/
image_build_cube_side_equirect.go
86 lines (72 loc) · 1.92 KB
/
image_build_cube_side_equirect.go
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package pack
import "github.com/mokiat/gomath/dprec"
type BuildCubeSideFromEquirectangularAction struct {
side CubeSide
imageProvider ImageProvider
image *Image
}
func (*BuildCubeSideFromEquirectangularAction) Describe() string {
return "build_cube_side_from_equirectangular()"
}
func (a *BuildCubeSideFromEquirectangularAction) Image() *Image {
if a.image == nil {
panic("reading data from unprocessed action")
}
return a.image
}
func (a *BuildCubeSideFromEquirectangularAction) Run() error {
srcImage := a.imageProvider.Image()
dimension := srcImage.Height / 2
texels := make([][]Color, dimension)
for y := range texels {
texels[y] = make([]Color, dimension)
}
uv := dprec.ZeroVec2()
startU := 0.0
deltaU := 1.0 / float64(dimension-1)
startV := 1.0
deltaV := -1.0 / float64(dimension-1)
uv.Y = startV
for y := 0; y < dimension; y++ {
uv.X = startU
for x := 0; x < dimension; x++ {
texels[y][x] = srcImage.TexelUV(UVWToEquirectangularUV(CubeUVToUVW(a.side, uv)))
uv.X += deltaU
}
uv.Y += deltaV
}
a.image = &Image{
Width: dimension,
Height: dimension,
Texels: texels,
}
return nil
}
func BuildCubeSideFromEquirectangular(srcImage *Image, side CubeSide) *Image {
return BuildCubeSideFromEquirectangularScaled(srcImage, side, srcImage.Height/2)
}
func BuildCubeSideFromEquirectangularScaled(srcImage *Image, side CubeSide, dimension int) *Image {
texels := make([][]Color, dimension)
for y := range texels {
texels[y] = make([]Color, dimension)
}
uv := dprec.ZeroVec2()
startU := 0.0
deltaU := 1.0 / float64(dimension-1)
startV := 1.0
deltaV := -1.0 / float64(dimension-1)
uv.Y = startV
for y := 0; y < dimension; y++ {
uv.X = startU
for x := 0; x < dimension; x++ {
texels[y][x] = srcImage.TexelUV(UVWToEquirectangularUV(CubeUVToUVW(side, uv)))
uv.X += deltaU
}
uv.Y += deltaV
}
return &Image{
Width: dimension,
Height: dimension,
Texels: texels,
}
}