Automatic commit of irc logs

Q:	What's the difference betweeen USL and the Graf Zeppelin?
A:	The Graf Zeppelin represented cutting edge technology for its time.

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 00:52 < sulix> (I guess you could have a "high-precision viewport" as well.)
 00:52 < sulix> - The actual upload of graphics data to OpenGL is done as 32-bit floats, no matter the type of real, as that's all OpenGL supports.
 00:53 < sulix>   (At some point we'll have to actually do some view transforms on the CPU rather than just passing all of the bounds and viewport straight to OpenGL)
+01:02 <@matches> Yeah I don't want to replace Real with templates
+01:02 <@matches> That'd be horrible
+01:03 <@matches> By the way, the introduction of SDL_Renderer in SDL2 is confusing
+01:05 <@matches> I thought it was replacing Surface with Renderer and Texture
+01:05 <@matches> But Surface seems to still be a thing
+01:13 < sulix> Yeah: basically Surfaces are in CPU memory, textures in GPU memory.
+01:13 <@matches> Right
+01:14 <@matches> And renderers magically put stuff on surfaces/textures
+01:14 < sulix> Yeah.
+01:14 < sulix> So it basically represents the graphics card.
+01:15 < sulix> But if you want to just use OpenGL yourself, you don't need to create a renderer at all.
+01:15 <@matches> Ah, but the plot thickens
+01:15 <@matches> I'm saving the window to a bmp
+01:16 <@matches> Which requires a renderer
+01:16 < sulix> Hmm... I'm not sure if that will work.
+01:16 <@matches> It does
+01:16 <@matches> It seems rather convoluted though to be honest
+01:16 < sulix> (In theory, it shouldn't, but it probably actually does)
+01:16 <@matches> I seem to remember it not being this convoluted in SDL1.2
+01:16 <@matches> -_-
+01:16 <@matches> So the procedure is
+01:17 <@matches> 1. Get a surface associated with the window
+01:17 <@matches> 2. Allocate buffer of unsigned char for the pixels
+01:17 < sulix> Yeah, TBH I prefer SDL1.2's rendering API, but I generally just use OpenGL anyway.
+01:17 <@matches> 3. Get renderer from the window (NB: Don't use SDL_CreateRenderer, only the (undocumented) SDL_GetRenderer works because the Window already has a Renderer because it has been created with an OpenGL flag)...
+01:18 < sulix> In theory we should probably use glReadPixels.
+01:18 <@matches> 4. Use the magical renderer power to put pixels into the pixel array
+01:18 <@matches> 5. Create an RGB surface from the pixel array
+01:18 <@matches> 6. Now you can call SDL_SaveBMP, congratulations
+01:18 <@matches> What's this about a glReadPixels
+01:18 <@matches> I was just about to commit this
+01:19 < sulix> Well, you can use glReadPixels instead of steps 1,3 and 4.
+01:19 < sulix> (This is what SDL is doing behind the scenes)
+01:20 < sulix> Unfortunately, the SDL wiki is still down thanks to heartbleed. :/
+01:20 <@matches> :O
+01:20 <@matches> It was up when I looked at it before
+01:20 <@matches> Throwing python exceptions when I tried the search function though
+01:21 < sulix> Ryan said that it was up, but I'm still getting revoked certificate errors.
+01:22 <@matches> Hmm, I needed to do step 1 in order to know the size of the pixel array in step 2...
+01:23 < sulix> Screen::ViewportWidth(), Screen::ViewportHeight()
+01:26 <@matches> Yeah this is looking a lot shorter than what I had
+01:33 <@matches> It doesn't seem to work though
+01:35 <@matches> I'm getting a segfault
+01:35 <@matches> And of course valgrind automatically exits when it gets more than 1000000 errors from the flgrx driver
+01:38 <@matches> First call to glReadPixels is OK but the bmp is just white, second call segfaults
+01:39 < sulix> Hmm... what's the call?
+01:44 <@matches> Segfault was due to me forgetting about the pixels needing 4 bytes for RGBA
+01:44 <@matches> Still white though
+01:45 < sulix> (That was going to be my guess)
+01:45 <@matches> The advantage of getting the SDL_Surface
+01:45 <@matches> Was that you just pass all the surf->format->format->stuff
+01:45 <@matches> Everywhere
+01:45 <@matches> Also makes it rather verbose
+01:46 < sulix> The white screen might just be an fglrx bug.
+01:46 <@matches> There we go
+01:47 <@matches> No, it helps to remember that the pixels need 4 bytes for RGBA
+01:47 <@matches> I have very selective memory
+01:47 <@matches> I had to remember it for each line individually
+01:47 <@matches> Right I guess it is slightly nicer now
+01:47 <@matches> Although it has a bunch of magical "*4" everywhere
+01:48 <@matches> I'm going to put this on Stack overflow as an alternative to the answer I was originally following
+01:48 < sulix> Well, I'm going to attempt to sleep...
+01:48 <@matches> Thank you for fixing my bug without seeing it :S
+01:49 < sulix> I have far too much experience breaking glReadPixels...
+01:53 <@matches> We need an easy way to compare our document rendering the same thing using a different Real and/or view representation
+01:53 <@matches> Templates would only solve changing the Real and really they probably wouldn't actually solve it
+01:53 <@matches> They'd just create nightmares
+01:53 <@matches> Hmm
+01:55 <@matches> Um
+01:55 <@matches> Just looking at View::Render
+01:55 <@matches> Why is there a seperate loop for each type of object...
+01:56 <@matches> With "continue" statements for the other types in each loop
+01:56 <@matches> Is this so you can just make one call to glBegin and glEnd...
+01:56 <@matches> I am suitable scared
+01:57 <@matches> suitably scared and also suitable scared
+22:05 <@matches> Ok, trying again. This is the sort of thing a template is supposed to be used for... I just seem to always end up suddenly having to make everything all the way back to Document into a template class :S
+22:07 <@matches> blergh
+22:07 <@matches> trying again
+22:07 <@matches> After getting coffee
+22:07 <@matches> I think
+22:30 <@matches> Ok, templates is way too complicated
+22:30 <@matches> I am going to do the following instead:
+22:31 <@matches> 1. Allow a "save this region to bmp" argument
+22:31 <@matches> 2. It reads the specified bmp, saves a new bmp with the current view overlayed in a different colour or something
+22:32 <@matches> 3. Makefile hacks to recompile the program using a different typedef of Real and then do 1. and 2. for them all
+22:32 <@matches> 4. Realise I probably should have used templates
+23:02 <@matches> So, according to my timeline that I haven't looked at since submitting the proposal, I will have done a draft literature review by tomorrow...
+23:02 <@matches> Hah
+--- Day changed Thu Apr 17 2014
+00:26 <@matches> I am not good at OpenGL/SDL
+00:26 <@matches> I am the master of producing a black screen
+00:26 <@matches> Also we have FILLED and OUTLINE the wrong way round still