obs-StreamFX/data/effects/mask.effect

// Parameters
/// OBS
uniform float4x4 ViewProj;
/// Input
uniform texture2d image_blur;
uniform texture2d image_orig;
/// Mask
uniform float mask_region_left;
uniform float mask_region_top;
uniform float mask_region_right;
uniform float mask_region_bottom;
uniform float mask_region_feather;
uniform float mask_region_feather_shift;
uniform texture2d mask_image;
uniform float4 mask_color;
uniform float mask_multiplier;

// Data
sampler_state pointSampler {
	Filter    = Point;
	AddressU  = Clamp;
	AddressV  = Clamp;
	MinLOD    = 0;
	MaxLOD    = 0;
};

sampler_state linearSampler {
	Filter    = Linear;
	AddressU  = Clamp;
	AddressV  = Clamp;
	MinLOD    = 0;
	MaxLOD    = 0;
};

struct VertDataIn {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

struct VertDataOut {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

VertDataOut VSDefault(VertDataIn v_out)
{
	VertDataOut vert_out;
	vert_out.pos = mul(float4(v_out.pos.xyz, 1.0), ViewProj);
	vert_out.uv  = v_out.uv;
	return vert_out;
}

float Region(float2 uv) {
	if ((uv.x < mask_region_left)
		|| (uv.x > mask_region_right)
		|| (uv.y < mask_region_top)
		|| (uv.y > mask_region_bottom)) {
		return 0.0;
	}
	return 1.0;
}

float RegionFeathered(float2 uv) {
	float halfFeather = (mask_region_feather / 2.0);
	float feather = max(mask_region_feather, 0.00000001);
	float leftFeather = clamp(((uv.x - mask_region_left + halfFeather) / feather) + mask_region_feather_shift, 0.0, 1.0);
	float rightFeather = clamp(((-(uv.x - mask_region_right) + halfFeather) / feather) + mask_region_feather_shift, 0.0, 1.0);
	float topFeather = clamp(((uv.y - mask_region_top + halfFeather) / feather) + mask_region_feather_shift, 0.0, 1.0);
	float bottomFeather = clamp(((-(uv.y - mask_region_bottom) + halfFeather) / feather) + mask_region_feather_shift, 0.0, 1.0);
	float finalFeather = min(min(leftFeather, rightFeather), min(topFeather, bottomFeather));
	return clamp(finalFeather, 0.0, 1.0);
}

float4 PSRegion(VertDataOut v_out) : TARGET {
	float alpha = Region(v_out.uv);
	float4 orig = image_orig.Sample(pointSampler, v_out.uv);
	float4 blur = image_blur.Sample(pointSampler, v_out.uv);	
	return lerp(orig, blur, alpha);
}

float4 PSRegionInverted(VertDataOut v_out) : TARGET {
	float alpha = 1.0 - Region(v_out.uv);
	float4 orig = image_orig.Sample(pointSampler, v_out.uv);
	float4 blur = image_blur.Sample(pointSampler, v_out.uv);	
	return lerp(orig, blur, alpha);
}

float4 PSRegionFeather(VertDataOut v_out) : TARGET {
	float alpha = RegionFeathered(v_out.uv);
	float4 orig = image_orig.Sample(pointSampler, v_out.uv);
	float4 blur = image_blur.Sample(pointSampler, v_out.uv);	
	return lerp(orig, blur, alpha);
}

float4 PSRegionFeatherInverted(VertDataOut v_out) : TARGET {
	float alpha = 1.0 - RegionFeathered(v_out.uv);
	float4 orig = image_orig.Sample(pointSampler, v_out.uv);
	float4 blur = image_blur.Sample(pointSampler, v_out.uv);	
	return lerp(orig, blur, alpha);
}

float4 PSImage(VertDataOut v_out) : TARGET {
	float4 mask = mask_image.Sample(linearSampler, v_out.uv) * mask_color * mask_multiplier;
	float alpha = clamp(mask.r + mask.g + mask.b + mask.a, 0.0, 1.0);
	float4 orig = image_orig.Sample(pointSampler, v_out.uv);
	float4 blur = image_blur.Sample(pointSampler, v_out.uv);	
	return lerp(orig, blur, alpha);
}

technique Region
{
	pass
	{
		vertex_shader = VSDefault(v_out);
		pixel_shader = PSRegion(v_out);
	}
}

technique RegionInverted
{
	pass
	{
		vertex_shader = VSDefault(v_out);
		pixel_shader = PSRegionInverted(v_out);
	}
}

technique RegionFeather
{
	pass
	{
		vertex_shader = VSDefault(v_out);
		pixel_shader = PSRegionFeather(v_out);
	}
}

technique RegionFeatherInverted
{
	pass
	{
		vertex_shader = VSDefault(v_out);
		pixel_shader = PSRegionFeatherInverted(v_out);
	}
}

technique Image
{
	pass
	{
		vertex_shader = VSDefault(v_out);
		pixel_shader = PSImage(v_out);		
	}
}