Ron Jeffries Space Invaders retro on Codea

Bri_G

@RonJeffries - been following your series on the development of both Asteroids and Space Invaders, both responsible for lost time in my ‘youth’. I am currently struggling to get anywhere near my old proficiency with your current generation (64), which I have put down to rheumatism, partial blindness, the control system (tilting) or the gradual dementia that seems to be taking over me. Then again - I looked at images of the the original (YouTube) and an image of your latest generation (64) and your alien rows seem to be a row lower - eyes again? Or just wishful thinking?

Images attached.

P.s. tried to email this to you from my folders but struggled to post anything!!! Hence the thread.

dave1707

@RonJeffries I verified @Bri_G comment. In the original game, the bottom of the bottom row is approx 4 1/2 times the height of the shields from the bottom of the shields. In your game, the distance is approx 3 1/2 times the shield height. That’s based on the 2 images Bri-G posted.

dave1707

@RonJeffries I scaled and overlayed the 2 images from @Bri_G to show the difference. See the image below.

RonJeffries

good info. i thought i got that height from the original code. easy enough to move them up, i'll do that next update, thanks!

timber

@RonJeffries thanks for the detailed series on developing and optimizing code, there is definitely more than three of us out there, so please keep up this engaging series. Although its the code and process that is most interesting - I'd be lying if I said I didn't enjoy the games. Were you aware that if you should be successful in destroying all the invaders, the screen just freezes with the last invader on screen and the missile about to hit it, no explosion, it just freezes.

RonJeffries

didn't know that, but not surprised it does something weird, i've not dealt with killing the whole rack. maybe tomorrow. today i'm moving invaders up and centralizing constant, but can't publish until me new mac keyboard arrives.

i'm glad you find the articles and game amusing!

thanks!

dave1707

@RonJeffries Played your latest invaders and noticed that when the invaders get to the bottom of the screen, they just pass thru the player. Shouldn’t they destroy the player. Otherwise, they just keep marching off the bottom of the screen and the game never ends. I just kept shooting the saucers racking up points until I just closed the game.

RonJeffries

yes, feature not done yet. i think as soon as they bottom you die w/o being touched. need to do multi racks, too. inch by inch. the idea is to improve bit by bit.

Bri_G

@RonJeffries - just loaded your version 68 and it’s much more like the old days.

One thing - wanted to run in FULLSCREEN_NO_BUTTONS mode so tried the following code one Gamerunner tab:

if lives == 0 then
        textMode(CENTER)
        text("GAME OVER", 112, 32)
        if Runner == true and lives == 0 then viewer.mode = OVERLAY end

This was intended to run in game mode as FULLSCREEN_NO_BUTTONS and switched to OVERLAY when you get down to zero lives, but - it started out with another game. Thought you might implement this when you finish (may need a new game button) your development (only a mod that does work - always risky trying to edit someone else’s code).

RonJeffries

Thanks, I understand ...

dave1707

@RonJeffries Read your latest article. Here’s a great circle calculation.

viewer.mode=STANDARD

-- great circle distance between 2 points

function setup() 
    fill(255)
    parameter.text("latitude1",0) 
    parameter.text("longitude1",0)
    parameter.text("latitude2",0)
    parameter.text("longitude2",0) 
    kilometers,miles=0,0
end

function draw()
    background(0)  
    text("Tap screen to calc",WIDTH/2,HEIGHT-100)
    text("Latitude 1... "..latitude1,WIDTH/2-100,HEIGHT/2+100)
    text("Longitude 1... "..longitude1,WIDTH/2+100,HEIGHT/2+100)
    text("Latitude 2... "..latitude2,WIDTH/2-100,HEIGHT/2-100)
    text("Longitude 2... "..longitude2,WIDTH/2+100,HEIGHT/2-100)
    text("kilometers  "..kilometers,WIDTH/2,HEIGHT/2-25)
    text("miles  "..miles,WIDTH/2,HEIGHT/2+25)
end

function touched(t)
    if t.state==BEGAN then
        output.clear()
        calc()
    end
end

function calc()
    rad=0.01745329252
    lat1=latitude1*rad or 0
    lat2=latitude2*rad or 0
    long1=longitude1*rad or 0
    long2=longitude2*rad or 0
    dx=(lat2-lat1)/2
    dy=(long2-long1)/2
    a=math.sin(dx)^2+math.cos(lat1)*math.cos(lat2)*math.sin(dy)^2
    kilometers=12745.6*math.asin(math.sqrt(a))
    miles=7919.8*math.asin(math.sqrt(a))
end

RonJeffries

thanks ... that was in 1961, so your help's a bit late ...

dave1707

@RonJeffries I always like something new to code. Any excuse is OK with me. I still have more to do with it. That was mostly just to make sure the calculations were correct.

Bri_G

@RonJeffries - ah but can @dave1707 get into SAC now?

dave1707

Here the finished code for the great circle calculator.

viewer.mode=FULLSCREEN

-- great circle distance between 2 points

function setup() 
    rectMode(CENTER)
    fill(255)
    kilometers,miles=0,0    
    str=""
    val=""
    buttonTab={}
    table.insert(buttonTab,buttons(WIDTH/2-100,HEIGHT-140,150,50,"Latitude 1","i"))
    table.insert(buttonTab,buttons(WIDTH/2+100,HEIGHT-140,150,50,"Longitude 1","i"))
    table.insert(buttonTab,buttons(WIDTH/2-100,HEIGHT-390,150,50,"Latitude 2","i"))
    table.insert(buttonTab,buttons(WIDTH/2+100,HEIGHT-390,150,50,"Longitude2","i"))
    table.insert(buttonTab,buttons(WIDTH/2,HEIGHT-220,200,50,"Statute Miles","o"))
    table.insert(buttonTab,buttons(WIDTH/2,HEIGHT-310,200,50,"Kilometers","o"))
end

function draw()
    background(224, 198, 136)  
    fontSize(20)
    for a,b in pairs(buttonTab) do
        b:draw()        
    end
    calc()
    fill(87, 88, 231)
    fontSize(30)
    text("Great Circle distance between two points",WIDTH/2,HEIGHT-30)
    text("tap lat / long boxes and input values",WIDTH/2,HEIGHT-60)
end

function touched(t)
    for a,b in pairs(buttonTab) do
        b:touched(t)
    end
end

function calc()
    rad=0.01745329252
    lat1=(tonumber(buttonTab[1].val) or 0)*rad
    long1=(tonumber(buttonTab[2].val) or 0)*rad
    lat2=(tonumber(buttonTab[3].val) or 0)*rad
    long2=(tonumber(buttonTab[4].val) or 0)*rad
    dx=(lat2-lat1)/2
    dy=(long2-long1)/2
    a=math.sin(dx)^2+math.cos(lat1)*math.cos(lat2)*math.sin(dy)^2
    buttonTab[5].val=7919.8*math.asin(math.sqrt(a))     -- miles
    buttonTab[6].val=12745.6*math.asin(math.sqrt(a))    -- kilometers
end

function keyboard(k)
    for a,b in pairs(buttonTab) do
        b:keyboard(k)
    end
end

buttons=class()

function buttons:init(x,y,w,h,name,t)
    self.x=x
    self.y=y
    self.w=w
    self.h=h
    self.sel=false
    self.val=0
    self.str=""
    self.name=name
    self.type=t
end

function buttons:draw()
    stroke(255)
    strokeWidth(5)
    if self.sel then
        stroke(255, 0, 0)
        if str~="" then
            self.val=str
        end
    end
    fill(200)
    rect(self.x,self.y,self.w,self.h)
    fill(255)
    text(self.name,self.x,self.y+self.h*.8)
    fill(0)
    text(self.val,self.x,self.y)
end

function buttons:touched(t)
    if t.state==BEGAN then
        self.sel=false
        str=""
        showKeyboard()
        if t.x>self.x-self.w/2 and t.x<self.x+self.w/2 and
                t.y>self.y-self.h/2 and t.y<self.y+self.h/2 then
            if self.type=="i" then
                self.val=""
                self.str=""
                self.sel=true 
            end
        end
    end
end

function buttons:keyboard(k)
    if self.sel then
        if k==BACKSPACE then
            self.str=string.sub(self.str,1,#self.str-1)
        else
            self.str=self.str..k
        end
        self.val=self.str
    end
end

RonJeffries

thanks! nice little ui

timber

@RonJeffries For info. seems like updated Codea 3.2.7 has broke your Space Invaders program. Suddenly there are no shields. This is the version from your article no. 79. The only thing that seems to have changed is the update of Codea ?

RonJeffries

That's interesting. I can confirm that they are gone. Well spotted. I'll see if I can figure out what has happened.

RonJeffries

No, appears that readImage is borked.