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opengl.go
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opengl.go
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// SPDX-License-Identifier: Unlicense OR MIT
package opengl
import (
"errors"
"fmt"
"image"
"runtime"
"strings"
"time"
"unsafe"
"github.com/xiaoshengduan/gio-fly/gpu/internal/driver"
"github.com/xiaoshengduan/gio-fly/internal/gl"
"gioui.org/shader"
)
// Backend implements driver.Device.
type Backend struct {
funcs *gl.Functions
clear bool
glstate glState
state state
savedState glState
sharedCtx bool
glver [2]int
gles bool
feats driver.Caps
// floatTriple holds the settings for floating point
// textures.
floatTriple textureTriple
// Single channel alpha textures.
alphaTriple textureTriple
srgbaTriple textureTriple
storage [storageBindings]*buffer
outputFBO gl.Framebuffer
sRGBFBO *SRGBFBO
// vertArray is bound during a frame. We don't need it, but
// core desktop OpenGL profile 3.3 requires some array bound.
vertArray gl.VertexArray
}
// State tracking.
type glState struct {
drawFBO gl.Framebuffer
readFBO gl.Framebuffer
vertAttribs [5]struct {
obj gl.Buffer
enabled bool
size int
typ gl.Enum
normalized bool
stride int
offset uintptr
}
prog gl.Program
texUnits struct {
active gl.Enum
binds [2]gl.Texture
}
arrayBuf gl.Buffer
elemBuf gl.Buffer
uniBuf gl.Buffer
uniBufs [2]gl.Buffer
storeBuf gl.Buffer
storeBufs [4]gl.Buffer
vertArray gl.VertexArray
srgb bool
blend struct {
enable bool
srcRGB, dstRGB gl.Enum
srcA, dstA gl.Enum
}
clearColor [4]float32
viewport [4]int
unpack_row_length int
pack_row_length int
}
type state struct {
pipeline *pipeline
buffer bufferBinding
}
type bufferBinding struct {
obj gl.Buffer
offset int
}
type timer struct {
funcs *gl.Functions
obj gl.Query
}
type texture struct {
backend *Backend
obj gl.Texture
fbo gl.Framebuffer
hasFBO bool
triple textureTriple
width int
height int
bindings driver.BufferBinding
foreign bool
}
type pipeline struct {
prog *program
inputs []shader.InputLocation
layout driver.VertexLayout
blend driver.BlendDesc
topology driver.Topology
}
type buffer struct {
backend *Backend
hasBuffer bool
obj gl.Buffer
typ driver.BufferBinding
size int
immutable bool
// For emulation of uniform buffers.
data []byte
}
type glshader struct {
backend *Backend
obj gl.Shader
src shader.Sources
}
type program struct {
backend *Backend
obj gl.Program
vertUniforms uniforms
fragUniforms uniforms
}
type uniforms struct {
locs []uniformLocation
size int
}
type uniformLocation struct {
uniform gl.Uniform
offset int
typ shader.DataType
size int
}
// textureTriple holds the type settings for
// a TexImage2D call.
type textureTriple struct {
internalFormat gl.Enum
format gl.Enum
typ gl.Enum
}
const (
storageBindings = 32
)
func init() {
driver.NewOpenGLDevice = newOpenGLDevice
}
// Supporting compute programs is theoretically possible with OpenGL ES 3.1. In
// practice, there are too many driver issues, especially on Android (e.g.
// Google Pixel, Samsung J2 are both broken i different ways). Disable support
// and rely on Vulkan for devices that support it, and the CPU fallback for
// devices that don't.
const brokenGLES31 = true
func newOpenGLDevice(api driver.OpenGL) (driver.Device, error) {
f, err := gl.NewFunctions(api.Context, api.ES)
if err != nil {
return nil, err
}
exts := strings.Split(f.GetString(gl.EXTENSIONS), " ")
glVer := f.GetString(gl.VERSION)
ver, gles, err := gl.ParseGLVersion(glVer)
if err != nil {
return nil, err
}
floatTriple, ffboErr := floatTripleFor(f, ver, exts)
srgbaTriple, srgbErr := srgbaTripleFor(ver, exts)
gles31 := gles && (ver[0] > 3 || (ver[0] == 3 && ver[1] >= 1))
b := &Backend{
glver: ver,
gles: gles,
funcs: f,
floatTriple: floatTriple,
alphaTriple: alphaTripleFor(ver),
srgbaTriple: srgbaTriple,
sharedCtx: api.Shared,
}
b.feats.BottomLeftOrigin = true
if srgbErr == nil {
b.feats.Features |= driver.FeatureSRGB
}
if ffboErr == nil {
b.feats.Features |= driver.FeatureFloatRenderTargets
}
if gles31 && !brokenGLES31 {
b.feats.Features |= driver.FeatureCompute
}
if hasExtension(exts, "GL_EXT_disjoint_timer_query_webgl2") || hasExtension(exts, "GL_EXT_disjoint_timer_query") {
b.feats.Features |= driver.FeatureTimers
}
b.feats.MaxTextureSize = f.GetInteger(gl.MAX_TEXTURE_SIZE)
if !b.sharedCtx {
// We have exclusive access to the context, so query the GL state once
// instead of at each frame.
b.glstate = b.queryState()
}
return b, nil
}
func (b *Backend) BeginFrame(target driver.RenderTarget, clear bool, viewport image.Point) driver.Texture {
b.clear = clear
if b.sharedCtx {
b.glstate = b.queryState()
b.savedState = b.glstate
}
b.state = state{}
var renderFBO gl.Framebuffer
if target != nil {
switch t := target.(type) {
case driver.OpenGLRenderTarget:
renderFBO = gl.Framebuffer(t)
case *texture:
renderFBO = t.ensureFBO()
default:
panic(fmt.Errorf("opengl: invalid render target type: %T", target))
}
}
b.outputFBO = renderFBO
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, renderFBO)
if b.gles {
// If the output framebuffer is not in the sRGB colorspace already, emulate it.
var fbEncoding int
if !renderFBO.Valid() {
fbEncoding = b.funcs.GetFramebufferAttachmentParameteri(gl.FRAMEBUFFER, gl.BACK, gl.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING)
} else {
fbEncoding = b.funcs.GetFramebufferAttachmentParameteri(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING)
}
if fbEncoding == gl.LINEAR && viewport != (image.Point{}) {
if b.sRGBFBO == nil {
sfbo, err := NewSRGBFBO(b.funcs, &b.glstate)
if err != nil {
panic(err)
}
b.sRGBFBO = sfbo
}
if err := b.sRGBFBO.Refresh(viewport); err != nil {
panic(err)
}
renderFBO = b.sRGBFBO.Framebuffer()
} else if b.sRGBFBO != nil {
b.sRGBFBO.Release()
b.sRGBFBO = nil
}
} else {
b.glstate.set(b.funcs, gl.FRAMEBUFFER_SRGB, true)
if !b.vertArray.Valid() {
b.vertArray = b.funcs.CreateVertexArray()
}
b.glstate.bindVertexArray(b.funcs, b.vertArray)
}
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, renderFBO)
if b.sRGBFBO != nil && !clear {
b.clearOutput(0, 0, 0, 0)
}
return &texture{backend: b, fbo: renderFBO, hasFBO: true, foreign: true}
}
func (b *Backend) EndFrame() {
if b.sRGBFBO != nil {
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, b.outputFBO)
if b.clear {
b.SetBlend(false)
} else {
b.BlendFunc(driver.BlendFactorOne, driver.BlendFactorOneMinusSrcAlpha)
b.SetBlend(true)
}
b.sRGBFBO.Blit()
}
if b.sharedCtx {
b.restoreState(b.savedState)
} else if runtime.GOOS == "android" {
// The Android emulator needs the output framebuffer to be current when
// eglSwapBuffers is called.
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, b.outputFBO)
}
}
func (b *Backend) queryState() glState {
s := glState{
prog: gl.Program(b.funcs.GetBinding(gl.CURRENT_PROGRAM)),
arrayBuf: gl.Buffer(b.funcs.GetBinding(gl.ARRAY_BUFFER_BINDING)),
elemBuf: gl.Buffer(b.funcs.GetBinding(gl.ELEMENT_ARRAY_BUFFER_BINDING)),
drawFBO: gl.Framebuffer(b.funcs.GetBinding(gl.FRAMEBUFFER_BINDING)),
clearColor: b.funcs.GetFloat4(gl.COLOR_CLEAR_VALUE),
viewport: b.funcs.GetInteger4(gl.VIEWPORT),
unpack_row_length: b.funcs.GetInteger(gl.UNPACK_ROW_LENGTH),
pack_row_length: b.funcs.GetInteger(gl.PACK_ROW_LENGTH),
}
s.blend.enable = b.funcs.IsEnabled(gl.BLEND)
s.blend.srcRGB = gl.Enum(b.funcs.GetInteger(gl.BLEND_SRC_RGB))
s.blend.dstRGB = gl.Enum(b.funcs.GetInteger(gl.BLEND_DST_RGB))
s.blend.srcA = gl.Enum(b.funcs.GetInteger(gl.BLEND_SRC_ALPHA))
s.blend.dstA = gl.Enum(b.funcs.GetInteger(gl.BLEND_DST_ALPHA))
s.texUnits.active = gl.Enum(b.funcs.GetInteger(gl.ACTIVE_TEXTURE))
if !b.gles {
s.srgb = b.funcs.IsEnabled(gl.FRAMEBUFFER_SRGB)
}
if !b.gles || b.glver[0] >= 3 {
s.vertArray = gl.VertexArray(b.funcs.GetBinding(gl.VERTEX_ARRAY_BINDING))
s.readFBO = gl.Framebuffer(b.funcs.GetBinding(gl.READ_FRAMEBUFFER_BINDING))
s.uniBuf = gl.Buffer(b.funcs.GetBinding(gl.UNIFORM_BUFFER_BINDING))
for i := range s.uniBufs {
s.uniBufs[i] = gl.Buffer(b.funcs.GetBindingi(gl.UNIFORM_BUFFER_BINDING, i))
}
}
if b.gles && (b.glver[0] > 3 || (b.glver[0] == 3 && b.glver[1] >= 1)) {
s.storeBuf = gl.Buffer(b.funcs.GetBinding(gl.SHADER_STORAGE_BUFFER_BINDING))
for i := range s.storeBufs {
s.storeBufs[i] = gl.Buffer(b.funcs.GetBindingi(gl.SHADER_STORAGE_BUFFER_BINDING, i))
}
}
active := s.texUnits.active
for i := range s.texUnits.binds {
s.activeTexture(b.funcs, gl.TEXTURE0+gl.Enum(i))
s.texUnits.binds[i] = gl.Texture(b.funcs.GetBinding(gl.TEXTURE_BINDING_2D))
}
s.activeTexture(b.funcs, active)
for i := range s.vertAttribs {
a := &s.vertAttribs[i]
a.enabled = b.funcs.GetVertexAttrib(i, gl.VERTEX_ATTRIB_ARRAY_ENABLED) != gl.FALSE
a.obj = gl.Buffer(b.funcs.GetVertexAttribBinding(i, gl.VERTEX_ATTRIB_ARRAY_ENABLED))
a.size = b.funcs.GetVertexAttrib(i, gl.VERTEX_ATTRIB_ARRAY_SIZE)
a.typ = gl.Enum(b.funcs.GetVertexAttrib(i, gl.VERTEX_ATTRIB_ARRAY_TYPE))
a.normalized = b.funcs.GetVertexAttrib(i, gl.VERTEX_ATTRIB_ARRAY_NORMALIZED) != gl.FALSE
a.stride = b.funcs.GetVertexAttrib(i, gl.VERTEX_ATTRIB_ARRAY_STRIDE)
a.offset = b.funcs.GetVertexAttribPointer(i, gl.VERTEX_ATTRIB_ARRAY_POINTER)
}
return s
}
func (b *Backend) restoreState(dst glState) {
src := &b.glstate
f := b.funcs
for i, unit := range dst.texUnits.binds {
src.bindTexture(f, i, unit)
}
src.activeTexture(f, dst.texUnits.active)
src.bindFramebuffer(f, gl.FRAMEBUFFER, dst.drawFBO)
src.bindFramebuffer(f, gl.READ_FRAMEBUFFER, dst.readFBO)
src.set(f, gl.BLEND, dst.blend.enable)
bf := dst.blend
src.setBlendFuncSeparate(f, bf.srcRGB, bf.dstRGB, bf.srcA, bf.dstA)
src.set(f, gl.FRAMEBUFFER_SRGB, dst.srgb)
src.bindVertexArray(f, dst.vertArray)
src.useProgram(f, dst.prog)
src.bindBuffer(f, gl.ELEMENT_ARRAY_BUFFER, dst.elemBuf)
for i, b := range dst.uniBufs {
src.bindBufferBase(f, gl.UNIFORM_BUFFER, i, b)
}
src.bindBuffer(f, gl.UNIFORM_BUFFER, dst.uniBuf)
for i, b := range dst.storeBufs {
src.bindBufferBase(f, gl.SHADER_STORAGE_BUFFER, i, b)
}
src.bindBuffer(f, gl.SHADER_STORAGE_BUFFER, dst.storeBuf)
col := dst.clearColor
src.setClearColor(f, col[0], col[1], col[2], col[3])
for i, attr := range dst.vertAttribs {
src.setVertexAttribArray(f, i, attr.enabled)
src.vertexAttribPointer(f, attr.obj, i, attr.size, attr.typ, attr.normalized, attr.stride, int(attr.offset))
}
src.bindBuffer(f, gl.ARRAY_BUFFER, dst.arrayBuf)
v := dst.viewport
src.setViewport(f, v[0], v[1], v[2], v[3])
src.pixelStorei(f, gl.UNPACK_ROW_LENGTH, dst.unpack_row_length)
src.pixelStorei(f, gl.PACK_ROW_LENGTH, dst.pack_row_length)
}
func (s *glState) setVertexAttribArray(f *gl.Functions, idx int, enabled bool) {
a := &s.vertAttribs[idx]
if enabled != a.enabled {
if enabled {
f.EnableVertexAttribArray(gl.Attrib(idx))
} else {
f.DisableVertexAttribArray(gl.Attrib(idx))
}
a.enabled = enabled
}
}
func (s *glState) vertexAttribPointer(f *gl.Functions, buf gl.Buffer, idx, size int, typ gl.Enum, normalized bool, stride, offset int) {
s.bindBuffer(f, gl.ARRAY_BUFFER, buf)
a := &s.vertAttribs[idx]
a.obj = buf
a.size = size
a.typ = typ
a.normalized = normalized
a.stride = stride
a.offset = uintptr(offset)
f.VertexAttribPointer(gl.Attrib(idx), a.size, a.typ, a.normalized, a.stride, int(a.offset))
}
func (s *glState) activeTexture(f *gl.Functions, unit gl.Enum) {
if unit != s.texUnits.active {
f.ActiveTexture(unit)
s.texUnits.active = unit
}
}
func (s *glState) bindTexture(f *gl.Functions, unit int, t gl.Texture) {
s.activeTexture(f, gl.TEXTURE0+gl.Enum(unit))
if !t.Equal(s.texUnits.binds[unit]) {
f.BindTexture(gl.TEXTURE_2D, t)
s.texUnits.binds[unit] = t
}
}
func (s *glState) bindVertexArray(f *gl.Functions, a gl.VertexArray) {
if !a.Equal(s.vertArray) {
f.BindVertexArray(a)
s.vertArray = a
}
}
func (s *glState) deleteFramebuffer(f *gl.Functions, fbo gl.Framebuffer) {
f.DeleteFramebuffer(fbo)
if fbo.Equal(s.drawFBO) {
s.drawFBO = gl.Framebuffer{}
}
if fbo.Equal(s.readFBO) {
s.readFBO = gl.Framebuffer{}
}
}
func (s *glState) deleteBuffer(f *gl.Functions, b gl.Buffer) {
f.DeleteBuffer(b)
if b.Equal(s.arrayBuf) {
s.arrayBuf = gl.Buffer{}
}
if b.Equal(s.elemBuf) {
s.elemBuf = gl.Buffer{}
}
if b.Equal(s.uniBuf) {
s.uniBuf = gl.Buffer{}
}
if b.Equal(s.storeBuf) {
s.uniBuf = gl.Buffer{}
}
for i, b2 := range s.storeBufs {
if b.Equal(b2) {
s.storeBufs[i] = gl.Buffer{}
}
}
for i, b2 := range s.uniBufs {
if b.Equal(b2) {
s.uniBufs[i] = gl.Buffer{}
}
}
}
func (s *glState) deleteProgram(f *gl.Functions, p gl.Program) {
f.DeleteProgram(p)
if p.Equal(s.prog) {
s.prog = gl.Program{}
}
}
func (s *glState) deleteVertexArray(f *gl.Functions, a gl.VertexArray) {
f.DeleteVertexArray(a)
if a.Equal(s.vertArray) {
s.vertArray = gl.VertexArray{}
}
}
func (s *glState) deleteTexture(f *gl.Functions, t gl.Texture) {
f.DeleteTexture(t)
binds := &s.texUnits.binds
for i, obj := range binds {
if t.Equal(obj) {
binds[i] = gl.Texture{}
}
}
}
func (s *glState) useProgram(f *gl.Functions, p gl.Program) {
if !p.Equal(s.prog) {
f.UseProgram(p)
s.prog = p
}
}
func (s *glState) bindFramebuffer(f *gl.Functions, target gl.Enum, fbo gl.Framebuffer) {
switch target {
case gl.FRAMEBUFFER:
if fbo.Equal(s.drawFBO) && fbo.Equal(s.readFBO) {
return
}
s.drawFBO = fbo
s.readFBO = fbo
case gl.READ_FRAMEBUFFER:
if fbo.Equal(s.readFBO) {
return
}
s.readFBO = fbo
case gl.DRAW_FRAMEBUFFER:
if fbo.Equal(s.drawFBO) {
return
}
s.drawFBO = fbo
default:
panic("unknown target")
}
f.BindFramebuffer(target, fbo)
}
func (s *glState) bindBufferBase(f *gl.Functions, target gl.Enum, idx int, buf gl.Buffer) {
switch target {
case gl.UNIFORM_BUFFER:
if buf.Equal(s.uniBuf) && buf.Equal(s.uniBufs[idx]) {
return
}
s.uniBuf = buf
s.uniBufs[idx] = buf
case gl.SHADER_STORAGE_BUFFER:
if buf.Equal(s.storeBuf) && buf.Equal(s.storeBufs[idx]) {
return
}
s.storeBuf = buf
s.storeBufs[idx] = buf
default:
panic("unknown buffer target")
}
f.BindBufferBase(target, idx, buf)
}
func (s *glState) bindBuffer(f *gl.Functions, target gl.Enum, buf gl.Buffer) {
switch target {
case gl.ARRAY_BUFFER:
if buf.Equal(s.arrayBuf) {
return
}
s.arrayBuf = buf
case gl.ELEMENT_ARRAY_BUFFER:
if buf.Equal(s.elemBuf) {
return
}
s.elemBuf = buf
case gl.UNIFORM_BUFFER:
if buf.Equal(s.uniBuf) {
return
}
s.uniBuf = buf
case gl.SHADER_STORAGE_BUFFER:
if buf.Equal(s.storeBuf) {
return
}
s.storeBuf = buf
default:
panic("unknown buffer target")
}
f.BindBuffer(target, buf)
}
func (s *glState) pixelStorei(f *gl.Functions, pname gl.Enum, val int) {
switch pname {
case gl.UNPACK_ROW_LENGTH:
if val == s.unpack_row_length {
return
}
s.unpack_row_length = val
case gl.PACK_ROW_LENGTH:
if val == s.pack_row_length {
return
}
s.pack_row_length = val
default:
panic("unsupported PixelStorei pname")
}
f.PixelStorei(pname, val)
}
func (s *glState) setClearColor(f *gl.Functions, r, g, b, a float32) {
col := [4]float32{r, g, b, a}
if col != s.clearColor {
f.ClearColor(r, g, b, a)
s.clearColor = col
}
}
func (s *glState) setViewport(f *gl.Functions, x, y, width, height int) {
view := [4]int{x, y, width, height}
if view != s.viewport {
f.Viewport(x, y, width, height)
s.viewport = view
}
}
func (s *glState) setBlendFuncSeparate(f *gl.Functions, srcRGB, dstRGB, srcA, dstA gl.Enum) {
if srcRGB != s.blend.srcRGB || dstRGB != s.blend.dstRGB || srcA != s.blend.srcA || dstA != s.blend.dstA {
s.blend.srcRGB = srcRGB
s.blend.dstRGB = dstRGB
s.blend.srcA = srcA
s.blend.dstA = dstA
f.BlendFuncSeparate(srcA, dstA, srcA, dstA)
}
}
func (s *glState) set(f *gl.Functions, target gl.Enum, enable bool) {
switch target {
case gl.FRAMEBUFFER_SRGB:
if s.srgb == enable {
return
}
s.srgb = enable
case gl.BLEND:
if enable == s.blend.enable {
return
}
s.blend.enable = enable
default:
panic("unknown enable")
}
if enable {
f.Enable(target)
} else {
f.Disable(target)
}
}
func (b *Backend) Caps() driver.Caps {
return b.feats
}
func (b *Backend) NewTimer() driver.Timer {
return &timer{
funcs: b.funcs,
obj: b.funcs.CreateQuery(),
}
}
func (b *Backend) IsTimeContinuous() bool {
return b.funcs.GetInteger(gl.GPU_DISJOINT_EXT) == gl.FALSE
}
func (t *texture) ensureFBO() gl.Framebuffer {
if t.hasFBO {
return t.fbo
}
b := t.backend
oldFBO := b.glstate.drawFBO
defer func() {
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, oldFBO)
}()
glErr(b.funcs)
fb := b.funcs.CreateFramebuffer()
b.glstate.bindFramebuffer(b.funcs, gl.FRAMEBUFFER, fb)
if err := glErr(b.funcs); err != nil {
b.funcs.DeleteFramebuffer(fb)
panic(err)
}
b.funcs.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, t.obj, 0)
if st := b.funcs.CheckFramebufferStatus(gl.FRAMEBUFFER); st != gl.FRAMEBUFFER_COMPLETE {
b.funcs.DeleteFramebuffer(fb)
panic(fmt.Errorf("incomplete framebuffer, status = 0x%x, err = %d", st, b.funcs.GetError()))
}
t.fbo = fb
t.hasFBO = true
return fb
}
func (b *Backend) NewTexture(format driver.TextureFormat, width, height int, minFilter, magFilter driver.TextureFilter, binding driver.BufferBinding) (driver.Texture, error) {
glErr(b.funcs)
tex := &texture{backend: b, obj: b.funcs.CreateTexture(), width: width, height: height, bindings: binding}
switch format {
case driver.TextureFormatFloat:
tex.triple = b.floatTriple
case driver.TextureFormatSRGBA:
tex.triple = b.srgbaTriple
case driver.TextureFormatRGBA8:
tex.triple = textureTriple{gl.RGBA8, gl.RGBA, gl.UNSIGNED_BYTE}
default:
return nil, errors.New("unsupported texture format")
}
b.BindTexture(0, tex)
b.funcs.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, toTexFilter(magFilter))
b.funcs.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, toTexFilter(minFilter))
b.funcs.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
b.funcs.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
if b.gles && b.glver[0] >= 3 {
// Immutable textures are required for BindImageTexture, and can't hurt otherwise.
b.funcs.TexStorage2D(gl.TEXTURE_2D, 1, tex.triple.internalFormat, width, height)
} else {
b.funcs.TexImage2D(gl.TEXTURE_2D, 0, tex.triple.internalFormat, width, height, tex.triple.format, tex.triple.typ)
}
if err := glErr(b.funcs); err != nil {
tex.Release()
return nil, err
}
return tex, nil
}
func (b *Backend) NewBuffer(typ driver.BufferBinding, size int) (driver.Buffer, error) {
glErr(b.funcs)
buf := &buffer{backend: b, typ: typ, size: size}
if typ&driver.BufferBindingUniforms != 0 {
if typ != driver.BufferBindingUniforms {
return nil, errors.New("uniforms buffers cannot be bound as anything else")
}
buf.data = make([]byte, size)
}
if typ&^driver.BufferBindingUniforms != 0 {
buf.hasBuffer = true
buf.obj = b.funcs.CreateBuffer()
if err := glErr(b.funcs); err != nil {
buf.Release()
return nil, err
}
firstBinding := firstBufferType(typ)
b.glstate.bindBuffer(b.funcs, firstBinding, buf.obj)
b.funcs.BufferData(firstBinding, size, gl.DYNAMIC_DRAW, nil)
}
return buf, nil
}
func (b *Backend) NewImmutableBuffer(typ driver.BufferBinding, data []byte) (driver.Buffer, error) {
glErr(b.funcs)
obj := b.funcs.CreateBuffer()
buf := &buffer{backend: b, obj: obj, typ: typ, size: len(data), hasBuffer: true}
firstBinding := firstBufferType(typ)
b.glstate.bindBuffer(b.funcs, firstBinding, buf.obj)
b.funcs.BufferData(firstBinding, len(data), gl.STATIC_DRAW, data)
buf.immutable = true
if err := glErr(b.funcs); err != nil {
buf.Release()
return nil, err
}
return buf, nil
}
func glErr(f *gl.Functions) error {
if st := f.GetError(); st != gl.NO_ERROR {
return fmt.Errorf("glGetError: %#x", st)
}
return nil
}
func (b *Backend) Release() {
if b.sRGBFBO != nil {
b.sRGBFBO.Release()
}
if b.vertArray.Valid() {
b.glstate.deleteVertexArray(b.funcs, b.vertArray)
}
*b = Backend{}
}
func (b *Backend) DispatchCompute(x, y, z int) {
for binding, buf := range b.storage {
if buf != nil {
b.glstate.bindBufferBase(b.funcs, gl.SHADER_STORAGE_BUFFER, binding, buf.obj)
}
}
b.funcs.DispatchCompute(x, y, z)
b.funcs.MemoryBarrier(gl.ALL_BARRIER_BITS)
}
func (b *Backend) BindImageTexture(unit int, tex driver.Texture) {
t := tex.(*texture)
var acc gl.Enum
switch t.bindings & (driver.BufferBindingShaderStorageRead | driver.BufferBindingShaderStorageWrite) {
case driver.BufferBindingShaderStorageRead:
acc = gl.READ_ONLY
case driver.BufferBindingShaderStorageWrite:
acc = gl.WRITE_ONLY
case driver.BufferBindingShaderStorageRead | driver.BufferBindingShaderStorageWrite:
acc = gl.READ_WRITE
default:
panic("unsupported access bits")
}
b.funcs.BindImageTexture(unit, t.obj, 0, false, 0, acc, t.triple.internalFormat)
}
func (b *Backend) BlendFunc(sfactor, dfactor driver.BlendFactor) {
src, dst := toGLBlendFactor(sfactor), toGLBlendFactor(dfactor)
b.glstate.setBlendFuncSeparate(b.funcs, src, dst, src, dst)
}
func toGLBlendFactor(f driver.BlendFactor) gl.Enum {
switch f {
case driver.BlendFactorOne:
return gl.ONE
case driver.BlendFactorOneMinusSrcAlpha:
return gl.ONE_MINUS_SRC_ALPHA
case driver.BlendFactorZero:
return gl.ZERO
case driver.BlendFactorDstColor:
return gl.DST_COLOR
default:
panic("unsupported blend factor")
}
}
func (b *Backend) SetBlend(enable bool) {
b.glstate.set(b.funcs, gl.BLEND, enable)
}
func (b *Backend) DrawElements(off, count int) {
b.prepareDraw()
// off is in 16-bit indices, but DrawElements take a byte offset.
byteOff := off * 2
b.funcs.DrawElements(toGLDrawMode(b.state.pipeline.topology), count, gl.UNSIGNED_SHORT, byteOff)
}
func (b *Backend) DrawArrays(off, count int) {
b.prepareDraw()
b.funcs.DrawArrays(toGLDrawMode(b.state.pipeline.topology), off, count)
}
func (b *Backend) prepareDraw() {
p := b.state.pipeline
if p == nil {
return
}
b.setupVertexArrays()
}
func toGLDrawMode(mode driver.Topology) gl.Enum {
switch mode {
case driver.TopologyTriangleStrip:
return gl.TRIANGLE_STRIP
case driver.TopologyTriangles:
return gl.TRIANGLES
default:
panic("unsupported draw mode")
}
}
func (b *Backend) Viewport(x, y, width, height int) {
b.glstate.setViewport(b.funcs, x, y, width, height)
}
func (b *Backend) clearOutput(colR, colG, colB, colA float32) {
b.glstate.setClearColor(b.funcs, colR, colG, colB, colA)
b.funcs.Clear(gl.COLOR_BUFFER_BIT)
}
func (b *Backend) NewComputeProgram(src shader.Sources) (driver.Program, error) {
// We don't support ES 3.1 compute, see brokenGLES31 above.
const GLES31Source = ""
p, err := gl.CreateComputeProgram(b.funcs, GLES31Source)
if err != nil {
return nil, fmt.Errorf("%s: %v", src.Name, err)
}
return &program{
backend: b,
obj: p,
}, nil
}
func (b *Backend) NewVertexShader(src shader.Sources) (driver.VertexShader, error) {
glslSrc := b.glslFor(src)
sh, err := gl.CreateShader(b.funcs, gl.VERTEX_SHADER, glslSrc)
return &glshader{backend: b, obj: sh, src: src}, err
}
func (b *Backend) NewFragmentShader(src shader.Sources) (driver.FragmentShader, error) {
glslSrc := b.glslFor(src)
sh, err := gl.CreateShader(b.funcs, gl.FRAGMENT_SHADER, glslSrc)
return &glshader{backend: b, obj: sh, src: src}, err
}
func (b *Backend) glslFor(src shader.Sources) string {
if b.gles {
return src.GLSL100ES
} else {
return src.GLSL150
}
}
func (b *Backend) NewPipeline(desc driver.PipelineDesc) (driver.Pipeline, error) {
p, err := b.newProgram(desc)
if err != nil {
return nil, err
}
layout := desc.VertexLayout
vsrc := desc.VertexShader.(*glshader).src
if len(vsrc.Inputs) != len(layout.Inputs) {
return nil, fmt.Errorf("opengl: got %d inputs, expected %d", len(layout.Inputs), len(vsrc.Inputs))
}
for i, inp := range vsrc.Inputs {
if exp, got := inp.Size, layout.Inputs[i].Size; exp != got {
return nil, fmt.Errorf("opengl: data size mismatch for %q: got %d expected %d", inp.Name, got, exp)
}
}
return &pipeline{
prog: p,
inputs: vsrc.Inputs,
layout: layout,
blend: desc.BlendDesc,
topology: desc.Topology,
}, nil
}
func (b *Backend) newProgram(desc driver.PipelineDesc) (*program, error) {
p := b.funcs.CreateProgram()
if !p.Valid() {
return nil, errors.New("opengl: glCreateProgram failed")
}
vsh, fsh := desc.VertexShader.(*glshader), desc.FragmentShader.(*glshader)
b.funcs.AttachShader(p, vsh.obj)
b.funcs.AttachShader(p, fsh.obj)
for _, inp := range vsh.src.Inputs {
b.funcs.BindAttribLocation(p, gl.Attrib(inp.Location), inp.Name)
}
b.funcs.LinkProgram(p)
if b.funcs.GetProgrami(p, gl.LINK_STATUS) == 0 {
log := b.funcs.GetProgramInfoLog(p)
b.funcs.DeleteProgram(p)
return nil, fmt.Errorf("opengl: program link failed: %s", strings.TrimSpace(log))
}
prog := &program{
backend: b,
obj: p,
}
b.glstate.useProgram(b.funcs, p)
// Bind texture uniforms.
for _, tex := range vsh.src.Textures {
u := b.funcs.GetUniformLocation(p, tex.Name)
if u.Valid() {
b.funcs.Uniform1i(u, tex.Binding)
}
}
for _, tex := range fsh.src.Textures {
u := b.funcs.GetUniformLocation(p, tex.Name)
if u.Valid() {
b.funcs.Uniform1i(u, tex.Binding)
}
}
prog.vertUniforms.setup(b.funcs, p, vsh.src.Uniforms.Size, vsh.src.Uniforms.Locations)
prog.fragUniforms.setup(b.funcs, p, fsh.src.Uniforms.Size, fsh.src.Uniforms.Locations)
return prog, nil
}
func (b *Backend) BindStorageBuffer(binding int, buf driver.Buffer) {
bf := buf.(*buffer)
if bf.typ&(driver.BufferBindingShaderStorageRead|driver.BufferBindingShaderStorageWrite) == 0 {
panic("not a shader storage buffer")
}
b.storage[binding] = bf
}
func (b *Backend) BindUniforms(buf driver.Buffer) {
bf := buf.(*buffer)
if bf.typ&driver.BufferBindingUniforms == 0 {
panic("not a uniform buffer")
}
b.state.pipeline.prog.vertUniforms.update(b.funcs, bf)
b.state.pipeline.prog.fragUniforms.update(b.funcs, bf)
}
func (b *Backend) BindProgram(prog driver.Program) {
p := prog.(*program)
b.glstate.useProgram(b.funcs, p.obj)
}
func (s *glshader) Release() {
s.backend.funcs.DeleteShader(s.obj)
}
func (p *program) Release() {
p.backend.glstate.deleteProgram(p.backend.funcs, p.obj)
}
func (u *uniforms) setup(funcs *gl.Functions, p gl.Program, uniformSize int, uniforms []shader.UniformLocation) {
u.locs = make([]uniformLocation, len(uniforms))
for i, uniform := range uniforms {
loc := funcs.GetUniformLocation(p, uniform.Name)
u.locs[i] = uniformLocation{uniform: loc, offset: uniform.Offset, typ: uniform.Type, size: uniform.Size}
}
u.size = uniformSize
}
func (p *uniforms) update(funcs *gl.Functions, buf *buffer) {
if buf.size < p.size {
panic(fmt.Errorf("uniform buffer too small, got %d need %d", buf.size, p.size))
}
data := buf.data