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examples/shapes: Bug fix: correct calculation

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This commit is contained in:
Hajime Hoshi 2018-09-15 18:15:16 +09:00
parent 5587af9d7e
commit 76ca296cdd
1 changed files with 13 additions and 12 deletions
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25
examples/shapes/main.go
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@ -42,11 +42,12 @@ func init() {
var count = 0
func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
const width = 0.5
const width = 1
theta := math.Atan2(float64(x1-x0), float64(y1-y0))
dx := float32(math.Cos(theta) - math.Sin(theta))
dy := float32(math.Sin(theta) + math.Cos(theta))
theta := math.Atan2(float64(y1-y0), float64(x1-x0))
theta += math.Pi / 2
dx := float32(math.Cos(theta))
dy := float32(math.Sin(theta))
r := float32(clr.R) / 0xff
g := float32(clr.G) / 0xff
@ -55,8 +56,8 @@ func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
return []ebiten.Vertex{
{
DstX: x0 - width*dx,
DstY: y0 - width*dy,
DstX: x0 - width*dx/2,
DstY: y0 - width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
@ -65,8 +66,8 @@ func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
ColorA: a,
},
{
DstX: x0 + width*dx,
DstY: y0 + width*dy,
DstX: x0 + width*dx/2,
DstY: y0 + width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
@ -75,8 +76,8 @@ func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
ColorA: a,
},
{
DstX: x1 - width*dx,
DstY: y1 - width*dy,
DstX: x1 - width*dx/2,
DstY: y1 - width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
@ -85,8 +86,8 @@ func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
ColorA: a,
},
{
DstX: x1 + width*dx,
DstY: y1 + width*dy,
DstX: x1 + width*dx/2,
DstY: y1 + width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,