I am trying to draw a grid on the screen of a Windows Phone; it will help me better position my sprites on the screen rather than guessing locations on the screen.
I have found several examples of a grid (2d or 3d) using XNA 3.0, but unfortunately the architectures are different and so the code doesnt work in XNA 4.0
Does anyone have something that could work?
Thanks!
You can download a PrimitiveBatch class here http://create.msdn.com/en-US/education/catalog/sample/primitives and use the code below to generate an appropriate grid as a texture.
PrimitiveBatch primitiveBatch;
private Texture2D GenerateGrid(Rectangle destRect, int cols, int rows, Color gridColor, int cellSize)
{
int w = (int)(cols * gridCellSize);
int h = (int)(rows * gridCellSize);
float uselessWidth = destRect.Width - w;
float uselessHeigth = destRect.Height - h;
Rectangle bounds = new Rectangle((int)(uselessWidth / 2) + destRect.X, (int)(uselessHeigth / 2) + destRect.Y, w, h);
RenderTarget2D grid = new RenderTarget2D(GraphicsDevice, GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height);
GraphicsDevice.SetRenderTarget(grid);
GraphicsDevice.Clear(Color.Transparent);
primitiveBatch.Begin(PrimitiveType.LineList);
float x = bounds.X;
float y = bounds.Y;
for (int col = 0; col < cols + 1; col++)
{
primitiveBatch.AddVertex(new Vector2(x + (col * gridCellSize), bounds.Top), gridColor);
primitiveBatch.AddVertex(new Vector2(x + (col * gridCellSize), bounds.Bottom), gridColor);
}
for (int row = 0; row < rows + 1; row++)
{
primitiveBatch.AddVertex(new Vector2(bounds.Left, y + (row * gridCellSize)), gridColor);
primitiveBatch.AddVertex(new Vector2(bounds.Right, y + (row * gridCellSize)), gridColor);
}
primitiveBatch.End();
GraphicsDevice.SetRenderTarget(null);
return grid;
}
One quick and dirty way you can do it (as it is for debugging the quicker the better) is to simply create a texture of a grid that is of the same resolution you are running your XNA game at (if you are running it at the same resolution as the phone, this will be 480x800). Most of the texture will simply be an alpha map and with grid lines of one pixel, you could create multiple resolutions or you can repeat a small texture of a single pixel cross dividing a section of the screen that is divisible by the resolution you are running at.
The draw method will be something as below and be called everyframe.
This code can declared inside your game class
Texture2D gridTexture;
Rectangle gridRectangle;
This code should be in your LoadContent method
//Best to use something like a png file
gridTexture = content.Load<Texture2D>("pathto/mygridtexture");
gridRectangle = new Rectangle(0,0,resolutionX,resolutionY);
This method should be called from your Draw method last to ensure it is on top assuming you are just using the standard spriteBatch.Begin() to render sprites (first if you are doing FrontToBack rendering).
public void DrawGrid()
{
spriteBatch.Draw(gridTexture, gridRectangle, Color.White);
}
This grid will remain stationary throughout the running of your application and should be useful when trying to line up your UI or objects that have relative positions in your game.
HTH.
You may want to take a look at the XPF project by RedBadger. It enables you to use XAML style layout in an XNA project.
Related
I'm trying to create a grid of an image (in the way one would tile a background with). Here's what I've been using:
PImage bgtile;
PGraphics bg;
int tilesize = 50;
void setup() {
int t = millis();
fullScreen(P2D);
background(0);
bgtile = loadImage("bgtile.png");
int bgw = ceil( ((float) width) / tilesize) + 1;
int bgh = ceil( ((float) height) / tilesize) + 1;
bg = createGraphics(bgw*tilesize,bgh*tilesize);
bg.beginDraw();
for(int i = 0; i < bgw; i++){
for(int j = 0; j < bgh; j++){
bg.image(bgtile, i*tilesize, j*tilesize, tilesize, tilesize);
}
}
bg.endDraw();
print(millis() - t);
}
The timing code says that this takes about a quarter of a second, but by my count there's a full second once the window opens before anything shows up on screen (which should happen as soon as draw is first run). Is there a faster way to get this same effect? (I want to avoid rendering bgtile hundreds of times in the draw loop for obvious reasons)
One way could be to make use of the GPU and let OpenGL repeat a texture for you.
Processing makes it fairly easy to repeat a texture via textureWrap(REPEAT)
Instead of drawing an image you'd make your own quad shape and instead of calling vertex(x, y) for example, you'd call vertex(x, y, u, v); passing texture coordinates (more low level info on the OpenGL link above). The simple idea is x,y would control the geometry on screen and u,v would control how the texture is applied to the geometry.
Another thing you can control is textureMode() which allows you control how you specify the texture coordinates (U, V):
IMAGE mode is the default: you use pixel coordinates (based on the dimensions of the texture)
NORMAL mode uses values between 0.0 and 1.0 (also known as normalised values) where 1.0 means the maximum the texture can go (e.g. image width for U or image height for V) and you don't need to worry about knowing the texture image dimensions
Here's a basic example based on the textureMode() example above:
PImage img;
void setup() {
fullScreen(P2D);
noStroke();
img = loadImage("https://processing.org/examples/moonwalk.jpg");
// texture mode can be IMAGE (pixel dimensions) or NORMAL (0.0 to 1.0)
// normal means 1.0 is full width (for U) or height (for V) without having to know the image resolution
textureMode(NORMAL);
// this is what will make handle tiling for you
textureWrap(REPEAT);
}
void draw() {
// drag mouse on X axis to change tiling
int tileRepeats = (int)map(constrain(mouseX,0,width), 0, width, 1, 100);
// draw a textured quad
beginShape(QUAD);
// set the texture
texture(img);
// x , y , U , V
vertex(0 , 0 , 0 , 0);
vertex(width, 0 , tileRepeats, 0);
vertex(width, height, tileRepeats, tileRepeats);
vertex(0 , height, 0 , tileRepeats);
endShape();
text((int)frameRate+"fps",15,15);
}
Drag the mouse on the Y axis to control the number of repetitions.
In this simple example both vertex coordinates and texture coordinates are going clockwise (top left, top right, bottom right, bottom left order).
There are probably other ways to achieve the same result: using a PShader comes to mind.
Your approach caching the tiles in setup is ok.
Even flattening your nested loop into a single loop at best may only shave a few milliseconds off, but nothing substantial.
If you tried to cache my snippet above it would make a minimal difference.
In this particular case, because of the back and forth between Java/OpenGL (via JOGL), as far as I can tell using VisualVM, it looks like there's not a lot of room for improvement since simply swapping buffers takes so long (e.g. bg.image()):
An easy way to do this would be to use processing's built in get(); which saves a PImage of the coordinates you pass, for example: PImage pic = get(0, 0, width, height); will capture a "screenshot" of your entire window. So, you can create the image like you already are, and then take a screenshot and display that screenshot.
PImage bgtile;
PGraphics bg;
PImage screenGrab;
int tilesize = 50;
void setup() {
fullScreen(P2D);
background(0);
bgtile = loadImage("bgtile.png");
int bgw = ceil(((float) width) / tilesize) + 1;
int bgh = ceil(((float) height) / tilesize) + 1;
bg = createGraphics(bgw * tilesize, bgh * tilesize);
bg.beginDraw();
for (int i = 0; i < bgw; i++) {
for (int j = 0; j < bgh; j++) {
bg.image(bgtile, i * tilesize, j * tilesize, tilesize, tilesize);
}
}
bg.endDraw();
screenGrab = get(0, 0, width, height);
}
void draw() {
image(screenGrab, 0, 0);
}
This will still take a little bit to generate the image, but once it does, there is no need to use the for loops again unless you change the tilesize.
#George Profenza's answer looks more efficient than my solution, but mine may take a little less modification to the code you already have.
The code is supposed to fade and copy the window's image to a buffer f, then draw f back onto the window but translated, rotated, and scaled. I am trying to create an effect like a feedback loop when you point a camera plugged into a TV at the TV.
I have tried everything I can think of, logged every variable I could think of, and still it just seems like image(f,0,0) is doing something wrong or unexpected.
What am I missing?
Pic of double image mirror about x-axis:
PGraphics f;
int rect_size;
int midX;
int midY;
void setup(){
size(1000, 1000, P2D);
f = createGraphics(width, height, P2D);
midX = width/2;
midY = height/2;
rect_size = 300;
imageMode(CENTER);
rectMode(CENTER);
smooth();
background(0,0,0);
fill(0,0);
stroke(255,255);
}
void draw(){
fade_and_copy_pixels(f); //fades window pixels and then copies pixels to f
background(0,0,0);//without this the corners dont get repainted.
//transform display window (instead of f)
pushMatrix();
float scaling = 0.90; // x>1 makes image bigger
float rot = 5; //angle in degrees
translate(midX,midY); //makes it so rotations are always around the center
rotate(radians(rot));
scale(scaling);
imageMode(CENTER);
image(f,0,0); //weird double image must have something not working around here
popMatrix();//returns window matrix to normal
int x = mouseX;
int y = mouseY;
rectMode(CENTER);
rect(x,y,rect_size,rect_size);
}
//fades window pixels and then copies pixels to f
void fade_and_copy_pixels(PGraphics f){
loadPixels(); //load windows pixels. dont need because I am only reading pixels?
f.loadPixels(); //loads feedback loops pixels
// Loop through every pixel in window
//it is faster to grab data from pixels[] array, so dont use get and set, use this
for (int i = 0; i < pixels.length; i++) {
//////////////FADE PIXELS in window and COPY to f:///////////////
color p = pixels[i];
//get color values, mask then shift
int r = (p & 0x00FF0000) >> 16;
int g = (p & 0x0000FF00) >> 8;
int b = p & 0x000000FF; //no need for shifting
// reduce value for each color proportional
// between fade_amount between 0-1 for 0 being totallty transparent, and 1 totally none
// min is 0.0039 (when using floor function and 255 as molorModes for colors)
float fade_percent= 0.005; //0.05 = 5%
int r_new = floor(float(r) - (float(r) * fade_percent));
int g_new = floor(float(g) - (float(g) * fade_percent));
int b_new = floor(float(b) - (float(b) * fade_percent));
//maybe later rewrite in a way to save what the difference is and round it differently, like maybe faster at first and slow later,
//round doesn't work because it never first subtracts one to get the ball rolling
//floor has a minimum of always subtracting 1 from each value each time. cant just subtract 1 ever n loops
//keep a list of all the pixel as floats? too much memory?
//ill stick with floor for now
// the lowest percent that will make a difference with floor is 0.0039?... because thats slightly more than 1/255
//shift back and or together
p = 0xFF000000 | (r_new << 16) | (g_new << 8) | b_new; // or-ing all the new hex together back into AARRGGBB
f.pixels[i] = p;
////////pixels now copied
}
f.updatePixels();
}
This is a weird one. But let's start with a simpler MCVE that isolates the problem:
PGraphics f;
void setup() {
size(500, 500, P2D);
f = createGraphics(width, height, P2D);
}
void draw() {
background(0);
rect(mouseX, mouseY, 100, 100);
copyPixels(f);
image(f, 0, 0);
}
void copyPixels(PGraphics f) {
loadPixels();
f.loadPixels();
for (int i = 0; i < pixels.length; i++) {
color p = pixels[i];
f.pixels[i] = p;
}
f.updatePixels();
}
This code exhibits the same problem as your code, without any of the extra logic. I would expect this code to show a rectangle wherever the mouse is, but instead it shows a rectangle at a position reflected over the X axis. If the mouse is on the top of the window, the rectangle is at the bottom of the window, and vice-versa.
I think this is caused by the P2D renderer being OpenGL, which has an inversed Y axis (0 is at the bottom instead of the top). So it seems like when you copy the pixels over, it's going from screen space to OpenGL space... or something. That definitely seems buggy though.
For now, there are two things that seem to fix the problem. First, you could just use the default renderer instead of P2D. That seems to fix the problem.
Or you could get rid of the for loop inside the copyPixels() function and just do f.pixels = pixels; for now. That also seems to fix the problem, but again it feels pretty buggy.
If somebody else (paging George) doesn't come along with a better explanation by tomorrow, I'd file a bug on Processing's GitHub. (I can do that for you if you want.)
Edit: I've filed an issue here, so hopefully we'll hear back from a developer in the next few days.
Edit Two: Looks like a fix has been implemented and should be available in the next release of Processing. If you need it now, you can always build Processing from source.
An easier one, and works like a charm:
add f.beginDraw(); before and f.endDraw(); after using f:
loadPixels(); //load windows pixels. dont need because I am only reading pixels?
f.loadPixels(); //loads feedback loops pixels
// Loop through every pixel in window
//it is faster to grab data from pixels[] array, so dont use get and set, use this
f.beginDraw();
and
f.updatePixels();
f.endDraw();
Processing must know when it's drawing in a buffer and when not.
In this image you can see that works
For my 2D Game; I have a panel with an image Component (with a sprite) and a GridLayout component.
On the panel i have also put a script that creates buttons for the panel (as children)
public void InitializeGrid(int rows, int columns, List<RbzFilteredWord> words)
{
RectTransform myRect = GetComponent<RectTransform>();
buttonHeight = myRect.rect.height / (float)rows;
buttonWidth = myRect.rect.width / (float)columns;
GridLayoutGroup grid = this.GetComponent<GridLayoutGroup>();
grid.cellSize = new Vector2(buttonWidth, buttonHeight);
...
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < columns; j++)
{
button = (Button)Instantiate(prefab);
button.transform.SetParent(transform, false);
...
}
Problem:
The text of each button must indicate the color of the pixel (from the underlying image) at the pivot location of that button
I know that this method is available: GetPixel(x,y), but i don't know which coordinates i need to use as parameters for this method, since i'm a noob at unity
x and y are the position indexes in the pixels bidimensional array of teh texture.
That is:
x goes from 0 to the width - 1 of the texture image (in pixels)
y goes from 0 to the height - 1 of the texture image (in pixels)
I am trying to store the motion detected from optical flow for frames in a video sequence and then use these stored motion vectors in order to predict the already known frames using just the first frame as a reference. I am currently using two processing sketches - the first sketch draws a motion vector for every pixel grid (each of width and height 10 pixels). This is done for every frame in the video sequence. The vector is only drawn in a grid if there is sufficient motion detected. The second sketch aims to reconstruct the video frames crudely from just the initial frame of the video sequence combined with information about the motion vectors got from the first sketch.
My approach so far is as follows: I am able to determine the size, position and direction of each motion vector drawn in the first sketch from four variables. By creating four arrays (two for the motion vector's x and y coordinate and another two for its length in the x and y direction), every time a motion vector is drawn I can append each of the four variables to the arrays mentioned above. This is done for each pixel grid throughout an entire frame where the vector is drawn and for each frame in the sequence - via for loops. Once the arrays are full, I can then save them to a text file as a list of strings. I then load these strings from the text file into the second sketch, along with the first frame of the video sequence. I load the strings into variables within a while loop in the draw function and convert them back into floats. I increment a variable by one each time the draw function is called - this moves on to the next frame (I used a specific number as a separator in my text-files which appears at the end of every frame - the loop searches for this number and then increments the variable by one, thus breaking the while loop and the draw function is called again for the subsequent frame). For each frame, I can draw 10 by 10 pixel boxes and move then by the parameters got from the text files in the first sketch. My problem is simply this: How do I draw the motion of a particular frame without letting what I've have blitted to the screen in the previous frame affect what will be drawn for the next frame. My only way of getting my 10 by 10 pixel box is by using the get() function which gets pixels that are already drawn to the screen.
Apologies for the length and complexity of my question. Any tips would be very much appreciated! I will add the code for the second sketch. I can also add the first sketch if required, but it's rather long and a lot of it is not my own. Here is the second sketch:
import processing.video.*;
Movie video;
PImage [] naturalMovie = new PImage [0];
String xlengths [];
String ylengths [];
String xpositions [];
String ypositions [];
int a = 0;
int c = 0;
int d = 0;
int p;
int gs = 10;
void setup(){
size(640, 480, JAVA2D);
xlengths = loadStrings("xlengths.txt");
ylengths = loadStrings("ylengths.txt");
xpositions = loadStrings("xpositions.txt");
ypositions = loadStrings("ypositions.txt");
video = new Movie(this, "sample1.mov");
video.play();
rectMode(CENTER);
}
void movieEvent(Movie m) {
m.read();
PImage f = createImage(m.width, m.height, ARGB);
f.set(0, 0, m);
f.resize(width, height);
naturalMovie = (PImage []) append(naturalMovie, f);
println("naturalMovie length: " + naturalMovie.length);
p = naturalMovie.length - 1;
}
void draw() {
if(naturalMovie.length >= p && p > 0){
if (c == 0){
image(naturalMovie[0], 0, 0);
}
d = c;
while (c == d && c < xlengths.length){
float u, v, x0, y0;
u = float(xlengths[a]);
v = float(ylengths[a]);
x0 = float(xpositions[a]);
y0 = float(ypositions[a]);
if (u != 1.0E-19){
//stroke(255,255,255);
//line(x0,y0,x0+u,y0+v);
PImage box;
box = get(int(x0-gs/2), int(y0 - gs/2), gs, gs);
image(box, x0-gs/2 +u, y0 - gs/2 +v, gs, gs);
if (a < xlengths.length - 1){
a += 1;
}
}
else if (u == 1.0E-19){
if (a < xlengths.length - 1){
c += 1;
a += 1;
}
}
}
}
}
Word to the wise: most people aren't going to read that wall of text. Try to "dumb down" your posts so they get to the details right away, without any extra information. You'll also be better off if you post an MCVE instead of only giving us half your code. Note that this does not mean posting your entire project. Instead, start over with a blank sketch and only create the most basic code required to show the problem. Don't include any of your movie logic, and hardcode as much as possible. We should be able to copy and paste your code onto our own machines to run it and see the problem.
All of that being said, I think I understand what you're asking.
How do I draw the motion of a particular frame without letting what I've have blitted to the screen in the previous frame affect what will be drawn for the next frame. My only way of getting my 10 by 10 pixel box is by using the get() function which gets pixels that are already drawn to the screen.
Separate your program into a view and a model. Right now you're using the screen (the view) to store all of your information, which is going to cause you headaches. Instead, store the state of your program into a set of variables (the model). For you, this might just be a bunch of PVector instances.
Let's say I have an ArrayList<PVector> that holds the current position of all of my vectors:
ArrayList<PVector> currentPositions = new ArrayList<PVector>();
void setup() {
size(500, 500);
for (int i = 0; i < 100; i++) {
currentPositions.add(new PVector(random(width), random(height)));
}
}
void draw(){
background(0);
for(PVector vector : currentPositions){
ellipse(vector.x, vector.y, 10, 10);
}
}
Notice that I'm just hardcoding their positions to be random. This is what your MCVE should do as well. And then in the draw() function, I'm simply drawing each vector. This is like drawing a single frame for you.
Now that we have that, we can create a nextFrame() function that moves the vectors based on the ArrayList (our model) and not what's drawn on the screen!
void nextFrame(){
for(PVector vector : currentPositions){
vector.x += random(-2, 2);
vector.y += random(-2, 2);
}
}
Again, I'm just hardcoding a random movement, but you would be reading these from your file. Then we just call the nextFrame() function as the last line in the draw() function:
If you're still having trouble, I highly recommend posting an MCVE similar to mine and posting a new question. Good luck.
I am working on a tool which distorts images, the purpose of the distortion is to project images to a sphere screen. The desired output is as the following image.
The code I use is as follow - for every Point(x, y) in the destination area, I calculate the corresponding pixel (sourceX, sourceY) in the original image to retrieve from.
But this approach is awkwardly slow, in my test, processing the sunset.jpg (800*600) requires more than 1500ms, if I remove the Mathematical/Trigonometrical calculations, calling cvGet2D and cvSet2D alone require more than 1200ms.
Is there a better way to do this? I am using Emgu CV (a .NET wrapper library for OpenCV) but examples in other language is also OK.
private static void DistortSingleImage()
{
System.Diagnostics.Stopwatch stopWatch = System.Diagnostics.Stopwatch.StartNew();
using (Image<Bgr, Byte> origImage = new Image<Bgr, Byte>("sunset.jpg"))
{
int frameH = origImage.Height;
using (Image<Bgr, Byte> distortImage = new Image<Bgr, Byte>(2 * frameH, 2 * frameH))
{
MCvScalar pixel;
for (int x = 0; x < 2 * frameH; x++)
{
for (int y = 0; y < 2 * frameH; y++)
{
if (x == frameH && y == frameH) continue;
int x1 = x - frameH;
int y1 = y - frameH;
if (x1 * x1 + y1 * y1 < frameH * frameH)
{
double radius = Math.Sqrt(x1 * x1 + y1 * y1);
double theta = Math.Acos(x1 / radius);
int sourceX = (int)(theta * (origImage.Width - 1) / Math.PI);
int sourceY = (int)radius;
pixel = CvInvoke.cvGet2D(origImage.Ptr, sourceY, sourceX);
CvInvoke.cvSet2D(distortImage, y, x, pixel);
}
}
}
distortImage.Save("Distort.jpg");
}
Console.WriteLine(stopWatch.ElapsedMilliseconds);
}
}
From my personal experience, I was doing some stereoscopic vision stuff, the best way to talk to openCV is through own wrapper, you could put your method in c++ and call it from c#, that would give you 1 call to native, faster code, and because under the hood Emgu's keeping OpenCV data, it's also possible to create an image with emgu, process it natively and enjoy processed image in c# again.
The get/set methods looks like Gdi's GetPixel / SetPixel ones, and, according to documentation they are "slow but safe way".
For staying with Emgu only, documentation tells that if you want to iterate over pixels, you should access .Data property:
The safe (slow) way
Suppose you are working on an Image. You can obtain the pixel on the y-th row and x-th column by calling
Bgr color = img[y, x];
Setting the pixel on the y-th row and x-th column is also simple
img[y,x] = color;
The fast way
The Image pixels values are stored in the Data property, a 3D array. Use this property if you need to iterate through the pixel values of the image.