Preformance With DrawImage!

Newbie & Debugging Questions
#1

ok am drawing this on my screen // this is backround for the 2d platformer btw

http://s7.postimg.org/4frzz3pi3/backround.png

but i don’t want to draw it all i only want to draw what the screen can see

for example here i want to only draw whats inside that red rectangle

http://s22.postimg.org/oy71dto9t/backround2.png

i got it working with tiles and stuff using a collision box but i have never done it with an full image

do i need to get the pixels that are colliding and so how do i do that?

#2

What are u using?
OpenGL: change the texture coords
Java2D: Graphics.setClip(x, y, width, height)
Thats all that I know

hope this helps! :smiley:

#3

Thanks so much! this is gonna make everything so much easier

so does it still load the pixels outside the clip?

#4

I would guess so , its a clip function not a modified load function , if you are going to do something like this take a look at buffered rendering.

#5

If you really care about performance move onto some framework that uses opengl.

But that does not really answer your question.

#6

Why use setClip when the drawImage method does it for you?

[icode]drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer)[/icode]

#7

would you mind giving those varibles names, first time am doing this… with and image!

#8

http://docs.oracle.com/javase/7/docs/api/java/awt/Graphics.html#drawImage(java.awt.Image,%20int,%20int,%20int,%20int,%20int,%20int,%20int,%20int,%20java.awt.image.ImageObserver)