How to Select and Draw a Portion of a 512 x 512 Image

[Eric]

How can I select and draw a portion of an Image. I have a 1024 x 1024 Image that consists of various buttons and display parts,

 

Currently I use this code to Draw and Rotate an Image, but I am unsure how to select a section of my image to draw.

 

Function DrawAndRotateImage(itr:TTexture, Ax:Int, Ay:Int, Sx:Int, Sy:Int, Ir:Float)
       glMatrixMode(GL_TEXTURE)
       glLoadIdentity()
       glTranslatef(0.5,0.5,0)
       glRotatef(Ir,0,0,1)
       glTranslatef(-0.5,-0.5,0)
       glMatrixMode(GL_MODELVIEW)
       glEnable itr.Target()
       itr.Bind()
       itr.Clamp(1,1,1)
       DrawRect(Ax,Ay,Sx,Sy)
       glDisable(GL_TEXTURE_2D)
       glMatrixMode(GL_TEXTURE)
       glLoadIdentity()
       glMatrixMode(GL_MODELVIEW)
       glScalef(1,1,1) 
End Function

 

How can I add to this code to allow me to select a portion of the image.

 

Thanks for any help.

Eric

[AnniXa]

How can I select and draw a portion of an Image. I have a 1024 x 1024 Image that consists of various buttons and display parts,

 

Currently I use this code to Draw and Rotate an Image, but I am unsure how to select a section of my image to draw.

 

Function DrawAndRotateImage(itr:TTexture, Ax:Int, Ay:Int, Sx:Int, Sy:Int, Ir:Float)
       glMatrixMode(GL_TEXTURE)
       glLoadIdentity()
       glTranslatef(0.5,0.5,0)
       glRotatef(Ir,0,0,1)
       glTranslatef(-0.5,-0.5,0)
       glMatrixMode(GL_MODELVIEW)
       glEnable itr.Target()
       itr.Bind()
       itr.Clamp(1,1,1)
       DrawRect(Ax,Ay,Sx,Sy)
       glDisable(GL_TEXTURE_2D)
       glMatrixMode(GL_TEXTURE)
       glLoadIdentity()
       glMatrixMode(GL_MODELVIEW)
       glScalef(1,1,1) 
End Function

 

How can I add to this code to allow me to select a portion of the image.

 

Thanks for any help.

Eric

 

You need the UV coordinates of the area that you want to draw, then you need the GL_TEXTURE_CORD_ARRAY state and you need to use glTexCoordPointer, and glVertexPointer and glDrawArrays to draw your image.

You can use my little 2d library if you want, it gives alot of nice drawing functions, like frames of images like in blitzmax native 2d stuff, a fast image text system, and some other stuff that makes life easyer with 2d,bmx and leadwerks.

PM me if you want it

 

 

edit:ooops that thread is very old...

[Eric]

You need the UV coordinates of the area that you want to draw, then you need the GL_TEXTURE_CORD_ARRAY state and you need to use glTexCoordPointer, and glVertexPointer and glDrawArrays to draw your image.

You can use my little 2d library if you want, it gives alot of nice drawing functions, like frames of images like in blitzmax native 2d stuff, a fast image text system, and some other stuff that makes life easyer with 2d,bmx and leadwerks.

PM me if you want it

 

 

edit:ooops that thread is very old...

 

Thanks... I sent you a message.

 

Eric