I making an Arduino-based X-Y laser cutter. I've built the mechanics for it and accomplished basic motion, but I am having trouble getting it to plot lines and curves. I eventually want to be able to convert SVG or Illustrator files to Gcode or have the Arduino interpret and plot them directly
A picture of my setup.
There are libraries like GRBL and Rstepper that provide 2-wire (step and direction) instructions based on Gcode. The problems is that I'm driving two stepper motors using ULN2003 chips, which use 4 wires to step through the phases of the motor.
Could I make either of these libraries work for 4-wire control?
If not, I will need to find another way to plot my designs.
How I'm currently thinking of making functions for SVG or G-code style instructions.
//given a new position to go to and how we want to get there (i.e. curves)
for (i=0;xposition!==newx;i++) //run until x gets to the right spot
{
//get the values for X, Y, NewX, NewY, and any other parameters (e.g. for curves)
//figure out how many steps (say, +1 or -1) x should take for cycle number i
//figure out how many steps y should move given new x
//make the x stepper step the right number of steps
//make the y stepper step the right number of steps
//delay (control speed for adequate laser burning & don't make the steppers angry)
}
Will that be too slow?
Having been down this road and wasted much time, I would strongly suggest that you just get a couple of Easy Drivers for $15-$20 ea. and move on with your project using GRBL. It is a great library and there is a nice Java-based open source laser cutter front end project called Visicut. Visicut can handle either SVG files or gcode.
If you must use the chips you have, the Connecting Grbl pages lists this site Driving stepper motor using ULN2003 but cautions: "It is out-dated and uses Grbl v0.7."
(But seriously, hardware choices because "that is what one has" rather than what might be easier to implement can really suck the joy out of a fun hacker project like you have going)
I might be late, but there are a few modified versions of GRBL that support unipolars now. Here are the links:
https://github.com/TGit-Tech/GRBL-28byj-48
https://github.com/ruizivo/GRBL-28byj-48-Servo (this one didn't work when I tried it but it might work on your setup)
Note that in my testing the x/y axis invert messed everything up. It might be because I'm using a coreXY setup though.
Related
I have a new project but I'm really not sure where to start, other than I think GNAT Ada would be good. I taught myself Ada three years ago and I have managed some static graphics with GNAT but this is different.
Please bear with me, all I need is a pointer or two towards where I might start, I'm not asking for a solution. My history is in back-end languages that are now mostly obsolete, so graphics is still a bit of a challenge.
So, the project:
With a static background image (a photograph) - and a moveable line with an adjustable cursor somewhere between the ends of the line. I need to rotate the line and adjust the length, as well as to move it around the screen and slide the cursor along the line; I have no problem calculating the positions of each element of the line. Once in place, I need to report on the position of the cursor relative to the overall length of the line. I can probably handle the reporting with what I already know but I have no clue as to how to create a graphic that I can slide around over another image. In the past I have failed to detect mouse events in GNAT Ada and I am sure I will need to get on top of that - in fact if I could, I would probably manage to control the line but doing it over an existing image is beyond me.
If I am wrong to choose GNAT Ada for this, please suggest an alternative.
I have looked in Stackoverflow for anything similar but have found answers only for Blackberry and Java, neither of which seems relevant.
For background, this will be a useful means of measuring relative lengths of the features of insect bodies from photographs, hopefully to set up some definitive identification guides for closely-related species.
With a static background image (a photograph)
So first you need a window to put your interface in. You can get this from any GUI framework (link as given by trashgod in the comments).
and a moveable line with an adjustable cursor somewhere between the ends of the line. I need to rotate the line and adjust the length, as well as to move it around the screen and slide the cursor along the line; I have no problem calculating the positions of each element of the line.
These are affine transformations. They are commonly employed in low-level graphics rendering. You can, like Zerte suggested, employ OpenGL – however modern OpenGL has a steep learning curve for beginners.
GtkAda includes a binding to the Cairo graphics library which supports such transformations, so you can create a window with GtkAda with a Cairo surface and then render your image & line on it. Cairo does have a learning curve and I never used the Ada binding, so I cannot really give an opinion about how complex this will be.
Another library that fully supports what you want to do is SDL which has Ada bindings here. The difference to GtkAda is that SDL is a pure graphics drawing library so you need to „draw“ any interactive controls yourself. On the other hand, setting up a window via SDL and drawing things will be somewhat simpler than doing it via GtkAda & Cairo.
SFML which has also been mentioned in comments is on the same level as SDL. I do not know it well enough to give a more informed opinion but what I said about SDL will most probably also apply to SFML.
In the past I have failed to detect mouse events in GNAT Ada and I am sure I will need to get on top of that - in fact if I could, I would probably manage to control the line but doing it over an existing image is beyond me.
HID event processing is handled by whatever GUI library you use. If you use SDL, you'll get mouse events from SDL; if you use GTK, you'll get mouse events from GTK, and so on.
I started Python a couple of weeks ago and I’d like to write a program that would be useful to myself.
I play a game that displays the in game X and Y (which is not the same as the screen X and Y)
I believe I know what to do but don’t know ‘how’ to do it.
I want to be able to type in X and Y coordinates and have the mouse direct me to said spot, I imagine I’d need a memory address of the in game coords and if statements to compare the user input to the current one in memory then move mouse and click in the appropriate direction?
Could someone provide an example that I can study or guide me to something made for this purpose?
Many thanks!
This can be done using pynput, a cross-platform python module that can set the mouse position, as well as checking what it is at any given time. Examples are on the other side of the link.
I am developing on a linux system using latest (at the moment) SDL2 (2.0.8) + openGL ES 2.0 (GLSL 1.0) eventually targeting a raspberry pi 3 board. I have so far done a few things like drawing text with freetype, drawing lines, text boxes (editable), text lists, waveform boxes (all i need to pass to a function is an array of vertices) and other shapes with glDrawArrays(). Now, there are things that need to be refreshed at, let's say, 10 times per sec and others that need 1 time per second. What would be the best approach to skip re-rendering everything at the rate of 10 times per sec? Because obviously openGL works by drawing everything from scratch on every 'frame'. However i know and you know that other approaches exist that include: rendering on top of the screen you already have or taking a screenshot and rendering on top of it only the fast changing things as well as other solutions. What do you thing would be the best approach to skip re-doing everything before calling SDL_GL_SwapWindow() ? How can i take a screen shot and render it on the invisible buffer then render only the fast changing objects and then call SDL_GL_SwapWindow() ?
This is a screen shot of the app so far drawing basic things
Thanks in advance.
i eventually had to realize that i should not have posted the question in the first place but since this is a place where people learn from others i now feel somewhat nicer :) . So, the thing i had to do was to simply stop clearing the invisible buffer (i will call it that for simplicity) and render on top of it only controls that change. Those that change are updated by covering the area that they take by a rectangle and then draw new stuff on that area. I have already done it and the frame rate just 'exploded'. I do not really think that there is a better approach since the way i do it requires no action at all. All i had to do was to add a few if conditions that selectively rendered or skipped every time the execution reached the point where functions iterate through the controls that have to be drawn on screen and therefore decide what to render and what not. However a well thought set of structures is required for every control instead of declaring and defining endlessly global variables which will only makes things confusing and difficult to maintain.
Regards to all.
I've been studying 3D graphics on my own for a while now and I want to get a greater understanding of just how everything works. What I would like to do is to create a simple game without using DirectX or OpenGL. I understand most of the math I believe, but the problem I am running up against is I do not know how to get control of the pixels being displayed in a window.
How do I specify what color I want each pixel in my window to be?
I understand I will probably run into issues with buffers and image shearing and probably terrible efficiency problems, but I want to create my own program so that I could see from the very lowest level, of the high level language, how the rendering process works. I really have no idea where to start though. I've figured out how to output BMPs, but I would like to have a running program spitting out 20+ frames per second. How do I accomplish this?
You could pick a environment that allows you to fill an array with values for pixels and display it as a bitmap. This way you come closest to poking RGB values in video memory. WPF, Silverlight, HTML5/Javascript can do this. If you do not make it full screen these technologies should suffice for now.
In WPF and Silverlight, use the WriteableBitmap.
In HTML5, use the canvas
Then it is up to you to implement the logic to draw lines, circles, bezier curves, 3D projections.
This is a lot of fun and you will learn a lot.
I'm reading between the lines that you're more interested in having full control over the rendering process from a low level, rather than having a specific interest in how to achieve that on one specific platform.
If that's the case then you will probably get a good bang for your buck looking at a library like SDL which provides you with a frame buffer that you can render to directly but abstracts away a lot of the platform specifics issues. It has been around for quite a while and there are some good tutorials to give you an idea of whether it's the kind of thing you're looking for - see this tutorial and the subsequent one in the same series, which should be enough to get you up and running.
You say you want to create some kind of a rendering engine, meaning desinging you own Pipeline and matrice classes. Which you are to use to transform 3D coordinates to 2D points.
When you have got the 2D points you've been looking for. You can use say for instance on windows, you can select a brush and draw you triangle values while coloring them at the same time.
I do not know why you would need Bitmaps, but if you want to practice say Texturing you can also do that yourself although off course on a weak computer this might take your frames per second significantly.
If you aim is to understand how rendering works on the lowest level. This is with no doubt a good practice.
Jt Schwinschwiga
I'm working on a game in XNA for Xbox 360. The game has 3D terrain with a collection of static objects that are connected by a graph of links. I want to draw the links connecting the objects as lines projected on to the terrain. I also want to be able to change the colors etc. of links as players move their selection around, though I don't need the links to move. However, I'm running into issues making this work correctly and efficiently.
Some ideas I've had are:
1) Render quads to a separate render target, and use the texture as an overlay on top of the terrain. I currently have this working, generating the texture only for the area currently visible to the camera to minimize aliasing. However, I'm still getting aliasing issues -- the lines look jaggy, and the game chugs frequently when moving the camera EDIT: it chugs all the time, I just don't have a frame rate counter on Xbox so I only notice it when things move.
2) Bake the lines into a texture ahead of time. This could increase performance, but makes the aliasing issue worse. Also, it doesn't let me dynamically change the properties of the lines without much munging.
3) Make geometry that matches the shape of the terrain by tessellating the line-quads over the terrain. This option seems like it could help, but I'm unsure if I should spend time trying it out if there's an easier way.
Is there some magical way to do this that I haven't thought of? Is one of these paths the best when done correctly?
Your 1) is a fairly good solution. You can reduce the jagginess by filtering -- first, make sure to use bilinear sampling when using the overlay. Then, try blurring the overlay after drawing it but before using it; if you choose a proper filter, it will remove the aliasing.
If it's taking too much time to render the overlay, try reducing its resolution. Without the antialiasing filter, that would just make it jaggier, but with a good filter, it might even look better.
I don't know why the game would chug only when moving the camera. Remember, you should have a separate camera for the overlay -- orthogonal, and pointing down onto the terrain.
Does XNA have a shadowing library? If so, yo could just pretend the lines are shadows.