obs-shaderfilter-plus-shaders/square.glsl

float4 render(float2 uv) {
	float2 newuv;
	newuv[0] = uv[0] - 0.5;
	newuv[1] = uv[1] - 0.5;
	newuv[0] = (newuv[0] < 0 ? -1 : 1) * newuv[0] * newuv[0] * 2;
	newuv[1] = (newuv[1] < 0 ? -1 : 1) * newuv[1] * newuv[1] * 2;
	
	newuv[0] = newuv[0] + 0.5;
	newuv[1] = newuv[1] + 0.5;
	float4 image_color = image.Sample(builtin_texture_sampler, newuv);
	return image_color;
}