53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package main
|
|
|
|
import (
|
|
"math"
|
|
)
|
|
|
|
// Draw a line using dumb
|
|
func LineDumb(fb *Framebuffer, color uint, x0 uint, y0 uint, x1 uint, y1 uint) {
|
|
var t float32
|
|
for t = 0; t < 1; t += 0.01 {
|
|
// Very simple interpolation between x and y
|
|
x := x0 + uint(float32(x1-x0)*t)
|
|
y := y0 + uint(float32(y1-y0)*t)
|
|
fb.Set(x, y, color)
|
|
}
|
|
}
|
|
|
|
func LineDumb2(fb *Framebuffer, color uint, x0 uint, y0 uint, x1 uint, y1 uint) {
|
|
for x := x0; x < x1; x++ {
|
|
// For each pixel across, compute how far across we are and interpolate y
|
|
t := float32(x-x0) / float32(x1-x0)
|
|
y := uint(float32(y0)*(1-t) + float32(y1)*t)
|
|
fb.Set(x, y, color)
|
|
}
|
|
}
|
|
|
|
func LineDumb3(fb *Framebuffer, color uint, x0 int, y0 int, x1 int, y1 int) {
|
|
steep := false
|
|
// This one makes sure that going pixel by pixel will not make holes in the
|
|
// other direction by always moving in the less steep direction.
|
|
if math.Abs(float64(x0-x1)) < math.Abs(float64(y0-y1)) {
|
|
x0, y0 = y0, x0
|
|
x1, y1 = y1, x1
|
|
steep = true
|
|
}
|
|
// Don't let lines be invisible, always go left to right
|
|
if x0 > x1 { // need to be left to right
|
|
x0, x1 = x1, x0
|
|
y0, y1 = y1, y0 // Why are we swapping these? I guess because we're swapping the points...
|
|
}
|
|
// Same as dumb2, going across pixel by pixel. But "x" here might actually be y
|
|
// because of the inverted direction
|
|
for x := x0; x <= x1; x++ {
|
|
t := float32(x-x0) / float32(x1-x0)
|
|
y := uint(float32(y0)*(1-t) + float32(y1)*t)
|
|
if steep {
|
|
fb.Set(y, uint(x), color)
|
|
} else {
|
|
fb.Set(uint(x), y, color)
|
|
}
|
|
}
|
|
}
|