277 lines
7.0 KiB
Go
277 lines
7.0 KiB
Go
package pixel
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import (
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"fmt"
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"image"
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"image/color"
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"image/draw"
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"math"
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)
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// TrianglesData specifies a list of Triangles vertices with three common properties:
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// TrianglesPosition, TrianglesColor and TrianglesPicture.
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type TrianglesData []struct {
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Position Vec
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Color RGBA
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Picture Vec
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Intensity float64
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}
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// MakeTrianglesData creates TrianglesData of length len initialized with default property values.
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//
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// Prefer this function to make(TrianglesData, len), because make zeros them, while this function
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// does the correct intialization.
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func MakeTrianglesData(len int) *TrianglesData {
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td := &TrianglesData{}
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td.SetLen(len)
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return td
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}
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// Len returns the number of vertices in TrianglesData.
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func (td *TrianglesData) Len() int {
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return len(*td)
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}
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// SetLen resizes TrianglesData to len, while keeping the original content.
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//
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// If len is greater than TrianglesData's current length, the new data is filled with default
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// values ((0, 0), white, (0, 0), 0).
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func (td *TrianglesData) SetLen(len int) {
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if len > td.Len() {
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needAppend := len - td.Len()
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for i := 0; i < needAppend; i++ {
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*td = append(*td, struct {
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Position Vec
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Color RGBA
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Picture Vec
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Intensity float64
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}{Color: RGBA{1, 1, 1, 1}})
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}
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}
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if len < td.Len() {
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*td = (*td)[:len]
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}
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}
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// Slice returns a sub-Triangles of this TrianglesData.
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func (td *TrianglesData) Slice(i, j int) Triangles {
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s := TrianglesData((*td)[i:j])
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return &s
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}
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func (td *TrianglesData) updateData(t Triangles) {
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// fast path optimization
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if t, ok := t.(*TrianglesData); ok {
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copy(*td, *t)
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return
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}
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// slow path manual copy
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if t, ok := t.(TrianglesPosition); ok {
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for i := range *td {
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(*td)[i].Position = t.Position(i)
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}
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}
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if t, ok := t.(TrianglesColor); ok {
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for i := range *td {
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(*td)[i].Color = t.Color(i)
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}
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}
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if t, ok := t.(TrianglesPicture); ok {
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for i := range *td {
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(*td)[i].Picture, (*td)[i].Intensity = t.Picture(i)
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}
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}
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}
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// Update copies vertex properties from the supplied Triangles into this TrianglesData.
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//
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// TrianglesPosition, TrianglesColor and TrianglesTexture are supported.
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func (td *TrianglesData) Update(t Triangles) {
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if td.Len() != t.Len() {
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panic(fmt.Errorf("(%T).Update: invalid triangles length", td))
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}
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td.updateData(t)
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}
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// Copy returns an exact independent copy of this TrianglesData.
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func (td *TrianglesData) Copy() Triangles {
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copyTd := TrianglesData{}
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copyTd.SetLen(td.Len())
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copyTd.Update(td)
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return ©Td
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}
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// Position returns the position property of i-th vertex.
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func (td *TrianglesData) Position(i int) Vec {
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return (*td)[i].Position
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}
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// Color returns the color property of i-th vertex.
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func (td *TrianglesData) Color(i int) RGBA {
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return (*td)[i].Color
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}
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// Picture returns the picture property of i-th vertex.
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func (td *TrianglesData) Picture(i int) (pic Vec, intensity float64) {
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return (*td)[i].Picture, (*td)[i].Intensity
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}
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// PictureData specifies an in-memory rectangular area of pixels and implements Picture and
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// PictureColor.
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//
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// Pixels are small rectangles of unit size of form (x, y, x+1, y+1), where x and y are integers.
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// PictureData contains and assigns a color to all pixels that are at least partially contained
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// within it's Bounds (Rect).
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//
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// The struct's innards are exposed for convenience, manual modification is at your own risk.
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//
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// The format of the pixels is color.RGBA and not pixel.RGBA for a very serious reason:
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// pixel.RGBA takes up 8x more memory than color.RGBA.
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type PictureData struct {
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Pix []color.RGBA
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Stride int
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Rect Rect
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}
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// MakePictureData creates a zero-initialized PictureData covering the given rectangle.
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func MakePictureData(rect Rect) *PictureData {
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w := int(math.Ceil(rect.Max.X)) - int(math.Floor(rect.Min.X))
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h := int(math.Ceil(rect.Max.Y)) - int(math.Floor(rect.Min.Y))
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pd := &PictureData{
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Stride: w,
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Rect: rect,
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}
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pd.Pix = make([]color.RGBA, w*h)
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return pd
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}
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func verticalFlip(rgba *image.RGBA) {
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bounds := rgba.Bounds()
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width := bounds.Dx()
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tmpRow := make([]uint8, width*4)
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for i, j := 0, bounds.Dy()-1; i < j; i, j = i+1, j-1 {
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iRow := rgba.Pix[i*rgba.Stride : i*rgba.Stride+width*4]
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jRow := rgba.Pix[j*rgba.Stride : j*rgba.Stride+width*4]
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copy(tmpRow, iRow)
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copy(iRow, jRow)
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copy(jRow, tmpRow)
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}
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}
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// PictureDataFromImage converts an image.Image into PictureData.
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//
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// The resulting PictureData's Bounds will be the equivalent of the supplied image.Image's Bounds.
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func PictureDataFromImage(img image.Image) *PictureData {
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var rgba *image.RGBA
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if rgbaImg, ok := img.(*image.RGBA); ok {
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rgba = rgbaImg
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} else {
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rgba = image.NewRGBA(img.Bounds())
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draw.Draw(rgba, rgba.Bounds(), img, img.Bounds().Min, draw.Src)
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}
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verticalFlip(rgba)
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pd := MakePictureData(R(
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float64(rgba.Bounds().Min.X),
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float64(rgba.Bounds().Min.Y),
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float64(rgba.Bounds().Max.X),
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float64(rgba.Bounds().Max.Y),
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))
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for i := range pd.Pix {
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pd.Pix[i].R = rgba.Pix[i*4+0]
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pd.Pix[i].G = rgba.Pix[i*4+1]
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pd.Pix[i].B = rgba.Pix[i*4+2]
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pd.Pix[i].A = rgba.Pix[i*4+3]
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}
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return pd
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}
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// PictureDataFromPicture converts an arbitrary Picture into PictureData (the conversion may be
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// lossy, because PictureData works with unit-sized pixels).
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//
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// Bounds are preserved.
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func PictureDataFromPicture(pic Picture) *PictureData {
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if pd, ok := pic.(*PictureData); ok {
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return pd
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}
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bounds := pic.Bounds()
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pd := MakePictureData(bounds)
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if pic, ok := pic.(PictureColor); ok {
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for y := math.Floor(bounds.Min.Y); y < bounds.Max.Y; y++ {
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for x := math.Floor(bounds.Min.X); x < bounds.Max.X; x++ {
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// this together with the Floor is a trick to get all of the pixels
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at := V(
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math.Max(x, bounds.Min.X),
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math.Max(y, bounds.Min.Y),
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)
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col := pic.Color(at)
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pd.Pix[pd.Index(at)] = color.RGBA{
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R: uint8(col.R * 255),
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G: uint8(col.G * 255),
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B: uint8(col.B * 255),
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A: uint8(col.A * 255),
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}
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}
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}
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}
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return pd
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}
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// Image converts PictureData into an image.RGBA.
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//
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// The resulting image.RGBA's Bounds will be equivalent of the PictureData's Bounds.
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func (pd *PictureData) Image() *image.RGBA {
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bounds := image.Rect(
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int(math.Floor(pd.Rect.Min.X)),
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int(math.Floor(pd.Rect.Min.Y)),
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int(math.Ceil(pd.Rect.Max.X)),
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int(math.Ceil(pd.Rect.Max.Y)),
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)
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rgba := image.NewRGBA(bounds)
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i := 0
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for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
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for x := bounds.Min.X; x < bounds.Max.X; x++ {
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off := pd.Index(V(float64(x), float64(y)))
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rgba.Pix[i*4+0] = pd.Pix[off].R
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rgba.Pix[i*4+1] = pd.Pix[off].G
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rgba.Pix[i*4+2] = pd.Pix[off].B
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rgba.Pix[i*4+3] = pd.Pix[off].A
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i++
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}
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}
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verticalFlip(rgba)
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return rgba
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}
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// Index returns the index of the pixel at the specified position inside the Pix slice.
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func (pd *PictureData) Index(at Vec) int {
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at = at.Sub(pd.Rect.Min.Map(math.Floor))
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x, y := int(at.X), int(at.Y)
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return y*pd.Stride + x
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}
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// Bounds returns the bounds of this PictureData.
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func (pd *PictureData) Bounds() Rect {
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return pd.Rect
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}
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// Color returns the color located at the given position.
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func (pd *PictureData) Color(at Vec) RGBA {
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if !pd.Rect.Contains(at) {
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return RGBA{0, 0, 0, 0}
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}
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return ToRGBA(pd.Pix[pd.Index(at)])
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}
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