Translucent pixels in textures don't render correctly.

[BadComoc]

The original texture.

The texture as rendered in game.

[Hopson97]

This would be caused by the fragment shaders having a hard if

if (colour.a == 0) 
{
    discard;
}

A fix could be to instead have something like if (colour.a < 0.2)

Or maybe some kind of alpha blending instead

[BadComoc]

This would be caused by the fragment shaders having a hard if

if (colour.a == 0) 
{
    discard;
}

A fix could be to instead have something like if (colour.a < 0.2)

Or maybe some kind of alpha blending instead

Changing it to 0.2 doesn't really add support for translucent pixels. it only changes the threshold on how many invisible pixels should appear. It's weird 'cause Fluid Blocks can be transparent but not Floral blocks.

[GrossoDev]

To add alpha blending to Floral voxels you only have to change 2 files:

The transparent_fragment shader

...
void main() {
-   outColour = passBasicLight * texture(textureArray, passTexCoord);

-   if (outColour.a == 0) {
-       discard;
-   }

+   // The alpha channel is half of its actual value, for some reason.
+   outColour = passBasicLight * texture(textureArray, passTexCoord) * vec4(1.0, 1.0, 1.0, 2.0);
}

chunk_renderer.cpp

...
  // Flora voxels
  m_floraShader.program.bind();
  gl::loadUniform(m_floraShader.projectionViewLocation, projectionViewMatrix);
  gl::loadUniform(m_floraShader.timeLocation, time);
  glDisable(GL_CULL_FACE);
+ glEnable(GL_BLEND); 
  ::renderChunks(floraDrawables, frustum, m_floraShader.chunkPositionLocation, result);
+ glDisable(GL_BLEND); 
  glEnable(GL_CULL_FACE);

However, alpha blending (at least this way) requires that you have already rendered everything behind the pixel you're rendering. This was the problem with the leaves not rendering underwater (#143), and in fact it's still a bug:

In this image, you can see the other voxels of water behind:

In this image, from the other side, you can't:

In the first image, the farthest water was drawn first and the closest was drawn after it.
In the second image, where we see it from the other side, the farthest water is now the closest (and vice-versa), but the rendering order hasn't changed, so the closest water will now render first without the farthest water behind it

As it is right now, the transparent flora might end up looking something like this (for clarity, I've changed the tall-grass texture):

If this is enough it can be implemented right now, but the only way I can think of to solve this is to sort the faces from farthest to closest before rendering.

(Oh, and the thing about the alpha channel being 1/2 of the original value might have been the problem here)

[obiwac]

The original texture really shouldn't have half-transparent pixels in the first place, as that will always cause problems.
Also, I don't understand why the leaves don't show up behind, as the pixels that make up the texture are either fully opaque or fully transparent. I assume it's because all the half-transparent objects are being rendered at the same time as the leaves, but that shouldn't be the case.
Last thing, if you really wanted to add alpha sorting, it would probably be pretty easy, as this is a voxel game and there are presumably no intersecting polygons.