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Raycast not capturing all Vector coordinates

I have a gameobject that occupies the whole screen just for testing purposes. I'm drawing a line btw. What I'm trying to achieve is if the mouse position hits a gameobject it will store the vector2 coordinates in a list. But raycast is not storing all the coordinates. Below is my code
private void Update()
{
if (Input.GetMouseButton(0))
{
Vector2 mousePos = Input.mousePosition;
Vector2 Pos = _camera.ScreenToWorldPoint(mousePos);
if(!mousePositions.Contains(Pos))
mousePositions.Add(Pos);
if (Physics.Raycast(Camera.main.ScreenPointToRay(mousePos), out RaycastHit hit))
{
Vector2 textureCoord = hit.textureCoord;
int pixelX = (int)(textureCoord.x * _templateDirtMask.width);
int pixelY = (int)(textureCoord.y * _templateDirtMask.height);
Vector2Int paintPixelPosition = new Vector2Int(pixelX, pixelY);
if (!linePositions.Contains(paintPixelPosition))
linePositions.Add(paintPixelPosition);
foreach (Vector2Int pos in linePositions)
{
int pixelXOffset = pos.x - (_brush.width / 2);
int pixelYOffset = pos.y - (_brush.height / 2);
for (int x = 0; x < _brush.width; x++)
{
for (int y = 0; y < _brush.height; y++)
{
_templateDirtMask.SetPixel(
pixelXOffset + x,
pixelYOffset + y,
Color.black
);
}
}
}
_templateDirtMask.Apply();
}
}
}
Everytime I checked the element count mousePositions are always greater than linePositions. I don't know what's causing this

the element count mousePositions are always greater than linePosition
well it is quite simple: In
int pixelX = (int)(textureCoord.x * _templateDirtMask.width);
int pixelY = (int)(textureCoord.y * _templateDirtMask.height);
you are casting to int and cut off any decimals after the comma (basically like doing Mathf.FloorToInt).
So you can totally have multiple mouse positions which result in float pixel positions like e.g.
1.2, 1.2
1.4, 1.7
1.02, 1.93
...
all these will map to
Vector2Int paintPixelPosition = new Vector2Int(1, 1);
Besides, you might want to look at some better line drawing algorithms like e.g. this simple one
And then note that calling SetPixel repeatedly is quite expensive. You want to do a single SetPixels call like e.g.
var pixels = _templateDirtMask.GetPixels();
foreach (Vector2Int pos in linePositions)
{
int pixelXOffset = pos.x - (_brush.width / 2);
int pixelYOffset = pos.y - (_brush.height / 2);
for (int x = 0; x < _brush.width; x++)
{
for (int y = 0; y < _brush.height; y++)
{
pixels[(pixelXOffset + x) + (pixelYOffset + y) * _templateDirtMask.width] = Color.black;
}
}
}
_templateDirtMask.SetPixels(pixels);
_templateDirtMask.Apply();

It happens because there is really could be a case, when several elements from mousePositions are associated with one elment from linePositions.
Rough example: your texture resolution is only 1x1px. In this case you linePositons will contain only one element. And this element will be associated with all elements from mosePositions.
So, relation of the number of elements in these lists depends on relation of your texture and screen resolutions.

Drawing Parabola using DrawLine C#

Good evening, I know on the web there are similar questions and a few tutorials about it, but I'd like you to check my code and correct it. I mean, I'd like to know what's wrong with my project.
I have to draw a parabola graph given its equation on my main panel.
I also must include two buttons, zoom in and zoom out, which are used to reduce and enlarge the "view" panel's view (and so the parabola).
I was recommended to use a scale var.
This is my code:
note: x0, y0 are panel_main x center, y center.
I have x, y that are used to determine x,y from the equation.
xpc, ypc are converted for the window scale (so are pixels).
xmin, xmax are the extreme values that, with a certain scale, stay on the panel
I hope you can give me a hint, thanks a lot!
public void DisegnaParabola()
{
Graphics gs = panel_main.CreateGraphics();
pen.Color = Color.Black;
scale = (x0*2) / zoom; //Pixels equivalent to 1x or 1y
n_punti = (x0*2) / scale; //Number of x math points that are visible in window
xmin = -(n_punti / 2);
xmax = n_punti / 2;
precision = 1 / scale; //Increment of x to have 1px
if (asse_parabola.SelectedIndex == 0) //if Y axis
{
for (double i = xmin + precision; i < xmax; i += precision)
{
rifx = i - precision; //Old points
rifxpc = rifx * scale;
rify = (a * Math.Pow(rifx, 2)) + b * rifx + c;
rifypc = y0 - (rify * scale);
x = i; //New points
y = (a * Math.Pow(x, 2)) + b * x + c;
ypc = y0 - (y * scale);
gs.DrawLine(pen, (float)rifxpc, (float)rifypc, (float)xpc, (float)ypc);
}
}
else
{
scale = (y0*2) / zoom; //Pixels for 1y
n_punti = (y0*2) / scale; //Numbers of y in the window
ymin = -(n_punti / 2);
ymax = n_punti / 2;
for(double i=ymin+precision; i<ymax; i+=precision)
{
rify = y - precision;
rifypc = (y0*2) - rify * scale;
rifx = (a * Math.Pow(rify, 2)) + b * rify + c;
rifxpc = x0 + (rifx * scale);
y = i;
x = (a * Math.Pow(y, 2)) + b * y + c;
xpc = x0 + (x * scale);
gs.DrawLine(pen, (float)rifypc, (float)rifxpc, (float)ypc, (float)xpc);
}
}
lbl_canc.Visible = true;
}

Your question actually consists of several tasks and as usual the key is to take and break those apart..
One issue is getting the data, I will leave the details to you but show how to sparate it from the rest.
The next issue is to scale the data. I'll show you how to avoid this one altogether and scale the drawing tool instead.
And the third one is to draw them to a display surface. As you'll see this is really simple once the other issues are taken care of.
Let's start with the most important step: Collecting the data. You try to create and scale and draw them all in the same piece of code. This has many disadvantages..
Let's first collect the data in a suitable structure:
List<PointF> points = new List<PointF>();
List<T> is the collection of choice most of the time; certainly much nicer than arrays! In some method you should fill that list with your data, calculated from some formula.
Here is an example:
List<PointF> getPoints(float start, float end, int count, float ymax)
{
List<PointF> points = new List<PointF>();
float deltaX = (end - start) / count;
for (int i = 0; i < count; i++)
{
float x = i * deltaX;
// insert your own formula(s) here!
float y = ymax + (float)Math.Sin(x * somefactor) * ymax;
points.Add(new PointF(x, y));
}
return points;
}
Now for the second important part: How to scale the data? This can be done either when creating them; but again, separating the two taks makes them both a lot simpler.
So here is a function that, instead of scaling the data scales the Graphics object we will use to plot them:
void ScaleGraphics(Graphics g, List<PointF> data)
{
float xmax = data.Select(x => x.X).Max();
float ymax = data.Select(x => x.Y).Max();
float xmin = data.Select(x => x.X).Min();
float ymin = data.Select(x => x.Y).Min();
float width = Math.Abs(xmax - xmin);
float height = Math.Abs(ymax - ymin);
var vr = g.VisibleClipBounds;
g.ScaleTransform(vr.Width / width, vr.Height / height);
}
This method makes sure that all the data in our list will fit into the drawing surface. If you want to restrict them to a different size you can pass it in and change the code accordingly..
Finally we need to do the actual drawing. We do that where we should, that is in the Paint event of our drawing surface control..:
private void panel1_Paint(object sender, PaintEventArgs e)
{
if (points.Count < 2) return; // no lines to draw, yet
ScaleGraphics(e.Graphics, points);
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
using ( Pen pen = new Pen(Color.Blue )
{ Width = 1.5f , LineJoin = LineJoin.Round, MiterLimit = 1f} )
e.Graphics.DrawLines(pen, points.ToArray());
}

C# DirectX Circle Drawing not working correctly

I've been trying to recode a C++ DirectX code to C# that would help me with Drawing a perfect circle. Currently I have this code that i translated by myself:
private void Circle(int X, int Y, int radius, int numSides, Color color)
{
Vector2[] Line = new Vector2[128];
float Step = (float)(Math.PI * 2.0 / numSides);
int Count = 0;
for (float a = 0; a < Math.PI * 2.0; a += Step)
{
float X1 = (float)(radius * Math.Cos(a) + X);
float Y1 = (float)(radius * Math.Sin(a) + Y);
float X2 = (float)(radius * Math.Cos(a + Step) + X);
float Y2 = (float)(radius * Math.Sin(a + Step) + Y);
Line[Count].X = X1;
Line[Count].Y = Y1;
Line[Count + 1].X = X2;
Line[Count + 1].Y = Y2;
Count += 2;
}
line.Begin();
line.Draw(Line, color);
line.End();
}
The problem is that the circle is drawn but also a Line from a point in the circle to the left top corner, like this.

Don't iterate with a floating point variable. They might get imprecise during the iteration. In your case, the last step is probably very close behind the upper bound (instead of hitting it exactly). So it won't get calculated and left as the default (0, 0).
So use an integer iteration variable:
for (int i = 0; i < numSides; ++i)
{
float a = i * Step;
...
}
Then, you can also get rid of Count.
Furthermore, you should make your coordinate buffer dynamic:
Vector2[] Line = new Vector2[2 * numSides];

Traverse Pixels in a circle from the center

I need an algorithm like Bresenham's circle algorithm, but with some modifications.
The algorithm must visit all pixels in the radius (so essentially a fill).
The algorithm must start from the center of the circle
It must visit all points that would normally be visited (no holes)
It must visit each point in the circle exactly once
One technique I came up with would first determine all pixel coordinates inside the circle by just going through the rectangle of the circle and checking with Math.Sqrt if it is inside the circle.
Then it would order the pixels by distance and then visit each of them.
That would be exactly what I want, with the exception of being fast.
So my questions is:
Is there a fast way to do this without fetching,ordering and then visiting each pixel?
Just for clarification I do not actually want to draw onto the image, I only want to traverse them in the described order.

First, we can use fact, that circle can be divided in 8 octants. So we just need to fill single octant and use simple +- coordinate change to get full circle. So if we try to fill only one octant, we need to worry only about 2 directions from center : left and left top. Also, clever use of data structures like priority queue (.NET doesn't have it, so you need to find it somewhere else) and hash map can drastically improve performance.
/// <summary>
/// Make sure it is structure.
/// </summary>
public struct Point
{
public int X { get; set; }
public int Y { get; set; }
public int DistanceSqrt()
{
return X * X + Y * Y;
}
}
/// <summary>
/// Points ordered by distance from center that are on "border" of the circle.
/// </summary>
public static PriorityQueue<Point> _pointsToAdd = new PriorityQueue<Point>();
/// <summary>
/// Set of pixels that were already added, so we don't visit single pixel twice. Could be replaced with 2D array of bools.
/// </summary>
public static HashSet<Point> _addedPoints = new HashSet<Point>();
public static List<Point> FillCircle(int radius)
{
List<Point> points = new List<Point>();
_pointsToAdd.Enqueue(new Point { X = 1, Y = 0 }, 1);
_pointsToAdd.Enqueue(new Point { X = 1, Y = 1 }, 2);
points.Add(new Point {X = 0, Y = 0});
while(true)
{
var point = _pointsToAdd.Dequeue();
_addedPoints.Remove(point);
if (point.X >= radius)
break;
points.Add(new Point() { X = -point.X, Y = point.Y });
points.Add(new Point() { X = point.Y, Y = point.X });
points.Add(new Point() { X = -point.Y, Y = -point.X });
points.Add(new Point() { X = point.X, Y = -point.Y });
// if the pixel is on border of octant, then add it only to even half of octants
bool isBorder = point.Y == 0 || point.X == point.Y;
if(!isBorder)
{
points.Add(new Point() {X = point.X, Y = point.Y});
points.Add(new Point() {X = -point.X, Y = -point.Y});
points.Add(new Point() {X = -point.Y, Y = point.X});
points.Add(new Point() {X = point.Y, Y = -point.X});
}
Point pointToLeft = new Point() {X = point.X + 1, Y = point.Y};
Point pointToLeftTop = new Point() {X = point.X + 1, Y = point.Y + 1};
if(_addedPoints.Add(pointToLeft))
{
// if it is first time adding this point
_pointsToAdd.Enqueue(pointToLeft, pointToLeft.DistanceSqrt());
}
if(_addedPoints.Add(pointToLeftTop))
{
// if it is first time adding this point
_pointsToAdd.Enqueue(pointToLeftTop, pointToLeftTop.DistanceSqrt());
}
}
return points;
}
I will leave the expansion to full list on you. Also make sure borders of the octants don't cause doubling of the points.
Ok, I couldn't handle it and did it myself. Also, to make sure it has properties you desire I did simple test :
var points = FillCircle(50);
bool hasDuplicates = points.Count != points.Distinct().Count();
bool isInOrder = points.Zip(points.Skip(1), (p1, p2) => p1.DistanceSqrt() <= p2.DistanceSqrt()).All(x => x);

I found a solution that satisfies my performance needs.
It's very simple, just a offset array.
static Point[] circleOffsets;
static int[] radiusToMaxIndex;
static void InitCircle(int radius)
{
List<Point> results = new List<Point>((radius * 2) * (radius * 2));
for (int y = -radius; y <= radius; y++)
for (int x = -radius; x <= radius; x++)
results.Add(new Point(x, y));
circleOffsets = results.OrderBy(p =>
{
int dx = p.X;
int dy = p.Y;
return dx * dx + dy * dy;
})
.TakeWhile(p =>
{
int dx = p.X;
int dy = p.Y;
var r = dx * dx + dy * dy;
return r < radius * radius;
})
.ToArray();
radiusToMaxIndex = new int[radius];
for (int r = 0; r < radius; r++)
radiusToMaxIndex[r] = FindLastIndexWithinDistance(circleOffsets, r);
}
static int FindLastIndexWithinDistance(Point[] offsets, int maxR)
{
int lastIndex = 0;
for (int i = 0; i < offsets.Length; i++)
{
var p = offsets[i];
int dx = p.X;
int dy = p.Y;
int r = dx * dx + dy * dy;
if (r > maxR * maxR)
{
return lastIndex + 1;
}
lastIndex = i;
}
return 0;
}
With this code you just get the index where to stop from radiusToMaxIndex, then loop through circleOffsets and visit those pixels.
It will cost lot of memory like this, but you can always change the datatype of the offsets from Point to a custom one with Bytes as members.
This solution is extremely fast, fast enough for my needs. It obviously has the drawback of using some memory, but lets be honest, instantiating a System.Windows.Form uses up more memory than this...

You have already mentioned Bresenhams's circle algorithm. That is a good starting point: You could start with the centre pixel and then draw Bresenham circles of increasing size.
The problem is that the Bresenham circle algorithm will miss pixels near the diagonals in a kind of Moiré effect. In another question, I have adopted the Bresenham algorithm for drawing between an inner and outer circle. With that algorithm as base, the strategy of drawing circles in a loop works.
Because the Bresenham algorithm can place pixels only at discrete integer coordinates, the order of visiting pixels will not be strictly in order of increasing distance. But the distance will always be within one pixel of the current circle you are drawing.
An implementation is below. That's in C, but it only uses scalars, so it shouldn't be hard to adapt to C#. The setPixel is what you do to each pixel when iterating.
void xLinePos(int x1, int x2, int y)
{
x1++;
while (x1 <= x2) setPixel(x1++, y);
}
void yLinePos(int x, int y1, int y2)
{
y1++;
while (y1 <= y2) setPixel(x, y1++);
}
void xLineNeg(int x1, int x2, int y)
{
x1--;
while (x1 >= x2) setPixel(x1--, y);
}
void yLineNeg(int x, int y1, int y2)
{
y1--;
while (y1 >= y2) setPixel(x, y1--);
}
void circle2(int xc, int yc, int inner, int outer)
{
int xo = outer;
int xi = inner;
int y = 0;
int erro = 1 - xo;
int erri = 1 - xi;
int patch = 0;
while (xo >= y) {
if (xi < y) {
xi = y;
patch = 1;
}
xLinePos(xc + xi, xc + xo, yc + y);
yLineNeg(xc + y, yc - xi, yc - xo);
xLineNeg(xc - xi, xc - xo, yc - y);
yLinePos(xc - y, yc + xi, yc + xo);
if (y) {
yLinePos(xc + y, yc + xi, yc + xo);
xLinePos(xc + xi, xc + xo, yc - y);
yLineNeg(xc - y, yc - xi, yc - xo);
xLineNeg(xc - xi, xc - xo, yc + y);
}
y++;
if (erro < 0) {
erro += 2 * y + 1;
} else {
xo--;
erro += 2 * (y - xo + 1);
}
if (y > inner) {
xi = y;
} else {
if (erri < 0) {
erri += 2 * y + 1;
} else {
xi--;
erri += 2 * (y - xi + 1);
}
}
}
if (patch) {
y--;
setPixel(xc + y, yc + y);
setPixel(xc + y, yc - y);
setPixel(xc - y, yc - y);
setPixel(xc - y, yc + y);
}
}
/*
* Scan pixels in circle in order of increasing distance
* from centre
*/
void scan(int xc, int yc, int r)
{
int i;
setPixel(xc, yc);
for (i = 0; i < r; i++) {
circle2(xc, yc, i, i + 1);
}
}
This code takes care of not visiting pixels that are in two octants by skipping coincident picels on alterante octants. (Edit: There was still abug in the original code, but it's fixed now by means of the ´patch` variable.)
There's also room for improvement: The inner circle is basically the outer circle of the previous iteration, so there's no point in calculating it twice; you could keep an array of the outer points of the previous circle.
The xLinePos functions are also a bit too complicated. There are never more than two pixels drawn in that function, usually only one.
If the roughness of the search order bothers you, you can run a more exact algorithm once at the beginning of the program, where you calculate a traversing order for all circles up to a reasonable maximum radius. You can then keep that data and use it for iterating all circles with smaller radii.

C# smooth object movement

I have all the necessary code to move and click the mouse via C# code, but I don't want to just set the mouse position to X and Y; that will look jerky. Instead, I want to have a smooth transition from point X1, Y1 to point X2, Y2 over Z seconds. Similar to keyframing.
I'm looking for a method similar to this:
public void TransitionMouse(int x, int y, double durationInSecs)
It will just smoothly move the mouse from its current position to x and y in durationInSecs seconds. I have a function called:
public void MoveMouse(int x, int y)
That moves the mouse to x, y immediately.
EDIT
Thanks for the help guys! Here's the finished, and tested, code:
[DllImport("user32.dll")]
static extern bool SetCursorPos(int X, int Y);
public void TransitionMouseTo(double x, double y, double durationSecs)
{
double frames = durationSecs*100;
PointF vector = new PointF();
PointF mousePos = Cursor.Position;
vector.X = (float)((x - mousePos.X) / frames);
vector.Y = (float)((y - mousePos.Y) / frames);
for (int i = 0; i < frames; i++)
{
SetCursorPos((int)(mousePos.X += vector.X), (int)(mousePos.Y += vector.Y));
Thread.Sleep((int)((durationSecs / frames) * 1000.0));
}
}

You could do this in several ways. One option would be to calculate the vector required to move the mouse every frame and apply it over the time period to the mouse position.
So, if we are at position 5,5 and want to move to 20,30 over 10 frames, our vector would be the following:
val = (target - start) / frames;
x = (20 - 5) / 10;
y = (30 - 5) / 10;
Vector = 1.5,2.5
Then, in your TransitionMouse method, you apply the vector to the mouse position slowly over whatever duration you wish, using the Thread.Sleep method to control the speed. The code might look like this:
public void TransitionMouseTo(int x, int y, int durationSecs)
{
int frames = 10;
PointF vector = new PointF();
vector.X = (x - Cursor.Position.X) / frames;
vector.Y = (y - Cursor.Position.Y) / frames;
for (int i = 0; i < frames; i++)
{
Point pos = Cursor.Position;
pos.X += vector.X;
pos.Y += vector.Y;
Cursor.Position = pos;
Thread.Sleep((durationSecs / frames) * 1000);
}
}
Another way of doing it would be to use Bresenhams algorithm to calculate all the points the mouse cursor will move through and then loop through each point and apply it to the cursor again using Thread.Sleep to keep the timing correct.
Steve

really depend on your definition of smooth, however most algorithm of "smooth" motion use spline to interpolate between 2 or more data points.
this could help
http://geekswithblogs.net/JuanDoNeblo/archive/2007/10/25/Data-Interpolation-with-SPLINE-in-Csharp.aspx