ebiten/image.go
2014-12-29 00:21:40 +09:00

208 lines
5.2 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// 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 ebiten
import (
"github.com/hajimehoshi/ebiten/internal"
"github.com/hajimehoshi/ebiten/internal/opengl"
"github.com/hajimehoshi/ebiten/internal/opengl/internal/shader"
"image"
"image/color"
)
type innerImage struct {
framebuffer *opengl.Framebuffer
texture *opengl.Texture
}
func newInnerImage(texture *opengl.Texture) (*innerImage, error) {
framebuffer, err := opengl.NewFramebufferFromTexture(texture)
if err != nil {
return nil, err
}
return &innerImage{framebuffer, texture}, nil
}
func (i *innerImage) size() (width, height int) {
return i.framebuffer.Size()
}
func (i *innerImage) Clear() error {
return i.Fill(color.Transparent)
}
func (i *innerImage) Fill(clr color.Color) error {
if err := i.framebuffer.SetAsViewport(); err != nil {
return err
}
r, g, b, a := internal.RGBA(clr)
opengl.Clear(r, g, b, a)
return nil
}
func (i *innerImage) drawImage(img *innerImage, options *DrawImageOptions) error {
if options == nil {
options = &DrawImageOptions{}
}
parts := options.Parts
if parts == nil {
w, h := img.size()
parts = []ImagePart{
{
Dst: image.Rect(0, 0, w, h),
Src: image.Rect(0, 0, w, h),
},
}
}
geo := options.GeoM
clr := options.ColorM
if err := i.framebuffer.SetAsViewport(); err != nil {
return err
}
w, h := img.texture.Size()
quads := textureQuads(parts, w, h)
projectionMatrix := i.framebuffer.ProjectionMatrix()
return shader.DrawTexture(img.texture.Native(), projectionMatrix, quads, geo, clr)
}
func u(x float64, width int) float32 {
return float32(x) / float32(internal.NextPowerOf2Int(width))
}
func v(y float64, height int) float32 {
return float32(y) / float32(internal.NextPowerOf2Int(height))
}
func textureQuads(parts []ImagePart, width, height int) []shader.TextureQuad {
quads := make([]shader.TextureQuad, 0, len(parts))
for _, part := range parts {
dst, src := part.Dst, part.Src
x1 := float32(dst.Min.X)
x2 := float32(dst.Max.X)
y1 := float32(dst.Min.Y)
y2 := float32(dst.Max.Y)
u1 := u(float64(src.Min.X), width)
u2 := u(float64(src.Max.X), width)
v1 := v(float64(src.Min.Y), height)
v2 := v(float64(src.Max.Y), height)
quad := shader.TextureQuad{x1, x2, y1, y2, u1, u2, v1, v2}
quads = append(quads, quad)
}
return quads
}
type syncer interface {
Sync(func())
}
// Image represents an image.
// The pixel format is alpha-premultiplied.
// Image implements image.Image.
type Image struct {
syncer syncer
inner *innerImage
pixels []uint8
}
// Size returns the size of the image.
func (i *Image) Size() (width, height int) {
return i.inner.size()
}
// Clear resets the pixels of the image into 0.
func (i *Image) Clear() (err error) {
i.pixels = nil
i.syncer.Sync(func() {
err = i.inner.Clear()
})
return
}
// Fill fills the image with a solid color.
func (i *Image) Fill(clr color.Color) (err error) {
i.pixels = nil
i.syncer.Sync(func() {
err = i.inner.Fill(clr)
})
return
}
// DrawImage draws the given image on the receiver image.
//
// This method accepts the options.
// The parts of the given image at the parts of the destination.
// After determining parts to draw, this applies the geometry matrix and the color matrix.
//
// Here are the default values:
// Parts: (0, 0) - (source width, source height) to (0, 0) - (source width, source height)
// (i.e. the whole source image)
// GeoM: Identity matrix
// ColorM: Identity matrix (that changes no colors)
func (i *Image) DrawImage(image *Image, options *DrawImageOptions) (err error) {
return i.drawImage(image.inner, options)
}
func (i *Image) drawImage(image *innerImage, option *DrawImageOptions) (err error) {
i.pixels = nil
i.syncer.Sync(func() {
err = i.inner.drawImage(image, option)
})
return
}
// Bounds returns the bounds of the image.
func (i *Image) Bounds() image.Rectangle {
w, h := i.inner.size()
return image.Rect(0, 0, w, h)
}
// ColorModel returns the color model of the image.
func (i *Image) ColorModel() color.Model {
return color.RGBAModel
}
// At returns the color of the image at (x, y).
//
// This method loads pixels from GPU to VRAM if necessary.
func (i *Image) At(x, y int) color.Color {
if i.pixels == nil {
i.syncer.Sync(func() {
var err error
i.pixels, err = i.inner.texture.Pixels()
if err != nil {
panic(err)
}
})
}
w, _ := i.inner.size()
w = internal.NextPowerOf2Int(w)
idx := 4*x + 4*y*w
r, g, b, a := i.pixels[idx], i.pixels[idx+1], i.pixels[idx+2], i.pixels[idx+3]
return color.RGBA{r, g, b, a}
}
type ImagePart struct {
Dst image.Rectangle
Src image.Rectangle
}
// A DrawImageOptions represents options to render an image on an image.
type DrawImageOptions struct {
Parts []ImagePart
GeoM GeoM
ColorM ColorM
}