mosra/magnum

Lightweight and modular C++11/C++14 graphics middleware for games and dataviz

hsdk123

@hsdk123

SourceAlpha / OneMinusSourceAlpha

@FoNz99089892_twitter
I was so hoping disabling depth test would work, but sadly it didn't. Any other ideas?

hsdk123

@hsdk123

@mosra
I'm using One Zero to overlay the first texture on to the frame buffer - would this be incorrect?

Vladimír Vondruš

@mosra

i have no better suggestion than loading the two textures in https://www.andersriggelsen.dk/glblendfunc.php and doing trial&error until it does the right thing

Igal Alkon

@alkavan

I'm having some trouble drawing multiple lines in 3D space. In Drawable3D::draw() have this:

_buffer.setData(_lines, GL::BufferUsage::StreamDraw);
_mesh.setCount(_lines.size());

I added 4 points to the _lines vector, but only two (one line) is drawn. GL::BufferUsage::StreamDraw is not the way?

Hans Loeblich

@thehans

Is there documentation on how to get started with a user-defined shader? I think I was reading such a page the other day, but can't find it now. The overall organization of the docs is very confusing to me.

Guillaume Jacquemin

@williamjcm

IMO, the best documentation is the textured triangle example.

It'll only show the Magnum way of using a custom shader, though, so if you need help writing the actual shader code, there are other resources for that.

Hans Loeblich

@thehans

ok, I'll review that one, thanks. 2nd question, just curious is there a list of projects which use Magnum?

I think i've got the GLSL aspect of it covered, no worries.

Guillaume Jacquemin

@williamjcm

2nd question, just curious is there a list of projects which use Magnum?

I don't remember seeing one of these on the website itself, but the blog post announcing the 2020.06 release mentions a few of them, and other posts might mention more.

Vladimír Vondruš

@mosra

@alkavan how did you add the vertex buffer to the mesh? how are the attributes set up? for example, if the mesh would expect a position and a normal (for whatever reasons) for every vertex but you specify just positions, then it ends up looking at just half of the points

the BufferUsage has nothing to do with this, it's merely a suggestion to the driver where to best put the memory

Igal Alkon

@alkavan

@mosra I already found the issue, kind of stupid. It all worked actually, the issue was I also have a wireframe grid, at y=0.0 and the other lines I added were exactly where grid is and so I didn't see them :)

Vladimír Vondruš

@mosra

ahah :)

@thehans out of the public projects, there's also habitat-sim, and you can find various projects under the #magnum topic on github: https://github.com/topics/magnum

The overall organization of the docs is very confusing to me.

do you have an idea how it could be improved? regular users get blind to the deficiencies over time, so fresh ideas are always welcome :)

11 replies

Igal Alkon

@alkavan

btw, something just a little annoying, CLion (Clang-Tidy) inspection produce a warning on:

_mesh.setCount(_lines.size());
// Clang-Tidy: Narrowing conversion from 'std::vector::size_type' (aka 'unsigned long') to signed type 'Magnum::Int' (aka 'int') is implementation-defined

I can do Magnum::Int(_lines.size()), this part if I'm not wrong taken from an example, this how I should do it?

Vladimír Vondruš

@mosra

clang tidy is a bit overmotivated, i'd say

the relevant GL API takes a (signed) int, and if i'd make setCount(std::size_t), then it would complain if passing an int to it again

Guillaume Jacquemin

@williamjcm

Today, I learnt Magnum types such as Color4 or Vector3 were trivially copyable, and thus made one of my struct types trivially copyable as well.

Fo Nz

@FoNz99089892_twitter

Today, I learnt Magnum types such as Color4 or Vector3 were trivially copyable, and thus made one of my struct types trivially copyable as well.

As I saw, basically they have a data method where it returns the base address for the internal array. I think you can just memcpy them.

Jordan Peck

@Auburn

@mosra I've updated my Nvidia drivers to latest version on Windows and I'm now having an issue with ImGui not correctly handling alpha

ImGui is rendering a fullscreen quad with this color data

I'm sure it is caused by the driver update, since a user was having the issue on the latest driver. So I updated then I had the same issue

Fo Nz

@FoNz99089892_twitter

I'm trying to use AnySceneImporter on iOS, but when it's loaded by the PluginManager, the application says that the plugin is not present. I can see the library being statically linked into my Xcode project. I all the dependencies by myself. What's the error? Any idea? Thanks in advance.

Jordan Peck

@Auburn

I found a fix by changing ImGui window flags, seems odd though that a driver update would cause the behaviour to change? I would have thought OpenGL doesn't get touched much these days

Vladimír Vondruš

@mosra

@Auburn what was the flag that fixed it? all i can think of is the new driver not clearing framebuffer attachments by default (or vice versa) so you end up with something different if you forgot to clear explicitly

@FoNz99089892_twitter if you're not using CMake to link the static plugins, you have to perform an additional step to register them for the plugin manager, basically the following in a file that's compiled directly to the final executable (and not any intermediate static library):

#include <MagnumPlugins/AnySceneImporter/importStaticPlugin.cpp>

Relevant docs: https://doc.magnum.graphics/magnum/plugins.html#plugins-static

Fo Nz

@FoNz99089892_twitter

@mosra Thanks a lot! I completely missed that.

Jordan Peck

@Auburn

@mosra It was this flag for a dock node, which in turn sets the fullscreen imgui window flag ImGuiWindowFlags_NoBackground https://github.com/Auburn/FastNoise2/commit/732577d86dbdf7f79de949b86c3ef3589ba82699#diff-13f4704b60755926950ac5d2b0ca1e4850f8a69d0a51ebc2cce9418b8dfefa95L550

if (dockspace_flags & ImGuiDockNodeFlags_PassthruCentralNode)
        host_window_flags |= ImGuiWindowFlags_NoBackground;

Which makes me wonder how it was working before...

Jordan Peck

@Auburn

Linux and MacOS are fine without the fix, but it seems like that behaviour is wrong

Jordan Peck

@Auburn

With the fix

Without

My only guess is that there was something in driver hiding the fullscreen quad previously

Vladimír Vondruš

@mosra

Which makes me wonder how it was working before...

huh, yeah exactly

is it possible that the fullscreen quad got clipped away for some reason? though i don't see why the quad would but not the rest of imgui

Jordan Peck

@Auburn

The fullscreen quad is a fullscreen imgui window

Vladimír Vondruš

@mosra

crazy, but .. is it possible that you hit some nvidia game-specific workaround before? :D

does anything change if you rename the broken exectuable?

Jordan Peck

@Auburn

That doesn't explain why the issue doesn't exist on Linux though?

Vladimír Vondruš

@mosra

i mean, certain drivers are known to check if the executable is named rage.exe and then applying certain shader patches etc

so you might be hitting something similar, and that it works on linux is maybe just because there's no .exe

but that's a crazy idea, i don't have anything better, sorry :)

Vladimír Vondruš

@mosra

https://github.com/Auburn/FastNoise2

huh, i wonder how did i miss your project, or did i just forget it existed? .. i remember we were discussing something related to noise and SIMD detection but don't remember seeing this fancy tool :sweat_smile:

(can you add the #magnum topic to the repo description? unless you want to keep it a secret, of course)

Jordan Peck

@Auburn

Ya sure

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