
I tried something with CCClippingNode but it looks not nice. Furthermore the clip on the edges was always a bit pixelated.
I thought about using something like a GLSL Shader to achieve the effect but i am not so familiar with GLSL and i can't find an example.
The effect is for an app game developed for an iphone. I use the cocos2d framework in version 3 (the current one).
Has somebody an idea how to get this effect? An idea where i can start to search?
Thank you in advance
The physics behind is simple you change the light shining on the moon. So
I would create a 1D gradient texture representing the lighting conditions
compute each rendered pixel of moon
you obviously have the 2D texture of moon. So you now need to obtain the position of each pixel inside the 1D lighting texture. So if moon is fully visible you are in sunlight. When partially eclipsed then you are in the umbra region. And finaly while total eclipse you are in penumbra region. so just compute the middle point's of the moon position. And for the rest use relative position in the moons motion direction.
So now just multiply the Moon surface with the lighting texture and render the output.
when working you can add the curvature correction
Now you got linerly cutted Moon phases but the real phases are curved as the lighting conditions differs also with radial distance from motion direction and moons center. To fix this you can do
convert the lighting to 2D texture
or shift the texture coordinate by some curvature dependent on the radial distance
I would like to move a 3D plane in a 3D space, and have the movement match
the screens pixels so I can snap the plane to the edges of the screen.
I have played around with the focal length, camera position and camera scale,
and I have managed to get a plane to match the screen pixels in terms of size,
however when moving the plane things are not correct anymore.
So basically my current status is that I feed the plane size with values
assuming that I am working with standard 2D graphics.
So if I set the plane size to 128x128, it more or less is viewed as a 2D sqaure with that
exact size.
I am not using and will not use Orthographic view, I am using and will be using Projection view because my application needs some perspective to it.
How can this be calculated?
Does anyone have any links to resources that I can read?
you need to grab the transformation matrices you use in the vertex shader and apply them to the point/some points that represents the plane
that will result in a set of points in -1,-1 to 1,1 (after dividing by w) which you will need to map to the viewport
I am new to OpenGL-es 2.0 and GLKit,
and would like to ask a question.
I tried to find a good example on 2D camera but couldn't find any,
so I hope that you guys can help me :D
--
1)
Firstly, I have an object, and I store its position in GLKVector2.
I would like to know how to draw it in the world space.
2)
I have a "2D Camera" class, storing as a CGRect with its world position and size.
Its size may change depending on the "zoom" I want.
Is there any way to easily draw the objects from world space into this 2D Camera?
Is any optimization required too? such as not drawing objects outside this 2D Camera,
and clipping objects that have some parts outside of 2D Camera.
3)
If the objects are drawn into this 2D camera, how do I apply effects like clip/scale/etc so that it fits on the device screen, and draw it on the screen?
--
I have seen many things about model, view, and projection matrix, but I don't get them. I have only done XNA/Android bitmap drawing calls, which is drawing them onto a Bitmap, and resizing the Bitmap onto the screen.