graphicscommand: Refactoring

internal/graphics/math.go

@@ -17,7 +17,7 @@ package graphics
 // minInternalImageSize is the minimum size of internal images (texture/framebuffer).
 //
 // For example, the image size less than 15 is not supported on some iOS devices.
-// See also: https://stackoverflow.com/questions/15935651/certain-framebuffer-sizes-fail-on-ios-devices-gl-framebuffer-unsupported
+// See also: https://stackoverflow.com/questions/15935651
 const minInternalImageSize = 16
 
 // InternalImageSize returns a nearest appropriate size as an internal image.
@@ -34,13 +34,3 @@ func InternalImageSize(x int) int {
 	}
 	return r
 }
-
-func isInternalImageSize(x int) bool {
-	if x <= 0 {
-		return false
-	}
-	if x < minInternalImageSize {
-		return false
-	}
-	return (x & (x - 1)) == 0
-}

internal/graphicscommand/image.go

@@ -31,11 +31,13 @@ const (
 
 // Image represents an image that is implemented with OpenGL.
 type Image struct {
-	image       driver.Image
-	width       int
-	height      int
-	screen      bool
-	lastCommand lastCommand
+	image          driver.Image
+	width          int
+	height         int
+	internalWidth  int
+	internalHeight int
+	screen         bool
+	lastCommand    lastCommand
 }
 
 // NewImage returns a new image.
@@ -43,8 +45,10 @@ type Image struct {
 // Note that the image is not initialized yet.
 func NewImage(width, height int) *Image {
 	i := &Image{
-		width:  width,
-		height: height,
+		width:          width,
+		height:         height,
+		internalWidth:  graphics.InternalImageSize(width),
+		internalHeight: graphics.InternalImageSize(height),
 	}
 	c := &newImageCommand{
 		result: i,
@@ -57,9 +61,11 @@ func NewImage(width, height int) *Image {
 
 func NewScreenFramebufferImage(width, height int) *Image {
 	i := &Image{
-		width:  width,
-		height: height,
-		screen: true,
+		width:          width,
+		height:         height,
+		internalWidth:  graphics.InternalImageSize(width),
+		internalHeight: graphics.InternalImageSize(height),
+		screen:         true,
 	}
 	c := &newScreenFramebufferImageCommand{
 		result: i,
@@ -82,6 +88,10 @@ func (i *Image) Size() (int, int) {
 	return i.width, i.height
 }
 
+func (i *Image) InternalSize() (int, int) {
+	return i.internalWidth, i.internalHeight
+}
+
 func (i *Image) DrawTriangles(src *Image, vertices []float32, indices []uint16, clr *affine.ColorM, mode graphics.CompositeMode, filter graphics.Filter, address graphics.Address) {
 	if src.screen {
 		panic("graphicscommand: the screen image cannot be the rendering source")

internal/restorable/image.go

@@ -108,9 +108,6 @@ type Image struct {
 	// screen indicates whether the image is used as an actual screen.
 	screen bool
 
-	w2 int
-	h2 int
-
 	// priority indicates whether the image is restored in high priority when context-lost happens.
 	priority bool
 }
@@ -234,12 +231,7 @@ func (i *Image) Size() (int, int) {
 
 // internalSize returns the size of the internal texture.
 func (i *Image) internalSize() (int, int) {
-	if i.w2 == 0 || i.h2 == 0 {
-		w, h := i.image.Size()
-		i.w2 = graphics.InternalImageSize(w)
-		i.h2 = graphics.InternalImageSize(h)
-	}
-	return i.w2, i.h2
+	return i.image.InternalSize()
 }
 
 func (i *Image) PutVertex(vs []float32, dx, dy, sx, sy float32, bx0, by0, bx1, by1 float32, cr, cg, cb, ca float32) {