Consider adding a VertexFormat::Mat3 as well

[EriKWDev]

Heyope :)

It would be nice to also be able to have mat3 as vertex attributes which would require a VertexFormat::Mat3

I use the transpose of the inverse of a model matrix for correcting normal orientations per instance and it's nice to not have to compute it in the shader since it's a bit expensive and also without wasting space with a Mat4, and it would look nicer than my current setup:

attribute mediump vec3 instance_normal_0;
attribute mediump vec3 instance_normal_1;
attribute mediump vec3 instance_normal_2;

with attributes and layout as so:

            miniquad::BufferLayout {
                step_func: miniquad::VertexStep::PerInstance,
                stride: std::mem::size_of::<[[f32; 3]; 3]>() as _,
                ..Default::default()
            },

// ...
            miniquad::VertexAttribute::with_buffer("instance_normal_0", miniquad::VertexFormat::Float3, 3),
            miniquad::VertexAttribute::with_buffer("instance_normal_1", miniquad::VertexFormat::Float3, 3),
            miniquad::VertexAttribute::with_buffer("instance_normal_2", miniquad::VertexFormat::Float3, 3),

To my understanding, it seems that it would only require changing in new_pipeline_with_params with an added case that sets attributes_len and attributes_count to 3 for a VertexFormat::Mat3.

Possibly also apply_uniforms_from_bytes If we're also adding a UniformType::Mat3 while we're at it.

Anything I'm missing about GL ES compatability or would that suffice and work?