When i am using code below to draw points over my image, each time i draw a new point, i am loosing my previous point, though i want to keep that as well.
void imageviewer :: paintEvent(QPaintEvent * e)
{
QLabel::paintEvent(e);
if(mpaintflag)
{
QPainter painter(this);
QPen paintpen(Qt::red);
paintpen.setWidth(10);
QPoint p1;
p1.setX(mFirstX);
p1.setY(mFirstY);
painter.setPen(paintpen);
painter.drawPoint(p1);
}
}
I think that i can keep my previous points using QList, tried a lot, but still no idea how to do it using QList.
I did it, i make a list (QList) to store the coordinate points, and then paint all the points in the list every time on image. That's how i did it.
Thanks
Related
I want to use Visual C++ to animate fill paths to screen. I have done it with C# before, but now switch to C++ for better perfomance and want do more complex works in the future.
Here is the concept in C#:
In a Canvas I have a number of Path. These paths are closed geometries combine of LineTo and QuadraticBezierTo functions.
Firstly, I fill Silver color for all path.
Then for each path, I fill Green color from one end to other end (up/down/left/right direction) (imagine a progress bar increase its value from min to max). I do it by set the Fill brush of the path to a LinearGradientBrush with two color Green and Silver with same offset, then increase the offset from 0 to 1 by Timer.
When a path is fully green, continue with next path.
When all path is fill with Green, come back first step.
I want to do same thing in Visual C++. I need to know an effective way to:
Create and store paths in a collection to reuse. Because the path is quite lot of point, recreate them repeatly take lots of CPU usage.
Draw all paths to a window.
Do animation fill like step 2, 3, 4 in above concept.
So, what I need is:
A suitable way to create and store closed paths. Note: paths are combine of points connect by functions same with C# LineTo and QuadraticBezierTo function.
Draw and animated fill the paths to screen.
Can you please suggest one way to do above step? (outline what I have to read, then I can study about it myself). I know basic of Visual C++, Win32 GUI and a little about draw context (HDC) and GDI, but only start to learn Graphic/Drawing.
Sorry about my English! If anythings I explain dont clear, please let me know.
how many is quite lot of point ? what is the target framerate? for low enough counts you can use GDI for this otherwise you need HW acceleration like OpenGL,DirectX.
I assume 2D so You need:
store your path as list of segments
for example like this:
struct path_segment
{
int p0[2],p1[2],p2[2]; // points
int type; // line/bezier
float length; // length in pixels or whatever
};
const int MAX=1024; // max number of segments
path_segment path[MAX]; // list of segments can use any template like List<path_segment> path; instead
int paths=0; // actual number of segments;
float length=0.0; // while path length in pixels or whatever
write functions to load and render path[]
The render is just for visual check if you load is OK ... for now atlest
rewrite the render so
it take float t=<0,1> as input parameter which will render path below t with one color and the rest with other. something like this:
int i;
float l=0.0,q,l0=t*length; // separation length;
for (i=0;i<paths;i++)
{
q=l+path[i].length;
if (q>=l0)
{
// split/render path[i] to < 0,l-l0> with color1
// split/render path[i] to <l-l0,q-l0> with color2
// if you need split parameter in <0,1> then =(l-l0)/path[i].length;
i++; break;
}
else
{
//render path[i] with color1
}
l=q;
}
for (;i<paths;i++)
{
//render path[i] with color2
}
use backbuffer for speedup
so render whole path with color1 to some bitmap. On each animation step just render the newly added color1 stuff. And on each redraw just copy the bitmap to screen instead of rendering the same geometry over and over. Of coarse if you have zoom/pan/resize capabilities you need to redraw the bitmap fully on each of those changes ...
I've got a question about libGDX collision detection. Because it's a rather specific question I have not found any good solution on the internet yet.
So, I already created "humans" that consist of different body parts, each with rectangle-shaped collision detection.
Now I want to implement weapons and skills, which for example look like this:
Skill example image
Problem
Working with rectangles in collision detections would be really frustrating for players when there are skills like this: They would dodge a skill successfully but the collision detector would still damage them.
Approach 1:
Before I started working with Libgdx I have created an Android game with a custom engine and similar skills. There I solved the problem following way:
Detect rectangle collision
Calculate overlapping rectangle section
Check every single pixel of the overlapping part of the skill for transparency
If there is any non-transparent pixel found -> Collision
That's a kind of heavy way, but as only overlapping pixels are checked and the rest of the game is really light, it works completely fine.
At the moment my skill images are loaded as "TextureRegion", where it is not possible to access single pixels.
I have found out that libGDX has a Pixmap class, which would allow such pixel checks. Problem is: having them loaded as Pixmaps additionally would 1. be even more heavy and 2. defeat the whole purpose of the Texture system.
An alternative could be to load all skills as Pixmap only. What do you think: Would this be a good way? Is it possible to draw many Pixmaps on the screen without any issues and lag?
Approach 2:
An other way would be to create Polygons with the shape of the skills and use them for the collision detection.
a)
But how would I define a Polygon shape for every single skill (there are over 150 of them)? Well after browsing a while, I found this useful tool: http://www.aurelienribon.com/blog/projects/physics-body-editor/
it allows to create Polygon shapes by hand and then save them as JSON files, readable by the libGDX application. Now here come the difficulties:
The Physics Body Editor is connected to Box2d (which I am not using). I would either have to add the whole Box2d physics engine (which I do not need at all) just because of one tiny collision detection OR I would have to write a custom BodyEditorLoader which would be a tough, complicated and time-intensive task
Some images of the same skill sprite have a big difference in their shapes (like the second skill sprite example). When working with the BodyEditor tool, I would have to not only define the shape of every single skill, but I would have to define the shape of several images (up to 12) of every single skill. That would be extremely time-intensive and a huge mess when implementing these dozens of polygon shapes
b)
If there is any smooth way to automatically generate Polygons out of images, that could be the solution. I could simply connect every sprite section to a generated polygon and check for collisions that way. There are a few problems though:
Is there any smooth tool which can generate Polygon shapes out of an image (and does not need too much time therefor)?
I don't think that a tool like this (if one exists) can directly work with Textures. It would probably need Pixmaps. It would not be needed to keep te Pixmaps loaded after the Polygon creation though. Still an extremely heavy task!
My current thoughts
I'm stuck at this point because there are several possible approaches but all of them have their difficulties. Before I choose one path and continue coding, it would be great if you could leave some of your ideas and knowledge.
There might be helpful classes and code included in libGDX that solve my problems within seconds - as I am really new at libGDX I just don't know a lot about it yet.
Currently I think I would go with approach 1: Work with pixel detection. That way I made exact collision detections possible in my previous Android game.
What do you think?
Greetings
Felix
I, personally, would feel like pixel-to-pixel collision would be overkill on performance and provide some instances where I would still feel cheated - (I got hit by the handle of the axe?)
If it were me, I would add a "Hitbox" to each skill. StreetFighter is a popular game which uses this technique. (newer versions are in 3D, but hitbox collision is still 2D) Hitboxes can change frame-by-frame along with the animation.
Empty spot here to add example images - google "Streetfighter hitbox" in the meantime
For your axe, there could be a defined rectangle hitbox along the edge of one or both ends - or even over the entire metal head of the axe.
This keeps it fairly simple, without having to mess with exact polygons, but also isn't overly performance heavy like having every single pixel being its own hitbox.
I've used that exact body editor you referenced and it has the ability to generate polygons and/or circles for you. I also made a loader for the generated JSON with the Jackson library. This may not be the answer for you since you'd have to implement box2d. But here's how how I did it anyway.
/**
* Adds all the fixtures defined in jsonPath with the name'lookupName', and
* attach them to the 'body' with the properties defined in 'fixtureDef'.
* Then converts to the proper scale with 'width'.
*
* #param body the body to attach fixtures to
* #param fixtureDef the fixture's properties
* #param jsonPath the path to the collision shapes definition file
* #param lookupName the name to find in jsonPath json file
* #param width the width of the sprite, used to scale fixtures and find origin.
* #param height the height of the sprite, used to find origin.
*/
public void addFixtures(Body body, FixtureDef fixtureDef, String jsonPath, String lookupName, float width, float height) {
JsonNode collisionShapes = null;
try {
collisionShapes = json.readTree(Gdx.files.internal(jsonPath).readString());
} catch (JsonProcessingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
for (JsonNode node : collisionShapes.findPath("rigidBodies")) {
if (node.path("name").asText().equals(lookupName)) {
Array<PolygonShape> polyShapes = new Array<PolygonShape>();
Array<CircleShape> circleShapes = new Array<CircleShape>();
for (JsonNode polygon : node.findPath("polygons")) {
Array<Vector2> vertices = new Array<Vector2>(Vector2.class);
for (JsonNode vector : polygon) {
vertices.add(new Vector2(
(float)vector.path("x").asDouble() * width,
(float)vector.path("y").asDouble() * width)
.sub(width/2, height/2));
}
polyShapes.add(new PolygonShape());
polyShapes.peek().set(vertices.toArray());
}
for (final JsonNode circle : node.findPath("circles")) {
circleShapes.add(new CircleShape());
circleShapes.peek().setPosition(new Vector2(
(float)circle.path("cx").asDouble() * width,
(float)circle.path("cy").asDouble() * width)
.sub(width/2, height/2));
circleShapes.peek().setRadius((float)circle.path("r").asDouble() * width);
}
for (PolygonShape shape : polyShapes) {
Vector2 vectors[] = new Vector2[shape.getVertexCount()];
for (int i = 0; i < shape.getVertexCount(); i++) {
vectors[i] = new Vector2();
shape.getVertex(i, vectors[i]);
}
shape.set(vectors);
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
}
for (CircleShape shape : circleShapes) {
fixtureDef.shape = shape;
body.createFixture(fixtureDef);
}
}
}
}
And I would call it like this:
physics.addFixtures(body, fixtureDef, "ship/collision_shapes.json", shipType, width, height);
Then for collision detection:
public ContactListener shipsExplode() {
ContactListener listener = new ContactListener() {
#Override
public void beginContact(Contact contact) {
Body bodyA = contact.getFixtureA().getBody();
Body bodyB = contact.getFixtureB().getBody();
for (Ship ship : ships) {
if (ship.body == bodyA) {
ship.setExplode();
}
if (ship.body == bodyB) {
ship.setExplode();
}
}
}
};
return listener;
}
then you would add the listener to the world:
world.setContactListener(physics.shipsExplode());
my sprites' width and height were small since you're dealing in meters not pixels once you start using box2d. One sprite height was 0.8f and width was 1.2f for example. If you made the sprites width and height in pixels the physics engine hits speed limits that are built in http://www.iforce2d.net/b2dtut/gotchas
Don't know if this still matter to you guys, but I built a small python script that returns the pixels positions of the points in the edges of the image. There is room to improve the script, but for me, for now its ok...
from PIL import Image, ImageFilter
filename = "dship1"
image = Image.open(filename + ".png")
image = image.filter(ImageFilter.FIND_EDGES)
image.save(filename + "_edge.png")
cols = image.width
rows = image.height
points = []
w = 1
h = 1
i = 0
for pixel in list(image.getdata()):
if pixel[3] > 0:
points.append((w, h))
if i == cols:
w = 0
i = 0
h += 1
w += 1
i += 1
with open(filename + "_points.txt", "wb") as nf:
nf.write(',\n'.join('%s, %s' % x for x in points))
In case of updates you can find them here: export positions
I have a character made of up child objects that are animated using Unity3D's animation system.
While the player is walking, I can programmatically move the hand object up to catch a ball using the following code.
hand.position.y = ball.transform.position.y;
I need the hand object to go back to following the walk animation after it touches the ball, but instead it just stays at the exact position since it was set.
You want to use inverse kinematics and let Unity do the work of figuring out positioning for you. Here's a quick-and-dirty (untested) example for catching a ball (it's in C#, but it should be pretty similar for UnityScript):
// in a script on the same GameObject as your animation controller
bool isCatching;
Transform ball;
void OnAnimatorIK (int layer) {
if (isCatching) {
// set position and rotation weights for your catching hand
animator.SetIKPosition(AvatarIKGoal.RightHand, ball.position);
animator.SetIKRotation(AvatarIKGoal.RightHand, ball.rotation);
} else {
// return your position and rotation weights back to their defaults (probably 0f?)
}
}
You'll need to do some work (possibly raycasting or just checking distance and direction) to determine when to set the isCatching flag to true, and you'll want to play with the weights for position and rotation to make it look natural. The IK manual entry has more detailed information.
I'm trying to make a time lapse geographic twitter visualization inspired by Jer Thorp's "Just Landed". I am using the latest version of processing.
I'm using an SVG image for my map because I want to be able to zoom into the map at an arbitrary angle, to focus on certain localities, then show the twitter connections on a global scale. I'm running into several problems, the first of which is a flickering of path boundaries of the countries when I rotate my map. Here's a screenshot of my problem:
Here is my code which is causing the problem:
import processing.opengl.*;
import java.awt.event.*;
PShape map;
PShape test1;
PShape test2;
//camera position/movement intialization
PVector position = new PVector(450, 450);
PVector movement = new PVector();
PVector rotation = new PVector();
PVector velocity = new PVector();
float rotationSpeed = 0.035;
float panningsSpeed = 0.035;
float movementSpeed = 0.05;
float scaleSpeed = 0.25;
float fScale = 2;
void setup(){
map = loadShape("blank_merc.svg"); //swap out for whatever file
size(900, 900, OPENGL);
smooth();
fill(150, 200, 250);
addMouseWheelListener(new MouseWheelListener(){
public void mouseWheelMoved(MouseWheelEvent mwe){
mouseWheel(mwe.getWheelRotation());
}
});
}
void draw(){
if (mousePressed) {
if (mouseButton==LEFT) velocity.add( (pmouseY-mouseY) * 0.01, (mouseX-pmouseX) * 0.01, 0);
if (mouseButton==RIGHT) movement.add( (mouseX-pmouseX) * movementSpeed, (mouseY-pmouseY) * movementSpeed, 0);
}
//TODO: implement reset functionality: DONE
if (keyPressed){
if (key=='r'){
position.set(450,450);
rotation.sub(rotation.get());
velocity.sub(velocity.get());
movement.sub(movement.get());
}
}
velocity.mult(0.95);
rotation.add(velocity);
movement.mult(0.95);
position.add(movement);
background(255);
//lights();
translate(position.x, position.y, position.z);
rotateX(rotation.x*rotationSpeed);
rotateY(rotation.y*rotationSpeed);
scale(fScale);
shape(map,-250,-250,1000,1000);
}
void mouseWheel(int delta){
fScale -= delta * scaleSpeed;
fScale = max(0.5, fScale);
}
I was told it might be z-fighting amongst the paths, and I think this might be the problem because the flickering is more problematic when the map is mid rotation, especially at angles that are non orthogonal to the viewing plane. I tried to remedy this by "translating" a PShape child of the file a small amount in the Z direction with the test1.translate(0,0,0.1); command, but I get an error telling me illegal argument exception: cannot use translate(x,y,z) on a PMatrix2D.
I've also had trouble testing my code with other SVG map files and generally getting the SVG to look like what I think it should look like. There are a bunch of cities and other weird markers on my SVG map, and even when i download the completely "blank" svg world map mercator projection from wikimedia commons. There are these city marker/region attributes which show up in the processing render that dont show up in the browser view. I'm trying to figure out how to "clean" my SVG file up in Inkscape, but I'm unsure what specifically to look for.
For example, I've run it with this map: http://commons.wikimedia.org/wiki/File:Mercator_Projection.svg
but the dots and lines I have no use for, and I'm having to resort to manually selecting and deleting the paths, which is not a very thorough process
and when I use this map, which is supposed to be the "blank version" of the above without all the markers, I see not only a bunch of markers (presumably hidden with some style attribute in the SVG XML?) but also this weird vertical banding, and my camera controls are super slow. The applet appears to be behaving as if the file is way too large, but its like 2MB. Here's a screenshot of what this looks like:
I'm really just looking for a way to get a "clean" SVG world map into Processing so I can spin it around and zoom in on it, and if I can get that to work I can start the Arc-Drawing part. I would sincerely appreciate any assistance anyone could give me.
Thanks
If I understand your question correctly, the flickering is only on the edges, presumably where they overlap. That would suggest z-fighting to me. I usually find that a simple test outside your main sketch is best, just as a quick way to see what's happening and how you might fix it.
If you make a simple SVG with two overlapping shapes, sharing just one edge, does the same thing happen?
If so, I think the easiest solution (though not that easy) would be either:
Select all the countries in Illustrator
Use Object > Transform > Scale... and shrink by a tiny amount
Then share your fixed map for everyone else!
G'day all,
In short, I'm using a for loop to create a bunch of identical sprites that I want to bounce around the screen. The problem is how do I write a collision detection process for the sprites. I have used the process of placing rectangles around sprites and using the .intersects method for rectangles but in that case I created each sprite separately and could identify each one uniquely. Now I have a bunch of sprites but no apparent way to pick one from another.
In detail, if I create an object called Bouncer.cs and give it the movement instructions in it's update() method then create a bunch of sprites using this in Game.cs:
for (int i = 1; i < 5; ++i)
{
Vector2 position = new Vector2(i * 50, i * 50);
Vector2 direction = new Vector2(i * 10, i * 10);
Vector2 velocity = new Vector2(10);
Components.Add(new Bouncer(this, position, direction, velocity, i));
}
base.Initialize();
I can draw a rectangle around each one using:
foreach (Bouncer component1 in Components)
{
Bouncer thing = (Bouncer)component1;
Rectangle thingRectangle;
thingRectangle = new Rectangle((int)thing.position.X, (int)thing.position.Y, thing.sprite.Width, thing.sprite.Height);
But now, how do I check for a collision? I can hardly use:
if (thingRectangle.Intersects(thingRectangle))
I should point out I'm a teacher by trade and play with coding to keep my brain from turning to mush. Recently I have been working with Python and with Python I could just put all the sprites into a list:
sprites[];
Then I could simply refer to each as sprite[1] or sprite[2] or whatever its index in the list is. Does XNA have something like this?
Please let me know if any more code needs to be posted.
Thanks,
Andrew.
One solution, which I use in my game engine, is to have a Logic code run inside the objects for every game Update, ie. every frame. It seems you already do this, according to the variable names, which indicate you run some physics code in the objects to update their positions.
You might also want to create the collision rectangle inside the Bouncer's constructor so it's more accessible and you make good use of object oriented programming, maybe even make it an accessor, so you can make it update every time you call it instead of manually updating the bounding/collision box. For example:
public Rectangle #BoundingBox {
get { return new Rectangle(_Position.X, _Position.Y, width, height); }
}
Whichever way works, but the collision checks can be run inside the Bouncer object. You can either make the reference list of the Bouncer objects static or pass it to the objects itself. The code for collisions is very simply:
foreach(Bouncer bouncer in Components) //Components can be a static List or you can pass it on in the constructor of the Bouncer object
{
if (bouncer.BoundingBox.Intersects(this.BoundingBox))
{
//they collided
}
}