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Topic: transparent gifs and screen wraparound (Read 784 times) |
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pollux
 
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transparent gifs and screen wraparound
« on: Apr 25th, 2003, 5:58am » |
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i've been using the Sprite class Glen wrote (the one running around some [Learning] examples) but now i have a problem with the screen wraparound result. i need transparent gifs but i need their pixels to dissapear if outside the screen.
any help? doesn't seems like too difficult a task. i'm urged, i need it urgently, so please get me out of my misery...
i'm including the class code (for at-a-glance feedback?):
// Sprite class for transparent GIFs
class Sprite
{
int wh; // Size of the sprite (width*height)
int[] px; // Array for storing the sprite
int swidth; // Width of the sprite
int sheight; // Height of the sprite
BImage img; // The image that is the sprite
Sprite(String imageName) {
loadSprite(imageName);
swidth = img.width;
sheight = img.height;
wh = swidth*sheight;
px = new int[wh];
// Load the image into the px[] array
for(int i=0; i < wh; i++) {
px[i] = img.pixels[i];
}
}
void loadSprite(String name) {
img = loadImage(name);
}
void display(float x, float y) {
int pix;
for(int i=0; i < wh; i++) {
// If the pixel of the image is not transparent,
// draw the pixel into the pixels[] array of the window
if(px[i] != 0x00FFFFFF) {
pix = (int)x+((int)y*width)+(i%swidth)+((i/swidth)*width);
if(pix < width*height && pix > 0) {
pixels[pix] = px[i];
}
}
}
}
}
(btw, how do you post quoted code?)
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pollux | www.frwrd.net
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toxi
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Re: transparent gifs and screen wraparound
« Reply #1 on: Apr 27th, 2003, 10:25pm » |
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hey pollux,
hope it's not too late, but simply replace the existing display() method with the one below...
Code:
void display(int x, int y) {
if (-x>=swidth || -y>=sheight) return;
int tw=(x<0) ? x+swidth : min(width-x,swidth);
int th=(y<0) ? y+sheight : min(height-y, sheight);
int offset1=((x<0) ? -x : 0)+((y<0) ? -y : 0)*swidth;
int offset2=((x<0) ? 0 : x)+((y<0) ? 0 : y)*width;
int yy=-1;
while(++yy<th) {
int xx=-1;
while(++xx<tw) {
if(px[offset1] != 0x00FFFFFF) pixels[offset2] = px[offset1];
offset1++;
offset2++;
}
offset1+=(swidth-tw);
offset2+=(width-tw);
}
} |
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also note: the method now expects integer coordinates to avoid further type conversions within the loops.
btw. use [ code ] tags (w/o spaces between brackets) to post code samples...
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| « Last Edit: Apr 27th, 2003, 10:27pm by toxi » |
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http://toxi.co.uk/
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pollux
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Re: transparent gifs and screen wraparound
« Reply #2 on: Apr 28th, 2003, 9:38am » |
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thanxs a lot, toxi. i am *still* on schedule, and it works like a charm!
(btw, i like what you do with director...)
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pollux | www.frwrd.net
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