chromium/third_party/skia/src/gpu/ganesh/geometry/GrQuadUtils.h

/*
 * Copyright 2019 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrQuadUtils_DEFINED
#define GrQuadUtils_DEFINED

#include "src/base/SkVx.h"
#include "src/gpu/ganesh/geometry/GrQuad.h"

#include <cstdint>

enum class GrAA : bool;
enum class GrAAType : unsigned int;
enum class GrQuadAAFlags;
struct SkRect;

namespace GrQuadUtils {

    // Resolve disagreements between the overall requested AA type and the per-edge quad AA flags.
    // Both outAAType and outEdgeFlags will be updated.
    void ResolveAAType(GrAAType requestedAAType, GrQuadAAFlags requestedEdgeFlags,
                       const GrQuad& quad, GrAAType* outAAtype, GrQuadAAFlags* outEdgeFlags);

    /**
     * Clip the device vertices of 'quad' to be in front of the W = 0 plane (w/in epsilon). The
     * local coordinates will be updated to match the new clipped vertices. This returns the number
     * of clipped quads that need to be drawn: 0 if 'quad' was entirely behind the plane, 1 if
     * 'quad' did not need to be clipped or if 2 or 3 vertices were clipped, or 2 if 'quad' had one
     * vertex clipped (producing a pentagonal shape spanned by 'quad' and 'extraVertices').
     */
    int ClipToW0(DrawQuad* quad, DrawQuad* extraVertices);

    /**
     * Crops quad to the provided device-space axis-aligned rectangle. If the intersection of this
     * quad (projected) and cropRect results in a quadrilateral, this returns true. If not, this
     * quad may be updated to be a smaller quad of the same type such that its intersection with
     * cropRect is visually the same. This function assumes that the 'quad' coordinates are finite.
     *
     * The provided edge flags are updated to reflect edges clipped by cropRect (toggling on or off
     * based on cropAA policy). If provided, the local coordinates will be updated to reflect the
     * updated device coordinates of this quad.
     *
     * If 'computeLocal' is false, the local coordinates in 'quad' will not be modified.
     */
    bool CropToRect(const SkRect& cropRect, GrAA cropAA, DrawQuad* quad, bool computeLocal=true);

    inline void Outset(const skvx::float4& edgeDistances, GrQuad* quad);

    bool WillUseHairline(const GrQuad& quad, GrAAType aaType, GrQuadAAFlags edgeFlags);

    class TessellationHelper { … };

} // namespace GrQuadUtils

void GrQuadUtils::Outset(const skvx::float4& edgeDistances, GrQuad* quad) { … }

#endif