Primitive.hpp

// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef sw_Primitive_hpp
#define sw_Primitive_hpp

#include "Vertex.hpp"
#include "Main/Config.hpp"

namespace sw
{
	struct Triangle
	{
		Vertex v0;
		Vertex v1;
		Vertex v2;
	};

	struct PlaneEquation   // z = A * x + B * y + C
	{
		float4 A;
		float4 B;
		float4 C;
	};

	struct Primitive
	{
		int yMin;
		int yMax;

		float4 xQuad;
		float4 yQuad;

		PlaneEquation z;
		PlaneEquation w;

		union
		{
			struct
			{
				PlaneEquation C[2][4];
				PlaneEquation T[8][4];
				PlaneEquation f;
			};

			PlaneEquation V[MAX_FRAGMENT_INPUTS][4];
		};

		float area;

		// Masks for two-sided stencil
		int64_t clockwiseMask;
		int64_t invClockwiseMask;

		struct Span
		{
			unsigned short left;
			unsigned short right;
		};

		// The rasterizer adds a zero length span to the top and bottom of the polygon to allow
		// for 2x2 pixel processing. We need an even number of spans to keep accesses aligned.
		Span outlineUnderflow[2];
		Span outline[OUTLINE_RESOLUTION];
		Span outlineOverflow[2];
	};
}

#endif   // sw_Primitive_hpp