I'm working on a simple "3D engine". I have studied a lot and everything till now is fine. But, there is a problem I haven't solved yet. How to determine which solid to draw first and which last. The solids more far from the camera should be drawn first, the solids near, last. But this is difficult to be implemented in code. I tried different ways. The first was calculating the distance from the camera to the center of the solid and compare all values. It works partially. But, for example, if you have a large solid near, and a small one back of this, the small one will be drawn last because it's center is near than the center of the large one... This is an error... Take a look to the attached picture... Thanks. I want to sort the solids in order to get the correct drawing order. Thanks for any help!
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I am trying to draw a concave circle, e.g. something like a soup bowl to form the "pips" on a die in a Yahtzee like program I am working on using C#.
It seems to me that in graphics "concave" has a different, and quite complex, meaning to what I am trying to achieve - the opposite of convex.
I can draw quite a realistic ball using a PathGradientBrush with white at a position one third of the way across and one third down and SurroundColors of the ball colour and I had hoped by moving the white spot to two thirds across and down I might get what I want but sadly not.
Can anybody give me a steer please? Even a pointer to what might be better search term would be a good start.
Many thanks.
enter image description here
My goal is to take the image above and "open" it along the center so that the 9 black doublets are in a straight line rather than in a circle. I have tried using the cv2.toPolar() function in OpenCV but the image is quite distorted, as can be seen below:
enter image description here
I am attempting to try a different approach now. From the center, I would like to access each of the doublet individually, like a pizza slice, and place them side by side
Initially I was thinking of slicing each doublet using two lines from the center of the image to the mid point between the doublets on either side.
My question is: how can I draw contours from the center of the image to the edge of the image, passing through the mid point between any two doublet. If I can draw one, I know that the angle between any two such consecutive contour is 40 degrees.
Any help is greatly appreciated!
I noted a few problems here:
The toPolar() conversion might have been around the center of the image file, but it is not the center of the object. This causes part of the distortion. If you share your code, I could try playing with the code and improving it.
2.The object is somewhat elliptical, not circular. This means you will still have a wave after correcting the above problem.
If you don't mind a semi-automatic solution, you could use OpenCV mouse events to specify the first line and let the program use the 40 degree angle to calculate the rest.
<------This is an image I made in Photoshop...
It's basically a 160 x 160 box of white with a texture applied.
Below is what it looks like with "background-repeat" in the CSS. I was hoping it'd balance out. Is there a certain percentage the textile has to be at, or size of the original box? For it to be a perfect repeatable texture?
Im trying to do this myself, since I cant find grid patterns that fit the style.
Question: Whats the trick on making textures in Photoshop, that appear as balanced whole backgrounds when repeated?
If you look at the below image where it's in effect, on the very basic start of what Im working on, you can notice it doesnt quite fit together.
Any and all help greatly appreciated. Thanks in advance.
If you want that background for a webpage is better the use of repeating-linear-gradient. It is very easy of implement, less assets to download and it is supported by major browsers.
Look in the top left corner of your image. You'll note that the dark line starts at roughly 4-5 pixels from the top. Then look at the top right corner, and you'll note that the top line starts at just perhaps 2px from the top.
When this image is repeated twice side by side, there will be a disconnect. Just crop the image and shave off the two or three pixels until your lines connect. Repeat by cropping the bottom of the image for vertical alignment.
If you want to do this experimentally, increase the size of your canvas, and copy the pattern into a new 160x160 layer. Place them side by side, and then move the layers one pixel at a time so that they overlap. Where the overlap aligns is where you should crop the image.
I'm building a 2D game where player can only see things that are not blocked by other objects. Consider this example on how it looks now:
I've implemented raytracing algorithm for this and it seems to work just fine (I've reduced the boundaries for demo to make all edges visible).
As you can see, lighter area is built with a bunch of triangles, each of them having common point in the position of player. Each two neighbours have two common points.
However I'm willing to calculate bounds for external the part of the polygon to fill it with black-colored triangles "hiding" what player cannot see.
One way to do it is to "mask" the black rectangle with current polygon, but I'm afraid it's very ineffective.
Any ideas about an effective algorithm to achieve this?
Thanks!
A non-analytical, rough solution.
Cast rays with gradually increasing polar angle
Record when a ray first hits an object (and the point where it hits)
Keep going until it no longer hits the same object (and record where it previously hits)
Using the two recorded points, construct a trapezoid that extends to infinity (or wherever)
Caveats:
Doesn't work too well with concavities - need to include all points in-between as well. May need Delaunay triangulation etc... messy!
May need extra states to account for objects tucked in behind each other.
I would like to identify the center of an SVG, so that I can manipulate multiple SVGs with ease.
I am trying to make multiple examples of the basic polygons (3 to 8 sides), and quickly realized that I either hade to make my own, which involves a lot of math, or I could pull from wikipedia the current ones. The problem with the former is that it takes a lot of time to translate the coordinates from Sketchup. The problem with the latter is that they are oriented differently and of different size.
I know that you can transform, scale, and rotate the SVG, but I need to know the coordinates of the center of the SVG. How do I find this out, so I can set universal manipulations?
Take the transform="rotate(degrees x y)", I need to know the center to accomplish this.
JS Fiddle
Here, I would like to set all the centers to the same, and then scale them to the same height and width, and potentially rotate them individually so that they all have a flat bottom, not a vertex.
The generic answer to your question isn't obvious...
It might be simpler for polygons, particularly convex polygons: you can iterate on the path and find its bounding box by computing the max and min of the x and y coordinates of each point of the path.
Then you can decide that the center of the shape is the center of the of the bounding box.
An alternative is to put an invisible element at what you estimate to be the center (for complex shapes, the concept of "center" can be variable), and get its coordinates to find out where the center is. Particularly for rotating purpose: you might want to do this rotation around a specific point which might not be the geometrical center.