This week we did some basic modelling in Blender. Blender is a very powerful 3D graphics package that is free and open-source. It is supported across all major desktop platforms.
Blender is so large and fully featured that it can be quite intimidating to learn. Knowledge of a few shortcut keys for common operations can really improve the experience of working with the program. We were indebted to Giuliano D’Angelo’s wonderful Blender shortcut infographic for providing us with some quick reference in this regard:
Moving About and Zooming
The first thing we covered in Blender was moving about. Practically speaking, Blender requires a three button mouse to operate. In Blender the middle mouse button (MMB) is used to control the view. Used on its own, it tilts the camera. When used with the SHIFT key, it pans the camera instead. CTRL and the MMB are use to zoom, but this is also more often achieved by scrolling the mouse wheel.
Object Mode and Edit Mode
We used Blender in two modes: Object Mode and Edit Mode. The TAB key can be used to switch between these. In Object Mode we can create, select and reposition objects but we cannot do any detailed editing on them. In Edit Mode, we can do any detailed editing we require on the currently selected object. Note that selecting items in Blender is done with the right mouse button (RMB).
Hi everybody, this week we changed from preprogrammed automated robots to remote-controlled robots. We converted our simple Pygame script from last week which controlled a small rectangle on our screens so it could control our robots.
As Pygame needs a screen to operate we had to get VNC going before we could start, I think we had it working for most people by the time the session ended. VNC will be a hugh advantage to us as we start to write more code as we can use a mouse and copy and paste with a GUI text editor instead of Nano on Putty.
We also added a webcam to our robots which worked well, we would probably need to work on mounting them properly if we wanted to use them for real life applications.
Here is a video of them in action.
I will go over the code again next week, if you want to take a look at the code check out pygame_robot.py and robot_cam.py here.
We will leave robots for a while and go back to basic electronics for the next few weeks.
This time we did our work online using the awesome website “codepen” rather than a local text editor. This website is a place for web developers to play with web code and share it with others. Using it allowed us to work without getting bogged down with install problems on people’s PCs. It is great for smaller sketches, but if you want to develop something really big like a complex game it will be much easier to use a local text editor like we did last week. If you get a chance and have an email address (or your parent has one), sign up for a codepen account. This will allow you to create and share your own sketches – I’ll link any and all of them on the coderdojo athenry website!
Today we basically just fooled around with it and tried to draw our own picture just with code. We mostly drew robots as they are fairly easy to draw with rectangles and ellipses!
What we covered:
- We watched the neat introduction video from the authors of p5: http://hello.p5js.org/
- We looked at the P5 reference page which has great instructions and examples for all P5 functions: https://p5js.org/reference/. Every good library you ever use will have a similar reference page – this is a great example of one.
- Similar to how scratch has blocks in different categories (sound, movement, control, etc), p5 groups all its functions into different categories – color, maths, shape, sound, etc.
- The canvas, resizing and changing the color using the createCanvas function
- Using colours in P5 – We used the following functions to set colours:
- background: to set the background color
- fill: to set the fill color
- stroke: to set the line color
- In all cases, colors can be either:
- one number in which case it’s a shade of grey from 0 (black) to 255 (white) e.g. background (0) sets the background to black.
- three numbers separated by commas, in which case each colour is a shade of RED, GREEN and BLUE – e.g. background(255, 0,0) sets the background to red, background(255, 255, 0) mixes red and green to make yellow. You can make every colour by mixing red, green and blue!
- four numbers separated by commas, in which case it is RED, GREEN, BLUE, TRANSPARENCY. e.g. fill(0,0,255, 100) will make any shape you draw see-through shade of blue. This is like the ghost effect in scratch.
- Some drawing functions in P5:
- strokeWeight to set how thick the lines are – e.g. strokeWeight(10) gives thick lines
- point to draw a point e.g. point(100, 100) draws a point at 100, 100.
- line to draw a line e.g. line(0,0,200, 150) draws a line from 0, 0 to 200, 150.
- rect to draw a rectangle – e.g. rect(0,0, 100, 100) will draw a square 100 wide, 100 high at point 0,0.
- ellipse to draw an ellipse – e.g. ellipse(0,0, 100, 100) will draw an ellipse 100 wide, 100 high (i.e. a circle) at point 0,0.
- triangle to draw a triangle – e.g. triangle(0,0, 100, 100, 200, 200) will draw a triangle between (0,0), (100, 100) and (200, 200).
- One other function we used was random. This can be used in a few ways, but the way we used was to give it one number, in which case it picked a random number between 0 and that number. E.g. random(255) picks a random number from 0 to 255. So fill(random(255)) will set the fill to a random shade of grey.
We played about with the all the above to draw a (pretty poor) robot with flashing eyes that fires lasers – the sketch we did is below. Play around with this and build on it to do something cooler!!
Sorry for the delay in posting, I’ve been very busy this week. Last Saturday we started the session by testing our robots on an obstacle course. Here is a video of them in action.
Then we had a quick look at Pygame which we will use to control our robots this week. If you missed last week don’t worry as I will do a recap tomorrow. Meanwhile here is a very good Pygame tutorial. Here are my slides from last week pygame-101.
This week we worked on random pin placement for our game. We updated the existing PinManager component to randomly (as opposed to regularly) place a number of pins into the scene.
An array is a way for a variable to hold more than one value. It’s a a very useful concept in programming; complex programs would be practically impossible without them. In C# arrays are declared as follows:
int nums = new int;
bool[,] grid = new bool[rows, cols];
The first line creates a one-dimensional array called nums which has four entries: nums, nums, nums and nums.
The second line creates a two-dimensional array called grid. Note the size in this case depends on the values of the variables rows and cols. The first entry is grid[0,0] and the last is grid[rows – 1, cols – 1]. The total number of locations in this array is rows * cols.
Good to see you back after the Halloween break.
Last Saturday we did a slightly different game to usual., There was no movement, no sensing when something happened. It was a Maths Game, a guessing game where the computer picks a random number and we had to guess the number.
We had to first make sure that a random number was picked using an Operator. Previously we have used a Variable to store a Score or Lives, but this time it was storing the random number and our guesses. Leaving them on screen as we were testing allowed us to understand more about the variable and what it does…it also made the testing a little easier.
Depending how any guesses we were given we repeated our code that number of times. As well as having to make decisions, i.e If_then, we also had to do a comparison before making the decision, to determine whether the guess was correct, too low or too high.
Some of you tried to add a timer and below is the code you will need if you didn’t get it to work. Take a look and add it to your own game/games.
Here is a link to last weeks notes. cda-s6-week_06-guessnumbers.pdf
See you next week!
This week we tried something different with some text based coding. We learned that for text based coding, we need a good text editor. The text editor we picked was called “Atom” as it’s a free, powerful text editor that works on Mac, Linux and Windows.
Unfortunately.. with some network and pc problems.. it took longer than I hoped to get things installed on people’s PCs, but even then we managed to make a great start on some code and actually built some quite cool stuff.
For anyone that missed last week.. it would be great if you could run through the steps below and we will be ready for the next stage!