![](https://turtlespaces.org/wp-content/uploads/2021/08/rocket.png)
Rocket Orbit
This simple commented project allows for the introduction of 3D movements and shapes (the rocket procedure) including a basic introduction to repeat, the creation of turtle models and the use of premodel, an introduction to the orbit primitives and the use of a new worker (thread) for orbiting the camera!
TO rocket forward 70 down 90 ;these two commands orient the rocket better for use as ;a turtle model setfillcolor yellow ;yellow is a function that returns the value 13 ;it is a shortcut used for convenience in learning ;as is red, green, blue etc. cylinder 20 120 10 ;cylinder takes rollright 180 ;flip the turtle over to create the nose cone cone 20 50 10 lower 50 ;lower the turtle to create the 'nose' setfillcolor red icosphere 3 setfillcolor orange ra 50 + 120 ;ra is short for raise rr 180 ;rr is shorthand for rollright cutcone 20 30 30 10 ;move the turtle to the bottom of the rocket and ;create the tail up 90 bk 30.1 ;bk is short for back setfillcolor white repeat 2 [cylinderslice 40 5 20 10 rr 90] ;create the fins setfillcolor red dn 90 sl 10 bk 10 cylinder 10 10 10 ;sl is short for slideleft fd 20 cylinder 10 10 10 sr 20 ;fd is short for forward ;sr is short for slideright cylinder 10 10 10 bk 20 cylinder 10 10 10 ;create the jets END TO createmodel clearscreen ;cs is short for clearscreen begintag "rocketmodel ;tags are used to create turtle models ;among other uses. You can also use them to ;show or hide parts of the 'turtle track' rocket ;run the rocket procedure endtag ;close the tag newmodel "rocket "rocketmodel ;create a new model called 'rocket' based on the ;rocketmodel tag setmodel "rocket ;set the turtle's model to the rocket model clearscreen ;clear away the tagged model, leaving only the ;turtle END TO starfield :number hideturtle norender ;suspend rendering of the scene until we're done drawing the stars penup repeat :number [ home randomvectors randomfillcolor ;randomvectors orients the turtle randomly ;while randomfillcolor sets a random fill color forward 1000 + random 1000 ;move forward a random distance up 90 ;orient the turtle up in preparation of creating a spot ;because the spot is created around and below the turtle spot 10 + random 10 ;create a randomly-sized spot ] home showturtle render ;resume rendering END TO main reset ;resets turtleSpaces to a default state createmodel ;execute the createmodel procedure starfield 200 ;execute the starfield procedure, passing the parameter value 200 setmodelscale 0.5 ;decrease the size of the turtle model to half normal setpremodel [lt 90] ;inserts 'left 90' into the turtle track between the scene ;and the turtle model ('pre' the model) setfillcolor 14 ;sets the fillcolor to 14. Type 'showcolors' or 'sc' in the console ;to see a list of default colors. You can also definecolor your own! ico 50 ;create an icosphere (the planet) penup dropanchor ;set the 'anchor point', or the point the turtle 'orbits' around ;using the orbit commands, to the current turtle position pullout 80 ;pull away 80 turtle units from the anchor point snappy:newworker [forever [orbitleft 0.1]] ;tell snappy the camera turtle to create a new routine or thread ;that forever orbits around the scene to its left one tenth of ;a degree at a time make "rotation 0 ;define a container (variable) called 'rotation' ;and set it to 0. We're going to use it to keep track of the ;rotation of the rocket forever [ inc "rotation ;same as make "rotation :rotation + 1 ;there is also dec (decrement) setpremodel {"lt 90 "rollright :rotation % 360} ;curly braces indicate a 'softlist', a list that is evaluated ;at runtime. In this case, so that we can have a dynamic ;rotation value we pass to setpremodel ;% is shorthand for modulus orbitleft 1 ;orbit the rocket one degree to the left wait 1 ;wait one sixtieth of a second ] END