ebiten/internal/graphicscommand/commandqueue.go

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// Copyright 2023 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package graphicscommand
import (
"fmt"
"image"
"math"
"sync"
"sync/atomic"
"github.com/hajimehoshi/ebiten/v2/internal/debug"
"github.com/hajimehoshi/ebiten/v2/internal/graphics"
"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
)
const (
is32bit = 1 >> (^uint(0) >> 63)
is64bit = 1 - is32bit
// MaxVertexCount is the maximum number of vertices for one draw call.
//
// On 64bit architectures, this value is 2^32-1, as the index type is uint32.
// This value cannot be exactly 2^32 especially with WebGL 2, as 2^32th vertex is not rendered correctly.
// See https://registry.khronos.org/webgl/specs/latest/2.0/#5.18 .
//
// On 32bit architectures, this value is an adjusted number so that maxVertexFloatCount doesn't overflow int.
MaxVertexCount = is64bit*math.MaxUint32 + is32bit*(math.MaxInt32/graphics.VertexFloatCount)
maxVertexFloatCount = MaxVertexCount * graphics.VertexFloatCount
)
var vsyncEnabled atomic.Bool
func init() {
vsyncEnabled.Store(true)
}
func SetVsyncEnabled(enabled bool, graphicsDriver graphicsdriver.Graphics) {
vsyncEnabled.Store(enabled)
runOnRenderThread(func() {
graphicsDriver.SetVsyncEnabled(enabled)
}, true)
}
// FlushCommands flushes the command queue and present the screen if needed.
// If endFrame is true, the current screen might be used to present.
func FlushCommands(graphicsDriver graphicsdriver.Graphics, endFrame bool) error {
if err := theCommandQueueManager.flush(graphicsDriver, endFrame); err != nil {
return err
}
return nil
}
// commandQueue is a command queue for drawing commands.
type commandQueue struct {
// commands is a queue of drawing commands.
commands []command
// vertices represents a vertices data in OpenGL's array buffer.
vertices []float32
indices []uint32
tmpNumVertexFloats int
drawTrianglesCommandPool drawTrianglesCommandPool
uint32sBuffer uint32sBuffer
finalizers []func()
err atomic.Value
}
// addFinalizer adds a finalizer function to this queue.
// A finalizer is executed when the command queue is flushed at the end of the frame.
func (q *commandQueue) addFinalizer(f func()) {
q.finalizers = append(q.finalizers, f)
}
func (q *commandQueue) appendIndices(indices []uint32, offset uint32) {
n := len(q.indices)
q.indices = append(q.indices, indices...)
for i := n; i < len(q.indices); i++ {
q.indices[i] += offset
}
}
// mustUseDifferentVertexBuffer reports whether a different vertex buffer must be used.
func mustUseDifferentVertexBuffer(nextNumVertexFloats int) bool {
return nextNumVertexFloats > maxVertexFloatCount
}
// EnqueueDrawTrianglesCommand enqueues a drawing-image command.
func (q *commandQueue) EnqueueDrawTrianglesCommand(dst *Image, srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
if len(vertices) > maxVertexFloatCount {
panic(fmt.Sprintf("graphicscommand: len(vertices) must equal to or less than %d but was %d", maxVertexFloatCount, len(vertices)))
}
split := false
if mustUseDifferentVertexBuffer(q.tmpNumVertexFloats + len(vertices)) {
q.tmpNumVertexFloats = 0
split = true
}
// Assume that all the image sizes are same.
// Assume that the images are packed from the front in the slice srcs.
q.vertices = append(q.vertices, vertices...)
q.appendIndices(indices, uint32(q.tmpNumVertexFloats/graphics.VertexFloatCount))
q.tmpNumVertexFloats += len(vertices)
// prependPreservedUniforms not only prepends values to the given slice but also creates a new slice.
// Allocating a new slice is necessary to make EnqueueDrawTrianglesCommand safe so far.
// TODO: This might cause a performance issue (#2601).
uniforms = q.prependPreservedUniforms(uniforms, shader, dst, srcs, dstRegion, srcRegions)
// Remove unused uniform variables so that more commands can be merged.
shader.ir.FilterUniformVariables(uniforms)
// TODO: If dst is the screen, reorder the command to be the last.
if !split && 0 < len(q.commands) {
if last, ok := q.commands[len(q.commands)-1].(*drawTrianglesCommand); ok {
if last.CanMergeWithDrawTrianglesCommand(dst, srcs, vertices, blend, shader, uniforms, fillRule) {
last.setVertices(q.lastVertices(len(vertices) + last.numVertices()))
if last.dstRegions[len(last.dstRegions)-1].Region == dstRegion {
last.dstRegions[len(last.dstRegions)-1].IndexCount += len(indices)
} else {
last.dstRegions = append(last.dstRegions, graphicsdriver.DstRegion{
Region: dstRegion,
IndexCount: len(indices),
})
}
return
}
}
}
c := q.drawTrianglesCommandPool.get()
c.dst = dst
c.srcs = srcs
c.vertices = q.lastVertices(len(vertices))
c.blend = blend
c.dstRegions = []graphicsdriver.DstRegion{
{
Region: dstRegion,
IndexCount: len(indices),
},
}
c.shader = shader
c.uniforms = uniforms
c.fillRule = fillRule
q.commands = append(q.commands, c)
}
func (q *commandQueue) lastVertices(n int) []float32 {
return q.vertices[len(q.vertices)-n : len(q.vertices)]
}
// Enqueue enqueues a drawing command other than a draw-triangles command.
//
// For a draw-triangles command, use EnqueueDrawTrianglesCommand.
func (q *commandQueue) Enqueue(command command) {
// TODO: If dst is the screen, reorder the command to be the last.
q.commands = append(q.commands, command)
}
// Flush flushes the command queue.
func (q *commandQueue) Flush(graphicsDriver graphicsdriver.Graphics, endFrame bool) error {
if err := q.err.Load(); err != nil {
return err.(error)
}
var sync bool
2023-12-17 14:42:34 +01:00
// Disable asynchronous rendering when vsync is on, as this causes a rendering delay (#2822).
if endFrame && vsyncEnabled.Load() {
sync = true
}
if !sync {
for _, c := range q.commands {
if c.NeedsSync() {
sync = true
break
}
}
}
logger := debug.SwitchLogger()
var flushErr error
runOnRenderThread(func() {
defer logger.Flush()
if err := q.flush(graphicsDriver, endFrame, logger); err != nil {
if sync {
flushErr = err
return
}
q.err.Store(err)
return
}
theCommandQueueManager.putCommandQueue(q)
}, sync)
if sync && flushErr != nil {
return flushErr
}
return nil
}
// flush must be called the render thread.
func (q *commandQueue) flush(graphicsDriver graphicsdriver.Graphics, endFrame bool, logger debug.Logger) (err error) {
// If endFrame is true, Begin/End should be called to ensure the framebuffer is swapped.
if len(q.commands) == 0 && !endFrame {
return nil
}
es := q.indices
vs := q.vertices
logger.Logf("Graphics commands:\n")
if err := graphicsDriver.Begin(); err != nil {
return err
}
defer func() {
// Call End even if an error causes, or the graphics driver's state might be stale (#2388).
if err1 := graphicsDriver.End(endFrame); err1 != nil && err == nil {
err = err1
}
// Release the commands explicitly (#1803).
// Apparently, the part of a slice between len and cap-1 still holds references.
// Then, resetting the length by [:0] doesn't release the references.
for i, c := range q.commands {
if c, ok := c.(*drawTrianglesCommand); ok {
q.drawTrianglesCommandPool.put(c)
}
q.commands[i] = nil
}
q.commands = q.commands[:0]
q.vertices = q.vertices[:0]
q.indices = q.indices[:0]
q.tmpNumVertexFloats = 0
if endFrame {
q.uint32sBuffer.reset()
for i, f := range q.finalizers {
f()
q.finalizers[i] = nil
}
q.finalizers = q.finalizers[:0]
}
}()
cs := q.commands
for len(cs) > 0 {
nv := 0
ne := 0
nc := 0
for _, c := range cs {
if dtc, ok := c.(*drawTrianglesCommand); ok {
if nc > 0 && mustUseDifferentVertexBuffer(nv+dtc.numVertices()) {
break
}
nv += dtc.numVertices()
ne += dtc.numIndices()
}
nc++
}
if 0 < ne {
if err := graphicsDriver.SetVertices(vs[:nv], es[:ne]); err != nil {
return err
}
es = es[ne:]
vs = vs[nv:]
}
indexOffset := 0
for _, c := range cs[:nc] {
if err := c.Exec(q, graphicsDriver, indexOffset); err != nil {
return err
}
logger.Logf(" %s\n", c)
// TODO: indexOffset should be reset if the command type is different
// from the previous one. This fix is needed when another drawing command is
// introduced than drawTrianglesCommand.
if dtc, ok := c.(*drawTrianglesCommand); ok {
indexOffset += dtc.numIndices()
}
}
cs = cs[nc:]
}
return nil
}
type rectangleF32 struct {
x float32
y float32
width float32
height float32
}
func imageRectangleToRectangleF32(r image.Rectangle) rectangleF32 {
return rectangleF32{
x: float32(r.Min.X),
y: float32(r.Min.Y),
width: float32(r.Dx()),
height: float32(r.Dy()),
}
}
func (q *commandQueue) prependPreservedUniforms(uniforms []uint32, shader *Shader, dst *Image, srcs [graphics.ShaderSrcImageCount]*Image, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle) []uint32 {
origUniforms := uniforms
uniforms = q.uint32sBuffer.alloc(len(origUniforms) + graphics.PreservedUniformUint32Count)
copy(uniforms[graphics.PreservedUniformUint32Count:], origUniforms)
// Set the destination texture size.
dw, dh := dst.InternalSize()
uniforms[0] = math.Float32bits(float32(dw))
uniforms[1] = math.Float32bits(float32(dh))
uniformIndex := 2
for i := 0; i < graphics.ShaderSrcImageCount; i++ {
var floatW, floatH uint32
if srcs[i] != nil {
w, h := srcs[i].InternalSize()
floatW = math.Float32bits(float32(w))
floatH = math.Float32bits(float32(h))
}
uniforms[uniformIndex+i*2] = floatW
uniforms[uniformIndex+1+i*2] = floatH
}
uniformIndex += graphics.ShaderSrcImageCount * 2
dr := imageRectangleToRectangleF32(dstRegion)
if shader.unit() == shaderir.Texels {
dr.x /= float32(dw)
dr.y /= float32(dh)
dr.width /= float32(dw)
dr.height /= float32(dh)
}
// Set the destination region origin.
uniforms[uniformIndex] = math.Float32bits(dr.x)
uniforms[uniformIndex+1] = math.Float32bits(dr.y)
uniformIndex += 2
// Set the destination region size.
uniforms[uniformIndex] = math.Float32bits(dr.width)
uniforms[uniformIndex+1] = math.Float32bits(dr.height)
uniformIndex += 2
var srs [graphics.ShaderSrcImageCount]rectangleF32
for i, r := range srcRegions {
srs[i] = imageRectangleToRectangleF32(r)
}
if shader.unit() == shaderir.Texels {
for i, src := range srcs {
if src == nil {
continue
}
w, h := src.InternalSize()
srs[i].x /= float32(w)
srs[i].y /= float32(h)
srs[i].width /= float32(w)
srs[i].height /= float32(h)
}
}
// Set the source region origins.
for i := 0; i < graphics.ShaderSrcImageCount; i++ {
uniforms[uniformIndex+i*2] = math.Float32bits(srs[i].x)
uniforms[uniformIndex+1+i*2] = math.Float32bits(srs[i].y)
}
uniformIndex += graphics.ShaderSrcImageCount * 2
// Set the source region sizes.
for i := 0; i < graphics.ShaderSrcImageCount; i++ {
uniforms[uniformIndex+i*2] = math.Float32bits(srs[i].width)
uniforms[uniformIndex+1+i*2] = math.Float32bits(srs[i].height)
}
uniformIndex += graphics.ShaderSrcImageCount * 2
// Set the projection matrix.
uniforms[uniformIndex] = math.Float32bits(2 / float32(dw))
uniforms[uniformIndex+1] = 0
uniforms[uniformIndex+2] = 0
uniforms[uniformIndex+3] = 0
uniforms[uniformIndex+4] = 0
uniforms[uniformIndex+5] = math.Float32bits(2 / float32(dh))
uniforms[uniformIndex+6] = 0
uniforms[uniformIndex+7] = 0
uniforms[uniformIndex+8] = 0
uniforms[uniformIndex+9] = 0
uniforms[uniformIndex+10] = math.Float32bits(1)
uniforms[uniformIndex+11] = 0
uniforms[uniformIndex+12] = math.Float32bits(-1)
uniforms[uniformIndex+13] = math.Float32bits(-1)
uniforms[uniformIndex+14] = 0
uniforms[uniformIndex+15] = math.Float32bits(1)
return uniforms
}
type commandQueuePool struct {
cache []*commandQueue
m sync.Mutex
}
func (c *commandQueuePool) get() (*commandQueue, error) {
c.m.Lock()
defer c.m.Unlock()
if len(c.cache) == 0 {
return &commandQueue{}, nil
}
for _, q := range c.cache {
if err := q.err.Load(); err != nil {
return nil, err.(error)
}
}
q := c.cache[len(c.cache)-1]
c.cache[len(c.cache)-1] = nil
c.cache = c.cache[:len(c.cache)-1]
return q, nil
}
func (c *commandQueuePool) put(queue *commandQueue) {
c.m.Lock()
defer c.m.Unlock()
c.cache = append(c.cache, queue)
}
type commandQueueManager struct {
pool commandQueuePool
current *commandQueue
}
var theCommandQueueManager commandQueueManager
func (c *commandQueueManager) enqueueCommand(command command) {
if c.current == nil {
c.current, _ = c.pool.get()
}
c.current.Enqueue(command)
}
// put can be called from any goroutines.
func (c *commandQueueManager) putCommandQueue(commandQueue *commandQueue) {
c.pool.put(commandQueue)
}
func (c *commandQueueManager) enqueueDrawTrianglesCommand(dst *Image, srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
if c.current == nil {
c.current, _ = c.pool.get()
}
c.current.EnqueueDrawTrianglesCommand(dst, srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
}
func (c *commandQueueManager) flush(graphicsDriver graphicsdriver.Graphics, endFrame bool) error {
// Switch the command queue.
prev := c.current
q, err := c.pool.get()
if err != nil {
return err
}
c.current = q
if prev == nil {
return nil
}
if err := prev.Flush(graphicsDriver, endFrame); err != nil {
return err
}
return nil
}
// uint32sBuffer is a reusable buffer to allocate []uint32.
type uint32sBuffer struct {
buf []uint32
}
func roundUpPower2(x int) int {
p2 := 1
for p2 < x {
p2 *= 2
}
return p2
}
func max(a, b int) int {
if a < b {
return b
}
return a
}
func (b *uint32sBuffer) alloc(n int) []uint32 {
buf := b.buf
if len(buf)+n > cap(buf) {
buf = make([]uint32, 0, max(roundUpPower2(len(buf)+n), 16))
}
s := buf[len(buf) : len(buf)+n]
b.buf = buf[:len(buf)+n]
return s
}
func (b *uint32sBuffer) reset() {
b.buf = b.buf[:0]
}