About Store Forum Documentation Contact
Donations:
309$/mo



Post Reply 
[SOLVED] EE::Image rotation method
Author Message
Hokan Offline
Member

Post: #1
[SOLVED] EE::Image rotation method
I have really dumb question.

Is there anywhere in EE rotation image method?

Sure, I can use image rotation formulas, like:
Code:
resultXPixelPosition = Cos(DegToRad(angleInDegrees)) *
(originalPixelXPosition - centerPixelXPosition) - Sin(DegToRad(angleInDegrees)) * (originalPixelYPosition  - centerPixelYPosition) + centerPixelXPosition;

resultYPixelPosition = Sin(DegToRad(angleInDegrees)) *
(originalPixelXPosition  - centerPixelXPosition) + Cos(DegToRad(angleInDegrees)) * (originalPixelYPosition  - centerPixelYPosition) + centerPixelYPosition;

And iterate through all image pixels. But all this code will run on CPU, which is really slow.

Sure, I can write shade and use it over image, but doesn't EE already support GPU-based rotation image code?
(This post was last modified: 08-10-2015 08:05 AM by Hokan.)
08-06-2015 04:49 PM
Find all posts by this user Quote this message in a reply
Esenthel Offline
Administrator

Post: #2
RE: EE::Image rotation method
GPU based rotation drawing:
Image.drawRotate
http://www.esenthel.com/?id=doc#API/Graphics/Image

or

VI.face to manually specify triangles
http://www.esenthel.com/?id=doc#API/Grap...dex_Buffer
there are tutorials for using VI
08-07-2015 12:29 AM
Find all posts by this user Quote this message in a reply
Houge Offline
Silver Supporter

Post: #3
RE: EE::Image rotation method
Let me write another question about image rotation here, not to create a new topic.
Minimap consists of many image pieces, each one is drawn separtely to make a picture be without borders. Is there a built-in way to draw rotated minimap, and not to calculate manually tile position depending on current angle every frame?
08-07-2015 12:57 PM
Visit this user's website Find all posts by this user Quote this message in a reply
Esenthel Offline
Administrator

Post: #4
RE: EE::Image rotation method
Hi,

There is no built-in way to do that.
Having source you'd have to combine the drawRotate method with the masked draw if you want a circle based minimap.
If you're ok with a square based mini map then you can just use D.clip combined with Image.drawRotate
08-08-2015 12:57 AM
Find all posts by this user Quote this message in a reply
Hokan Offline
Member

Post: #5
RE: EE::Image rotation method
Thanks for answer, but Image.drawRotate really draw rotated image. I'm searching for in-memory rotation method.

Is it possible to load image in GPURAM, run rotation shader once, than upload result image back in RAM, and would it worth passing image pixels back and forth, rather than just make CPU-based rotation?

Goal is - rare (once per 20-30 minutes) 512x512 (or 1024x1024) texture rotation
08-09-2015 09:17 AM
Find all posts by this user Quote this message in a reply
Esenthel Offline
Administrator

Post: #6
RE: EE::Image rotation method
I would just go with CPU algorithm, because capturing data from GPU is slow.
08-10-2015 07:04 AM
Find all posts by this user Quote this message in a reply
Hokan Offline
Member

Post: #7
RE: EE::Image rotation method
Thanks again, I'll mark post as solved
08-10-2015 08:05 AM
Find all posts by this user Quote this message in a reply
Post Reply