sokol_gfx.h: Pipeline desc without attributes should be valid

[agorgl]

Hello there,

It is perfectly valid to be able to call the draw functions without any vertex or index buffer bound.
For example this vertex shader is a neat trick to draw a fullscreen pass without any vertex buffer:

#version 330 core
out vec2 uv;

void main()
{
    uv = vec2((gl_VertexID << 1) & 2, gl_VertexID & 2);
    gl_Position = vec4(uv * 2.0f + -1.0f, 0.0f, 1.0f);
}

Sokol pipeline validation though does not permit this, using the following validation:
https://github.com/floooh/sokol/blob/master/sokol_gfx.h#L10440

This is not valid, and we should allow pipelines without any layout attributes to be created.

[floooh]

Hi, the reason why attribute-less rendering isn't allow in sokol_gfx.h is that this isn't supported by GLES2 and WebGL (gl_VertexID was only added to GLES3 and WebGL2).

It might make sense to declare this as an optional feature though, I'll think about it.

Thanks for writing the issue!

[SanderMertens]

Just ran into the same issue, support for this would be great.

[aganm]

@floooh Why keep GLES2 and WebGL around? Can't they be replaced by GLES3 and WebGL2 across the board?

[Maeiky]

It's also required with WebGL2 and angle backend (d3d9)

[KTRosenberg]

@floooh Why keep GLES2 and WebGL around? Can't they be replaced by GLES3 and WebGL2 across the board?

Believe it or not, Apple has never moved beyond a mostly un-implemented webgl2 support on its devices. We'll have to wait until they bother with WebGPU, most likely, as that uses Metal underneath. I think that there should be a WebGL 1 extension for hacking-in some things optionally.

[floooh]

Apple has never moved beyond a mostly un-implemented webgl2 support

Safari Technology Review on macOS now actually has a working WebGL2 implementation based on ANGLE (it was just enabled by default a couple of days ago), I don't know how far along the iOS version is. But once this lands in the stable version I might indeed start plotting to remove the GLES2/WebGL1 support.

[iOrange]

Upvoting this. Something like a feature flag would be greatly appreciated.

[floooh]

Closing this ticket in favour of: #922

(now that GLES2/WebGL1 has been dropped it's time to look into that topic again)

[floooh]

("closed as not planned" actually means "closed as duplicate"!)