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mobile/sprite/portable/portable.go
Nigel Tao fab1e51609 go.mobile/geom: rename Scale to PixelsPerPt.
LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/160160043
2014-10-22 13:50:04 +11:00

148 lines
4.0 KiB
Go

// 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.
// Package portable blah blah blah TODO.
package portable
import (
"fmt"
"image"
"image/draw"
"code.google.com/p/go.mobile/f32"
"code.google.com/p/go.mobile/geom"
"code.google.com/p/go.mobile/sprite"
"code.google.com/p/go.mobile/sprite/clock"
)
func Engine(dst *image.RGBA) sprite.Engine {
return &engine{
dst: dst,
nodes: []*node{nil},
sheets: []*image.RGBA{nil},
textures: []*image.RGBA{nil},
}
}
type node struct {
// TODO: move this into package sprite as Node.EngineFields.RelTransform??
relTransform f32.Affine
}
var _ sprite.Engine = (*engine)(nil)
type engine struct {
dst *image.RGBA
nodes []*node
sheets []*image.RGBA
textures []*image.RGBA
absTransforms []f32.Affine
}
func (e *engine) Register(n *sprite.Node) {
if n.EngineFields.Index != 0 {
panic("portable: 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) LoadSheet(a image.Image) (sprite.Sheet, error) {
rgba, ok := a.(*image.RGBA)
if !ok {
b := a.Bounds()
rgba = image.NewRGBA(b)
draw.Draw(rgba, b, a, b.Min, draw.Src)
}
e.sheets = append(e.sheets, rgba)
return sprite.Sheet(len(e.sheets) - 1), nil
}
func (e *engine) LoadTexture(s sprite.Sheet, bounds image.Rectangle) (sprite.Texture, error) {
if s < 0 || len(e.sheets) <= int(s) {
return 0, fmt.Errorf("portable: LoadTexture: sheet %d is out of bounds", s)
}
e.textures = append(e.textures, e.sheets[s].SubImage(bounds).(*image.RGBA))
return sprite.Texture(len(e.textures) - 1), nil
}
func (e *engine) UnloadSheet(s sprite.Sheet) error {
panic("todo")
}
func (e *engine) UnloadTexture(x sprite.Texture) error {
panic("todo")
}
func (e *engine) SetTexture(n *sprite.Node, t clock.Time, x sprite.Texture) {
n.EngineFields.Dirty = true // TODO: do we need to propagate dirtiness up/down the tree?
n.EngineFields.Texture = x
}
func (e *engine) SetTransform(n *sprite.Node, t clock.Time, 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) {
// Affine transforms are done in geom.Pt. When finally drawing
// the geom.Pt onto an image.Image we need to convert to system
// pixels. We scale by geom.Scale to do this.
e.absTransforms = append(e.absTransforms[:0], f32.Affine{
{geom.PixelsPerPt, 0, 0},
{0, geom.PixelsPerPt, 0},
})
e.render(scene, t)
}
func (e *engine) render(n *sprite.Node, t clock.Time) {
if n.EngineFields.Index == 0 {
panic("portable: 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 := e.textures[n.EngineFields.Texture]; x != nil {
b := x.Bounds()
// Affine transforms work in geom.Pt, which is entirely
// independent of the number of pixels in a texture. A texture
// of any image.Rectangle bounds rendered with
//
// Affine{{1, 0, 0}, {0, 1, 0}}
//
// should have the dimensions (1pt, 1pt). To do this we divide
// by the pixel width and height, reducing the texture to
// (1px, 1px) of the destination image. Multiplying by geom.Scale
// makes it (1pt, 1pt).
m.Scale(&m, 1/float32(b.Dx()), 1/float32(b.Dy()))
m.Inverse(&m) // See the documentation on the affine function.
affine(e.dst, x, &m, draw.Over)
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
e.render(c, t)
}
// Pop absTransforms.
e.absTransforms = e.absTransforms[:len(e.absTransforms)-1]
}