Graphics in Go

Transcript

1. 1.

   Graphics in Go

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   @peterhellberg

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   Interfaces!

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   image.Image // Image is a finite rectangular // grid of

   color.Color values taken from a color model. type Image interface { // ColorModel returns the Image's color model. ColorModel() color.Model // Bounds returns the domain for which At can return non-zero color. // The bounds do not necessarily contain the point (0, 0). Bounds() Rectangle // At returns the color of the pixel at (x, y). At(x, y int) color.Color }
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   // Model can convert any Color to one from its

   own color model. // The conversion may be lossy. type Model interface { Convert(c Color) Color } color.Model
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   color.Color // Color can convert itself to alpha-premultiplied 16-bits per

   channel RGBA. // The conversion may be lossy. type Color interface { // RGBA returns the alpha-premultiplied red, green, blue and alpha values // for the color. Each value ranges within [0, 0xffff], but is represented // by a uint32 so that multiplying by a blend factor up to 0xffff will not // overflow. // // An alpha-premultiplied color component c has been scaled by alpha (a), // so has valid values 0 <= c <= a. RGBA() (r, g, b, a uint32) }
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   draw.Image // Image is an image.Image with a Set method

   to change a single pixel. type Image interface { image.Image Set(x, y int, c color.Color) }
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   WHAT ABOUT THE ELEPHANT IN 
 THE ROOM?(Shaders)

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   Packages?

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    go get github.com/peterhellberg/gfx gfx

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    go get github.com/hajimehoshi/ebiten ebiten

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    go get github.com/faiface/pixel pixel

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    #gamedev #gamedev slack.gopher.se

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    None
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    Experiments

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    The XOR texture ⊕ lodev.org/cgtutor/xortexture.html

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    The XOR texture package main import "github.com/peterhellberg/gfx" func main() {

    m := gfx.NewImage(640, 360) gfx.EachPixel(m.Bounds(), func(x, y int) { c := uint8(x ^ y) m.Set(x, y, gfx.ColorNRGBA(c, c%192, c, 255)) }) gfx.SavePNG("xor.png", gfx.NewScaledImage(m, 4)) }
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    None
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    Plasma lodev.org/cgtutor/plasma.html

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    The Plasma effect package main import ( "github.com/peterhellberg/gfx" "github.com/peterhellberg/plasma" "github.com/peterhellberg/plasma/palette"

    ) func main() { w, h, scale, seed := 2560, 1440, 64.0, 1234 gfx.SavePNG("plasma.png", plasma.New(w, h, scale). Image(w, h, seed, palette.MaterialDesign700), ) }
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    None
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    Tunnel lodev.org/cgtutor/tunnel.html

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    None
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    None
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    Starfield vendian.org/mncharity/dir3/starcolor

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    None
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    None
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    None
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    None
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    DOOM fire fabiensanglard.net/doom_fire_psx

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    None
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    Particles

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    None
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    Fractals

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    The Julia set

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    None
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    Popcorn fractals paulbourke.net/fractals/popcorn

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    None
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    Procedural Tree

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    None
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    None
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    None
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    None
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    None
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    Domain warping iquilezles.org/www/articles/warp/warp.htm

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    None
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    None
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    None
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    Tiles

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    package main import "github.com/peterhellberg/gfx" func main() { gfx.SavePNG("fireflower.png", gfx.NewScaledImage( gfx.NewTile(palette,

    8, []uint8{ 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 2, 2, 2, 2, 1, 1, 1, 2, 3, 3, 3, 3, 2, 1, 1, 1, 2, 2, 2, 2, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 4, 4, 0, 0, 0, 0, 0, 0, 4, 4, 0, 0, 0, 4, 4, 0, 4, 4, 0, 4, 4, 0, 4, 0, 4, 4, 0, 4, 0, 0, 4, 4, 4, 4, 4, 4, 0, 0, 0, 4, 4, 4, 4, 0, 0, }), 128)) } var palette = gfx.Palette{{}, {0xA4, 0xE8, 0xFE, 0xFF}, {0xFD, 0xB7, 0x2C, 0xFF}, {0xFC, 0x59, 0x29, 0xFF}, {0x31, 0xAB, 0x4B, 0xFF}, }
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    package main import "github.com/peterhellberg/gfx" func main() { gfx.SavePNG("layer.png", gfx.NewScaledImage( gfx.NewLayer(tileset,

    5, gfx.LayerData{ 4, 7, 7, 7, 4, 5, 2, 0, 2, 6, 5, 0, 3, 0, 6, 5, 2, 0, 2, 6, 4, 8, 8, 8, 4, }), 128), ) } var tileset = gfx.NewTileset( gfx.PaletteEN4, gfx.Pt(2, 2), gfx.TilesetData{ {0, 0, 0, 0}, {1, 1, 1, 1}, {2, 2, 2, 2}, {3, 3, 3, 3}, {9, 9, 9, 9}, {1, 2, 1, 2}, {2, 1, 2, 1}, {1, 1, 2, 2}, {2, 2, 1, 1}, })
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    Triangles

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    package main import "github.com/peterhellberg/gfx" var p = gfx.PaletteFamicube func vx(x,

    y float64, n int) gfx.Vertex { return gfx.Vertex{Position: gfx.V(x, y), Color: p.Color(n)} } func main() { m := gfx.NewPaletted(640, 1080, p, p.Color(57)) gfx.NewDrawTarget(m).MakeTriangles(&gfx.TrianglesData{ vx(128, 12, 51), vx(12, 244, 52), vx(604, 244, 53), vx(12, 300, 54), vx(300, 300, 55), vx(240, 972, 56), }).Draw() gfx.SavePNG("triangles.png", m) } Triangles
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    Isometric blocks

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    package main import "github.com/peterhellberg/gfx" func main() { m := gfx.NewImage(1080,

    1080) v := gfx.V(1.2, -1.94) o := gfx.BoundsCenterOrigin(m.Bounds(), v, 320) b := gfx.Blocks{ {gfx.V3(0, 0, 0), gfx.V3(1, 1, 1), gfx.BlockColorRed}, {gfx.V3(0, 1, 0), gfx.V3(1, 1, 1), gfx.BlockColorGreen}, {gfx.V3(1, 1, 0), gfx.V3(1, 1, 1), gfx.BlockColorBlue}, } b.Sort() b.DrawPolygons(m, o) gfx.SavePNG("three-blocks.png", m) } Three blocks
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    None
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    None
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    SDF iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm

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    package main import "github.com/peterhellberg/gfx" func main() { c := gfx.PaletteEDG36.Color

    m := gfx.NewImage(2560, 1440, c(5)) gfx.EachImageVec(m, gfx.ZV, func(u gfx.Vec) { sd := gfx.SignedDistance{u} if d := sd.OpRepeat(gfx.V(256, 256), func(sd gfx.SignedDistance) float64 { return sd.OpSubtraction(sd.Circle(50), sd.Line(gfx.V(0, 0), gfx.V(64, 64))) }); d < 40 { gfx.SetVec(m, u, c(int(gfx.MathAbs(d/5)))) } }) gfx.SavePNG("sdf-repeat.png", m) } Repeat: Subtract Circle from Line
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    None
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    SmoothUnion of Rectangle and IsoscelesTriangle EquilateralTriangle

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    Domain coloring

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    package main import "github.com/peterhellberg/gfx" const ( w, h, fovY =

    2560, 1440, 1.9 aspect = float64(w) / float64(h) ahc = aspect * fovY / 2.0 hfc = fovY / 2.0 ) func pixelCoordinates(px, py int) gfx.Vec { return gfx.V( ((float64(px)/(w-1))*2-1)*ahc, ((float64(h-py-1)/(h-1))*2-1)*hfc, ) } Domain coloring func main() { var ( p0 = pixelCoordinates(0, 0) p1 = pixelCoordinates(w-1, h-1) y = p0.Y d = gfx.V((p1.X-p0.X)/(w-1), (p1.Y-p0.Y)/(h-1)) m = gfx.NewImage(w, h) ) for py := 0; py < h; py++ { x := p0.X for px := 0; px < w; px++ { z := gfx.CmplxSin(1 / complex(x, y)) c := gfx.PaletteEN4.CmplxPhaseAt(z) m.Set(px, py, c) x += d.X } y += d.Y } gfx.SavePNG("domain-coloring.png", m) }
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    None
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    None
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    None
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    None
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    None
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    Ray Casting

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    None
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    None
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    None
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    Ray Marching

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    KABOOM! github.com/ssloy/tinykaboom

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    Draw a sphere

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    Diffuse shading

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    Draw a pattern

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    Displacement mapping

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    Another implicit surface

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    Pseudorandom Noise

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    Fire colors

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    None
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    gist.github.com/peterhellberg