I was surfing the net looking for a nice effect for turning pages on Android and there just doesn't seem to be one. Since I'm learning the platform it seemed like a nice thing to be able to do is this.
I managed to find a page here: http://wdnuon.blogspot.com/2010/05/implementing-ibooks-page-curling-using.html
- (void)deform
{
Vertex2f vi; // Current input vertex
Vertex3f v1; // First stage of the deformation
Vertex3f *vo; // Pointer to the finished vertex
CGFloat R, r, beta;
for (ushort ii = 0; ii < numVertices_; ii++)
{
// Get the current input vertex.
vi = inputMesh_[ii];
// Radius of the circle circumscribed by vertex (vi.x, vi.y) around A on the x-y plane
R = sqrt(vi.x * vi.x + pow(vi.y - A, 2));
// Now get the radius of the cone cross section intersected by our vertex in 3D space.
r = R * sin(theta);
// Angle subtended by arc |ST| on the cone cross section.
beta = asin(vi.x / R) / sin(theta);
// *** MAGIC!!! ***
v1.x = r * sin(beta);
v1.y = R + A - r * (1 - cos(beta)) * sin(theta);
v1.z = r * (1 - cos(beta)) * cos(theta);
// Apply a basic rotation transform around the y axis to rotate the curled page.
// These two steps could be combined through simple substitution, but are left
// separate to keep the math simple for debugging and illustrative purposes.
vo = &outputMesh_[ii];
vo->x = (v1.x * cos(rho) - v1.z * sin(rho));
vo->y = v1.y;
vo->z = (v1.x * sin(rho) + v1.z * cos(rho));
}
}
that gives an example (above) code for iPhone but I have no idea how I would go about implementing this on android. Could any of the Math gods out there please help me out with how I would go about implementing this in Android Java.
Is it possible using the native draw APIs, would I have to use openGL? Could I mimik the behaviour somehow?
Any help would be appreciated. Thanks.
****************EDIT**********************************************
I found a Bitmap Mesh example in the Android API demos: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics/BitmapMesh.html
Maybe someone could help me out on an equation to simply fold the top right corner inward diagnally across the page to create a similar effect that I can later apply shadows to to gie it more depth?
I'm doing some experimenting on page curl effect on Android using OpenGL ES at the moment. It's quite a sketch actually but maybe gives some idea how to implement page curl for your needs. If you're interested in 3D page flip implementation that is.
As for the formula you're referring to - I tried it out and didn't like the result too much. I'd say it simply doesn't fit small screen very well and started to hack a more simple solution.
Code can be found here:
https://github.com/harism/android_page_curl/
While writing this I'm in the midst of deciding how to implement 'fake' soft shadows - and whether to create a proper application to show off this page curl effect. Also this is pretty much one of the very few OpenGL implementations I've ever done and shouldn't be taken too much as a proper example.
I just created a open source project which features a page curl simulation in 2D using the native canvas: https://github.com/moritz-wundke/android-page-curl
I'm still working on it to add adapters and such to make it usable as a standalone view.
EDIT: Links updated.
EDIT: Missing files has been pushed to repo.
I'm pretty sure, that you'd have to use OpenGL for a nice effect. The basic UI framework's capabilities are quite limited, you can only do basic transformations (alpha, translate, rotate) on Views using animations.
Tho it might be possible to mimic something like that in 2D using a FrameLayout, and a custom View in it.
Related
I'm building an Augmented Reality app with Unity and ARToolkit for Android. I have multiple GameObjects on screen that are children of my marker. Works well. I then created a very simple script to move one of the objects and I attached the script to the game object. It looks like:
void Update()
{
Vector3 currentPos = transform.position;
transform.position = new Vector3(currentPos.x + (.01f * xDirection * xSpeed), currentPos.y + (.01f * yDirection * ySpeed), currentPos.z);
}
The rest of the script does nothing other than alter the value of the direction and speed variables. It works and goes in the directions that I expect, however the object shrinks in size visually. Possible it's just lower on the z axis so it appears smaller, or possible scaling is getting affected. I think it may be related to the movement of the phone up and down while looking at the marker.
I suppose I have to move GameObjects in a different manner than normal when using ARToolkit. What's the proper way?
Thanks
I've no connection with ARToolkit by try checking out their Coordinate System
I want to create a map from some opengl code that I wrote :
In order to do that I though about taking a screen shot of the upperview of the gl screen.
Yet I cant seem to find how to do that...
any suggestions?
Similar problem has been solved in OSG example code here.
First you need to set your view such that you are looking at center from the TOP VIEW.
osg::Vec3 center = scene->getBound().center();
double radius = scene->getBound().radius();
view->getCamera()->setViewMatrixAsLookAt( center - lookDir*(radius*3.0), center, up );
view->getCamera()->setProjectionMatrixAsPerspective(
30.0f, static_cast<double>(width)/static_cast<double>(height), 1.0f, 10000.0f );
Then, you need to use some OS specific API to do similar to logic below:
osgViewer::ScreenCaptureHandler* scrn = new osgViewer::ScreenCaptureHandler();
osgViewer::ScreenCaptureHandler::WriteToFile* captureOper = new osgViewer::ScreenCaptureHandler::WriteToFile(tmpStr.m_szBuffer, "png");
scrn->setCaptureOperation(captureOper);
scrn->captureNextFrame(*_viewer);
_viewer->frame();
Of course if you are not using OSG then you need to find equivalent APIs (of library you are using) to achieve the same task.
So I'm trying to understand how I can properly use hardware acceleration (when available) in a custom View that is persistently animating. This is the basic premise of my onDraw():
canvas.drawColor(mBackgroundColor);
for (Layer layer : mLayers) {
canvas.save();
canvas.translate(layer.x, layer.y);
//Draw that number of images in a grid, offset by -1
for (int i = -1; i < layer.xCount - 1; i++) {
for (int j = -1; j < layer.yCount - 1; j++) {
canvas.drawBitmap(layer.bitmap, layer.w * i, layer.h * j, null);
}
}
//If the layer's x has moved past its width, reset back to a seamless position
layer.x += ((difference * layer.xSpeed) / 1000f);
float xOverlap = layer.x % layer.w;
if (xOverlap > 0) {
layer.x = xOverlap;
}
//If the layer's y has moved past its height, reset back to a seamless position
layer.y += ((difference * layer.ySpeed) / 1000f);
float yOverlap = layer.y % layer.h;
if (yOverlap > 0) {
layer.y = yOverlap;
}
canvas.restore();
}
//Redraw the view
ViewCompat.postInvalidateOnAnimation(this);
I'm enabling hardware layers in onAttachedToWindow() and disabling them in onDetachedFromWindow(), but I'm trying to understand whether or not I'm actually using it. Essentially, the i/j loop that calls drawBitmap() never changes; the only thing that changes is the Canvas translation. Is the Bitmap automatically saved to the GPU as a texture behind the scenes, or is there something I need to do manually to do so?
On what view(s) are you setting View.LAYER_TYPE_HARDWARE exactly? If you are setting a hardware layer on the view that contains the drawing code shown above, you are causing the system to do a lot more work than necessary. Since you are only drawing bitmaps you don't need to do anything here. If you call Canvas.drawBitmap() the framework will cache the resulting OpenGL texture on your behalf.
You could however optimize your code a little more. Instead of calling drawBitmap(), you could use child views. If you move these children using the offset*() methods (or setX()/setY()) the framework will apply further optimizations to avoid calling the draw() methods again.
In general, hardware layers should be set on views that are expensive to draw and whose content won't change often (so pretty much the opposite of what you're doing :)
You can use Android's Tracer for OpenGL ES to see if your view issue OpenGL commands.
From developer.android.com
Tracer is a tool for analyzing OpenGL for Embedded Systems (ES) code in your Android application. The tool allows you to capture OpenGL ES commands and frame by frame images to help you understand how your graphics commands are being executed.
There is also a tutorial about Android Performance Study by Romain Guy which describes its use almost step by step.
I try to create game for Android and I have problem with high speed objects, they don't wanna to collide.
I have Sphere with Sphere Collider and Bouncy material, and RigidBody with this param (Gravity=false, Interpolate=Interpolate, Collision Detection = Continuous Dynamic)
Also I have 3 walls with Box Collider and Bouncy material.
This is my code for Sphere
function IncreaseBallVelocity() {
rigidbody.velocity *= 1.05;
}
function Awake () {
rigidbody.AddForce(4, 4, 0, ForceMode.Impulse);
InvokeRepeating("IncreaseBallVelocity", 2, 2);
}
In project Settings I set: "Min Penetration For Penalty Force"=0.001, "Solver Interation Count"=50
When I play on the start it work fine (it bounces) but when speed go to high, Sphere just passes the wall.
Can anyone help me?
Thanks.
Edited
var hit : RaycastHit;
var mainGameScript : MainGame;
var particles_splash : GameObject;
function Awake () {
rigidbody.AddForce(4, 4, 0, ForceMode.Impulse);
InvokeRepeating("IncreaseBallVelocity", 2, 2);
}
function Update() {
if (rigidbody.SweepTest(transform.forward, hit, 0.5))
Debug.Log(hit.distance + "mts distance to obstacle");
if(transform.position.y < -3) {
mainGameScript.GameOver();
//Application.LoadLevel("Menu");
}
}
function IncreaseBallVelocity() {
rigidbody.velocity *= 1.05;
}
function OnCollisionEnter(collision : Collision) {
Instantiate(particles_splash, transform.position, transform.rotation);
}
EDITED added more info
Fixed Timestep = 0.02 Maximum Allowed Tir = 0.333
There is no difference between running the game in editor player and on Android
No. It looks OK when I set 0.01
My Paddle is Box Collider without Rigidbody, walls are the same
There are all in same layer (when speed is normal it all works) value in PhysicsManager are the default (same like in image) exept "Solver Interation Co..." = 50
No. When I change speed it pass other wall
I am using standard cube but I expand/shrink it to fit my screen and other objects, when I expand wall more then it's OK it bouncing
No. It's simple project simple example from Video http://www.youtube.com/watch?v=edfd1HJmKPY
I don't use gravity
See:
Similar SO Question
A community script that uses ray tracing to help manage fast objects
UnityAnswers post leading to the script in (2)
You could also try changing the fixed time step for physics. The smaller this value, the more times Unity calculates the physics of a scene. But be warned, making this value too small, say <= 0.005, will likely result in an unstable game, especially on a portable device.
The script above is best for bullets or small objects. You can manually force rigid body collisions tests:
public class example : MonoBehaviour {
public RaycastHit hit;
void Update() {
if (rigidbody.SweepTest(transform.forward, out hit, 10))
Debug.Log(hit.distance + "mts distance to obstacle");
}
}
I think the main problem is the manipulation of Rigidbody's velocity. I would try the following to solve the problem.
Redesign your code to ensure that IncreaseBallVelocity and every other manipulation of Rigidbody is called within FixedUpdate. Check that there are no other manipulations to Transform.position.
Try to replace setting velocity directly by using AddForce or similar methods so the physics engine has a higher chance to calculate all dependencies.
If there are more items (main player character, ...) involved related to the physics calculation, ensure that their code runs in FixedUpdate too.
Another point I stumbled upon were meshes that are scaled very much. Having a GameObject with scale <= 0.01 or >= 100 has definitely a negative impact on physics calculation. According to the docs and this Unity forum entry from one of the gurus you should avoid Transform.scale values != 1
Still not happy? OK then the next test is starting with high velocities but no acceleration. At this phase we want to know, if the high velocity itself or the acceleration is to blame for the problem. It would be interesting to know the velocities' values at which the physics engine starts to fail - please post them so that we can compare them.
EDIT: Some more things to investigate
6.7 m/sec does not sound that much so that I guess there is a special reason or a combination of reasons why things go wrong.
Is your Maximum Allowed Timestep high enough? For testing I suggest 5 to 10x Fixed Timestep. Note that this might kill the frame rate but that can be dfixed later.
Is there any difference between running the game in editor player and on Android?
Did you notice any drops in frame rate because of the 0.01 FixedTimestep? This would indicate that the physics engine might be in trouble.
Could it be that there are static colliders (objects having a collider but no Rigidbody) that are moved around or manipulated otherwise? This would cause heavy recalculations within PhysX.
What about the layers: Are all walls on the same layer resp. are the involved layers are configured appropriately in collision detection matrix?
Does the no-bounce effect always happen at the same wall? If so, can you just copy the 1st wall and put it in place of the second one to see if there is something wrong with this specific wall.
If not to much effort, I would try to set up some standard cubes as walls just to be sure that transform.scale is not to blame for it (I made really bad experience with this).
Do you manipulate gravity or TimeManager.timeScale from within a script?
BTW: are you using gravity? (Should be no problem just
I am porting some code to Android from Visual C++. The VC++ ArcTo function takes the bounding rectangle and the start and end points as parameters to define the arc. The android.graphics.Path function arcTo takes the bounding rectangle and the "start angle" and "sweep angle" as parameters.
I am not clear how to convert from the VC set of coordinates to the Android set, or what these two angles are. The arc also has direction (CW or ACW) - I am not clear how to incorporate these in a single Path, or how to switch between one and the other.
One oddity I came across is that in the Android function, angles are expressed in degrees, rather than radians which is what most calculations would use and what one would expect.
I hope my question makes some sort of sense and that someone can help!
Edit: following on from the help I got from Dr Dredel, and with much drawing of diagrams, here's how I eventually translated the VC++ call to Android:
else if (coord.isArc())
{
ptCentre = getPoint(new Coord(coord.getArcLat(), coord.getArcLong()));
nRadius = getPixels(coord.getArcRadius());
rect = new RectF(ptCentre.x - nRadius, ptCentre.y - nRadius,
ptCentre.x + nRadius, ptCentre.y + nRadius);
if (coord.isClockwise())
{
alpha = Math.atan2(ptCentre.y - ptStart.y, ptCentre.x - ptStart.x) *
Constants.k_d180Pi;
beta = Math.atan2(ptCentre.y - ptEnd.y, ptEnd.x - ptCentre.x) *
Constants.k_d180Pi;
path.arcTo(rect, (float)(alpha + 180), (float)(180 - beta - alpha));
}
else
{
}
As you can see, I haven't done the anti-clockwise arc yet, but it should be similar. My calculation wasn't perfect, as I originally had (360 - beta - alpha) instead of (180 - beta - alpha), and the original version gave some very funny results!
(Wow! this formatting mechanism is the other side of weird!)