Introduce ImageParts

example/blocks/blocks/font.go

@@ -15,12 +15,11 @@
 package blocks
 
 import (
-	"errors"
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
-	"image"
 	"image/color"
 	"math"
+	"strings"
 )
 
 var imageFont *ebiten.Image
@@ -41,43 +40,51 @@ func textWidth(str string) int {
 	return charWidth * len(str)
 }
 
-var fontImageParts = make([]ebiten.ImagePart, 0, 256)
+type fontImageParts string
+
+func (f fontImageParts) Len() int {
+	return len(f)
+}
+
+func (f fontImageParts) Dst(i int) (x0, y0, x1, y1 int) {
+	x := i - strings.LastIndex(string(f)[:i], "\n") - 1
+	y := strings.Count(string(f)[:i], "\n")
+	x *= charWidth
+	y *= charHeight
+	if x < 0 {
+		return 0, 0, 0, 0
+	}
+	return x, y, x + charWidth, y + charHeight
+}
+
+func (f fontImageParts) Src(i int) (x0, y0, x1, y1 int) {
+	code := int(f[i])
+	if code == '\n' {
+		return 0, 0, 0, 0
+	}
+	x := (code % 16) * charWidth
+	y := ((code - 32) / 16) * charHeight
+	return x, y, x + charWidth, y + charHeight
+}
 
 func drawText(rt *ebiten.Image, str string, ox, oy, scale int, c color.Color) error {
-	if cap(fontImageParts) < len(str) {
-		return errors.New("str is too long")
-	}
-	parts := fontImageParts[:0]
-
-	locationX, locationY := 0, 0
-	for _, c := range str {
-		if c == '\n' {
-			locationX = 0
-			locationY += charHeight
-			continue
-		}
-		code := int(c)
-		x := (code % 16) * charWidth
-		y := ((code - 32) / 16) * charHeight
-		parts = append(parts, ebiten.ImagePart{
-			Dst: image.Rect(locationX, locationY, locationX+charWidth, locationY+charHeight),
-			Src: image.Rect(x, y, x+charWidth, y+charHeight),
-		})
-		locationX += charWidth
-	}
-
 	options := &ebiten.DrawImageOptions{
-		Parts: parts,
+		ImageParts: fontImageParts(str),
 	}
 	options.GeoM.Scale(float64(scale), float64(scale))
 	options.GeoM.Translate(float64(ox), float64(oy))
 
-	c2 := color.NRGBA64Model.Convert(c).(color.NRGBA64)
+	ur, ug, ub, ua := c.RGBA()
 	const max = math.MaxUint16
-	r := float64(c2.R) / max
-	g := float64(c2.G) / max
-	b := float64(c2.B) / max
-	a := float64(c2.A) / max
+	r := float64(ur) / max
+	g := float64(ug) / max
+	b := float64(ub) / max
+	a := float64(ua) / max
+	if 0 < a {
+		r /= a
+		g /= a
+		b /= a
+	}
 	options.ColorM.Scale(r, g, b, a)
 
 	return rt.DrawImage(imageFont, options)

example/blocks/blocks/piece.go

@@ -17,7 +17,6 @@ package blocks
 import (
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
-	"image"
 )
 
 var imageBlocks *ebiten.Image
@@ -143,28 +142,36 @@ const blockHeight = 10
 const fieldBlockNumX = 10
 const fieldBlockNumY = 20
 
-var blocksImageParts = make([]ebiten.ImagePart, 0, fieldBlockNumX*fieldBlockNumY)
+type blocksImageParts [][]BlockType
+
+func (b blocksImageParts) Len() int {
+	return len(b) * len(b[0])
+}
+
+func (b blocksImageParts) Dst(i int) (x0, y0, x1, y1 int) {
+	i, j := i%len(b), i/len(b)
+	x := i * blockWidth
+	y := j * blockHeight
+	return x, y, x + blockWidth, y + blockHeight
+}
+
+func (b blocksImageParts) Src(i int) (x0, y0, x1, y1 int) {
+	i, j := i%len(b), i/len(b)
+	block := b[i][j]
+	if block == BlockTypeNone {
+		return 0, 0, 0, 0
+	}
+	x := (int(block) - 1) * blockWidth
+	return x, 0, x + blockWidth, blockHeight
+}
 
 func drawBlocks(r *ebiten.Image, blocks [][]BlockType, x, y int, clr ebiten.ColorM) error {
-	parts := blocksImageParts[:0]
-	for i, blockCol := range blocks {
-		for j, block := range blockCol {
-			if block == BlockTypeNone {
-				continue
-			}
-			locationX := i*blockWidth + x
-			locationY := j*blockHeight + y
-			srcX := (int(block) - 1) * blockWidth
-			parts = append(parts, ebiten.ImagePart{
-				Dst: image.Rect(locationX, locationY, locationX+blockWidth, locationY+blockHeight),
-				Src: image.Rect(srcX, 0, srcX+blockWidth, blockHeight),
-			})
-		}
+	op := &ebiten.DrawImageOptions{
+		ImageParts: blocksImageParts(blocks),
+		ColorM:     clr,
 	}
-	return r.DrawImage(imageBlocks, &ebiten.DrawImageOptions{
-		Parts:  parts,
-		ColorM: clr,
-	})
+	op.GeoM.Translate(float64(x), float64(y))
+	return r.DrawImage(imageBlocks, op)
 }
 
 func (p *Piece) InitialPosition() (int, int) {

image.go

@@ -49,22 +49,56 @@ func (i *innerImage) Fill(c *opengl.Context, clr color.Color) error {
 	return i.framebuffer.Fill(c, r, g, b, a)
 }
 
+// TODO: Remove this in the future.
+type imageParts []ImagePart
+
+func (p imageParts) Len() int {
+	return len(p)
+}
+
+func (p imageParts) Dst(i int) (x0, y0, x1, y1 int) {
+	dst := &p[i].Dst
+	return dst.Min.X, dst.Min.Y, dst.Max.X, dst.Max.Y
+}
+
+func (p imageParts) Src(i int) (x0, y0, x1, y1 int) {
+	src := &p[i].Src
+	return src.Min.X, src.Min.Y, src.Max.X, src.Max.Y
+}
+
+type wholeImage struct {
+	width  int
+	height int
+}
+
+func (w *wholeImage) Len() int {
+	return 1
+}
+
+func (w *wholeImage) Dst(i int) (x0, y0, x1, y1 int) {
+	return 0, 0, w.width, w.height
+}
+
+func (w *wholeImage) Src(i int) (x0, y0, x1, y1 int) {
+	return 0, 0, w.width, w.height
+}
+
 func (i *innerImage) drawImage(c *opengl.Context, img *innerImage, options *DrawImageOptions) error {
 	if options == nil {
 		options = &DrawImageOptions{}
 	}
-	parts := options.Parts
+	parts := options.ImageParts
 	if parts == nil {
-		w, h := img.size()
-		parts = []ImagePart{
-			{
-				Dst: image.Rect(0, 0, w, h),
-				Src: image.Rect(0, 0, w, h),
-			},
+		dparts := options.Parts
+		if dparts != nil {
+			parts = imageParts(dparts)
+		} else {
+			w, h := img.size()
+			parts = &wholeImage{w, h}
 		}
 	}
 	w, h := img.size()
-	quads := &textureQuads{parts, w, h}
+	quads := &textureQuads{parts: parts, width: w, height: h}
 	return i.framebuffer.DrawTexture(c, img.texture, quads, &options.GeoM, &options.ColorM)
 }
 
@@ -77,26 +111,24 @@ func v(y float32, height int) float32 {
 }
 
 type textureQuads struct {
-	parts  []ImagePart
+	parts  ImageParts
 	width  int
 	height int
 }
 
 func (t *textureQuads) Len() int {
-	return len(t.parts)
+	return t.parts.Len()
 }
 
 func (t *textureQuads) Vertex(i int) (x0, y0, x1, y1 float32) {
-	p := &t.parts[i]
-	dst := &p.Dst
-	return float32(dst.Min.X), float32(dst.Min.Y), float32(dst.Max.X), float32(dst.Max.Y)
+	ix0, iy0, ix1, iy1 := t.parts.Dst(i)
+	return float32(ix0), float32(iy0), float32(ix1), float32(iy1)
 }
 
 func (t *textureQuads) Texture(i int) (u0, v0, u1, v1 float32) {
-	p := &t.parts[i]
-	src := &p.Src
+	x0, y0, x1, y1 := t.parts.Src(i)
 	w, h := t.width, t.height
-	return u(float32(src.Min.X), w), v(float32(src.Min.Y), h), u(float32(src.Max.X), w), v(float32(src.Max.Y), h)
+	return u(float32(x0), w), v(float32(y0), h), u(float32(x1), w), v(float32(y1), h)
 }
 
 // Image represents an image.
@@ -184,14 +216,25 @@ func (i *Image) At(x, y int) color.Color {
 	return color.RGBA{r, g, b, a}
 }
 
+// Deprecated: Use ImageParts instead.
 type ImagePart struct {
 	Dst image.Rectangle
 	Src image.Rectangle
 }
 
+// An ImageParts represents the parts of the destination image and the parts of the source image.
+type ImageParts interface {
+	Len() int
+	Dst(i int) (x0, y0, x1, y1 int)
+	Src(i int) (x0, y0, x1, y1 int)
+}
+
 // A DrawImageOptions represents options to render an image on an image.
 type DrawImageOptions struct {
-	Parts  []ImagePart
-	GeoM   GeoM
-	ColorM ColorM
+	ImageParts ImageParts
+	GeoM       GeoM
+	ColorM     ColorM
+
+	// Deprecated: Use ImageParts instead.
+	Parts []ImagePart
 }

internal/graphics/internal/shader/drawtexture.go

@@ -76,6 +76,9 @@ func DrawTexture(c *opengl.Context, texture opengl.Texture, projectionMatrix *[4
 	for i := 0; i < quads.Len(); i++ {
 		x0, y0, x1, y1 := quads.Vertex(i)
 		u0, v0, u1, v1 := quads.Texture(i)
+		if x0 == x1 || y0 == y1 || u0 == u1 || v0 == v1 {
+			continue
+		}
 		vertices = append(vertices,
 			x0, y0, u0, v0,
 			x1, y0, u1, v0,
@@ -83,7 +86,10 @@ func DrawTexture(c *opengl.Context, texture opengl.Texture, projectionMatrix *[4
 			x1, y1, u1, v1,
 		)
 	}
+	if len(vertices) == 0 {
+		return nil
+	}
 	c.BufferSubData(c.ArrayBuffer, vertices)
-	c.DrawElements(6 * quads.Len())
+	c.DrawElements(6 * len(vertices) / 16)
 	return nil
 }

readme.md

@@ -56,7 +56,7 @@ If you want to use GopherJS, execute this:
 
 ## Versioning
 
-* We adopted [Semantic Versioning](http://semver.org/)
+* We obey [Semantic Versioning](http://semver.org/) basically
 
 ## License