ebiten/examples/shader/lighting.go
2020-09-19 19:01:05 +09:00

31 lines
1009 B
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 ignore
package main
var Time float
var Cursor vec2
var ScreenSize vec2
func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
lightpos := vec3(Cursor, 50)
lightdir := normalize(lightpos - position.xyz)
normal := normalize(imageSrc1UnsafeAt(texCoord) - 0.5)
ambient := 0.25
diffuse := 0.75 * max(0.0, dot(normal.xyz, lightdir))
return imageSrc0UnsafeAt(texCoord) * (ambient + diffuse)
}