Full example

// Source: https://github.com/mellinoe/veldrid/blob/d60e5a036add2123a15f0da02f1da65a80503d54/src/Veldrid.ImGui/Assets/HLSL/imgui-frag.hlsl

struct PS_INPUT
{
	float4 pos : SV_POSITION;
	float4 col : COLOR0;
	float2 uv  : TEXCOORD0;
};

Texture2D FontTexture : register(t0);
sampler FontSampler : register(s0);

float4 FS(PS_INPUT input) : SV_Target
{
	float4 out_col = input.col * FontTexture.Sample(FontSampler, input.uv);
	return out_col;
}