blob: 3282dae452f1a69b2f3d87f2dcd298790e2cf026 [file] [log] [blame]
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin linux windows
// Package glsprite implements a sprite Engine using OpenGL ES 2.
//
// Each sprite.Texture is loaded as a GL texture object and drawn
// to the screen via an affine transform done in a simple shader.
package glsprite // import "golang.org/x/mobile/exp/sprite/glsprite"
import (
"image"
"image/draw"
"golang.org/x/mobile/event/size"
"golang.org/x/mobile/exp/f32"
"golang.org/x/mobile/exp/gl/glutil"
"golang.org/x/mobile/exp/sprite"
"golang.org/x/mobile/exp/sprite/clock"
"golang.org/x/mobile/geom"
)
type node struct {
// TODO: move this into package sprite as Node.EngineFields.RelTransform??
relTransform f32.Affine
}
type texture struct {
e *engine
glImage *glutil.Image
b image.Rectangle
}
func (t *texture) Bounds() (w, h int) { return t.b.Dx(), t.b.Dy() }
func (t *texture) Download(r image.Rectangle, dst draw.Image) {
panic("TODO")
}
func (t *texture) Upload(r image.Rectangle, src image.Image) {
draw.Draw(t.glImage.RGBA, r, src, src.Bounds().Min, draw.Src)
t.glImage.Upload()
}
func (t *texture) Release() {
t.glImage.Release()
delete(t.e.textures, t)
}
// Engine creates an OpenGL-based sprite.Engine.
func Engine(images *glutil.Images) sprite.Engine {
return &engine{
nodes: []*node{nil},
images: images,
textures: make(map[*texture]struct{}),
}
}
type engine struct {
images *glutil.Images
textures map[*texture]struct{}
nodes []*node
absTransforms []f32.Affine
}
func (e *engine) Register(n *sprite.Node) {
if n.EngineFields.Index != 0 {
panic("glsprite: sprite.Node already registered")
}
o := &node{}
o.relTransform.Identity()
e.nodes = append(e.nodes, o)
n.EngineFields.Index = int32(len(e.nodes) - 1)
}
func (e *engine) Unregister(n *sprite.Node) {
panic("todo")
}
func (e *engine) LoadTexture(src image.Image) (sprite.Texture, error) {
b := src.Bounds()
t := &texture{
e: e,
glImage: e.images.NewImage(b.Dx(), b.Dy()),
b: b,
}
e.textures[t] = struct{}{}
t.Upload(b, src)
// TODO: set "glImage.Pix = nil"?? We don't need the CPU-side image any more.
return t, nil
}
func (e *engine) SetSubTex(n *sprite.Node, x sprite.SubTex) {
n.EngineFields.Dirty = true // TODO: do we need to propagate dirtiness up/down the tree?
n.EngineFields.SubTex = x
}
func (e *engine) SetTransform(n *sprite.Node, m f32.Affine) {
n.EngineFields.Dirty = true // TODO: do we need to propagate dirtiness up/down the tree?
e.nodes[n.EngineFields.Index].relTransform = m
}
func (e *engine) Render(scene *sprite.Node, t clock.Time, sz size.Event) {
e.absTransforms = append(e.absTransforms[:0], f32.Affine{
{1, 0, 0},
{0, 1, 0},
})
e.render(scene, t, sz)
}
func (e *engine) render(n *sprite.Node, t clock.Time, sz size.Event) {
if n.EngineFields.Index == 0 {
panic("glsprite: sprite.Node not registered")
}
if n.Arranger != nil {
n.Arranger.Arrange(e, n, t)
}
// Push absTransforms.
// TODO: cache absolute transforms and use EngineFields.Dirty?
rel := &e.nodes[n.EngineFields.Index].relTransform
m := f32.Affine{}
m.Mul(&e.absTransforms[len(e.absTransforms)-1], rel)
e.absTransforms = append(e.absTransforms, m)
if x := n.EngineFields.SubTex; x.T != nil {
x.T.(*texture).glImage.Draw(
sz,
geom.Point{
geom.Pt(m[0][2]),
geom.Pt(m[1][2]),
},
geom.Point{
geom.Pt(m[0][2] + m[0][0]),
geom.Pt(m[1][2] + m[1][0]),
},
geom.Point{
geom.Pt(m[0][2] + m[0][1]),
geom.Pt(m[1][2] + m[1][1]),
},
x.R,
)
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
e.render(c, t, sz)
}
// Pop absTransforms.
e.absTransforms = e.absTransforms[:len(e.absTransforms)-1]
}
func (e *engine) Release() {
for img := range e.textures {
img.Release()
}
}