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surface02

master
dewjjj 1 year ago
parent
commit
e7aaf41ff0
  1. 72
      surface/surface.go

72
surface/surface.go

@ -3,43 +3,79 @@ package main
import (
"fmt"
"math"
"net/http"
"strconv"
)
const (
width, height = 600, 320
cells = 100
xyrange = 30.0
xyscale = width / 2 / xyrange
zscale = height * 0.4
angle = math.Pi / 6
)
var height, width float64 = 300, 600
var cells float64 = 100 // number of grid cells
var xyrange float64 = 30.0 // axis ranges (-xyrange..+xyrange)
var xyscale float64 = width / 2 / xyrange // pixels per x or y unit
var zscale float64 = height * 0.4 // pixels per z unit
var angle float64 = math.Pi / 6 // angle of x, y axes (=30°)
var sin30, cos30 = math.Sin(angle), math.Cos(angle)
var sin30, cos30 = math.Sin(angle), math.Cos(angle) // sin(30°), cos(30°)
func main() {
fmt.Printf("<svg xmlns='http://www.w3.org/2000/svg'"+
"style='stroke: grey; fill: white; stroke-width:0.7' "+
//http服务
http.HandleFunc("/", handle)
http.ListenAndServe("0.0.0.0:8000", nil)
}
func handle(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "image/svg+xml")
if err := r.ParseForm(); err != nil {
return
}
//var height int
//var width int
for k, v := range r.Form {
if k == "height" {
h, _ := strconv.ParseFloat(v[0], 64)
if h > 0 {
height = h
}
}
if k == "width" {
w, _ := strconv.ParseFloat(v[0], 64)
if w > 0 {
width = w
}
}
}
xyscale = width / 2 / xyrange
zscale = height * 0.4
fmt.Fprintf(w, "<svg xmlns='http://www.w3.org/2000/svg' "+
"style='stroke: #ff0000; fill: #0000ff; stroke-width: 0.7' "+
"width='%d' height='%d'>", width, height)
for i := 0; i < cells; i++ {
for j := 0; j < cells; j++ {
for i := 0; i < int(cells); i++ {
for j := 0; j < int(cells); j++ {
ax, ay := corner(i+1, j)
bx, by := corner(i, j)
cx, cy := corner(i, j+1)
dx, dy := corner(i+1, j+1)
fmt.Printf("<polygon points='%g,%g %g,%g %g,%g %g,%g'/>\n", ax, ay, bx, by, cx, cy, dx, dy)
fmt.Fprintf(w, "<polygon points='%g,%g %g,%g %g,%g %g,%g'/>\n",
ax, ay, bx, by, cx, cy, dx, dy)
}
fmt.Println("</svg>")
}
fmt.Fprintf(w, "</svg>")
}
func corner(i, j int) (float64, float64) {
// Find point (x,y) at corner of cell (i,j).
x := xyrange * (float64(i)/cells - 0.5)
y := xyrange * (float64(i)/cells - 0.5)
y := xyrange * (float64(j)/cells - 0.5)
// Compute surface height z.
z := f(x, y)
// Project (x,y,z) isometrically onto 2-D SVG canvas (sx,sy).
sx := width/2 + (x-y)*cos30*xyscale
sy := height/2 + (x+y)*sin30*xyscale - z*zscale
return sx, sy
}
func f(x, y float64) float64 {
r := math.Hypot(x, y)
return math.Sin(r)
r := math.Hypot(x, y) // distance from (0,0)
return math.Sin(r) / r
}
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