I'm working on animating an element in Raphael along a path. I need to be able to show the element not only animated along the entire path, but also "frozen" at a specific time point. For example, if I have a circle moving from one point to another point, rotating along the way, for 5 seconds, I would like to be able to "jump" directly to show the circle after 2 seconds without having to start the animation from beginning and stopping it after 2 seconds.
Is that possible?
Thanks.
Related
The title of this question isn't great at explaining what I want to do, so have this gif of the effect I want to emulate: https://i.imgur.com/zRqTSqf.gif (quality of the gif is shite, ik, please bear with me)
I think I need to use the LoopOut() expression for well, the loop, but I don't know how to animate the colors like that. Do I assign different colors in a shape? I'm fairly new to motion graphics, so I'm not familiar with technical terms and all that. Any help/guidance is appreciated!
I would recommend the following:
Create the square shape you are looking for, as a shape layer with a stroke and no fill
Duplicate the shape layer, for example, 4 times
Apply the Trim Paths effect to these layers and distribute it as you wish (for example, if using 4 layers first one from 0 to 25, second one from 25 to 50, third 50 to 75 and fourth one 75 to 100%.
Set a different color for each layer
Create a new Null Object and assign the Slider Control effect to it
Set the Trim Paths Offset property to be driven by the Slider property of the Slider Control (using the pick whip from each layer)
Animating the Slider property of the Slider control in the Null Object, driving the color of all the sides.
Use masks to fix the possible glitches on the vertices and to make it look nice
you can then alt-click on the stopwatch of the Slider property inside the Slider Control of the Null Object and type LoopOut(). Make sure that the first and last keyframes are correct so once the looping is activated the end is the same as the beginning and you should be good to go!
I think this should more or less point you in a possible way of solving it, let me know if you need more help!
In Illustrator, draw a square with a stroke, no fill, and rotate it 45 degrees. And on a separate layer, draw 6 triangles in the desired colours. Example below:
Save as an AI file. Import this artwork into After Effects, setting Import Kind to Composition.
Set the composition length to 4 seconds.
Set the track matte for the triangles layer to the Alpha Matte of the square layer. (#1 in the above)
Open the rotation property of triangles, set a key frame on frame 1, then go to 4 seconds, and set a key frame of 1 rotation. (#2 in the above)
Precompose these layers, then apply a CC Light Burst 2.5 effect for the glow.
Result is as below.
I have data for an actors movement which is being read in from a file at the start of the game. The data that gets read in contains Vector positions where the Actor should move to next. I currently have the Actor moving from Position to Position no problem... until I start to add animation to a Skeletal Mesh attached to the Actor.
My problem: How can I found out the velocity to work out which animation to play idle, walk, jog and running? It currently doesnt have a velocity as i am lerping the position:
SetActorLocation(FMath::Lerp(GetActorLocation(), newPos, 0.01));
Any thoughts on how to set the right animation based on distance travel and speed?
Should I move my Actors movement to Character so I can use AddMovementInput to get velocity. Then, If i go down that route, how to I say:
Move this character from my current position, to my next position in X amount of time giving the character the correct velocity to use in the animation selection.
Can you normalize the difference between the two vector lengths (GetWorldLocation) and use the abs(floating point) result as the X variable to put into 1D Blend Space to do idle, walk, jog, run in your Animation BP? Also be sure to account for an "acceptance radius" or else once it gets to location it won't quite get it and keep turning quickly.
Not sure why you're Lerping from Vector to Vector. I would've personally used (MoveToActor or MoveToLocation):
AMyPawn->MoveToActor(AMyActor, 90.f,true,true,false,0,true);
So much cleaner! Also MoveToLocation, using BT/BB.
I'm working on a Little Mobile Game with Cocos2D-X and Box2D.
The Point where I got stuck is the movement of a box2d-body (the main actor) and the according Sprite. Now I want to :
move this Body with a constant velocity along the x-axis, no matter if it's rolling (it's a circleshape) upwards or downwards
keep the body nearly sticking to the ground on which it's rolling
keep the Body and the according Sprite in the Center of the Screen.
What I tried :
in the update()- method I used body->SetLinearVelocity(b2Vec2(x,y)) to higher/lower values, if the Body was passing a constant value for his velocity
I used to set very high y-Values in body->SetLinearVelocity(b2Vec2(x,y))
First tried to use CCFollow with my playerSprite, which was also Scrolling along the y-axis, as i only need to scroll along the x-axis, so I decided to move the whole layer which is containing the ambience (platforms etc.) to the left of my Screen and my Player Body & Player sprite to the right of the Screen, adjusting the speed values to Keep the Player in the Center of the Screen.
Well...
...didn't work as i wanted it to, because each time i set the velocity manually (I also tried to use body->applyLinearImpulse(...) when the Body is moving upwards just as playing around with the value of velocityIterations in world->Step(...)) there's a small delay, which pushes the player Body more or less further of the Center of the Screen.
... didn't also work as I expected it to, because I needed to adjust the x-Values, when the Body was moving upwards to Keep it not getting slowed down, this made my Body even less sticky to the ground....
... CCFollow did a good Job, except that I didn't want to scroll along the y-axis also and it Forces the overgiven sprite to start in the Center of the Screen. Moving the whole Layer even brought no good results, I have tried a Long time to adjust values of the movement Speed of the layer and the Body to Keep it negating each other, that the player stays nearly in the Center of the Screen....
So my question is :
Does anyone of you have any Kind of new Approach for me to solve this cohesive bunch of Problems ?
Cheers,
Seb
To make it easy to control the body, the main figure to which the force is applied should be round. This should be done because of the processing mechanism of collisions. More details in this article: Why does the character get stuck?.
For processing collisions with the present contour of the body you can use the additional fixtures and sensors with an id or using category and mask bits. For of constant velocity is often better to use SetLinearVelocity, because even when using impulse velocity gets lost at sharp uphill or when jumping. If you want to use the implulse to change the position of the body, then you need to use the code for the type of this:
b2Vec2 vel = m_pB2Body->GetLinearVelocity();
float desiredVel = mMoveSpeed.x; //set there your speed x value
float velChange = desiredVel - vel.x;
float impulse = m_pB2Body->GetMass() * velChange;
m_pB2Body->ApplyLinearImpulse( b2Vec2(impulse, mMoveSpeed.y), m_pB2Body->GetWorldCenter());
This will allow maintain a constant speed most of the time. Do not forget that these functions must be called every time in your game loop. You can combine these forces, depending on the situation. For example, if the at the beginning you need to make a small acceleration, it is possible to use ApplyForce to the body, and when a desired speed is to use ApplyLinearImpulse or SetLinearVelocity. How correctly to use it is described here: Moving at constant speed
If you use world with the normal gravity(b2Vec2(0, -9.81)), then it should not be a problem.
I answer for this question here: Cocos2D-x - Issues when with using CCFollow. I use this code, it may be useful to you:
CCPoint position = ccpClamp(playerPosition, mLeftBounds, mRightBounds);
CCPoint diff = ccpSub(mWorldScrollBound, mGameNode->convertToWorldSpace(position));
CCPoint newGameNodePosition = ccpAdd(mGameNode->getPosition(), mGameNode->getParent()->convertToNodeSpace(diff));
mGameNode->setPosition(newGameNodePosition);
P.S. If you are new to box2d, it is advisable to read all the articles iforce2d(tuts), they are among the best in the network, as well as his Box2D Editor - RUBE. At one time they really helped me.
I do not know if this is possible but I have an idea:
Keep the circle at a fixed position and move the background relatively. For example, during the course of the game, if the circle has a velocity of 5 towards left then keep circle fixed and move screen with velocity 5 towards right. If circle has 5 velocity towards left and screen has 3 velocity towards right, then keep circle fixed and move screen with 8 velocity towards left and so on. This should allow you to fix the circle at the center of the screen.
Another method would be to translate the entire screen along with the ball. Make everything on the screen an object that can have a velocity. And the x-component of the velocity of the ball (circle) should be the velocity of all other objects. This way, whenever the circle moves, all the other objects will try and keep up with it.
I'm trying to build a program using opencv library.
I intend to make a laser pointer mouse.
so far, the program can detect laser point and move the cursor location that location in realtime.
now i want to give the program an ability to perform click and if possible a double click.
the only idea I have, is to do this by playing with the coordinate value for certain frame and subtract current frame coordinate with last frame coordinate.
my problem is...I dont know how implement it in code
should I use array to store the coordinate?? or any other solution i could use??
thanks in advance..
A click could be represented by the laser pointer disappearing and appearing near the same spot, and only if this happens within 1 second.
You could store the coordinates of the last frames in a std::vector of CvPoint and do a simple search in this vector when the laser pointer appears again. The last 30 coordinates or so should be stored, so you will always have the coordinates of that last 1 second of recording (at 30fps).
The double click is a small enhancement of the single click. For simplicity purposes, the double click could seen as 2 single clicks being detected within 2 seconds.
I just want to do a simple animation (for example in C++ using OpenGL) of some moving object - let's say simple horizontal movement of a square from left to right.
In OpenGL, I can use "double-buffering" method and let's say a user (running my application with the animation) have turned "vertical sync" on - so I can call some function every time when a monitor refreshes itself (I can achieve that for example using Qt toolkit and its function "swapBuffers").
So, I think, the "smoothest" animation that I can achieve, is to "move the square by for example 1 pixel (can be other values) every time monitor refreshes", so at each "frame" the square is 1 pixel further - "I HAVE TESTED THIS, AND IT SURELY WORKS SMOOTHLY".
But the problem arises when I want to have "separate" thread for "game logic" (moving the square by 1 pixel to the right) and for "animation" (displaying current position of the square on the screen). Because let's say the game logic thread is a while loop where I move the square by 1 pixel and then "sleep" the thread for some time, for example 10 milliseconds, and my monitor refreshes for example every 16 milliseconds - the movement of the square "won't be 100% smooth" because sometimes the monitor will refresh two times where the square moves by only by 1 pixel and not by 2 pixels (because there two "different" frequencies of monitor and game logic thread) - and the movement will look "little jerky".
So, logically, I could stay with the first super smooth method, but, it cannot be used in for example "multiplayer" (for example "server-client") games - because different computers have different monitor frequencies (so I should use different threads for game logic (on the server) and for animation (on the clients) ).
So my question is:
Is there some method, using different threads for game logic and animation, which do "100% smooth" animation of some moving object and if some exists, please describe it here, or when I just had some "more complex scene to render", I just would not see that "little jerky movement" which I see now, when I move some simple square horizontally, and I deeply concentrate on it :) ?
Well, this is actually typical separate game-loop behavior. You manage all you physics (movement) related actions in one thread, letting the render thread to do its work. This is actually desirable.
Don´t forget this way of implementation of game loop is to have maximum available frame rate while preserving constant physics speed. At higher FPS, you can not see this effect by any chance, if there is not any other code related problem. Some hooking between framerate and physics for example.
If you want to achieve what you describe as perfect smoothness, you could synchronize your physics engine with VSync. Simply do all your physics BEFORE refresh kicks in, than wait for another.
But this all applies to constant speed objects. If you have object with dynamic speed, you can never know when to draw it to be "in sync". Same problem arises then you want multiple object with different constant speeds.
Also, this is NOT what you want in complex scenes. The whole idea of V-sync is to limit screen tearing effect. You should definitely NOT hook your physics or rendering code to display refresh rate. You want you physics code to run independent of users display refresh rate. This could be REAL pain in multiplayer games for example. For start, look at this page: How A Game Loop Works
EDIT:
I say your vision of perfect smoothness is unrealistic. You can mask it using techniques Kevin wrote. But you will always struggle with HW limits as refresh rate, or display pixelation. For example, you have window of 640x480 px. Now, you want your object to move horizontally. You can move your object by vector heading towards bottom right corner, BUT you must increment object coordinates by float number (640/480). But in rendering, you go to integers. So your object moves jagged. No way around this. In small speed, you can notice it. You can blur it, or make it move faster, but never get rid of it...
Allow your object to move by fractions of a pixel. In OpenGL, this can be done for your example of a square by drawing the square onto a texture (i.e. a one-pixel or larger border), rather than letting it be just the polygon edge. If you are rendering 2D sprite graphics, then you get this pretty much automatically (but if you have 1:1 pixel art it will be blurred/sharp/blurred as it crosses pixel boundaries).
Smooth (antialias) the polygon edge (GL_POLYGON_SMOOTH). The problem with this technique is that it does not work with Z-buffer-based rendering since it causes transparency, but if you are doing a 2D scene you can make sure to always draw back-to-front.
Enable multisample/supersample antialiasing, which is more expensive but doesn't have the above problem.
Make your object have a sufficiently animated appearance that the pixel shifts aren't easy to notice because there's much more going on at that edge (i.e. it is itself moving in place at much more than 1 pixel/frame).
Make your game sufficiently complex and engrossing that players are distracted from looking at the pixels. :)