Version 10 of a little hail storm

Arjen Markus (10 july 2003) A very quick script to make procedures work independently, to simulate the concept of sprites. Well, I was lazy and there is only one procedure that moves coloured balls around, but it is invoked for each ball separately in a way that is outside the flow of the script itself.

You will enjoy turning this into independent agents in a game :)

If you want Brownian movement: see the comments

 # A quick attempt at independently called procs
 # - let us call them sprites
 #
 proc mkSprite { colour speed } {
    global speed_data
    set id [.c create oval 0 0 10 10 -fill $colour]
    set speed_data($id) $speed
    moveSprite $id
 }
 proc moveSprite { id } {
    global speed_data
    set speed $speed_data($id)
    set coords [.c coords $id]
    .c move $id [expr {rand()*$speed}] [expr {rand()*$speed}]

    # 
    # Use this one for Brownian movement 
    #
    # .c move $id [expr {(rand()-0.5)*$speed}] [expr {(rand()-0.5)*$speed}]
    #

    if { [lindex $coords 0] <   0 } {
       .c move $id  200 0
    }
    if { [lindex $coords 1] <   0 } {
       .c move $id 0  200
    }
    if { [lindex $coords 2] > 200 } {
       .c move $id -200 0
    }
    if { [lindex $coords 3] > 200 } {
       .c move $id 0 -200
    }
    after 10 [list moveSprite $id]
 }

 canvas .c -width 200 -height 200 -background white
 pack   .c -fill both
 foreach {colour speed} {red 10  green 20  blue 3} {
    mkSprite $colour $speed
 }

test of offsite image retrieval

Screenshots Section

figure 1.

Sumerian Circular Segment Coefficients and Calculator Demo Example geometry grid

figure 2.

Sumerian Circular Segment Coefficients and Calculator Demo Example geometry grid

Arts and Crafts of Tcl-Tk Programming