skgpu::tess::CullTest Class Reference

#include <CullTest.h>

Public Member Functions
	CullTest ()=default
	CullTest (const SkRect &devCullBounds, const SkMatrix &m)
void	set (const SkRect &devCullBounds, const SkMatrix &m)
bool	isVisible (SkPoint p) const
bool	areVisible3 (const SkPoint p[3]) const
bool	areVisible4 (const SkPoint p[4]) const

Detailed Description

Definition at line 26 of file CullTest.h.

Constructor & Destructor Documentation

CullTest() [1/2]

skgpu::tess::CullTest::CullTest ( )

default

CullTest() [2/2]

skgpu::tess::CullTest::CullTest ( const SkRect &  devCullBounds, const SkMatrix &  m  )

inline

Definition at line 30 of file CullTest.h.

                                                             {
        this->set(devCullBounds, m);
    }

Member Function Documentation

areVisible3()

bool skgpu::tess::CullTest::areVisible3 ( const SkPoint  p[3] ) const

inline

Definition at line 57 of file CullTest.h.

                                               {
        // Transform p0..2 to device space.
        auto val0 = fMatY * p[0].fY;
        auto val1 = fMatY * p[1].fY;
        auto val2 = fMatY * p[2].fY;
        val0 = fMatX*p[0].fX + val0;
        val1 = fMatX*p[1].fX + val1;
        val2 = fMatX*p[2].fX + val2;
        // At this point: valN = {xN, yN, -xN, -yN} in device space.
 
        // Find the device-space bounding box of p0..2.
        val0 = max(val0, val1);
        val0 = max(val0, val2);
        // At this point: val0 = [r, b, -l, -t] of the device-space bounding box of p0..2.
 
        // Does fCullBounds intersect the device-space bounding box of p0..2?
        // i.e., l0 < r1 && t0 < b1 && r0 > l1 && b0 > t1.
        return all(fCullBounds < val0);
    }

areVisible4()

bool skgpu::tess::CullTest::areVisible4 ( const SkPoint  p[4] ) const

inline

Definition at line 78 of file CullTest.h.

                                               {
        // Transform p0..3 to device space.
        auto val0 = fMatY * p[0].fY;
        auto val1 = fMatY * p[1].fY;
        auto val2 = fMatY * p[2].fY;
        auto val3 = fMatY * p[3].fY;
        val0 = fMatX*p[0].fX + val0;
        val1 = fMatX*p[1].fX + val1;
        val2 = fMatX*p[2].fX + val2;
        val3 = fMatX*p[3].fX + val3;
        // At this point: valN = {xN, yN, -xN, -yN} in device space.
 
        // Find the device-space bounding box of p0..3.
        val0 = max(val0, val1);
        val2 = max(val2, val3);
        val0 = max(val0, val2);
        // At this point: val0 = [r, b, -l, -t] of the device-space bounding box of p0..3.
 
        // Does fCullBounds intersect the device-space bounding box of p0..3?
        // i.e., l0 < r1 && t0 < b1 && r0 > l1 && b0 > t1.
        return all(fCullBounds < val0);
    }

isVisible()

bool skgpu::tess::CullTest::isVisible ( SkPoint  p ) const

inline

Definition at line 49 of file CullTest.h.

                                    {
        // devPt = [x, y, -x, -y] in device space.
        auto devPt = fMatX*p.fX + fMatY*p.fY;
        // i.e., l < x && t < y && r > x && b > y.
        return all(fCullBounds < devPt);
    }

set()

void skgpu::tess::CullTest::set ( const SkRect &  devCullBounds, const SkMatrix &  m  )

inline

Definition at line 34 of file CullTest.h.

                                                             {
        SkASSERT(!m.hasPerspective());
        // [fMatX, fMatY] maps path coordinates to the float4 [x, y, -x, -y] in device space.
        fMatX = {m.getScaleX(), m.getSkewY(), -m.getScaleX(), -m.getSkewY()};
        fMatY = {m.getSkewX(), m.getScaleY(), -m.getSkewX(), -m.getScaleY()};
        // Store the cull bounds as [l, t, -r, -b] for faster math.
        // Also subtract the matrix translate from the cull bounds ahead of time, rather than adding
        // it to every point every time we test.
        fCullBounds = {devCullBounds.fLeft - m.getTranslateX(),
                       devCullBounds.fTop - m.getTranslateY(),
                       m.getTranslateX() - devCullBounds.fRight,
                       m.getTranslateY() - devCullBounds.fBottom};
    }

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The documentation for this class was generated from the following file:

• third_party/skia/src/gpu/tessellate/CullTest.h