ebiten/examples/shapes/main.go

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// Copyright 2017 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build example jsgo
package main
import (
"fmt"
"image/color"
"log"
"math"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
)
const (
screenWidth = 640
screenHeight = 480
)
var (
emptyImage, _ = ebiten.NewImage(16, 16, ebiten.FilterDefault)
)
func init() {
emptyImage.Fill(color.White)
}
var count = 0
func line(x0, y0, x1, y1 float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
const width = 1
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
b := float32(clr.B) / 0xff
a := float32(clr.A) / 0xff
return []ebiten.Vertex{
{
DstX: x0 - width*dx/2,
DstY: y0 - width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x0 + width*dx/2,
DstY: y0 + width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x1 - width*dx/2,
DstY: y1 - width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x1 + width*dx/2,
DstY: y1 + width*dy/2,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
}, []uint16{0, 1, 2, 1, 2, 3}
}
func rect(x, y, w, h float32, clr color.RGBA) ([]ebiten.Vertex, []uint16) {
r := float32(clr.R) / 0xff
g := float32(clr.G) / 0xff
b := float32(clr.B) / 0xff
a := float32(clr.A) / 0xff
x0 := x
y0 := y
x1 := x + w
y1 := y + h
return []ebiten.Vertex{
{
DstX: x0,
DstY: y0,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x1,
DstY: y0,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x0,
DstY: y1,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
{
DstX: x1,
DstY: y1,
SrcX: 1,
SrcY: 1,
ColorR: r,
ColorG: g,
ColorB: b,
ColorA: a,
},
}, []uint16{0, 1, 2, 1, 2, 3}
}
func update(screen *ebiten.Image) error {
count++
count %= 240
if ebiten.IsDrawingSkipped() {
return nil
}
cf := float64(count)
v, i := line(100, 100, 300, 100, color.RGBA{0xff, 0xff, 0xff, 0xff})
screen.DrawTriangles(v, i, emptyImage, nil)
v, i = line(50, 150, 50, 350, color.RGBA{0xff, 0xff, 0x00, 0xff})
screen.DrawTriangles(v, i, emptyImage, nil)
v, i = line(50, 100+float32(cf), 200+float32(cf), 250, color.RGBA{0x00, 0xff, 0xff, 0xff})
screen.DrawTriangles(v, i, emptyImage, nil)
v, i = rect(50+float32(cf), 50+float32(cf), 100+float32(cf), 100+float32(cf), color.RGBA{0x80, 0x80, 0x80, 0x80})
screen.DrawTriangles(v, i, emptyImage, nil)
v, i = rect(300-float32(cf), 50, 120, 120, color.RGBA{0x00, 0x80, 0x00, 0x80})
screen.DrawTriangles(v, i, emptyImage, nil)
ebitenutil.DebugPrint(screen, fmt.Sprintf("TPS: %0.2f", ebiten.CurrentTPS()))
return nil
}
func main() {
if err := ebiten.Run(update, screenWidth, screenHeight, 1, "Shapes (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
}