ebiten/internal/pixels/pixels.go
2016-08-23 00:05:23 +09:00

188 lines
4.7 KiB
Go

// Copyright 2016 The Ebiten 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 pixels
import (
"errors"
"image"
"image/color"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
)
type drawImageHistoryItem struct {
image *graphics.Image
vertices []int16
geom graphics.Matrix
colorm graphics.Matrix
mode opengl.CompositeMode
}
// Pixels represents pixels of an image for restoring when GL context is lost.
type Pixels struct {
// basePixels and baseColor are exclusive.
basePixels []uint8
baseColor color.Color
drawImageHistory []*drawImageHistoryItem
stale bool
}
func (p *Pixels) IsStale() bool {
return p.stale
}
func (p *Pixels) MakeStale() {
p.basePixels = nil
p.baseColor = nil
p.drawImageHistory = nil
p.stale = true
}
func (p *Pixels) Clear() {
p.basePixels = nil
p.baseColor = nil
p.drawImageHistory = nil
p.stale = false
}
func (p *Pixels) Fill(clr color.Color) {
p.basePixels = nil
p.baseColor = clr
p.drawImageHistory = nil
p.stale = false
}
func (p *Pixels) ReplacePixels(pixels []uint8) {
if p.basePixels == nil {
p.basePixels = make([]uint8, len(pixels))
}
copy(p.basePixels, pixels)
p.baseColor = nil
p.drawImageHistory = nil
p.stale = false
}
func (p *Pixels) AppendDrawImageHistory(image *graphics.Image, vertices []int16, geom graphics.Matrix, colorm graphics.Matrix, mode opengl.CompositeMode) {
if p.stale {
return
}
// All images must be resolved and not stale each after frame.
// So we don't have to care if image is stale or not here.
item := &drawImageHistoryItem{
image: image,
vertices: vertices,
geom: geom,
colorm: colorm,
mode: mode,
}
p.drawImageHistory = append(p.drawImageHistory, item)
}
// At returns a color value at idx.
//
// Note that this must not be called until context is available.
// This means Pixels members must match with acutal state in VRAM.
func (p *Pixels) At(idx int, image *graphics.Image, context *opengl.Context) (color.Color, error) {
if p.basePixels == nil || p.drawImageHistory != nil || p.stale {
if err := p.readPixelsFromVRAM(image, context); err != nil {
return nil, err
}
}
r, g, b, a := p.basePixels[idx], p.basePixels[idx+1], p.basePixels[idx+2], p.basePixels[idx+3]
return color.RGBA{r, g, b, a}, nil
}
func (p *Pixels) DependsOn(target *graphics.Image) bool {
if p.stale {
return false
}
// TODO: Performance is bad when drawImageHistory is too many.
for _, c := range p.drawImageHistory {
if c.image == target {
return true
}
}
return false
}
func (p *Pixels) readPixelsFromVRAM(image *graphics.Image, context *opengl.Context) error {
var err error
p.basePixels, err = image.Pixels(context)
if err != nil {
return err
}
p.baseColor = nil
p.drawImageHistory = nil
p.stale = false
return nil
}
func (p *Pixels) ReadPixelsFromVRAMIfStale(image *graphics.Image, context *opengl.Context) error {
if !p.stale {
return nil
}
return p.readPixelsFromVRAM(image, context)
}
func (p *Pixels) HasDependency() bool {
if p.stale {
return false
}
return p.drawImageHistory != nil
}
// CreateImage restores *graphics.Image from the pixels using its state.
func (p *Pixels) CreateImage(context *opengl.Context, width, height int, filter opengl.Filter) (*graphics.Image, error) {
if p.stale {
return nil, errors.New("pixels: pixels must not be stale when restoring")
}
img := image.NewRGBA(image.Rect(0, 0, width, height))
if p.basePixels != nil {
for j := 0; j < height; j++ {
copy(img.Pix[j*img.Stride:], p.basePixels[j*width*4:(j+1)*width*4])
}
}
gimg, err := graphics.NewImageFromImage(img, filter)
if err != nil {
return nil, err
}
if p.baseColor != nil {
if p.basePixels != nil {
panic("not reach")
}
if err := gimg.Fill(p.baseColor); err != nil {
return nil, err
}
}
for _, c := range p.drawImageHistory {
// c.image.impl must be already restored.
/*if c.image.impl.hasHistory() {
panic("not reach")
}*/
if err := gimg.DrawImage(c.image, c.vertices, c.geom, c.colorm, c.mode); err != nil {
return nil, err
}
}
p.basePixels, err = gimg.Pixels(context)
if err != nil {
return nil, err
}
p.baseColor = nil
p.drawImageHistory = nil
p.stale = false
return gimg, nil
}