xna - randomness from spritemap in spritebatch -

im sure fixed, , have searched both high , low, traversed net both east, west, north , south no prevail...

my problem this. im in middle of trying make bejeweled clone, me started in xna. im stuck on random plotting of gems/icons/pictures.

this have.

first generated list of positions, random , rectangle:

list<vector2> platser = new list<vector2>(); random slump = new random(); rectangle bildsourcen;  protected override void initialize() {  (int j = 0; j < 5; j++)         {             (int = 0; < 5; i++)             {                 platser.add(new vector2((i*100),(j*100)));             }         } base.initialize(); } 

pretty straight-forward.

i have loaded texture, 5 icons/gems/pictures -> 5*100px = width of 500px.

allimage = content.load<texture2d>("icons/all"); 

then comes "error".

protected override void draw(gametime gametime) {         graphicsdevice.clear(color.cornflowerblue);          spritebatch.begin();          int x = slump.next(2);         bildsourcen = new rectangle((x * 100), 0, 100, 100);          (int = 0; < platser.count; i++)         {         spritebatch.draw(allimage, new rectangle((int)platser[i].x, (int)platser[i].y, 100, 100), bildsourcen, color.white);          } 

so, there code. , happens: want randomly pick part of image , plot @ given coords taken vector2-list. however, puts same image @ coords , keeps randomly replacing them, not random images same. whole board keeps flickering same icons. ie, instead of generating 15231 , keeping frozen, 1 second puts 11111 , next second puts 33333.

does understand im trying describe ? i'm @ point of pulling own hair out. cat's hair has been pulled...

thx in advance

the draw function called once each frame. line:

int x = slump.next(2); 

is generating random number (either 0 or 1 in case) each frame, hence flicker.

the line after selects sprite sprite atlas based on number (specifically specifies rectangle containing sprite). , in loop follows you're drawing multiple copies of sprite (always same image).

you should doing of game logic in update function. function give time , want implement method of waiting amount of time pass before generate random block (so keep accumulating time passes between each update, until reaches threshold). exact mechanics of when want generate random block you.

of course, not mention there other flaws in structure of code. bejewelled played on fixed-sized board different coloured blocks (each block represent number 1 x). location of blocks should be implicit in data structure (so don't need generate platser list).

so game class should have like:

const int boardwidth = 10; const int boardheight = 10; int[,] board = new int[boardwidth, boardheight]; 

then in initialize function should fill board , perhaps use 0 empty space , 1 x represent colours, so:

for(int x = 0; x < boardwidth; x++) for(int y = 0; y < boardheight; y++) {     board[x,y] = slump.next(1, 6); // gives 5 different sprites } 

then in update wait user input or time-out before modifying board (depending on gameplay).

then in draw function this:

for(int x = 0; x < boardwidth; x++) for(int y = 0; y < boardheight; y++) {     if(board[x,y] == 0) continue; // don't render empty space      vector2 position = new vector2(100*x, 100*y);     rectangle bildsourcen = new rectangle(100*(board[x,y]-1), 0, 100, 100);     sb.draw(allimage, position, bildsourcen, color.white); }