/
gpu.go
1011 lines (933 loc) · 25.5 KB
/
gpu.go
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// SPDX-License-Identifier: Unlicense OR MIT
package gpu
import (
"encoding/binary"
"fmt"
"image"
"image/color"
"math"
"strings"
"time"
"unsafe"
"github.com/gop9/olt/gio/app/internal/gl"
"github.com/gop9/olt/gio/f32"
"github.com/gop9/olt/gio/internal/opconst"
"github.com/gop9/olt/gio/internal/ops"
"github.com/gop9/olt/gio/internal/path"
"github.com/gop9/olt/gio/op"
"github.com/gop9/olt/gio/op/paint"
)
type GPU struct {
pathCache *opCache
cache *resourceCache
timers *timers
frameStart time.Time
zopsTimer, stencilTimer, coverTimer, cleanupTimer *timer
drawOps drawOps
ctx *context
renderer *renderer
}
type renderer struct {
ctx *context
blitter *blitter
pather *pather
packer packer
intersections packer
}
type drawOps struct {
reader ops.Reader
cache *resourceCache
viewport image.Point
clearColor [3]float32
imageOps []imageOp
// zimageOps are the rectangle clipped opaque images
// that can use fast front-to-back rendering with z-test
// and no blending.
zimageOps []imageOp
pathOps []*pathOp
pathOpCache []pathOp
}
type drawState struct {
clip f32.Rectangle
t op.TransformOp
cpath *pathOp
rect bool
z int
matType materialType
// Current paint.ImageOp
image imageOpData
// Current paint.ColorOp, if any.
color color.RGBA
}
type pathOp struct {
off f32.Point
// clip is the union of all
// later clip rectangles.
clip image.Rectangle
pathKey ops.Key
path bool
pathVerts []byte
parent *pathOp
place placement
}
type imageOp struct {
z float32
path *pathOp
off f32.Point
clip image.Rectangle
material material
clipType clipType
place placement
}
type material struct {
material materialType
opaque bool
// For materialTypeColor.
color [4]float32
// For materialTypeTexture.
texture *texture
uvScale f32.Point
uvOffset f32.Point
}
// clipOp is the shadow of clip.Op.
type clipOp struct {
bounds f32.Rectangle
}
// imageOpData is the shadow of paint.ImageOp.
type imageOpData struct {
src *image.RGBA
handle interface{}
}
func (op *clipOp) decode(data []byte) {
if opconst.OpType(data[0]) != opconst.TypeClip {
panic("invalid op")
}
bo := binary.LittleEndian
r := f32.Rectangle{
Min: f32.Point{
X: math.Float32frombits(bo.Uint32(data[1:])),
Y: math.Float32frombits(bo.Uint32(data[5:])),
},
Max: f32.Point{
X: math.Float32frombits(bo.Uint32(data[9:])),
Y: math.Float32frombits(bo.Uint32(data[13:])),
},
}
*op = clipOp{
bounds: r,
}
}
func decodeImageOp(data []byte, refs []interface{}) imageOpData {
if opconst.OpType(data[0]) != opconst.TypeImage {
panic("invalid op")
}
handle := refs[1]
if handle == nil {
panic("nil handle")
}
return imageOpData{
src: refs[0].(*image.RGBA),
handle: handle,
}
}
func decodeColorOp(data []byte) color.RGBA {
if opconst.OpType(data[0]) != opconst.TypeColor {
panic("invalid op")
}
return color.RGBA{
R: data[1],
G: data[2],
B: data[3],
A: data[4],
}
}
func decodePaintOp(data []byte) paint.PaintOp {
bo := binary.LittleEndian
if opconst.OpType(data[0]) != opconst.TypePaint {
panic("invalid op")
}
r := f32.Rectangle{
Min: f32.Point{
X: math.Float32frombits(bo.Uint32(data[1:])),
Y: math.Float32frombits(bo.Uint32(data[5:])),
},
Max: f32.Point{
X: math.Float32frombits(bo.Uint32(data[9:])),
Y: math.Float32frombits(bo.Uint32(data[13:])),
},
}
return paint.PaintOp{
Rect: r,
}
}
type clipType uint8
type resource interface {
release(ctx *context)
}
type texture struct {
src *image.RGBA
id gl.Texture
}
type blitter struct {
ctx *context
viewport image.Point
prog [2]gl.Program
vars [2]struct {
z gl.Uniform
uScale, uOffset gl.Uniform
uUVScale, uUVOffset gl.Uniform
uColor gl.Uniform
}
quadVerts gl.Buffer
}
type materialType uint8
const (
clipTypeNone clipType = iota
clipTypePath
clipTypeIntersection
)
const (
materialColor materialType = iota
materialTexture
)
var (
blitAttribs = []string{"pos", "uv"}
attribPos gl.Attrib = 0
attribUV gl.Attrib = 1
)
func New(ctx *gl.Functions) (*GPU, error) {
g := &GPU{
pathCache: newOpCache(),
cache: newResourceCache(),
}
if err := g.init(ctx); err != nil {
return nil, err
}
return g, nil
}
func (g *GPU) init(glctx *gl.Functions) error {
ctx, err := newContext(glctx)
if err != nil {
return err
}
g.ctx = ctx
g.renderer = newRenderer(ctx)
return nil
}
func (g *GPU) Release() {
g.renderer.release()
g.pathCache.release(g.ctx)
g.cache.release(g.ctx)
if g.timers != nil {
g.timers.release()
}
}
func (g *GPU) Collect(profile bool, viewport image.Point, frameOps *op.Ops) {
g.drawOps.reset(g.cache, viewport)
g.drawOps.collect(g.cache, frameOps, viewport)
g.frameStart = time.Now()
if profile && g.timers == nil && g.ctx.caps.EXT_disjoint_timer_query {
g.timers = newTimers(g.ctx)
g.zopsTimer = g.timers.newTimer()
g.stencilTimer = g.timers.newTimer()
g.coverTimer = g.timers.newTimer()
g.cleanupTimer = g.timers.newTimer()
}
for _, p := range g.drawOps.pathOps {
if _, exists := g.pathCache.get(p.pathKey); !exists {
data := buildPath(g.ctx, p.pathVerts)
g.pathCache.put(p.pathKey, data)
}
p.pathVerts = nil
}
}
func (g *GPU) Frame(profile bool, viewport image.Point) {
g.renderer.blitter.viewport = viewport
g.renderer.pather.viewport = viewport
for _, img := range g.drawOps.imageOps {
expandPathOp(img.path, img.clip)
}
if profile {
g.zopsTimer.begin()
}
g.ctx.DepthFunc(gl.GREATER)
g.ctx.ClearColor(g.drawOps.clearColor[0], g.drawOps.clearColor[1], g.drawOps.clearColor[2], 1.0)
g.ctx.ClearDepthf(0.0)
g.ctx.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
g.ctx.Viewport(0, 0, viewport.X, viewport.Y)
g.renderer.drawZOps(g.drawOps.zimageOps)
g.zopsTimer.end()
g.stencilTimer.begin()
g.ctx.Enable(gl.BLEND)
g.renderer.packStencils(&g.drawOps.pathOps)
g.renderer.stencilClips(g.pathCache, g.drawOps.pathOps)
g.renderer.packIntersections(g.drawOps.imageOps)
g.renderer.intersect(g.drawOps.imageOps)
g.stencilTimer.end()
g.coverTimer.begin()
g.ctx.Viewport(0, 0, viewport.X, viewport.Y)
g.renderer.drawOps(g.drawOps.imageOps)
g.ctx.Disable(gl.BLEND)
g.renderer.pather.stenciler.invalidateFBO()
g.coverTimer.end()
}
func (g *GPU) EndFrame(profile bool) string {
g.cleanupTimer.begin()
g.cache.frame(g.ctx)
g.pathCache.frame(g.ctx)
g.cleanupTimer.end()
var summary string
if profile && g.timers.ready() {
zt, st, covt, cleant := g.zopsTimer.Elapsed, g.stencilTimer.Elapsed, g.coverTimer.Elapsed, g.cleanupTimer.Elapsed
ft := zt + st + covt + cleant
q := 100 * time.Microsecond
zt, st, covt = zt.Round(q), st.Round(q), covt.Round(q)
frameDur := time.Since(g.frameStart).Round(q)
ft = ft.Round(q)
summary = fmt.Sprintf("draw:%7s gpu:%7s zt:%7s st:%7s cov:%7s", frameDur, ft, zt, st, covt)
}
return summary
}
func (r *renderer) texHandle(t *texture) gl.Texture {
if t.id.Valid() {
return t.id
}
t.id = createTexture(r.ctx)
r.ctx.BindTexture(gl.TEXTURE_2D, t.id)
r.uploadTexture(t.src)
return t.id
}
func (t *texture) release(ctx *context) {
if t.id.Valid() {
ctx.DeleteTexture(t.id)
}
}
func newRenderer(ctx *context) *renderer {
r := &renderer{
ctx: ctx,
blitter: newBlitter(ctx),
pather: newPather(ctx),
}
r.packer.maxDim = ctx.GetInteger(gl.MAX_TEXTURE_SIZE)
r.intersections.maxDim = r.packer.maxDim
return r
}
func (r *renderer) release() {
r.pather.release()
r.blitter.release()
}
func newBlitter(ctx *context) *blitter {
prog, err := createColorPrograms(ctx, blitVSrc, blitFSrc)
if err != nil {
panic(err)
}
quadVerts := ctx.CreateBuffer()
ctx.BindBuffer(gl.ARRAY_BUFFER, quadVerts)
ctx.BufferData(gl.ARRAY_BUFFER,
gl.BytesView([]float32{
-1, +1, 0, 0,
+1, +1, 1, 0,
-1, -1, 0, 1,
+1, -1, 1, 1,
}),
gl.STATIC_DRAW)
b := &blitter{
ctx: ctx,
prog: prog,
quadVerts: quadVerts,
}
for i, prog := range prog {
ctx.UseProgram(prog)
switch materialType(i) {
case materialTexture:
uTex := gl.GetUniformLocation(ctx.Functions, prog, "tex")
ctx.Uniform1i(uTex, 0)
b.vars[i].uUVScale = gl.GetUniformLocation(ctx.Functions, prog, "uvScale")
b.vars[i].uUVOffset = gl.GetUniformLocation(ctx.Functions, prog, "uvOffset")
case materialColor:
b.vars[i].uColor = gl.GetUniformLocation(ctx.Functions, prog, "color")
}
b.vars[i].z = gl.GetUniformLocation(ctx.Functions, prog, "z")
b.vars[i].uScale = gl.GetUniformLocation(ctx.Functions, prog, "scale")
b.vars[i].uOffset = gl.GetUniformLocation(ctx.Functions, prog, "offset")
}
return b
}
func (b *blitter) release() {
b.ctx.DeleteBuffer(b.quadVerts)
for _, p := range b.prog {
b.ctx.DeleteProgram(p)
}
}
func createColorPrograms(ctx *context, vsSrc, fsSrc string) ([2]gl.Program, error) {
var prog [2]gl.Program
frep := strings.NewReplacer(
"HEADER", `
uniform sampler2D tex;
`,
"GET_COLOR", `texture2D(tex, vUV)`,
)
fsSrcTex := frep.Replace(fsSrc)
var err error
prog[materialTexture], err = gl.CreateProgram(ctx.Functions, vsSrc, fsSrcTex, blitAttribs)
if err != nil {
return prog, err
}
frep = strings.NewReplacer(
"HEADER", `
uniform vec4 color;
`,
"GET_COLOR", `color`,
)
fsSrcCol := frep.Replace(fsSrc)
prog[materialColor], err = gl.CreateProgram(ctx.Functions, vsSrc, fsSrcCol, blitAttribs)
if err != nil {
ctx.DeleteProgram(prog[materialTexture])
return prog, err
}
return prog, nil
}
func (r *renderer) stencilClips(pathCache *opCache, ops []*pathOp) {
if len(r.packer.sizes) == 0 {
return
}
fbo := -1
r.pather.begin(r.packer.sizes)
for _, p := range ops {
if fbo != p.place.Idx {
fbo = p.place.Idx
f := r.pather.stenciler.cover(fbo)
bindFramebuffer(r.ctx, f.fbo)
r.ctx.Clear(gl.COLOR_BUFFER_BIT)
}
data, _ := pathCache.get(p.pathKey)
r.pather.stencilPath(p.clip, p.off, p.place.Pos, data.(*pathData))
}
r.pather.end()
}
func (r *renderer) intersect(ops []imageOp) {
if len(r.intersections.sizes) == 0 {
return
}
fbo := -1
r.pather.stenciler.beginIntersect(r.intersections.sizes)
r.ctx.BindBuffer(gl.ARRAY_BUFFER, r.blitter.quadVerts)
r.ctx.VertexAttribPointer(attribPos, 2, gl.FLOAT, false, 4*4, 0)
r.ctx.VertexAttribPointer(attribUV, 2, gl.FLOAT, false, 4*4, 4*2)
r.ctx.EnableVertexAttribArray(attribPos)
r.ctx.EnableVertexAttribArray(attribUV)
for _, img := range ops {
if img.clipType != clipTypeIntersection {
continue
}
if fbo != img.place.Idx {
fbo = img.place.Idx
f := r.pather.stenciler.intersections.fbos[fbo]
bindFramebuffer(r.ctx, f.fbo)
r.ctx.Clear(gl.COLOR_BUFFER_BIT)
}
r.ctx.Viewport(img.place.Pos.X, img.place.Pos.Y, img.clip.Dx(), img.clip.Dy())
r.intersectPath(img.path, img.clip)
}
r.ctx.DisableVertexAttribArray(attribPos)
r.ctx.DisableVertexAttribArray(attribUV)
r.pather.stenciler.endIntersect()
}
func (r *renderer) intersectPath(p *pathOp, clip image.Rectangle) {
if p.parent != nil {
r.intersectPath(p.parent, clip)
}
if !p.path {
return
}
o := p.place.Pos.Add(clip.Min).Sub(p.clip.Min)
uv := image.Rectangle{
Min: o,
Max: o.Add(clip.Size()),
}
fbo := r.pather.stenciler.cover(p.place.Idx)
r.ctx.BindTexture(gl.TEXTURE_2D, fbo.tex)
coverScale, coverOff := texSpaceTransform(toRectF(uv), fbo.size)
r.ctx.Uniform2f(r.pather.stenciler.uIntersectUVScale, coverScale.X, coverScale.Y)
r.ctx.Uniform2f(r.pather.stenciler.uIntersectUVOffset, coverOff.X, coverOff.Y)
r.ctx.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)
}
func (r *renderer) packIntersections(ops []imageOp) {
r.intersections.clear()
for i, img := range ops {
var npaths int
var onePath *pathOp
for p := img.path; p != nil; p = p.parent {
if p.path {
onePath = p
npaths++
}
}
switch npaths {
case 0:
case 1:
place := onePath.place
place.Pos = place.Pos.Sub(onePath.clip.Min).Add(img.clip.Min)
ops[i].place = place
ops[i].clipType = clipTypePath
default:
sz := image.Point{X: img.clip.Dx(), Y: img.clip.Dy()}
place, ok := r.intersections.add(sz)
if !ok {
panic("internal error: if the intersection fit, the intersection should fit as well")
}
ops[i].clipType = clipTypeIntersection
ops[i].place = place
}
}
}
func (r *renderer) packStencils(pops *[]*pathOp) {
r.packer.clear()
ops := *pops
// Allocate atlas space for cover textures.
var i int
for i < len(ops) {
p := ops[i]
if p.clip.Empty() {
ops[i] = ops[len(ops)-1]
ops = ops[:len(ops)-1]
continue
}
sz := image.Point{X: p.clip.Dx(), Y: p.clip.Dy()}
place, ok := r.packer.add(sz)
if !ok {
// The clip area is at most the entire screen. Hopefully no
// screen is larger than GL_MAX_TEXTURE_SIZE.
panic(fmt.Errorf("clip area %v is larger than maximum texture size %dx%d", p.clip, r.packer.maxDim, r.packer.maxDim))
}
p.place = place
i++
}
*pops = ops
}
// intersects intersects clip and b where b is offset by off.
// ceilRect returns a bounding image.Rectangle for a f32.Rectangle.
func boundRectF(r f32.Rectangle) image.Rectangle {
return image.Rectangle{
Min: image.Point{
X: int(floor(r.Min.X)),
Y: int(floor(r.Min.Y)),
},
Max: image.Point{
X: int(ceil(r.Max.X)),
Y: int(ceil(r.Max.Y)),
},
}
}
func toRectF(r image.Rectangle) f32.Rectangle {
return f32.Rectangle{
Min: f32.Point{
X: float32(r.Min.X),
Y: float32(r.Min.Y),
},
Max: f32.Point{
X: float32(r.Max.X),
Y: float32(r.Max.Y),
},
}
}
func ceil(v float32) int {
return int(math.Ceil(float64(v)))
}
func floor(v float32) int {
return int(math.Floor(float64(v)))
}
func (d *drawOps) reset(cache *resourceCache, viewport image.Point) {
d.clearColor = [3]float32{1.0, 1.0, 1.0}
d.cache = cache
d.viewport = viewport
d.imageOps = d.imageOps[:0]
d.zimageOps = d.zimageOps[:0]
d.pathOps = d.pathOps[:0]
d.pathOpCache = d.pathOpCache[:0]
}
func (d *drawOps) collect(cache *resourceCache, root *op.Ops, viewport image.Point) {
d.reset(cache, viewport)
clip := f32.Rectangle{
Max: f32.Point{X: float32(viewport.X), Y: float32(viewport.Y)},
}
d.reader.Reset(root)
state := drawState{
clip: clip,
rect: true,
color: color.RGBA{A: 0xff},
}
d.collectOps(&d.reader, state)
}
func (d *drawOps) newPathOp() *pathOp {
d.pathOpCache = append(d.pathOpCache, pathOp{})
return &d.pathOpCache[len(d.pathOpCache)-1]
}
func (d *drawOps) collectOps(r *ops.Reader, state drawState) int {
var aux []byte
var auxKey ops.Key
loop:
for encOp, ok := r.Decode(); ok; encOp, ok = r.Decode() {
switch opconst.OpType(encOp.Data[0]) {
case opconst.TypeTransform:
dop := ops.DecodeTransformOp(encOp.Data)
state.t = state.t.Multiply(op.TransformOp(dop))
case opconst.TypeAux:
aux = encOp.Data[opconst.TypeAuxLen:]
// The first data byte stores whether the MaxY
// fields have been initialized.
maxyFilled := aux[0] == 1
aux[0] = 1
aux = aux[1:]
if !maxyFilled {
fillMaxY(aux)
}
auxKey = encOp.Key
case opconst.TypeClip:
var op clipOp
op.decode(encOp.Data)
off := state.t.Transform(f32.Point{})
state.clip = state.clip.Intersect(op.bounds.Add(off))
if state.clip.Empty() {
continue
}
npath := d.newPathOp()
*npath = pathOp{
parent: state.cpath,
off: off,
}
state.cpath = npath
if len(aux) > 0 {
state.rect = false
state.cpath.pathKey = auxKey
state.cpath.path = true
state.cpath.pathVerts = aux
d.pathOps = append(d.pathOps, state.cpath)
}
aux = nil
auxKey = ops.Key{}
case opconst.TypeColor:
state.matType = materialColor
state.color = decodeColorOp(encOp.Data)
case opconst.TypeImage:
state.matType = materialTexture
state.image = decodeImageOp(encOp.Data, encOp.Refs)
case opconst.TypePaint:
op := decodePaintOp(encOp.Data)
off := state.t.Transform(f32.Point{})
clip := state.clip.Intersect(op.Rect.Add(off))
if clip.Empty() {
continue
}
bounds := boundRectF(clip)
mat := state.materialFor(d.cache, op.Rect, off, 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.zimageOps = d.zimageOps[:0]
d.imageOps = d.imageOps[:0]
state.z = 0
copy(d.clearColor[:], mat.color[:3])
continue
}
state.z++
// Assume 16-bit depth buffer.
const zdepth = 1 << 16
// Convert z to window-space, assuming depth range [0;1].
zf := float32(state.z)*2/zdepth - 1.0
img := imageOp{
z: zf,
path: state.cpath,
off: off,
clip: bounds,
material: mat,
}
if state.rect && img.material.opaque {
d.zimageOps = append(d.zimageOps, img)
} else {
d.imageOps = append(d.imageOps, img)
}
case opconst.TypePush:
state.z = d.collectOps(r, state)
case opconst.TypePop:
break loop
}
}
return state.z
}
func expandPathOp(p *pathOp, clip image.Rectangle) {
for p != nil {
pclip := p.clip
if !pclip.Empty() {
clip = clip.Union(pclip)
}
p.clip = clip
p = p.parent
}
}
func (d *drawState) materialFor(cache *resourceCache, rect f32.Rectangle, off f32.Point, clip image.Rectangle) material {
var m material
switch d.matType {
case materialColor:
m.material = materialColor
m.color = gamma(d.color.RGBA())
m.opaque = m.color[3] == 1.0
case materialTexture:
m.material = materialTexture
dr := boundRectF(rect.Add(off))
sz := d.image.src.Bounds().Size()
sr := f32.Rectangle{
Max: f32.Point{
X: float32(sz.X),
Y: float32(sz.Y),
},
}
if dx := float32(dr.Dx()); dx != 0 {
// Don't clip 1 px width sources.
if sdx := sr.Dx(); sdx > 1 {
sr.Min.X += (float32(clip.Min.X-dr.Min.X)*sdx + dx/2) / dx
sr.Max.X -= (float32(dr.Max.X-clip.Max.X)*sdx + dx/2) / dx
}
}
if dy := float32(dr.Dy()); dy != 0 {
// Don't clip 1 px height sources.
if sdy := sr.Dy(); sdy > 1 {
sr.Min.Y += (float32(clip.Min.Y-dr.Min.Y)*sdy + dy/2) / dy
sr.Max.Y -= (float32(dr.Max.Y-clip.Max.Y)*sdy + dy/2) / dy
}
}
tex, exists := cache.get(d.image.handle)
if !exists {
t := &texture{
src: d.image.src,
}
cache.put(d.image.handle, t)
tex = t
}
m.texture = tex.(*texture)
m.uvScale, m.uvOffset = texSpaceTransform(sr, sz)
}
return m
}
func (r *renderer) drawZOps(ops []imageOp) {
r.ctx.Enable(gl.DEPTH_TEST)
r.ctx.BindBuffer(gl.ARRAY_BUFFER, r.blitter.quadVerts)
r.ctx.VertexAttribPointer(attribPos, 2, gl.FLOAT, false, 4*4, 0)
r.ctx.VertexAttribPointer(attribUV, 2, gl.FLOAT, false, 4*4, 4*2)
r.ctx.EnableVertexAttribArray(attribPos)
r.ctx.EnableVertexAttribArray(attribUV)
// Render front to back.
for i := len(ops) - 1; i >= 0; i-- {
img := ops[i]
m := img.material
switch m.material {
case materialTexture:
r.ctx.BindTexture(gl.TEXTURE_2D, r.texHandle(m.texture))
}
drc := img.clip
scale, off := clipSpaceTransform(drc, r.blitter.viewport)
r.blitter.blit(img.z, m.material, m.color, scale, off, m.uvScale, m.uvOffset)
}
r.ctx.DisableVertexAttribArray(attribPos)
r.ctx.DisableVertexAttribArray(attribUV)
r.ctx.Disable(gl.DEPTH_TEST)
}
func (r *renderer) drawOps(ops []imageOp) {
r.ctx.Enable(gl.DEPTH_TEST)
r.ctx.DepthMask(false)
r.ctx.BlendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA)
r.ctx.BindBuffer(gl.ARRAY_BUFFER, r.blitter.quadVerts)
r.ctx.VertexAttribPointer(attribPos, 2, gl.FLOAT, false, 4*4, 0)
r.ctx.VertexAttribPointer(attribUV, 2, gl.FLOAT, false, 4*4, 4*2)
r.ctx.EnableVertexAttribArray(attribPos)
r.ctx.EnableVertexAttribArray(attribUV)
var coverTex gl.Texture
for _, img := range ops {
m := img.material
switch m.material {
case materialTexture:
r.ctx.BindTexture(gl.TEXTURE_2D, r.texHandle(m.texture))
}
drc := img.clip
scale, off := clipSpaceTransform(drc, r.blitter.viewport)
var fbo stencilFBO
switch img.clipType {
case clipTypeNone:
r.blitter.blit(img.z, m.material, m.color, scale, off, m.uvScale, m.uvOffset)
continue
case clipTypePath:
fbo = r.pather.stenciler.cover(img.place.Idx)
case clipTypeIntersection:
fbo = r.pather.stenciler.intersections.fbos[img.place.Idx]
}
if !coverTex.Equal(fbo.tex) {
coverTex = fbo.tex
r.ctx.ActiveTexture(gl.TEXTURE1)
r.ctx.BindTexture(gl.TEXTURE_2D, coverTex)
r.ctx.ActiveTexture(gl.TEXTURE0)
}
uv := image.Rectangle{
Min: img.place.Pos,
Max: img.place.Pos.Add(drc.Size()),
}
coverScale, coverOff := texSpaceTransform(toRectF(uv), fbo.size)
r.pather.cover(img.z, m.material, m.color, scale, off, m.uvScale, m.uvOffset, coverScale, coverOff)
}
r.ctx.DisableVertexAttribArray(attribPos)
r.ctx.DisableVertexAttribArray(attribUV)
r.ctx.DepthMask(true)
r.ctx.Disable(gl.DEPTH_TEST)
}
func (r *renderer) uploadTexture(img *image.RGBA) {
var pixels []byte
b := img.Bounds()
w, h := b.Dx(), b.Dy()
if img.Stride != w*4 {
panic("unsupported stride")
}
start := (b.Min.X + b.Min.Y*w) * 4
end := (b.Max.X + (b.Max.Y-1)*w) * 4
pixels = img.Pix[start:end]
tt := r.ctx.caps.srgbaTriple
r.ctx.TexImage2D(gl.TEXTURE_2D, 0, tt.internalFormat, w, h, tt.format, tt.typ, pixels)
}
func gamma(r, g, b, a uint32) [4]float32 {
color := [4]float32{float32(r) / 0xffff, float32(g) / 0xffff, float32(b) / 0xffff, float32(a) / 0xffff}
// Assume that image.Uniform colors are in sRGB space. Linearize.
for i := 0; i <= 2; i++ {
c := color[i]
// Use the formula from EXT_sRGB.
if c <= 0.04045 {
c = c / 12.92
} else {
c = float32(math.Pow(float64((c+0.055)/1.055), 2.4))
}
color[i] = c
}
return color
}
func (b *blitter) blit(z float32, mat materialType, col [4]float32, scale, off, uvScale, uvOff f32.Point) {
b.ctx.UseProgram(b.prog[mat])
switch mat {
case materialColor:
b.ctx.Uniform4f(b.vars[mat].uColor, col[0], col[1], col[2], col[3])
case materialTexture:
b.ctx.Uniform2f(b.vars[mat].uUVScale, uvScale.X, uvScale.Y)
b.ctx.Uniform2f(b.vars[mat].uUVOffset, uvOff.X, uvOff.Y)
}
b.ctx.Uniform1f(b.vars[mat].z, z)
b.ctx.Uniform2f(b.vars[mat].uScale, scale.X, scale.Y)
b.ctx.Uniform2f(b.vars[mat].uOffset, off.X, off.Y)
b.ctx.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)
}
// texSpaceTransform return the scale and offset that transforms the given subimage
// into quad texture coordinates.
func texSpaceTransform(r f32.Rectangle, bounds image.Point) (f32.Point, f32.Point) {
size := f32.Point{X: float32(bounds.X), Y: float32(bounds.Y)}
scale := f32.Point{X: r.Dx() / size.X, Y: r.Dy() / size.Y}
offset := f32.Point{X: r.Min.X / size.X, Y: r.Min.Y / size.Y}
return scale, offset
}
// clipSpaceTransform returns the scale and offset that transforms the given
// rectangle from a viewport into OpenGL clip space.
func clipSpaceTransform(r image.Rectangle, viewport image.Point) (f32.Point, f32.Point) {
// First, transform UI coordinates to OpenGL coordinates:
//
// [(-1, +1) (+1, +1)]
// [(-1, -1) (+1, -1)]
//
x, y := float32(r.Min.X), float32(r.Min.Y)
w, h := float32(r.Dx()), float32(r.Dy())
vx, vy := 2/float32(viewport.X), 2/float32(viewport.Y)
x = x*vx - 1
y = 1 - y*vy
w *= vx
h *= vy
// Then, compute the transformation from the fullscreen quad to
// the rectangle at (x, y) and dimensions (w, h).
scale := f32.Point{X: w * .5, Y: h * .5}
offset := f32.Point{X: x + w*.5, Y: y - h*.5}
return scale, offset
}
func bindFramebuffer(ctx *context, fbo gl.Framebuffer) {
ctx.BindFramebuffer(gl.FRAMEBUFFER, fbo)
if st := ctx.CheckFramebufferStatus(gl.FRAMEBUFFER); st != gl.FRAMEBUFFER_COMPLETE {
panic(fmt.Errorf("AA FBO not complete; status = 0x%x, err = %d", st, ctx.GetError()))
}
}
func createTexture(ctx *context) gl.Texture {
tex := ctx.CreateTexture()
ctx.BindTexture(gl.TEXTURE_2D, tex)
ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
return tex
}
// Fill in maximal Y coordinates of the NW and NE corners.
func fillMaxY(verts []byte) {
contour := 0
bo := binary.LittleEndian
for len(verts) > 0 {
maxy := float32(math.Inf(-1))
i := 0
for ; i+path.VertStride*4 <= len(verts); i += path.VertStride * 4 {
vert := verts[i : i+path.VertStride]
// MaxY contains the integer contour index.
pathContour := int(bo.Uint32(vert[int(unsafe.Offsetof(((*path.Vertex)(nil)).MaxY)):]))
if contour != pathContour {
contour = pathContour
break
}
fromy := math.Float32frombits(bo.Uint32(vert[int(unsafe.Offsetof(((*path.Vertex)(nil)).FromY)):]))
ctrly := math.Float32frombits(bo.Uint32(vert[int(unsafe.Offsetof(((*path.Vertex)(nil)).CtrlY)):]))
toy := math.Float32frombits(bo.Uint32(vert[int(unsafe.Offsetof(((*path.Vertex)(nil)).ToY)):]))
if fromy > maxy {
maxy = fromy
}
if ctrly > maxy {
maxy = ctrly
}
if toy > maxy {
maxy = toy
}
}
fillContourMaxY(maxy, verts[:i])
verts = verts[i:]
}
}
func fillContourMaxY(maxy float32, verts []byte) {
bo := binary.LittleEndian
for i := 0; i < len(verts); i += path.VertStride {
off := int(unsafe.Offsetof(((*path.Vertex)(nil)).MaxY))
bo.PutUint32(verts[i+off:], math.Float32bits(maxy))
}
}
const blitVSrc = `
#version 100
precision highp float;
uniform float z;
uniform vec2 scale;
uniform vec2 offset;
attribute vec2 pos;
attribute vec2 uv;
uniform vec2 uvScale;
uniform vec2 uvOffset;
varying vec2 vUV;
void main() {
vec2 p = pos;
p *= scale;
p += offset;
gl_Position = vec4(p, z, 1);
vUV = uv*uvScale + uvOffset;
}
`
const blitFSrc = `
#version 100