mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-25 19:28:57 +01:00
45 lines
1.2 KiB
Go
45 lines
1.2 KiB
Go
// Copyright 2022 The Ebitengine 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
|
|
|
|
//kage:unit pixels
|
|
|
|
// Reference: a public domain CRT effect
|
|
// https://github.com/libretro/glsl-shaders/blob/master/crt/shaders/crt-lottes.glsl
|
|
|
|
package main
|
|
|
|
func Warp(pos vec2) vec2 {
|
|
const (
|
|
warpX = 0.031
|
|
warpY = 0.041
|
|
)
|
|
pos = pos*2 - 1
|
|
pos *= vec2(1+(pos.y*pos.y)*warpX, 1+(pos.x*pos.x)*warpY)
|
|
return pos/2 + 0.5
|
|
}
|
|
|
|
func Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {
|
|
// Adjust the texture position to [0, 1].
|
|
origin := imageSrc0Origin()
|
|
size := imageSrc0Size()
|
|
pos := srcPos
|
|
pos -= origin
|
|
pos /= size
|
|
|
|
pos = Warp(pos)
|
|
return imageSrc0At(pos*size + origin)
|
|
}
|