I keep loosing this function, somehow, so here it is.

PixelPerfectSpriteSample.glsl

// vec2 uv: XY=[0..1]
// vec4 size: XY=1.0/TEXSIZE, ZW=TEXSIZE.
// sampler2D samplr: MIN,MAG = LINEAR
vec4 pixel_perfect_sample(vec2 uv, vec4 size, in sampler2D samplr) {
    vec2 boxSize = clamp(fwidth(uv) * size.zw, 1e-5, 1.0);
    vec2 tx = uv * size.zw - 0.5 * boxSize;
    vec2 txOffset = smoothstep(1.0 - boxSize, vec2(1.0), fract(tx));
    vec2 finaluv = (floor(tx) + 0.5 + txOffset) * size.xy;
    return textureGrad(samplr, finaluv, dFdx(uv), dFdy(uv));
}

Note: Copied Inspired by https://www.youtube.com/watch?v=d6tp43wZqps