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gpu: [compute] compute and store clipping path hashes during construction

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The hash of the clipping paths that affect drawing operations are computed
and used to quickly determine that two operations are not equal, the
most likely outcome of a comparison.

However, for paths that are constructed once and cached computing the
hash at every frame is wasteful. This is especially true for text, which
is both cached and also among the largest paths in a frame.

This change moves the hashing to op/clip.Path construction time, and
stores the hash in the ops list so it won't be re-computed at every use.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
This commit is contained in:
Elias Naur
2021-07-19 17:19:26 +02:00
parent 88fb798cca
commit 5197f637a7
3 changed files with 31 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
gpu/compute.go
+9 -5
View File
@@ -201,6 +201,7 @@ type clipKey struct {
bounds f32.Rectangle
stroke clip.StrokeStyle
relTrans f32.Affine2D
pathHash uint64
}
// paintKey completely defines a paint operation. It is suitable for hashing and
@@ -1321,7 +1322,7 @@ func (c *opsCollector) reset() {
c.layers = c.layers[:0]
}
func (c *collector) addClip(state *encoderState, viewport, bounds f32.Rectangle, path []byte, key ops.Key, stroke clip.StrokeStyle) {
func (c *collector) addClip(state *encoderState, viewport, bounds f32.Rectangle, path []byte, key ops.Key, hash uint64, stroke clip.StrokeStyle) {
// Rectangle clip regions.
if len(path) == 0 {
// If the rectangular clip region contains a previous path it can be discarded.
@@ -1348,6 +1349,7 @@ func (c *collector) addClip(state *encoderState, viewport, bounds f32.Rectangle,
bounds: bounds,
relTrans: state.relTrans,
stroke: stroke,
pathHash: hash,
},
})
state.intersect = state.intersect.Intersect(absBounds)
@@ -1369,11 +1371,12 @@ func (c *collector) collect(root *op.Ops, viewport image.Point) {
pathData struct {
data []byte
key ops.Key
hash uint64
}
str clip.StrokeStyle
)
c.save(opconst.InitialStateID, state)
c.addClip(&state, fview, fview, nil, ops.Key{}, clip.StrokeStyle{})
c.addClip(&state, fview, fview, nil, ops.Key{}, 0, clip.StrokeStyle{})
for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
switch opconst.OpType(encOp.Data[0]) {
case opconst.TypeProfile:
@@ -1385,16 +1388,18 @@ func (c *collector) collect(root *op.Ops, viewport image.Point) {
case opconst.TypeStroke:
str = decodeStrokeOp(encOp.Data)
case opconst.TypePath:
hash := bo.Uint64(encOp.Data[1:])
encOp, ok = r.Decode()
if !ok {
panic("unexpected end of path operation")
}
pathData.data = encOp.Data[opconst.TypeAuxLen:]
pathData.key = encOp.Key
pathData.hash = hash
case opconst.TypeClip:
var op clipOp
op.decode(encOp.Data)
c.addClip(&state, fview, op.bounds, pathData.data, pathData.key, str)
c.addClip(&state, fview, op.bounds, pathData.data, pathData.key, pathData.hash, str)
pathData.data = nil
str = clip.StrokeStyle{}
case opconst.TypeColor:
@@ -1415,7 +1420,7 @@ func (c *collector) collect(root *op.Ops, viewport image.Point) {
if paintState.matType == materialTexture {
// Clip to the bounds of the image, to hide other images in the atlas.
bounds := paintState.image.src.Bounds()
c.addClip(&paintState, fview, layout.FRect(bounds), nil, ops.Key{}, clip.StrokeStyle{})
c.addClip(&paintState, fview, layout.FRect(bounds), nil, ops.Key{}, 0, clip.StrokeStyle{})
}
if paintState.intersect.Empty() {
break
@@ -1504,7 +1509,6 @@ func (c *collector) collect(root *op.Ops, viewport image.Point) {
func (c *collector) hashOp(op paintOp) uint64 {
c.hasher.Reset()
for _, cl := range op.clipStack {
c.hasher.Write(cl.path)
k := cl.state
keyBytes := (*[unsafe.Sizeof(k)]byte)(unsafe.Pointer(unsafe.Pointer(&k)))
c.hasher.Write(keyBytes[:])
internal/opconst/ops.go
+1 -1
View File
@@ -59,7 +59,7 @@ const (
TypeClipLen = 1 + 4*4 + 1
TypeProfileLen = 1
TypeCursorLen = 1 + 1
TypePathLen = 1
TypePathLen = 8 + 1
TypeStrokeLen = 1 + 4
)
op/clip/clip.go
+21 -4
View File
@@ -4,6 +4,7 @@ package clip
import (
"encoding/binary"
"hash/maphash"
"image"
"math"
@@ -15,6 +16,12 @@ import (
"gioui.org/op"
)
var pathSeed maphash.Seed
func init() {
pathSeed = maphash.MakeSeed()
}
// Op represents a clip area. Op intersects the current clip area with
// itself.
type Op struct {
@@ -38,9 +45,11 @@ func (p Op) Add(o *op.Ops) {
outline = true
}
bo := binary.LittleEndian
if path.hasSegments {
data := o.Write(opconst.TypePathLen)
data[0] = byte(opconst.TypePath)
bo.PutUint64(data[1:], path.hash)
path.spec.Add(o)
}
@@ -60,7 +69,6 @@ func (p Op) Add(o *op.Ops) {
data := o.Write(opconst.TypeClipLen)
data[0] = byte(opconst.TypeClip)
bo := binary.LittleEndian
bo.PutUint32(data[1:], uint32(bounds.Min.X))
bo.PutUint32(data[5:], uint32(bounds.Min.Y))
bo.PutUint32(data[9:], uint32(bounds.Max.X))
@@ -138,6 +146,7 @@ type PathSpec struct {
// hasSegments tracks whether there are any segments in the path.
hasSegments bool
bounds image.Rectangle
hash uint64
}
// Path constructs a Op clip path described by lines and
@@ -156,6 +165,7 @@ type Path struct {
start f32.Point
hasSegments bool
bounds f32.Rectangle
hash maphash.Hash
}
// Pos returns the current pen position.
@@ -163,6 +173,7 @@ func (p *Path) Pos() f32.Point { return p.pen }
// Begin the path, storing the path data and final Op into ops.
func (p *Path) Begin(ops *op.Ops) {
p.hash.SetSeed(pathSeed)
p.ops = ops
p.macro = op.Record(ops)
// Write the TypeAux opcode
@@ -178,6 +189,7 @@ func (p *Path) End() PathSpec {
open: p.open || p.pen != p.start,
hasSegments: p.hasSegments,
bounds: boundRectF(p.bounds),
hash: p.hash.Sum64(),
}
}
@@ -211,11 +223,16 @@ func (p *Path) LineTo(to f32.Point) {
data := p.ops.Write(scene.CommandSize + 4)
bo := binary.LittleEndian
bo.PutUint32(data[0:], uint32(p.contour))
ops.EncodeCommand(data[4:], scene.Line(p.pen, to))
p.cmd(data[4:], scene.Line(p.pen, to))
p.pen = to
p.expand(to)
}
func (p *Path) cmd(data []byte, c scene.Command) {
ops.EncodeCommand(data, c)
p.hash.Write(data)
}
func (p *Path) expand(pt f32.Point) {
if !p.hasSegments {
p.hasSegments = true
@@ -274,7 +291,7 @@ func (p *Path) QuadTo(ctrl, to f32.Point) {
data := p.ops.Write(scene.CommandSize + 4)
bo := binary.LittleEndian
bo.PutUint32(data[0:], uint32(p.contour))
ops.EncodeCommand(data[4:], scene.Quad(p.pen, ctrl, to))
p.cmd(data[4:], scene.Quad(p.pen, ctrl, to))
p.pen = to
p.expand(ctrl)
p.expand(to)
@@ -315,7 +332,7 @@ func (p *Path) CubeTo(ctrl0, ctrl1, to f32.Point) {
data := p.ops.Write(scene.CommandSize + 4)
bo := binary.LittleEndian
bo.PutUint32(data[0:], uint32(p.contour))
ops.EncodeCommand(data[4:], scene.Cubic(p.pen, ctrl0, ctrl1, to))
p.cmd(data[4:], scene.Cubic(p.pen, ctrl0, ctrl1, to))
p.pen = to
p.expand(ctrl0)
p.expand(ctrl1)