sprite-image addressing?0, or 1?

Questions
1

an image’s lowest coords are 1,1. if you set context to an image and say sprite(s,0,0) does sprite pixel 0,0 go to image 1,1, or does sprite pixel 1,1 go to image 1,1?

i’ll try to devise a test, but i’m not sure i can even see one pixel. :smile:

2

An image created with set context can start at 1,1 to whatever size you set. If you sprite that image, then pixel 1,1 is whatever value you set in sprite. With spriteMode set to CORNER, sprite(0,0) will correspond to pixel 1,1 of the mage. sprite(-10,-10) will be pixel 1,1 of the image. Or am I misinterpreting your question.

3

that seems to be the answer i’m looking for. is there a typo in the last bit? how did you determine the answer?

4

@RonJeffries Heres the code I was playing with. When you create an image with setContext, the pixel positions don’t change for that image. You can move that image anywhere on the screen using sprite, but the pixel positions in the image don’t change. So sprite(-10,-10) places image pixel 1,1 at screen position -10,-10 provided spriteMode is set to CORNER.

viewer.mode=STANDARD

function setup() 
    parameter.integer("x",-50,50,0)
    parameter.integer("y",-50,50,0)
    noSmooth() 
    spriteMode(CORNER)
    img=image(100,100)
    setContext(img)
    background(255,0,0)
    setContext()      
end

function draw()
    background(0)
    sprite(img,x,y)
end

function touched(t)
    if t.state==BEGAN then
        r,g,b,a=img:get(1,1)
        print(r,"",g,"",b,"",a)
        print()
        r,g,b,a=img:get(100,100)
        print(r,"",g,"",b,"",a)
    end
end
5

ah. that’s not my question, or i think it isn’t. but your code gives me an idea how to ask and answer it. thanks, i may be back. :wink:

6

my question was, when you create an image, which is indexed 1-100, and you write a sprite into that image at 0,0, does sprite 0,0 go into image 1,1, or does sprite 1,1 go into image 1,1? the answer is that sprite 0,0 goes into image 1,1.

viewer.mode=STANDARD

function setup()
    noSmooth()
    spriteMode(CORNER)
    img=image(100,100)
    jmg = image(100,100)
    setContext(img)
    background(255,0,0)
    setContext(jmg)
    background(0,255,0)
    sprite(img,1,1)
    setContext()
end

function draw()
    background(0)
    sprite(jmg,100,100)
end

function touched(t)
    if t.state==BEGAN then
        r,g,b,a=jmg:get(1,1)
        print(r,"",g,"",b,"",a)
        print()
        r,g,b,a=jmg:get(100,100)
        print(r,"",g,"",b,"",a)
    end
end
7

@RonJeffries I guess I didn’t understand your original question. Glad you were able to take my wrong code and change it to get your answer. I now see what you were asking.

8

the whole 0 = 1 thing is weird. :smile: