mosra/magnum

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

Vladimír Vondruš

@mosra

and yeah those pictures on that link are maybe exactly what i remember

no visible results

i already saw a dataset that used like 10 of those fancy new extensions

pezcode

@pezcode

what I meant is that they have like 10 in the pipeline that aren't finished, but keep changing names and feature sets, only confusing everyone

Vladimír Vondruš

@mosra

ah :) yeah, true

though honestly i like this better than a total silence for 5 years and then "here's glTF 2.1 with PBR Next, enjoy!" with no community involvement

i imagine this is how the internal vulkan extension development looks like as well, only we don't see it :D

pezcode

@pezcode

yeah, this is probably the better alternative

Vladimír Vondruš

@mosra

I just made a commit ccccc9d9281f779b59ff587568fe4f869dab9eb3, does that already count as a mined cryptocurrency or do I need more cs?

pezcode

@pezcode

don't give Microsoft ideas :eyes:

Vladimír Vondruš

@mosra

you mean further gamification of github? :D

Mathew

@lectroMathew

mining on git commits would be the cleanest way to ensure that github's servers go down as quickly as possible and never go up again

Fo Nz

@FoNz99089892_twitter

so myOwnDefaultFramebuffer has a non-zero ID, right? just double-checking i understand this properly

Exactly. Both "default" framebuffer and "default" renderbuffer have a ID of 1, in my case.

irfna

@irfna

Hey, I'm having some issues rendering some basic textured cubes that use the same texture for each side, I end up with weird artifacts that change with every tiny change in the camera angle:

https://i.imgur.com/VH6HOuG.png

Currently using phong shader to test but the FlatGL shader has the same problem. My current vertices are just a copy and paste/rename of cubeSolid() and its dependencies, except I shoved in texture coordinates:

constexpr struct TileBlockVertex2 {
    Vector3 position;
    Vector3 normal;
    Vector2 textureCoordinates;
} TileBlockVertices2[]{
    {{-1.0f, -1.0f,  1.0f}, { 0.0f,  0.0f,  1.0f}, { 0.0f,  0.0f}},
    {{ 1.0f, -1.0f,  1.0f}, { 0.0f,  0.0f,  1.0f}, { 1.0f,  0.0f}},
    {{ 1.0f,  1.0f,  1.0f}, { 0.0f,  0.0f,  1.0f}, { 1.0f,  1.0f}}, /* +Z */
    {{-1.0f,  1.0f,  1.0f}, { 0.0f,  0.0f,  1.0f}, { 0.0f,  1.0f}},

...

And so on, then I'm just using cubeSolid() as is shown in examples. When I test FlatGL, I have a version of the array without the normal vector in it but is otherwise the same. There has to be something small/dumb I'm not seeing that is resulting in these errors, but everything I'm attempting is failing

Vladimír Vondruš

@mosra

hi! could it be just .. the depth test not being enabled?

leading to the (black) backfaces sometimes rendered after the faces that should be in front

irfna

@irfna

    GL::defaultFramebuffer.clear(GL::FramebufferClear::Color|GL::FramebufferClear::Depth);

    ViewRegion();

    GL::Renderer::enable(GL::Renderer::Feature::DepthTest);

    sprites.draw(*_camera);
    terrain.draw(*_camera);

I have actually experimented without depth test, but then some sides and other things are randomly missing as well. There's something really wrong that I can't nail down

I've used various textured cube vertex data from random people online to try different versions, but there's always artifacts and bugs in the cube. I'm able to render sprites on planes just fine, so I'm not sure why cubes are being so silly

 Shaders::PhongGL shader{Shaders::PhongGL::Flag::DiffuseTexture};

 GL::Mesh mesh = MeshTools::compile(cubeSolid());

  auto size = Vector3(TilePixelDimensions) / 4.0f;

  category.shader
  .setTransformationMatrix(transformation*Matrix4::scaling(size))
  .setProjectionMatrix(camera.projectionMatrix())
  .bindDiffuseTexture(*texture)
  .draw(category.mesh);

There's nothing really complicated going on in the code either, but maybe I'm missing a necessary feature or something?

Vladimír Vondruš

@mosra

huh

what's your setup? is it just a pure magnum application or combined with some 3rd party lib that could potentially touch OpenGL as well?

irfna

@irfna

This is a pure magnum setup based on the basic bootstrap project, setup just for testing out rendering sprites and cubes

Vladimír Vondruš

@mosra

ah that could be rather easy to go through, can you post the whole code somewhere? gist, pastebin... i'll look at it

the small stupid mistakes are always the most annoying :D

irfna

@irfna

haha ya. Thanks for the help and looking at this! I'm rounding this up, I guess I could just zip it up and post it somewhere? All I've changed are the CMakeLists.txt and MyApplication.cpp of the bootstrap. Let me toss this on google drive or something

The tricky part is that I have it launching in my c:\lib directory where I have my .dll files compiled, but it's grabbing sprites from a different hardcoded directory, so I'm figuring out how to package this together properly

Vladimír Vondruš

@mosra

i'm on linux anyway, so i'll just grab the code and see :)

even just the cpp file is enough

irfna

@irfna

https://pastebin.com/15p7G9B8

Ok, this is just the cpp file, I have imagepath at the top to be filled out with an image path, and can grab my really poorly drawn images as well

https://drive.google.com/file/d/1yMYjLDUgi4kOj0WBvigfm0pOQVMvOoil/view?usp=sharing

Here's the images

I changed it to using flatGL instead of phong in the mean time, so it will be using the flat shader in the pastebin, the error is clearer with it though I think

Vladimír Vondruš

@mosra

hmmm i get the same issue

investigating...

irfna

@irfna

I really appreciate the help!

Vladimír Vondruš

@mosra

btw, i find this hilariuous:

GetImage("dirt.png")

GetImage(object.png)

had to take a double look until i understood how it can even compile :D

irfna

@irfna

hahaha oops ya I should have fixed that debug output, I was copying and pasting example code

This is more of a test run of various features I need than making the actual game proper

Vladimír Vondruš

@mosra

okay the problem seems to be here:

.setProjectionMatrix(Matrix4::perspectiveProjection(35.0_degf, 4.0f/3.0f, 0.001f, 1000000.0f))

the near/far range is so huge that it's beyond what can be represented in a (I assume) 24bit depth buffer, and so the cube front and back faces get assigned the same depth value, which makes the output depend on the order the GPU processes the triangles and not the actual depth

i went with 0.1f, 10000.0f and it started looking acceptable, but if you see similar artifacts later you might want to narrow it down even further

irfna

@irfna

Ah I see, so I'll have to make sure everything gets scaled down a bunch so I can reduce that value

Vladimír Vondruš

@mosra

more like finding the right range

irfna

@irfna

Thanks, I knew it had to be some small thing like that

Vladimír Vondruš

@mosra

for example if you have everything 10 or 100 units from the camera anyway, then it doesn't make sense to make the near value so low

irfna

@irfna

Ok, I see

Yep, switching to 10.0f to 10000.0f seems to fix the issue completely!

Thanks for the help! Now all I have to do is figure out why the sprite transparency isn't working even when I enable blending haha

Vladimír Vondruš

@mosra

you need to call setBlendFunction() as well :)

irfna

@irfna

Cool, thanks!

Vladimír Vondruš

@mosra

actually i can't seem to get it work myself :D only AlphaMask enabled on the shader did work

what am i doing wrong?

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