ebiten/examples/shader/crt.go
2022-03-10 00:02:07 +09:00

57 lines
1.5 KiB
Go

// Copyright 2022 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.
//go:build ignore
// +build ignore
package main
var Time float
var Cursor vec2
var ScreenSize vec2
func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
const (
BLURSCALEX = 0.45
LOWLUMSCAN = 5.0
HILUMSCAN = 10.0
BRIGHTBOOST = 1.25
MASK_DARK = 0.25
MASK_FADE = 0.8
)
pos := texCoord
origin, size := imageDstRegionOnTexture()
pos -= origin
pos /= size
maskFade := 0.3333 * MASK_FADE
invDims := 1.0 / imageDstTextureSize().xy
p := pos * imageDstTextureSize()
i := floor(p) + 0.50
f := p - i
p = (i + 4.0*f*f*f) * invDims
p.x = mix(p.x, pos.x, BLURSCALEX)
Y := f.y * f.y
YY := Y * Y
whichmask := fract(pos.x * -0.4999)
mask := 1.0 + float(whichmask < 0.5)*-MASK_DARK
clr := imageSrc2At(p*size + origin).rgb
scanLineWeight := (BRIGHTBOOST - LOWLUMSCAN*(Y-2.05*YY))
scanLineWeightB := 1.0 - HILUMSCAN*(YY-2.8*YY*Y)
return vec4(clr.rgb*mix(scanLineWeight*mask, scanLineWeightB, dot(clr.rgb, vec3(maskFade))), 1.0)
}