ebiten/shader.go
2020-07-19 02:33:43 +09:00

89 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.
package ebiten
import (
"bytes"
"fmt"
"go/parser"
"go/token"
"github.com/hajimehoshi/ebiten/internal/buffered"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/shader"
)
var shaderSuffix string
func init() {
shaderSuffix = `
var __viewportSize vec2
func viewportSize() vec2 {
return __viewportSize
}
`
for i := 1; i < graphics.ShaderImageNum; i++ {
shaderSuffix += fmt.Sprintf(`
var __offset%d vec2
`, i)
}
for i := 0; i < graphics.ShaderImageNum; i++ {
var offset string
if i >= 1 {
offset = fmt.Sprintf(" + __offset%d", i)
}
// __t%d is a special variable for a texture variable.
shaderSuffix += fmt.Sprintf(`
func texture%[1]dAt(pos vec2) vec4 {
return texture2D(__t%[1]d, pos%[2]s)
}
`, i, offset)
}
}
type Shader struct {
shader *buffered.Shader
}
func NewShader(src []byte) (*Shader, error) {
var buf bytes.Buffer
buf.Write(src)
buf.WriteString(shaderSuffix)
fs := token.NewFileSet()
f, err := parser.ParseFile(fs, "", buf.Bytes(), parser.AllErrors)
if err != nil {
return nil, err
}
// TODO: Create a pseudo vertex entrypoint to treat the attribute values correctly.
s, err := shader.Compile(fs, f, "Vertex", "Fragment", graphics.ShaderImageNum)
if err != nil {
return nil, err
}
return &Shader{
shader: buffered.NewShader(s),
}, nil
}
func (s *Shader) Dispose() {
s.shader.MarkDisposed()
s.shader = nil
}