[Soc-2017-dev] vertex paint project - ply exporter

Wed Jul 26 13:53:08 CEST 2017

Yes, I understood the problem I will work on the subdivision modifier for
the alpha!

--Darshan

On Wed, Jul 26, 2017 at 4:57 PM, Howard Trickey <howard.trickey at gmail.com>
wrote:

> Hi Darshan,
>
> Thanks for the video, that explained it well.  And I agree, baking the
> vertex colors to image is working to save the correct alpha, as desired! So
> nothing for you to do in terms of baking.
>
> What do you want to work on next?  One thing that is left over from the
> work to make alpha visible in the 3d view (besides trying to figure out
> what is going on with those backfaces), is to also make it work when you
> add a subdivision surface modifier (which is different than hitting the
> subdivide function in edit mode). Alpha is not displayed there because a
> different derived mesh file is used to draw in that case (I told you about
> this in an earlier message).
>
>
> On Wed, Jul 26, 2017 at 5:49 AM Darshan kadu <darsh7807 at gmail.com> wrote:
>
>> I attached the video in the previous mail so its under moderation, but
>> here is the link of gdrie. https://drive.google.com/file/d/
>> 0B3ZxL0OKDmc7R3Z6NUZBSlo0QnM/view?usp=sharing
>>
>>
>> On Wed, Jul 26, 2017 at 2:56 PM, Darshan kadu <darsh7807 at gmail.com>
>> wrote:
>>
>>> Hello, Mr. Howard,
>>>
>>> I have attached the video for the previous instruction.
>>>
>>> Thank you.
>>>
>>>
>>> On Tue, Jul 25, 2017 at 11:11 PM, Darshan kadu <darsh7807 at gmail.com>
>>> wrote:
>>>
>>>> Hello, Mr. Howard,
>>>>
>>>> I can't create video now(the internet is too slow to download software
>>>> for that and upload video),
>>>> I did this to bake vertex color to PNG.
>>>> -->set  mode as UV editing
>>>> --> select the mesh in edit mode, press<space> select mark seam.
>>>> -->press<U> select unwrap
>>>> -->in render tab go to bake select bake mode to vertex color
>>>> -->bake color
>>>> -->come back to UV you will get color on uv.
>>>> -->save it as png file
>>>>
>>>> One thing I Notice if I use this png file then to bake vertex colors
>>>> then the alpha was properly assigned,
>>>> but if I use the other png file which I took from the internet alpha
>>>> was not getting properly assigned.
>>>>
>>>>
>>>> On Tue, Jul 25, 2017 at 5:24 PM, Howard Trickey <
>>>> howard.trickey at gmail.com> wrote:
>>>>
>>>>> Darshan,
>>>>>
>>>>> I'm sorry, I'm not figuring out how you did that (baking vertex color
>>>>> to a PNG file).  Could you explain the steps your followed in detail or
>>>>> maybe make a video showing how you did it?
>>>>>
>>>>> On Tue, Jul 25, 2017 at 6:35 AM Darshan kadu <darsh7807 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hello, Mr. Howard,
>>>>>>
>>>>>> I tried bake to vertex color,  I applied color to vertex color from
>>>>>> transparent PNG file, it took alpha properly and was showing it in 3d view.
>>>>>>
>>>>>> I then bake vertex color to PNG file, i got the transparent image.
>>>>>>
>>>>>> I think this shows that the bake color is working properly with the
>>>>>> alpha also, and don't need any modification what do you think?
>>>>>>
>>>>>> Thank you.
>>>>>>
>>>>>> On Mon, Jul 24, 2017 at 7:00 PM, Howard Trickey <
>>>>>> howard.trickey at gmail.com> wrote:
>>>>>>
>>>>>>> Hi Darshan,
>>>>>>>
>>>>>>> I will have to look more about baking to see if there is another
>>>>>>> way, but glad you found one way.
>>>>>>>
>>>>>>> Interesting about the backface culling. I was suspecting that the
>>>>>>> artifacts we were seeing were due to backfaces. But as you say, culling
>>>>>>> them is not really the best fix here. Still, a good clue.
>>>>>>>
>>>>>>> As discussed in IRC, I did the steps to the Builder to build your
>>>>>>> branch. It seemed to work.  Some builds are building now. For the record,
>>>>>>> here's what I did
>>>>>>> git checkout experimental-build
>>>>>>> git merge master
>>>>>>> git merge --squash soc-2017-vertex_paint
>>>>>>> git commit -a
>>>>>>> git revert HEAD
>>>>>>>
>>>>>>> noted that commit for the place where your code is merged in is:
>>>>>>> de3ee9f7bb
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Sun, Jul 23, 2017 at 11:08 AM Darshan kadu <darsh7807 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hello, Mr, Howard,
>>>>>>>>
>>>>>>>> I had a hard time in understanding how does the bake to vertex
>>>>>>>> color works, but I figured it out.
>>>>>>>>
>>>>>>>> I did the following steps:
>>>>>>>> 1) I set the texture are the random image.
>>>>>>>> 2)Set the UV map
>>>>>>>> 3)in the physics tab get to dynamic paint tab
>>>>>>>> 4)Add canvas
>>>>>>>> 5)dynamic output: add paintmap later
>>>>>>>> 6)dynamic initial color:
>>>>>>>>    initial color: UV texture
>>>>>>>>  and then set the texture
>>>>>>>> 7) go to object modifier tab
>>>>>>>>    click apply.
>>>>>>>>
>>>>>>>> If we subdivide sufficiently we can see the image in vertex paint.
>>>>>>>> Here alpha is by default 1.
>>>>>>>> I followed these instructions: https://blender.
>>>>>>>> stackexchange.com/questions/26503/how-to-bake-uv-map-
>>>>>>>> texture-to-vertex-color-selected-to-active/41677
>>>>>>>>
>>>>>>>> I just want to know whether is this the correct way to bake or any
>>>>>>>> other method is there to bake?
>>>>>>>> This was only for texture to vertex color baking.
>>>>>>>>
>>>>>>>> Well, I enabled the backface culling in the shading panel on the
>>>>>>>> right-hand side, the alpha for subdivide was showing properly. But it
>>>>>>>> doesn't consider the back faces and for things like a plane, it's not
>>>>>>>> good(as the one side in invisible).
>>>>>>>> We can set it as default by GL functions, but it won't be correct,
>>>>>>>> right?
>>>>>>>>
>>>>>>>> Thank you.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Sat, Jul 22, 2017 at 5:36 PM, Howard Trickey <
>>>>>>>> howard.trickey at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> Hi Darshan,
>>>>>>>>>
>>>>>>>>> The channel locks seem to work. Thanks.
>>>>>>>>>
>>>>>>>>> I think bake color is a great next step.
>>>>>>>>>
>>>>>>>>> On Sat, Jul 22, 2017 at 7:03 AM Darshan kadu <darsh7807 at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> Hello, Mr. Howard,
>>>>>>>>>>
>>>>>>>>>> I have implemented the color lock and the alpha blend, have a
>>>>>>>>>> look at it I have pushed the code.
>>>>>>>>>>
>>>>>>>>>> I am now planning to work on bake color. What do you think?
>>>>>>>>>>
>>>>>>>>>> Thank you.
>>>>>>>>>>
>>>>>>>>>> On Thu, Jul 20, 2017 at 6:15 PM, Howard Trickey <
>>>>>>>>>> howard.trickey at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi Darshan,
>>>>>>>>>>>
>>>>>>>>>>> Your plan to next work blending alpha according to mode, and
>>>>>>>>>>> locking color, seems good to me.
>>>>>>>>>>>
>>>>>>>>>>> Somehow I don't think depth ordering is the issue with the
>>>>>>>>>>> transparent display.  We'll have to leave this as a background task to fix
>>>>>>>>>>> while moving on to other things now.  This is only meant at the moment as a
>>>>>>>>>>> kind of quick hack so the user can see some effect of changing alpha in
>>>>>>>>>>> Vertex Paint mode, and that much is accomplished.
>>>>>>>>>>>
>>>>>>>>>>> The concept of padding is that each C data type takes a certain
>>>>>>>>>>> number of bytes and is (by default, and by most compilers) aligned on
>>>>>>>>>>> certain "address boundaries" because machines access them better that way.
>>>>>>>>>>> On typical machines today:
>>>>>>>>>>> char, bool - take 1 byte, can go at any address
>>>>>>>>>>> short - takes 2 bytes, goes on even addresses
>>>>>>>>>>> int, long, float, pointer - take 4 bytes, go on multiple-of-4
>>>>>>>>>>> addresses
>>>>>>>>>>> double - takes 8 bytes, goes on multiple-of-8 addresses
>>>>>>>>>>>
>>>>>>>>>>> So when you declare a struct, it puts them in order but if the
>>>>>>>>>>> next address available would not fit the above rules, internal padding
>>>>>>>>>>> (basically, unused bytes) is inserted in order to make the required
>>>>>>>>>>> alignment. For more information, read, say
>>>>>>>>>>> https://en.wikipedia.org/wiki/Data_structure_alignment
>>>>>>>>>>>
>>>>>>>>>>> With some structs in Blender that are to be persisted to disk,
>>>>>>>>>>> we want the total length of the struct to have size that is a multiple of
>>>>>>>>>>> 8. If by following the above rules, you end up with a struct that is not a
>>>>>>>>>>> multiple of 8, you may have to add declaration of some chars and possibly
>>>>>>>>>>> an int in order to end up with a multiple of 8. Also, it seems that we
>>>>>>>>>>> explicitly put in pad declarations rather than relying on the compiler to
>>>>>>>>>>> do it for 'jumps' caused by alignment concerns. I guess this is to make it
>>>>>>>>>>> easy for a program to do size calculations when looking at the struct defs
>>>>>>>>>>> in the makesdna directory.  E.g., see the ID and PreviewImage struct defs
>>>>>>>>>>> in makesdna/DNA_ID.h for both types of pads.
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Jul 20, 2017 at 6:07 AM Darshan kadu <
>>>>>>>>>>> darsh7807 at gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hello, Mr. Howard,
>>>>>>>>>>>>
>>>>>>>>>>>> Yes, I also think that the alpha should be blend similar to
>>>>>>>>>>>> rgb. It will be simple to implement.
>>>>>>>>>>>>
>>>>>>>>>>>> About the channel lock, the artists want it, so having it would
>>>>>>>>>>>> be good think, I can do it with r,g,b bool in the brush struct and changing
>>>>>>>>>>>> them from  UI,  Can you tell me the concept of padding you mention before
>>>>>>>>>>>> for adding element in the structure.
>>>>>>>>>>>>
>>>>>>>>>>>> For visualization section, Can cull face be useful? but for the
>>>>>>>>>>>> cases like plane the back view will not be displayed.
>>>>>>>>>>>>
>>>>>>>>>>>> Another thing that can be done is drawing according the depth
>>>>>>>>>>>> the most depth faces first, I haven't done it before). This blog explains
>>>>>>>>>>>> this very well https://learnopengl.com/#
>>>>>>>>>>>> !Advanced-OpenGL/Blending.
>>>>>>>>>>>>
>>>>>>>>>>>> But again why only some faces are behaving like that, why not
>>>>>>>>>>>> all? This is something interesting!
>>>>>>>>>>>>
>>>>>>>>>>>> Now, I will be adding the alpha blending similar to rgb, and
>>>>>>>>>>>> locking color.
>>>>>>>>>>>>
>>>>>>>>>>>> Thank you.
>>>>>>>>>>>>
>>>>>>>>>>>> On Wed, Jul 19, 2017 at 7:39 PM, Darshan kadu <
>>>>>>>>>>>> darsh7807 at gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Hello, Mr. Howard,
>>>>>>>>>>>>> Sorry, I was ill from yesterday afternoon. I should haven't
>>>>>>>>>>>>> told you before but internet wasn't very good its monsoon season(heàvy
>>>>>>>>>>>>> rain) in India.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Meanwhile, yesterday I changed the ply importer to take alpha
>>>>>>>>>>>>> into account. I have pushed the code. I thing the same problem comes with
>>>>>>>>>>>>> the fbx importer. I will check it. I will give reply to your mail as soon
>>>>>>>>>>>>> as possible.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Sorry, I should have told you yesterday itself.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thank you.
>>>>>>>>>>>>>
>>>>>>>>>>>>> On 19-Jul-2017 6:40 PM, "Howard Trickey" <
>>>>>>>>>>>>> howard.trickey at gmail.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> Darshan,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> What are you working on now?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I looked a little more at the issue of alpha display after
>>>>>>>>>>>>>> subdividing. I am pretty sure now that the alphas are set properly -- if
>>>>>>>>>>>>>> you remove all but, say, the front (subdivided) face, the display looks OK.
>>>>>>>>>>>>>> I tried changing the glBlendfunc call to:
>>>>>>>>>>>>>> glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA,
>>>>>>>>>>>>>> GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
>>>>>>>>>>>>>> which seems more correct, but it didn't make any difference.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Maybe someone reading this with more experience with OpenGL
>>>>>>>>>>>>>> and alpha-blending has an idea?  I wonder if somehow we have to turn on
>>>>>>>>>>>>>> drawing the elements in proper z-sorted order?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Tue, Jul 18, 2017 at 9:48 AM Howard Trickey <
>>>>>>>>>>>>>> howard.trickey at gmail.com> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Darshan,
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I made a little python function to dump the vertex (loop)
>>>>>>>>>>>>>>> colors on the console.  You may find this useful.  If you put this in, say,
>>>>>>>>>>>>>>> the release/scripts/startup folder then you can use the <Space>-menu to
>>>>>>>>>>>>>>> search for 'Dump Vertex Colors'.  To see which faces and vertices
>>>>>>>>>>>>>>> correspond to which dumped colors, you can start blender with --debug and
>>>>>>>>>>>>>>> then enable the 'indices' visualization box in the right-hand panel of
>>>>>>>>>>>>>>> view3d (when in Edit mode) to see the indices of the currently selected
>>>>>>>>>>>>>>> elements.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I think there may be a problem with the ply exporter,
>>>>>>>>>>>>>>> discovered by using this. I made a simple plane quad and put different
>>>>>>>>>>>>>>> colors and alphas on each, and then the ply exporter seemed to have an
>>>>>>>>>>>>>>> off-by-one error in lining up colors with vertices. But I looked briefly at
>>>>>>>>>>>>>>> the code and didn't see what was wrong.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I also checked the interpolation of alpha's when subdividing
>>>>>>>>>>>>>>> and agree with you that it seems to be doing approximately the right thing,
>>>>>>>>>>>>>>> so the problem is somehow in the visualization code.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> _______________________________________________
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>>>>>>>>>>>>>> https://lists.blender.org/mailman/listinfo/soc-2017-dev
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
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