func (im *Image) writeToPng(
pixelTypes ImagePixelTypes, outputPath string) (err error) {
image := image.NewNRGBA(image.Rect(0, 0, im.Width, im.Height))
xStart := maxInt(im.XStart, 0)
xEnd := minInt(im.XStart+im.XCount, im.Width)
yStart := maxInt(im.YStart, 0)
yEnd := minInt(im.YStart+im.YCount, im.Height)
for y := yStart; y < yEnd; y++ {
for x := xStart; x < xEnd; x++ {
k := im.getIndex(x, y)
var Ls Spectrum
if (pixelTypes & IM_SENSOR_PIXELS) != 0 {
sp := &im.sensorPixels[k]
if sp.n > 0 {
Ls.ScaleInv(&sp.sum, float32(sp.n))
}
}
var Lp Spectrum
if im.lightN > 0 &&
(pixelTypes&IM_LIGHT_PIXELS) != 0 {
lp := &im.lightPixels[k]
Lp.ScaleInv(&lp.sum, float32(im.lightN))
}
var L Spectrum
L.Add(&Ls, &Lp)
r, g, b := L.ToRGB()
c := color.NRGBA{
R: scaleRGB(r),
G: scaleRGB(g),
B: scaleRGB(b),
A: 255,
}
image.SetNRGBA(x, y, c)
}
}
f, err := os.Create(outputPath)
if err != nil {
return
}
defer func() {
if closeErr := f.Close(); err == nil && closeErr != nil {
err = closeErr
}
}()
if err = png.Encode(f, image); err != nil {
return
}
return
}
func RenderFractal() image.Image {
// Logical bounds are [-2, 2], but we want lots of pixels.
minX, maxX, minY, maxY := -2, 2, -2, 2
image := image.NewNRGBA(image.Rect(*factor*minX, *factor*minY,
*factor*maxX, *factor*maxY))
// 1 step per pixel.
xStepSize := float64(maxX-minX) / numSteps
yStepSize := float64(maxY-minY) / numSteps
// Walk through pixel space, compute each value.
for currX := float64(-2); currX < float64(2); currX += xStepSize {
for currY := float64(-2); currY < float64(2); currY += yStepSize {
currColor := GetColor(currX, currY)
image.SetNRGBA(int(float64(*factor)*currX),
int(float64(*factor)*currY), currColor)
}
}
return image
}