~eliasnaur/gio

b87cbc04f37453a064201a8590b0a23a169cf3f5 — Elias Naur 3 years ago 60a47e7
gpu: [compute] add compute renderer specific decoding of ops

Until now, the two renderers have shared structures and code for
decoding drawing ops and convert them to GPU-friendly structures.

However, the decoder is tailored to the old renderer and use
structures that poorly fits the new compute renderer.

This change copies the decoder and specializes the copy for the compute
renderer, avoiding a round-trip through the old renderer decoder.

Signed-off-by: Elias Naur <mail@eliasnaur.com>
3 files changed, 424 insertions(+), 200 deletions(-)

M gpu/caches.go
M gpu/compute.go
M gpu/gpu.go
M gpu/caches.go => gpu/caches.go +0 -2
@@ 26,8 26,6 @@ type opCache struct {

type opCacheValue struct {
	data pathData
	// computePath is the encoded path for compute.
	computePath encoder

	bounds f32.Rectangle
	// the fields below are handled by opCache

M gpu/compute.go => gpu/compute.go +407 -137
@@ 8,6 8,7 @@ import (
	"fmt"
	"image"
	"image/color"
	"math"
	"math/bits"
	"time"
	"unsafe"


@@ 16,19 17,21 @@ import (
	"gioui.org/gpu/internal/driver"
	"gioui.org/internal/byteslice"
	"gioui.org/internal/f32color"
	"gioui.org/internal/opconst"
	"gioui.org/internal/ops"
	"gioui.org/internal/scene"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
)

type compute struct {
	ctx driver.Device
	enc encoder

	drawOps       drawOps
	collector     collector
	enc           encoder
	texOps        []textureOp
	cache         *resourceCache
	viewport      image.Point
	maxTextureDim int

	programs struct {


@@ 105,6 108,59 @@ type materialUniforms struct {
	pos   [2]float32
}

type collector struct {
	profile      bool
	reader       ops.Reader
	states       []encoderState
	clear        bool
	clearColor   f32color.RGBA
	clipCache    []clipState
	clipCmdCache []clipCmd
	paintOps     []paintOp
}

type paintOp struct {
	clipStack []clipCmd
	state     encoderState
}

// clipCmd describes a clipping command ready to be used for the compute
// pipeline.
type clipCmd struct {
	// union of the bounds of the operations that are clipped.
	union    f32.Rectangle
	state    *clipState
	relTrans f32.Affine2D
}

type encoderState struct {
	t         f32.Affine2D
	relTrans  f32.Affine2D
	clip      *clipState
	intersect f32.Rectangle

	matType materialType
	// Current paint.ImageOp
	image imageOpData
	// Current paint.ColorOp, if any.
	color color.NRGBA

	// Current paint.LinearGradientOp.
	stop1  f32.Point
	stop2  f32.Point
	color1 color.NRGBA
	color2 color.NRGBA
}

type clipState struct {
	bounds    f32.Rectangle
	absBounds f32.Rectangle
	pathVerts []byte
	parent    *clipState
	relTrans  f32.Affine2D
	stroke    clip.StrokeStyle
}

// materialVertex describes a vertex of a quad used to render a transformed
// material.
type materialVertex struct {


@@ 118,13 174,15 @@ type textureKey struct {
	transform f32.Affine2D
}

// textureOp represents an imageOp that requires texture space.
// textureOp represents an paintOp that requires texture space.
type textureOp struct {
	// sceneIdx is the index in the scene that contains the fill image command
	// that corresponds to the operation.
	sceneIdx int
	key      textureKey
	img      imageOpData
	key      textureKey
	// offset is the integer offset, separated from key.transform to increase cache hit rate.
	off image.Point

	// pos is the position of the untransformed image in the images texture.
	pos image.Point


@@ 173,6 231,9 @@ type memoryHeader struct {
	mem_error  uint32
}

// rect is a oriented rectangle.
type rectangle [4]f32.Point

// GPU structure sizes and constants.
const (
	tileWidthPx       = 32


@@ 205,7 266,6 @@ func newCompute(ctx driver.Device) (*compute, error) {
	}
	g := &compute{
		ctx:           ctx,
		cache:         newResourceCache(),
		maxTextureDim: maxDim,
		conf:          new(config),
		memHeader:     new(memoryHeader),


@@ 243,9 303,6 @@ func newCompute(ctx driver.Device) (*compute, error) {
	g.materials.uniBuf = buf
	g.materials.prog.SetVertexUniforms(buf)

	g.drawOps.pathCache = newOpCache()
	g.drawOps.compute = true

	buf, err = ctx.NewBuffer(driver.BufferBindingShaderStorage, int(unsafe.Sizeof(config{})))
	if err != nil {
		g.Release()


@@ 277,30 334,33 @@ func newCompute(ctx driver.Device) (*compute, error) {
}

func (g *compute) Collect(viewport image.Point, ops *op.Ops) {
	g.drawOps.reset(g.cache, viewport)
	g.drawOps.collect(g.ctx, g.cache, ops, viewport)
	for _, img := range g.drawOps.allImageOps {
		expandPathOp(img.path, img.clip)
	}
	g.encode(viewport)
	g.viewport = viewport
	g.collector.reset()
	g.enc.reset()
	g.texOps = g.texOps[:0]

	// Flip Y-axis.
	flipY := f32.Affine2D{}.Scale(f32.Pt(0, 0), f32.Pt(1, -1)).Offset(f32.Pt(0, float32(viewport.Y)))
	g.collector.collect(ops, flipY, viewport)
	g.collector.encode(viewport, &g.enc, &g.texOps)
}

func (g *compute) Clear(col color.NRGBA) {
	g.drawOps.clear = true
	g.drawOps.clearColor = f32color.LinearFromSRGB(col)
	g.collector.clear = true
	g.collector.clearColor = f32color.LinearFromSRGB(col)
}

func (g *compute) Frame() error {
	viewport := g.drawOps.viewport
	viewport := g.viewport
	tileDims := image.Point{
		X: (viewport.X + tileWidthPx - 1) / tileWidthPx,
		Y: (viewport.Y + tileHeightPx - 1) / tileHeightPx,
	}

	defFBO := g.ctx.BeginFrame(g.drawOps.clear, viewport)
	defFBO := g.ctx.BeginFrame(g.collector.clear, viewport)
	defer g.ctx.EndFrame()

	if g.drawOps.profile && g.timers.t == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
	if g.collector.profile && g.timers.t == nil && g.ctx.Caps().Features.Has(driver.FeatureTimers) {
		t := &g.timers
		t.t = newTimers(g.ctx)
		t.materials = g.timers.t.newTimer()


@@ 327,10 387,8 @@ func (g *compute) Frame() error {
	}
	g.ctx.BindFramebuffer(defFBO)
	g.blitOutput(viewport)
	g.cache.frame()
	g.drawOps.pathCache.frame()
	t := &g.timers
	if g.drawOps.profile && t.t.ready() {
	if g.collector.profile && t.t.ready() {
		mat := t.materials.Elapsed
		et, tat, pct, bbt := t.elements.Elapsed, t.tileAlloc.Elapsed, t.pathCoarse.Elapsed, t.backdropBinning.Elapsed
		ct, k4t := t.coarse.Elapsed, t.kernel4.Elapsed


@@ 344,7 402,7 @@ func (g *compute) Frame() error {
		blit = blit.Round(q)
		t.profile = fmt.Sprintf("ft:%7s mat: %7s et:%7s tat:%7s pct:%7s bbt:%7s ct:%7s k4t:%7s blit:%7s", ft, mat, et, tat, pct, bbt, ct, k4t, blit)
	}
	g.drawOps.clear = false
	g.collector.clear = false
	return nil
}



@@ 359,7 417,7 @@ func (g *compute) Profile() string {
func (g *compute) blitOutput(viewport image.Point) {
	t := g.timers.blit
	t.begin()
	if !g.drawOps.clear {
	if !g.collector.clear {
		g.ctx.BlendFunc(driver.BlendFactorOne, driver.BlendFactorOneMinusSrcAlpha)
		g.ctx.SetBlend(true)
		defer g.ctx.SetBlend(false)


@@ 371,20 429,6 @@ func (g *compute) blitOutput(viewport image.Point) {
	t.end()
}

func (g *compute) encode(viewport image.Point) {
	g.texOps = g.texOps[:0]
	g.enc.reset()

	// Flip Y-axis.
	flipY := f32.Affine2D{}.Scale(f32.Pt(0, 0), f32.Pt(1, -1)).Offset(f32.Pt(0, float32(viewport.Y)))
	g.enc.transform(flipY)
	if g.drawOps.clear {
		g.enc.rect(f32.Rectangle{Max: layout.FPt(viewport)})
		g.enc.fillColor(f32color.NRGBAToRGBA(g.drawOps.clearColor.SRGB()))
	}
	g.encodeOps(flipY, viewport, g.drawOps.allImageOps)
}

func (g *compute) renderMaterials() error {
	m := &g.materials
	m.quads = m.quads[:0]


@@ 394,7 438,7 @@ restart:
	for {
		for _, op := range g.texOps {
			if off, exists := m.offsets[op.key]; exists {
				g.enc.setFillImageOffset(op.sceneIdx, off)
				g.enc.setFillImageOffset(op.sceneIdx, off.Sub(op.off))
				continue
			}
			quad, bounds := g.materialQuad(op.key.transform, op.img, op.pos)


@@ 434,7 478,7 @@ restart:
				m.offsets = make(map[textureKey]image.Point)
			}
			m.offsets[op.key] = offset
			g.enc.setFillImageOffset(op.sceneIdx, offset)
			g.enc.setFillImageOffset(op.sceneIdx, offset.Sub(op.off))
		}
		break
	}


@@ 636,86 680,13 @@ func min(p1, p2 f32.Point) f32.Point {
	return p
}

func (g *compute) encodeOps(trans f32.Affine2D, viewport image.Point, ops []imageOp) {
	for _, op := range ops {
		bounds := layout.FRect(op.clip)
		// clip is the union of all drawing affected by the clipping
		// operation. TODO: tighten.
		clip := f32.Rect(0, 0, float32(viewport.X), float32(viewport.Y))
		nclips := g.encodeClipStack(clip, bounds, op.path, false)
		m := op.material
		switch m.material {
		case materialTexture:
			t := trans.Mul(m.trans)
			g.texOps = append(g.texOps, textureOp{
				sceneIdx: len(g.enc.scene),
				img:      m.data,
				key: textureKey{
					transform: t,
					handle:    m.data.handle,
				},
			})
			// Add fill command, its offset is resolved and filled in renderMaterials.
			g.enc.fillImage(0)
		case materialColor:
			g.enc.fillColor(f32color.NRGBAToRGBA(op.material.color.SRGB()))
		case materialLinearGradient:
			// TODO: implement.
			g.enc.fillColor(f32color.NRGBAToRGBA(op.material.color1.SRGB()))
		default:
			panic("not implemented")
		}
		if op.path != nil && op.path.path {
			g.enc.fillMode(scene.FillModeNonzero)
			g.enc.transform(op.path.trans.Invert())
		}
		// Pop the clip stack.
		for i := 0; i < nclips; i++ {
			g.enc.endClip(clip)
		}
	}
}

// encodeClips encodes a stack of clip paths and return the stack depth.
func (g *compute) encodeClipStack(clip, bounds f32.Rectangle, p *pathOp, begin bool) int {
	nclips := 0
	if p != nil && p.parent != nil {
		nclips += g.encodeClipStack(clip, bounds, p.parent, true)
		nclips += 1
	}
	isStroke := p.stroke.Width > 0
	if p != nil && p.path {
		if isStroke {
			g.enc.fillMode(scene.FillModeStroke)
			g.enc.lineWidth(p.stroke.Width)
		}
		pathData, _ := g.drawOps.pathCache.get(p.pathKey)
		g.enc.transform(p.trans)
		g.enc.append(pathData.computePath)
	} else {
		g.enc.rect(bounds)
	}
	if begin {
		g.enc.beginClip(clip)
		if isStroke {
			g.enc.fillMode(scene.FillModeNonzero)
		}
		if p != nil && p.path {
			g.enc.transform(p.trans.Invert())
		}
	}
	return nclips
}

func encodePath(verts []byte) encoder {
	var enc encoder
func (enc *encoder) encodePath(verts []byte) {
	for len(verts) >= scene.CommandSize+4 {
		cmd := ops.DecodeCommand(verts[4:])
		enc.scene = append(enc.scene, cmd)
		enc.npathseg++
		verts = verts[scene.CommandSize+4:]
	}
	return enc
}

func (g *compute) render(tileDims image.Point) error {


@@ 731,12 702,13 @@ func (g *compute) render(tileDims image.Point) error {
		return fmt.Errorf("gpu: output too large (%dx%d)", tileDims.X*tileWidthPx, tileDims.Y*tileHeightPx)
	}

	enc := &g.enc
	// Pad scene with zeroes to avoid reading garbage in elements.comp.
	scenePadding := partitionSize - len(g.enc.scene)%partitionSize
	g.enc.scene = append(g.enc.scene, make([]scene.Command, scenePadding)...)
	scenePadding := partitionSize - len(enc.scene)%partitionSize
	enc.scene = append(enc.scene, make([]scene.Command, scenePadding)...)

	realloced := false
	scene := byteslice.Slice(g.enc.scene)
	scene := byteslice.Slice(enc.scene)
	if s := len(scene); s > g.buffers.scene.size {
		realloced = true
		paddedCap := s * 11 / 10


@@ 770,19 742,19 @@ func (g *compute) render(tileDims image.Point) error {
	}

	*g.conf = config{
		n_elements:      uint32(g.enc.npath),
		n_pathseg:       uint32(g.enc.npathseg),
		n_elements:      uint32(enc.npath),
		n_pathseg:       uint32(enc.npathseg),
		width_in_tiles:  uint32(tileDims.X),
		height_in_tiles: uint32(tileDims.Y),
		tile_alloc:      malloc(g.enc.npath * pathSize),
		bin_alloc:       malloc(round(g.enc.npath, wgSize) * binSize),
		tile_alloc:      malloc(enc.npath * pathSize),
		bin_alloc:       malloc(round(enc.npath, wgSize) * binSize),
		ptcl_alloc:      malloc(tileDims.X * tileDims.Y * ptclInitialAlloc),
		pathseg_alloc:   malloc(g.enc.npathseg * pathsegSize),
		anno_alloc:      malloc(g.enc.npath * annoSize),
		trans_alloc:     malloc(g.enc.ntrans * transSize),
		pathseg_alloc:   malloc(enc.npathseg * pathsegSize),
		anno_alloc:      malloc(enc.npath * annoSize),
		trans_alloc:     malloc(enc.ntrans * transSize),
	}

	numPartitions := (g.enc.numElements() + 127) / 128
	numPartitions := (enc.numElements() + 127) / 128
	// clearSize is the atomic partition counter plus flag and 2 states per partition.
	clearSize := 4 + numPartitions*stateStride
	if clearSize > g.buffers.state.size {


@@ 825,20 797,20 @@ func (g *compute) render(tileDims image.Point) error {
		t.elements.end()
		t.tileAlloc.begin()
		g.ctx.BindProgram(g.programs.tileAlloc)
		g.ctx.DispatchCompute((g.enc.npath+wgSize-1)/wgSize, 1, 1)
		g.ctx.DispatchCompute((enc.npath+wgSize-1)/wgSize, 1, 1)
		g.ctx.MemoryBarrier()
		t.tileAlloc.end()
		t.pathCoarse.begin()
		g.ctx.BindProgram(g.programs.pathCoarse)
		g.ctx.DispatchCompute((g.enc.npathseg+31)/32, 1, 1)
		g.ctx.DispatchCompute((enc.npathseg+31)/32, 1, 1)
		g.ctx.MemoryBarrier()
		t.pathCoarse.end()
		t.backdropBinning.begin()
		g.ctx.BindProgram(g.programs.backdrop)
		g.ctx.DispatchCompute((g.enc.npath+wgSize-1)/wgSize, 1, 1)
		g.ctx.DispatchCompute((enc.npath+wgSize-1)/wgSize, 1, 1)
		// No barrier needed between backdrop and binning.
		g.ctx.BindProgram(g.programs.binning)
		g.ctx.DispatchCompute((g.enc.npath+wgSize-1)/wgSize, 1, 1)
		g.ctx.DispatchCompute((enc.npath+wgSize-1)/wgSize, 1, 1)
		g.ctx.MemoryBarrier()
		t.backdropBinning.end()
		t.coarse.begin()


@@ 901,12 873,6 @@ func (g *compute) resizeOutput(size image.Point) error {
}

func (g *compute) Release() {
	if g.drawOps.pathCache != nil {
		g.drawOps.pathCache.release()
	}
	if g.cache != nil {
		g.cache.release()
	}
	progs := []driver.Program{
		g.programs.elements,
		g.programs.tileAlloc,


@@ 1062,9 1028,11 @@ func (e *encoder) setFillImageOffset(index int, offset image.Point) {
	e.scene[index][2] = uint32(uint16(x)) | uint32(uint16(y))<<16
}

func (e *encoder) fillImage(index int) {
func (e *encoder) fillImage(index int) int {
	idx := len(e.scene)
	e.scene = append(e.scene, scene.FillImage(index))
	e.npath++
	return idx
}

func (e *encoder) line(start, end f32.Point) {


@@ 1076,3 1044,305 @@ func (e *encoder) quad(start, ctrl, end f32.Point) {
	e.scene = append(e.scene, scene.Quad(start, ctrl, end))
	e.npathseg++
}

func (c *collector) reset() {
	c.profile = false
	c.clipCache = c.clipCache[:0]
	c.clipCmdCache = c.clipCmdCache[:0]
	c.paintOps = c.paintOps[:0]
}

func (c *collector) addClip(state *encoderState, viewport, bounds f32.Rectangle, path []byte, stroke clip.StrokeStyle) {
	// Rectangle clip regions.
	if len(path) == 0 {
		transView := transformBounds(state.t.Invert(), viewport)
		// If the rectangular clip contains the viewport it can be discarded.
		if transView.In(bounds) {
			return
		}
		// If the rectangular clip region contains a previous path it can be discarded.
		p := state.clip
		t := state.relTrans.Invert()
		for p != nil {
			// rect is the parent bounds transformed relative to the rectangle.
			rect := transformBounds(t, p.bounds)
			if rect.In(bounds) {
				return
			}
			t = p.relTrans.Invert().Mul(t)
			p = p.parent
		}
	}

	absBounds := transformBounds(state.t, bounds).Bounds()
	c.clipCache = append(c.clipCache, clipState{
		parent:    state.clip,
		bounds:    bounds,
		absBounds: absBounds,
		relTrans:  state.relTrans,
		stroke:    stroke,
		pathVerts: path,
	})
	state.intersect = state.intersect.Intersect(absBounds)
	state.clip = &c.clipCache[len(c.clipCache)-1]
	state.relTrans = f32.Affine2D{}
}

func (c *collector) collect(root *op.Ops, trans f32.Affine2D, viewport image.Point) {
	fview := f32.Rectangle{Max: layout.FPt(viewport)}
	c.reader.Reset(root)
	state := encoderState{
		color:     color.NRGBA{A: 0xff},
		intersect: fview,
		t:         trans,
		relTrans:  trans,
	}
	r := &c.reader
	var (
		pathData []byte
		str      clip.StrokeStyle
	)
	c.save(opconst.InitialStateID, state)
	for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
		switch opconst.OpType(encOp.Data[0]) {
		case opconst.TypeProfile:
			c.profile = true
		case opconst.TypeTransform:
			dop := ops.DecodeTransform(encOp.Data)
			state.t = state.t.Mul(dop)
			state.relTrans = state.relTrans.Mul(dop)
		case opconst.TypeStroke:
			str = decodeStrokeOp(encOp.Data)
		case opconst.TypePath:
			encOp, ok = r.Decode()
			if !ok {
				panic("unexpected end of path operation")
			}
			pathData = encOp.Data[opconst.TypeAuxLen:]

		case opconst.TypeClip:
			var op clipOp
			op.decode(encOp.Data)
			c.addClip(&state, fview, op.bounds, pathData, str)
			pathData = nil
			str = clip.StrokeStyle{}
		case opconst.TypeColor:
			state.matType = materialColor
			state.color = decodeColorOp(encOp.Data)
		case opconst.TypeLinearGradient:
			state.matType = materialLinearGradient
			op := decodeLinearGradientOp(encOp.Data)
			state.stop1 = op.stop1
			state.stop2 = op.stop2
			state.color1 = op.color1
			state.color2 = op.color2
		case opconst.TypeImage:
			state.matType = materialTexture
			state.image = decodeImageOp(encOp.Data, encOp.Refs)
		case opconst.TypePaint:
			paintState := state
			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, clip.StrokeStyle{})
			}
			if paintState.intersect.Empty() {
				break
			}

			// If the paint is a uniform opaque color that takes up the whole
			// screen, it covers all previous paints and we can discard all
			// rendering commands recorded so far.
			if paintState.clip == nil && paintState.matType == materialColor && paintState.color.A == 255 {
				c.clearColor = f32color.LinearFromSRGB(paintState.color).Opaque()
				c.clear = true
				c.paintOps = c.paintOps[:0]
				break
			}

			// Flatten clip stack.
			p := paintState.clip
			startIdx := len(c.clipCmdCache)
			for p != nil {
				c.clipCmdCache = append(c.clipCmdCache, clipCmd{state: p, relTrans: p.relTrans})
				p = p.parent
			}
			clipStack := c.clipCmdCache[startIdx:]
			c.paintOps = append(c.paintOps, paintOp{
				clipStack: clipStack,
				state:     paintState,
			})
		case opconst.TypeSave:
			id := ops.DecodeSave(encOp.Data)
			c.save(id, state)
		case opconst.TypeLoad:
			id, mask := ops.DecodeLoad(encOp.Data)
			s := c.states[id]
			if mask&opconst.TransformState != 0 {
				state.t = s.t
			}
			if mask&^opconst.TransformState != 0 {
				state = s
			}
		}
	}
	for i := range c.paintOps {
		op := &c.paintOps[i]
		// For each clip, cull rectangular clip regions that contain its
		// (transformed) bounds. addClip already handled the converse case.
		// TODO: do better than O(n²) to efficiently deal with deep stacks.
		for i := 0; i < len(op.clipStack)-1; i++ {
			cl := op.clipStack[i]
			p := cl.state
			r := transformBounds(cl.relTrans, p.bounds)
			for j := i + 1; j < len(op.clipStack); j++ {
				cl2 := op.clipStack[j]
				p2 := cl2.state
				if len(p2.pathVerts) == 0 && r.In(p2.bounds) {
					op.clipStack = append(op.clipStack[:j], op.clipStack[j+1:]...)
					j--
					op.clipStack[j].relTrans = cl2.relTrans.Mul(op.clipStack[j].relTrans)
				}
				r = transformRect(cl2.relTrans, r)
			}
		}
	}
}

func (c *collector) encode(viewport image.Point, enc *encoder, texOps *[]textureOp) {
	fview := f32.Rectangle{Max: layout.FPt(viewport)}
	fillMode := scene.FillModeNonzero
	if c.clear {
		enc.rect(fview)
		enc.fillColor(f32color.NRGBAToRGBA(c.clearColor.SRGB()))
	}
	for _, op := range c.paintOps {
		// Fill in clip bounds, which the shaders expect to be the union
		// of all affected bounds.
		var union f32.Rectangle
		for i, cl := range op.clipStack {
			union = union.Union(cl.state.absBounds)
			op.clipStack[i].union = union
		}

		var inv f32.Affine2D
		for i := len(op.clipStack) - 1; i >= 0; i-- {
			cl := op.clipStack[i]
			if str := cl.state.stroke; str.Width > 0 {
				enc.fillMode(scene.FillModeStroke)
				enc.lineWidth(str.Width)
				fillMode = scene.FillModeStroke
			} else if fillMode != scene.FillModeNonzero {
				enc.fillMode(scene.FillModeNonzero)
				fillMode = scene.FillModeNonzero
			}
			enc.transform(cl.relTrans)
			inv = inv.Mul(cl.relTrans)
			if len(cl.state.pathVerts) == 0 {
				enc.rect(cl.state.bounds)
			} else {
				enc.encodePath(cl.state.pathVerts)
			}
			if i != 0 {
				enc.beginClip(cl.union)
			}
		}
		if op.state.clip == nil {
			// No clipping; fill the entire view.
			enc.rect(fview)
		}

		switch op.state.matType {
		case materialTexture:
			// Add fill command. Its offset is resolved and filled in renderMaterials.
			idx := enc.fillImage(0)
			sx, hx, ox, hy, sy, oy := op.state.t.Elems()
			// Separate integer offset from transformation. TextureOps that have identical transforms
			// except for their integer offsets can share a transformed image.
			intx, fracx := math.Modf(float64(ox))
			inty, fracy := math.Modf(float64(oy))
			t := f32.NewAffine2D(sx, hx, float32(fracx), hy, sy, float32(fracy))
			*texOps = append(*texOps, textureOp{
				sceneIdx: idx,
				img:      op.state.image,
				off:      image.Pt(int(intx), int(inty)),
				key: textureKey{
					transform: t,
					handle:    op.state.image.handle,
				},
			})
		case materialColor:
			enc.fillColor(f32color.NRGBAToRGBA(op.state.color))
		case materialLinearGradient:
			// TODO: implement.
			enc.fillColor(f32color.NRGBAToRGBA(op.state.color1))
		default:
			panic("not implemented")
		}
		enc.transform(inv.Invert())
		// Pop the clip stack, except the first entry used for fill.
		for i := 1; i < len(op.clipStack); i++ {
			cl := op.clipStack[i]
			enc.endClip(cl.union)
		}
	}
}

func (c *collector) save(id int, state encoderState) {
	if extra := id - len(c.states) + 1; extra > 0 {
		c.states = append(c.states, make([]encoderState, extra)...)
	}
	c.states[id] = state
}

func transformBounds(t f32.Affine2D, bounds f32.Rectangle) rectangle {
	return rectangle{
		t.Transform(bounds.Min), t.Transform(f32.Pt(bounds.Max.X, bounds.Min.Y)),
		t.Transform(bounds.Max), t.Transform(f32.Pt(bounds.Min.X, bounds.Max.Y)),
	}
}

func transformRect(t f32.Affine2D, r rectangle) rectangle {
	var tr rectangle
	for i, c := range r {
		tr[i] = t.Transform(c)
	}
	return tr
}

func (r rectangle) In(b f32.Rectangle) bool {
	for _, c := range r {
		inside := b.Min.X <= c.X && c.X <= b.Max.X &&
			b.Min.Y <= c.Y && c.Y <= b.Max.Y
		if !inside {
			return false
		}
	}
	return true
}

func (r rectangle) Contains(b f32.Rectangle) bool {
	return true
}

func (r rectangle) Bounds() f32.Rectangle {
	bounds := f32.Rectangle{
		Min: f32.Pt(math.MaxFloat32, math.MaxFloat32),
		Max: f32.Pt(-math.MaxFloat32, -math.MaxFloat32),
	}
	for _, c := range r {
		if c.X < bounds.Min.X {
			bounds.Min.X = c.X
		}
		if c.Y < bounds.Min.Y {
			bounds.Min.Y = c.Y
		}
		if c.X > bounds.Max.X {
			bounds.Max.X = c.X
		}
		if c.Y > bounds.Max.Y {
			bounds.Max.Y = c.Y
		}
	}
	return bounds
}

M gpu/gpu.go => gpu/gpu.go +17 -61
@@ 80,10 80,7 @@ type drawOps struct {
	viewport   image.Point
	clear      bool
	clearColor f32color.RGBA
	// allImageOps is the combined list of imageOps and
	// zimageOps, in drawing order.
	allImageOps []imageOp
	imageOps    []imageOp
	imageOps   []imageOp
	// zimageOps are the rectangle clipped opaque images
	// that can use fast front-to-back rendering with z-test
	// and no blending.


@@ 92,9 89,6 @@ type drawOps struct {
	pathOpCache []pathOp
	qs          quadSplitter
	pathCache   *opCache
	// hack for the compute renderer to access
	// converted path data.
	compute bool
}

type drawState struct {


@@ 127,10 121,6 @@ type pathOp struct {
	pathVerts []byte
	parent    *pathOp
	place     placement

	// For compute
	trans  f32.Affine2D
	stroke clip.StrokeStyle
}

type imageOp struct {


@@ 174,9 164,6 @@ type material struct {
	// For materialTypeTexture.
	data    imageOpData
	uvTrans f32.Affine2D

	// For the compute backend.
	trans f32.Affine2D
}

// clipOp is the shadow of clip.Op.


@@ 794,7 781,6 @@ func (d *drawOps) reset(cache *resourceCache, viewport image.Point) {
	d.cache = cache
	d.viewport = viewport
	d.imageOps = d.imageOps[:0]
	d.allImageOps = d.allImageOps[:0]
	d.zimageOps = d.zimageOps[:0]
	d.pathOps = d.pathOps[:0]
	d.pathOpCache = d.pathOpCache[:0]


@@ 815,14 801,9 @@ func (d *drawOps) collect(ctx driver.Device, cache *resourceCache, root *op.Ops,
	for _, p := range d.pathOps {
		if v, exists := d.pathCache.get(p.pathKey); !exists || v.data.data == nil {
			data := buildPath(ctx, p.pathVerts)
			var computePath encoder
			if d.compute {
				computePath = encodePath(p.pathVerts)
			}
			d.pathCache.put(p.pathKey, opCacheValue{
				data:        data,
				bounds:      p.bounds,
				computePath: computePath,
				data:   data,
				bounds: p.bounds,
			})
		}
		p.pathVerts = nil


@@ 834,14 815,12 @@ func (d *drawOps) newPathOp() *pathOp {
	return &d.pathOpCache[len(d.pathOpCache)-1]
}

func (d *drawOps) addClipPath(state *drawState, aux []byte, auxKey opKey, bounds f32.Rectangle, off f32.Point, tr f32.Affine2D, stroke clip.StrokeStyle) {
func (d *drawOps) addClipPath(state *drawState, aux []byte, auxKey opKey, bounds f32.Rectangle, off f32.Point) {
	npath := d.newPathOp()
	*npath = pathOp{
		parent: state.cpath,
		bounds: bounds,
		off:    off,
		trans:  tr,
		stroke: stroke,
	}
	state.cpath = npath
	if len(aux) > 0 {


@@ 853,7 832,7 @@ func (d *drawOps) addClipPath(state *drawState, aux []byte, auxKey opKey, bounds
	}
}

// split a transform into two parts, one which is pur offset and the
// split a transform into two parts, one which is pure offset and the
// other representing the scaling, shearing and rotation part
func splitTransform(t f32.Affine2D) (srs f32.Affine2D, offset f32.Point) {
	sx, hx, ox, hy, sy, oy := t.Elems()


@@ 924,9 903,7 @@ loop:
						quads.aux, trans, op.outline, str,
					)
					op.bounds = bounds
					if !d.compute {
						quads.aux = pathData
					}
					quads.aux = pathData
					// add it to the cache, without GPU data, so the transform can be
					// reused.
					d.pathCache.put(quads.key, opCacheValue{bounds: op.bounds})


@@ 937,7 914,7 @@ loop:
				quads.key.SetTransform(trans) // TODO: This call has no effect.
			}
			state.clip = state.clip.Intersect(op.bounds.Add(off))
			d.addClipPath(&state, quads.aux, quads.key, op.bounds, off, state.t, str)
			d.addClipPath(&state, quads.aux, quads.key, op.bounds, off)
			quads = quadsOp{}
			str = clip.StrokeStyle{}



@@ 978,16 955,15 @@ loop:
				// this transformed rectangle.
				k := opKey{Key: encOp.Key}
				k.SetTransform(trans) // TODO: This call has no effect.
				d.addClipPath(&state, clipData, k, bnd, off, state.t, clip.StrokeStyle{})
				d.addClipPath(&state, clipData, k, bnd, off)
			}

			bounds := boundRectF(cl)
			mat := state.materialFor(bnd, off, partialTrans, bounds, state.t)
			mat := state.materialFor(bnd, off, partialTrans, bounds)

			if bounds.Min == (image.Point{}) && bounds.Max == d.viewport && state.rect && mat.opaque && (mat.material == materialColor) {
				// The image is a uniform opaque color and takes up the whole screen.
				// Scrap images up to and including this image and set clear color.
				d.allImageOps = d.allImageOps[:0]
				d.zimageOps = d.zimageOps[:0]
				d.imageOps = d.imageOps[:0]
				z = 0


@@ 1011,7 987,6 @@ loop:
				material: mat,
			}

			d.allImageOps = append(d.allImageOps, img)
			if state.rect && img.material.opaque {
				d.zimageOps = append(d.zimageOps, img)
			} else {


@@ 1049,7 1024,7 @@ func expandPathOp(p *pathOp, clip image.Rectangle) {
	}
}

func (d *drawState) materialFor(rect f32.Rectangle, off f32.Point, partTrans f32.Affine2D, clip image.Rectangle, trans f32.Affine2D) material {
func (d *drawState) materialFor(rect f32.Rectangle, off f32.Point, partTrans f32.Affine2D, clip image.Rectangle) material {
	var m material
	switch d.matType {
	case materialColor:


@@ 1084,7 1059,6 @@ func (d *drawState) materialFor(rect f32.Rectangle, off f32.Point, partTrans f32
		sr.Max.Y -= float32(dr.Max.Y-clip.Max.Y) * sdy / dy
		uvScale, uvOffset := texSpaceTransform(sr, sz)
		m.uvTrans = partTrans.Mul(f32.Affine2D{}.Scale(f32.Point{}, uvScale).Offset(uvOffset))
		m.trans = trans
		m.data = d.image
	}
	return m


@@ 1429,31 1403,13 @@ func (d *drawOps) boundsForTransformedRect(r f32.Rectangle, tr f32.Affine2D) (au

	// build the GPU vertices
	l := len(d.vertCache)
	if !d.compute {
		d.vertCache = append(d.vertCache, make([]byte, vertStride*4*4)...)
		aux = d.vertCache[l:]
		encodeQuadTo(aux, 0, corners[0], corners[0].Add(corners[1]).Mul(0.5), corners[1])
		encodeQuadTo(aux[vertStride*4:], 0, corners[1], corners[1].Add(corners[2]).Mul(0.5), corners[2])
		encodeQuadTo(aux[vertStride*4*2:], 0, corners[2], corners[2].Add(corners[3]).Mul(0.5), corners[3])
		encodeQuadTo(aux[vertStride*4*3:], 0, corners[3], corners[3].Add(corners[0]).Mul(0.5), corners[0])
		fillMaxY(aux)
	} else {
		d.vertCache = append(d.vertCache, make([]byte, (scene.CommandSize+4)*4)...)
		aux = d.vertCache[l:]
		buf := aux
		bo := binary.LittleEndian
		bo.PutUint32(buf, 0) // Contour
		ops.EncodeCommand(buf[4:], scene.Line(r.Min, f32.Pt(r.Max.X, r.Min.Y)))
		buf = buf[4+scene.CommandSize:]
		bo.PutUint32(buf, 0)
		ops.EncodeCommand(buf[4:], scene.Line(f32.Pt(r.Max.X, r.Min.Y), r.Max))
		buf = buf[4+scene.CommandSize:]
		bo.PutUint32(buf, 0)
		ops.EncodeCommand(buf[4:], scene.Line(r.Max, f32.Pt(r.Min.X, r.Max.Y)))
		buf = buf[4+scene.CommandSize:]
		bo.PutUint32(buf, 0)
		ops.EncodeCommand(buf[4:], scene.Line(f32.Pt(r.Min.X, r.Max.Y), r.Min))
	}
	d.vertCache = append(d.vertCache, make([]byte, vertStride*4*4)...)
	aux = d.vertCache[l:]
	encodeQuadTo(aux, 0, corners[0], corners[0].Add(corners[1]).Mul(0.5), corners[1])
	encodeQuadTo(aux[vertStride*4:], 0, corners[1], corners[1].Add(corners[2]).Mul(0.5), corners[2])
	encodeQuadTo(aux[vertStride*4*2:], 0, corners[2], corners[2].Add(corners[3]).Mul(0.5), corners[3])
	encodeQuadTo(aux[vertStride*4*3:], 0, corners[3], corners[3].Add(corners[0]).Mul(0.5), corners[0])
	fillMaxY(aux)

	// establish the transform mapping from bounds rectangle to transformed corners
	var P1, P2, P3 f32.Point