gpu: expose the rendering implementation

The rendering implementation is needed for using Gio UI with external
window libraries such as GLFW. Expose it in the new package gpu.

Updates #26

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/headless/headless.go

@@ -9,8 +9,8 @@ import (
 	"image"
 	"runtime"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu"
-	"gioui.org/app/internal/gpu"
+	"gioui.org/gpu/gl"
 	"gioui.org/op"
 )
 

app/headless/headless_darwin.go

@@ -2,8 +2,10 @@
 
 package headless
 
-import "gioui.org/app/internal/gl"
+import (
-import "gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
+	"gioui.org/gpu/gl"
+)
 
 /*
 #cgo CFLAGS: -DGL_SILENCE_DEPRECATION -Werror -Wno-deprecated-declarations -fmodules -fobjc-arc -x objective-c
@@ -21,7 +23,7 @@ type nsContext struct {
 
 func newContext() (context, error) {
 	ctx := C.gio_headless_newContext()
-	return &nsContext{ctx: ctx, c: new(impl.Functions)}, nil
+	return &nsContext{ctx: ctx, c: new(glimpl.Functions)}, nil
 }
 
 func (c *nsContext) MakeCurrent() error {

app/headless/headless_js.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 	"syscall/js"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
 )
 
 type jsContext struct {
@@ -27,7 +27,7 @@ func newContext() (*jsContext, error) {
 	if ctx.IsNull() {
 		return nil, errors.New("headless: webgl is not supported")
 	}
-	f := &impl.Functions{Ctx: ctx}
+	f := &glimpl.Functions{Ctx: ctx}
 	if err := f.Init(version); err != nil {
 		return nil, err
 	}

app/internal/egl/egl.go

@@ -10,8 +10,8 @@ import (
 	"runtime"
 	"strings"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/app/internal/glimpl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/gpu/gl"
 )
 
 type Context struct {
@@ -110,7 +110,7 @@ func NewContext(disp NativeDisplayType) (*Context, error) {
 	c := &Context{
 		disp:   eglDisp,
 		eglCtx: eglCtx,
-		c:      new(impl.Functions),
+		c:      new(glimpl.Functions),
 	}
 	return c, nil
 }

app/internal/egl/egl_windows.go

@@ -10,8 +10,8 @@ import (
 
 	syscall "golang.org/x/sys/windows"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
 )
 
 type (
@@ -57,7 +57,7 @@ func loadDLLs() error {
 	if err := loadDLL(libEGL, "libEGL.dll"); err != nil {
 		return err
 	}
-	if err := loadDLL(impl.LibGLESv2, "libGLESv2.dll"); err != nil {
+	if err := loadDLL(glimpl.LibGLESv2, "libGLESv2.dll"); err != nil {
 		return err
 	}
 	// d3dcompiler_47.dll is needed internally for shader compilation to function.

app/internal/glimpl/gl.go

@@ -2,14 +2,14 @@
 
 // +build darwin linux freebsd openbsd
 
-package impl
+package glimpl
 
 import (
 	"runtime"
 	"strings"
 	"unsafe"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 )
 
 /*

app/internal/glimpl/gl_js.go

@@ -1,13 +1,13 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-package impl
+package glimpl
 
 import (
 	"errors"
 	"strings"
 	"syscall/js"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 )
 
 type Functions struct {

app/internal/glimpl/gl_windows.go

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-package impl
+package glimpl
 
 import (
 	"math"
@@ -10,7 +10,7 @@ import (
 
 	"golang.org/x/sys/windows"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 )
 
 var (

app/internal/window/gl_ios.go

@@ -16,8 +16,8 @@ import (
 	"errors"
 	"fmt"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
 )
 
 type context struct {
@@ -45,7 +45,7 @@ func newContext(w *window) (*context, error) {
 		ctx:   ctx,
 		owner: w,
 		layer: C.CFTypeRef(w.contextLayer()),
-		c:     new(impl.Functions),
+		c:     new(glimpl.Functions),
 	}
 	return c, nil
 }

app/internal/window/gl_js.go

@@ -6,8 +6,8 @@ import (
 	"errors"
 	"syscall/js"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
 )
 
 type context struct {
@@ -33,7 +33,7 @@ func newContext(w *window) (*context, error) {
 	if ctx.IsNull() {
 		return nil, errors.New("app: webgl is not supported")
 	}
-	f := &impl.Functions{Ctx: ctx}
+	f := &glimpl.Functions{Ctx: ctx}
 	if err := f.Init(version); err != nil {
 		return nil, err
 	}

app/internal/window/gl_macos.go

@@ -5,8 +5,8 @@
 package window
 
 import (
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
-	"gioui.org/app/internal/gl/impl"
+	"gioui.org/app/internal/glimpl"
 )
 
 /*
@@ -35,7 +35,7 @@ func newContext(w *window) (*context, error) {
 	ctx := C.gio_contextForView(view)
 	c := &context{
 		ctx:  ctx,
-		c:    new(impl.Functions),
+		c:    new(glimpl.Functions),
 		view: view,
 	}
 	return c, nil

app/internal/window/window.go

@@ -9,7 +9,7 @@ import (
 	"math"
 	"time"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 	"gioui.org/io/event"
 	"gioui.org/io/system"
 	"gioui.org/unit"

app/loop.go

@@ -6,8 +6,8 @@ import (
 	"image"
 	"runtime"
 
-	"gioui.org/app/internal/gpu"
 	"gioui.org/app/internal/window"
+	"gioui.org/gpu"
 	"gioui.org/op"
 )
 

gpu/context.go

@@ -6,7 +6,7 @@ import (
 	"errors"
 	"strings"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 )
 
 type context struct {

gpu/gpu.go

@@ -1,5 +1,10 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
+/*
+Package gpu implements the rendering of Gio drawing operations. It
+is used by package app and package app/headless and is otherwise not
+useful except for integrating with external window implementations.
+*/
 package gpu
 
 import (
@@ -12,8 +17,8 @@ import (
 	"time"
 	"unsafe"
 
-	"gioui.org/app/internal/gl"
 	"gioui.org/f32"
+	"gioui.org/gpu/gl"
 	"gioui.org/internal/opconst"
 	"gioui.org/internal/ops"
 	"gioui.org/internal/path"

gpu/path.go

@@ -9,8 +9,8 @@ import (
 	"image"
 	"unsafe"
 
-	"gioui.org/app/internal/gl"
 	"gioui.org/f32"
+	"gioui.org/gpu/gl"
 	"gioui.org/internal/path"
 )
 

gpu/timer.go

@@ -5,7 +5,7 @@ package gpu
 import (
 	"time"
 
-	"gioui.org/app/internal/gl"
+	"gioui.org/gpu/gl"
 )
 
 type timers struct {