(01-21-2023, 08:37 PM)SMcNeill Wrote: And here's a completely different way to check for pixel perfect collision with our two stars:

Code: (Select All)

TYPE PointType
    AS INTEGER x, y
END TYPE

SCREEN _NEWIMAGE(1280, 720, 32)
DIM AS _UNSIGNED LONG target
DIM SHARED Backdrop AS LONG: Backdrop = _COPYIMAGE(0)
REDIM CA(0) AS PointType
blueStar = _LOADIMAGE("Z:\starBlue.png", 32)
redStar = _LOADIMAGE("z:\starRed.png", 32)

CleanImage blueStar
CleanImage redStar
MakeCollisionArray redStar, CA()

t# = TIMER + 1
DO
    CLS , 0
    IF TIMER > t# THEN
        out$ = STR$(count)
        count = 0
        t# = TIMER + 1
    END IF
    count = count + 1
    LOCATE 2, 1: PRINT out$; "FPS"
    IF _KEYDOWN(18432) THEN yPos = yPos - 1
    IF _KEYDOWN(20480) THEN yPos = yPos + 1
    IF _KEYDOWN(19200) THEN xPos = xPos - 1
    IF _KEYDOWN(19712) THEN xPos = xPos + 1
    IF _KEYDOWN(32) THEN xPos = 0: yPos = 0 'reset
    IF _KEYDOWN(27) THEN SYSTEM

    _PUTIMAGE (xPos, yPos), redStar
    _PUTIMAGE (100, 100), blueStar
    CheckCollision xPos, yPos, CA()
    _DISPLAY
LOOP


SUB CheckCollision (xOffset AS INTEGER, yOffset AS INTEGER, CA() AS PointType)
    FOR i = 1 TO UBOUND(CA)
        x% = xOffset + CA(i).x
        y% = yOffset + CA(i).y
        IF POINT(x%, y%) <> &HFFFF0000&& THEN
            LOCATE 1, 1: PRINT "Collision at:"; x%, y%
            EXIT SUB
        END IF
    NEXT
END SUB

SUB MakeCollisionArray (image AS LONG, CA() AS PointType) 'CA = Collision Array
    REDIM CA(_WIDTH(image) * _HEIGHT(image)) AS PointType
    DIM AS LONG D, S: D = _DEST: S = _SOURCE
    DIM AS LONG count: count = -1
    _SOURCE image
    FOR y = 0 TO _HEIGHT - 1
        FOR x = 0 TO _WIDTH - 1
            IF POINT(x, y) = &HFFFF0000&& THEN
                IF y > 0 THEN
                    IF POINT(x, y - 1) = 0 THEN
                        count = count + 1
                        CA(count).x = x
                        CA(count).y = y
                        _CONTINUE
                    END IF
                END IF
                IF y < _HEIGHT - 1 THEN
                    IF POINT(x, y + 1) = 0 THEN
                        count = count + 1
                        CA(count).x = x
                        CA(count).y = y
                        _CONTINUE
                    END IF
                END IF
                IF x > 0 THEN
                    IF POINT(x - 1, y) = 0 THEN
                        count = count + 1
                        CA(count).x = x
                        CA(count).y = y
                        _CONTINUE
                    END IF
                END IF
                IF x < _WIDTH - 1 THEN
                    IF POINT(x + 1, y) = 0 THEN
                        count = count + 1
                        CA(count).x = x
                        CA(count).y = y
                        _CONTINUE
                    END IF
                END IF
            END IF
        NEXT
    NEXT
    REDIM _PRESERVE CA(count) AS PointType
    _DEST D: _SOURCE S
END SUB

SUB CleanImage (image AS LONG) 'make backdrop image
    DIM m AS _MEM: m = _MEMIMAGE(image)
    DIM AS _OFFSET o, l
    DIM AS _UNSIGNED LONG p
    o = m.OFFSET: l = m.OFFSET + m.SIZE
    $CHECKING:OFF
    DO UNTIL o >= l
        _MEMGET m, o, p
        SELECT CASE p
            CASE &HFFFF0000, &HFF0000FF
            CASE ELSE: _MEMPUT m, o, &H00000000 AS _UNSIGNED LONG
        END SELECT
        o = o + 4
    LOOP
    $CHECKING:ON
END SUB

This basically forms an array of the coordinates which are needed to create the outline for our red star, and then it compares to see if they're still red or not.  Simple enough, right?

And, would you guys believe that this little red star has 383 points in its outline?!  Even so, without trying to do anything fancy to optimize things (this is all software images and POINT calculations, with no hardware or mem at use at all), this still runs at over 500 FPS on my PC and has no issues with the collision detection at all, that I can find.

(01-22-2023, 08:59 PM)bplus Wrote: Aye, do you think if we saved the color with the x,y it would slow it down much?

Then for collision check, we can just see that point is the color it was.

Quote:@Bplus
I'm sorry, while I was typing the demo, very simple, in my mind grew up a dubt that need more test to do for getting an universal well working function of collision detection...
So,please gimme more Tempo to use for coding! I have no time in the week, I hope to have good time for weekend.

(01-24-2023, 03:10 PM)TempodiBasic Wrote: @Terry  a feedback on alpha channel

on the right the demo 5 in which the alpha 0 has been set on _rgb32(0)  (because in my pictures the background to be transparent is black).

(01-25-2023, 09:59 PM)TerryRitchie Wrote:

(01-24-2023, 03:10 PM)TempodiBasic Wrote: @Terry  a feedback on alpha channel

on the right the demo 5 in which the alpha 0 has been set on _rgb32(0)  (because in my pictures the background to be transparent is black).

_RGB32(0) is not valid. Remember, _RGBA32(0,0,0,0) and _RGB32(0) are not the same. _RGB32(0) returns the value of 4278190080 because _RGB32(0) is actually 255,0,0,0 (11111111000000000000000000000000) 11111111 = Alpha, 00000000=Red, 00000000=Green, 00000000=Blue.