kevin_karplus's Recent Projects

mini health bar

Demo of a mini-health bar using costumes

cat with glasses

This is a demo of layers and centers of rotation, with glasses on top of the cat. Arrow keys move the cat, T turns it. space bar changes glasses. To do this program from the original costumes, you need to change the rotation centers.

Kevin's Health Bar

Single-sprite health bar using stamp. Intended for easy export to other projects.

Kevin's Health Bar

Single-sprite health bar using stamp. Intended for easy export to other projects.

School Pinball 1.4

This version 1.4 pinball now has comments using real comment blocks! space to launch holding down space will make the launch harder, unless you hold it down too long. left and right arrow to control flippers

display_scientific

Displaying numbers with string joins. This program has a single sprite called digit, which responds to messages print_number, and print_scientific. It uses two input variables, print_after_decimal and print_number, and one output variable, display_out. When print_number is broadcast, number in print_number is displayed as a string in display_out, with fixed point notation. This version can print up to 15 places to the right of the decimal point, controlled by print_after_decimal. When print_scientific is called, the number is displayed in "scientific" notation, with a power of 10 after the letter E (unless the exponent is 0, then the output is the same as print_decimal). After the call, print_number is 0. There is a simple test script on the stage: clicking on s broadcasts print_scientific, d broadcasts print_number, while space clears the display. The scripts are in a sprite to make them easier to move to another project, and to hide some local variables.

pi from area

This project estimates pi by comparing the area of a circle to the area of a square, dropping points randomly in a square to esitmate area. This is not an efficient way to compute pi, but it nicely illustrates random sampling.

mouse round-paddle pong

Use mouse to control paddle. Two points for every hit, 5 for each time you hit one of the two pins. Lose 10 points for each ball that falls through. When the ball gets moving fast, it can go trhough the pins or paddle. You can also move the paddle fast enough to hit the ball more than once.

Round-paddle pong

Use left and right arrow keys to control paddle. Two points for every hit, 5 for each time you hit one of the two pins. Lose 10 points for each ball that falls through.

testing_volume

This script plays 10 notes getting louder when up arrow is pressed, and 10 notes getting quieter when down arrow is pressed. It is here just to test the volume control.

Big sprite flashlight

Yet another flashlight that follows the mouse. Just click to turn it on. This one has a hole that lets you see the background, so it allows color! It uses an oversize sprite to make a one-sprite flashlight. This only works when downloaded, as it exploits a bug in the Squeak scratch player that allows oversize sprites. The Java scratch player scales the oversize sprites down until they fit on the stage, ruining the project.

print_scientific

Printing numbers with the stamp tool. This program has a single sprite called digit, which responds to messages print_number, and print_scientific. It uses four global variables: print_x, print_y, print_after_decimal, and print_number to communicate parameters. When print_number is broadcast, the digit sprite prints out the number by stamping the digits with the bottom right of the final number at print_x, print_y. This version can print up to 15 places to the right of the decimal point, controlled by print_after_decimal. When print_scientific is called, the number is printed in "scientific" notation, with a power of 10 after the letter E (unless the exponent is 0, then the output is the same as print_decimal). After the call, print_number is 0 and print_x is to the left of the printed number. print_y is unchanged. There is a simple test script on the stage: clicking on s broadcasts print_scientific, d broadcasts print_number, while space clears the display.

RPN_v2_calculator

This project is a simple reverse-Polish notation calculator. Input and computation is maintained to the precision of the floating-point numbers, but there is no scientific notation (powers of ten). for input or output. New version uses Scratch v1.2.1 trig and exponential functions, making the calculator simpler and faster.

testing_note_duration

This is a single-script project to see how badly off the note durations are. On my machine, they are about 5 to 15 msec too long, which is enough to mess up any sort of music translation.

Smooth Glide

This is a demo of smooth gliding. Clicking on the stage will make the arrow glide to the clicked point. The controls are dest_x, dest_y (set from mouse position) and total_glide_time. The gliding does not use acceleration and velocity information, so clicking again while the arrow is moving will behave as if the arrow had been motionless when you clicked. This version points instantly in the direction it is about to glide.