ebiten/examples/shader/main.go

98 lines
2.0 KiB
Go

// Copyright 2020 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 (
"log"
"github.com/hajimehoshi/ebiten"
)
const (
screenWidth = 640
screenHeight = 480
)
const shaderSrc = `package main
// __viewportSize is a predefined uniform variable.
// TODO: Hide this by a function.
func Vertex(position vec2, texCoord vec2, color vec4) vec4 {
return mat4(
2.0/__viewportSize.x, 0, 0, 0,
0, 2.0/__viewportSize.y, 0, 0,
0, 0, 1, 0,
-1, -1, 0, 1,
) * vec4(position, 0, 1)
}
func Fragment(position vec4) vec4 {
return vec4(position.x/__viewportSize.x, position.y/__viewportSize.y, 0, 1)
}`
type Game struct {
shader *ebiten.Shader
}
func (g *Game) Update(screen *ebiten.Image) error {
if g.shader == nil {
var err error
g.shader, err = ebiten.NewShader([]byte(shaderSrc))
if err != nil {
return err
}
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
w, h := screen.Size()
vs := []ebiten.Vertex{
{
DstX: 0,
DstY: 0,
},
{
DstX: float32(w),
DstY: 0,
},
{
DstX: 0,
DstY: float32(h),
},
{
DstX: float32(w),
DstY: float32(h),
},
}
is := []uint16{0, 1, 2, 1, 2, 3}
screen.DrawTrianglesWithShader(vs, is, g.shader, nil)
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Shader (Ebiten Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}