583844 - ReadPixels fixes for PACK_ALIGNMENT and EXT_bgra

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Attachment: fix readpixels calls

For WebGL especially, GL_PACK_ALIGNMENT is under content control; we need to force it to be what we expect when calling glReadPixels.  Also fix correct usage of BGRA format and byte swap where needed.

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

Comment on attachment 462165 [details] [diff] [review]
fix readpixels calls

OK, just 1 argh,

-        // XXX byteswap
+
+        // swap B and R bytes
+        for (int j = 0; j < mBounds.height; ++j) {
+          PRUint32 *row = (PRUint32*) (isurf->Data() + isurf->Stride() * j);
+          for (int i = 0; i < mBounds.width; ++i) {
+            *row = (*row & 0xff00ff00) | ((*row & 0xff) << 16) | ((*row & 0xff0000) >> 16);
+            row++;
+          }
+        }

Argh, one more place where we have to loop over all pixels in the CPU...

Comment 2

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

http://hg.mozilla.org/mozilla-central/rev/09a07cc60743

part of this ended up going in inside

http://hg.mozilla.org/mozilla-central/rev/d879bb244890