struct vertex_t {
	UNITY_VERTEX_INPUT_INSTANCE_ID
	float4	position		: POSITION;
	float3	normal			: NORMAL;
	float4	color			: COLOR;
	float2	texcoord0		: TEXCOORD0;
	float2	texcoord1		: TEXCOORD1;
};

struct pixel_t {
	UNITY_VERTEX_INPUT_INSTANCE_ID
	UNITY_VERTEX_OUTPUT_STEREO
	float4	position		: SV_POSITION;
	float4	faceColor		: COLOR;
	float4	outlineColor	: COLOR1;
	float4	texcoord0		: TEXCOORD0;
	float4	param			: TEXCOORD1;		// weight, scaleRatio
	float2	mask			: TEXCOORD2;
	#if (UNDERLAY_ON || UNDERLAY_INNER)
	float4	texcoord2		: TEXCOORD3;
	float4	underlayColor	: COLOR2;
	#endif
};

float4 SRGBToLinear(float4 rgba) {
	return float4(lerp(rgba.rgb / 12.92f, pow((rgba.rgb + 0.055f) / 1.055f, 2.4f), step(0.04045f, rgba.rgb)), rgba.a);
}

pixel_t VertShader(vertex_t input)
{
	pixel_t output;

	UNITY_INITIALIZE_OUTPUT(pixel_t, output);
	UNITY_SETUP_INSTANCE_ID(input);
	UNITY_TRANSFER_INSTANCE_ID(input, output);
	UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);

	float bold = step(input.texcoord1.y, 0);

	float4 vert = input.position;
	vert.x += _VertexOffsetX;
	vert.y += _VertexOffsetY;

	float4 vPosition = UnityObjectToClipPos(vert);

	float weight = lerp(_WeightNormal, _WeightBold, bold) / 4.0;
	weight = (weight + _FaceDilate) * _ScaleRatioA * 0.5;

	// Generate UV for the Masking Texture
	float4 clampedRect = clamp(_ClipRect, -2e10, 2e10);
	float2 maskUV = (vert.xy - clampedRect.xy) / (clampedRect.zw - clampedRect.xy);

	float4 color = input.color;
	#if (FORCE_LINEAR && !UNITY_COLORSPACE_GAMMA)
	color = SRGBToLinear(input.color);
	#endif

	float opacity = color.a;
	#if (UNDERLAY_ON | UNDERLAY_INNER)
	opacity = 1.0;
	#endif

	float4 faceColor = float4(color.rgb, opacity) * _FaceColor;
	faceColor.rgb *= faceColor.a;

	float4 outlineColor = _OutlineColor;
	outlineColor.a *= opacity;
	outlineColor.rgb *= outlineColor.a;

	output.position = vPosition;
	output.faceColor = faceColor;
	output.outlineColor = outlineColor;
	output.texcoord0 = float4(input.texcoord0.xy, maskUV.xy);
	output.param = float4(0.5 - weight, 1.3333 * _GradientScale * (_Sharpness + 1) / _TextureWidth, _OutlineWidth * _ScaleRatioA * 0.5, 0);

	float2 mask = float2(0, 0);
	#if UNITY_UI_CLIP_RECT
	mask = vert.xy * 2 - clampedRect.xy - clampedRect.zw;
	#endif
	output.mask = mask;

	#if (UNDERLAY_ON || UNDERLAY_INNER)
	float4 underlayColor = _UnderlayColor;
	underlayColor.rgb *= underlayColor.a;

	float x = -(_UnderlayOffsetX * _ScaleRatioC) * _GradientScale / _TextureWidth;
	float y = -(_UnderlayOffsetY * _ScaleRatioC) * _GradientScale / _TextureHeight;

	output.texcoord2 = float4(input.texcoord0 + float2(x, y), input.color.a, 0);
	output.underlayColor = underlayColor;
	#endif

	return output;
}

float4 PixShader(pixel_t input) : SV_Target
{
	UNITY_SETUP_INSTANCE_ID(input);

	float d = tex2D(_MainTex, input.texcoord0.xy).a;

	float2 UV = input.texcoord0.xy;
	float scale = rsqrt(abs(ddx(UV.x) * ddy(UV.y) - ddy(UV.x) * ddx(UV.y))) * input.param.y;

	#if (UNDERLAY_ON | UNDERLAY_INNER)
	float layerScale = scale;
	layerScale /= 1 + ((_UnderlaySoftness * _ScaleRatioC) * layerScale);
	float layerBias = input.param.x * layerScale - .5 - ((_UnderlayDilate * _ScaleRatioC) * .5 * layerScale);
	#endif

	scale /= 1 + (_OutlineSoftness * _ScaleRatioA * scale);

	float4 faceColor = input.faceColor * saturate((d - input.param.x) * scale + 0.5);

	#ifdef OUTLINE_ON
	float4 outlineColor = lerp(input.faceColor, input.outlineColor, sqrt(min(1.0, input.param.z * scale * 2)));
	faceColor = lerp(outlineColor, input.faceColor, saturate((d - input.param.x - input.param.z) * scale + 0.5));
	faceColor *= saturate((d - input.param.x + input.param.z) * scale + 0.5);
	#endif

	#if UNDERLAY_ON
	d = tex2D(_MainTex, input.texcoord2.xy).a * layerScale;
	faceColor += float4(_UnderlayColor.rgb * _UnderlayColor.a, _UnderlayColor.a) * saturate(d - layerBias) * (1 - faceColor.a);
	#endif

	#if UNDERLAY_INNER
	float bias = input.param.x * scale - 0.5;
	float sd = saturate(d * scale - bias - input.param.z);
	d = tex2D(_MainTex, input.texcoord2.xy).a * layerScale;
	faceColor += float4(_UnderlayColor.rgb * _UnderlayColor.a, _UnderlayColor.a) * (1 - saturate(d - layerBias)) * sd * (1 - faceColor.a);
	#endif

	#ifdef MASKING
	float a = abs(_MaskInverse - tex2D(_MaskTex, input.texcoord0.zw).a);
	float t = a + (1 - _MaskWipeControl) * _MaskEdgeSoftness - _MaskWipeControl;
	a = saturate(t / _MaskEdgeSoftness);
	faceColor.rgb = lerp(_MaskEdgeColor.rgb * faceColor.a, faceColor.rgb, a);
	faceColor *= a;
	#endif

	// Alternative implementation to UnityGet2DClipping with support for softness
	#if UNITY_UI_CLIP_RECT
	float2 maskZW = 0.25 / (0.25 * half2(_MaskSoftnessX, _MaskSoftnessY) + (1 / scale));
	float2 m = saturate((_ClipRect.zw - _ClipRect.xy - abs(input.mask.xy)) * maskZW);
	faceColor *= m.x * m.y;
	#endif

	#if (UNDERLAY_ON | UNDERLAY_INNER)
	faceColor *= input.texcoord2.z;
	#endif

	#if UNITY_UI_ALPHACLIP
	clip(faceColor.a - 0.001);
	#endif

	return faceColor;
}
