/
main.go
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/
main.go
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// Copyright 2016 The G3N Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// g3nshaders reads shaders files with ".glsl" extensions and generates
// a Go file containing strings with the content of these files.
// Also it builds maps associating include and shader names to its respective
// source strings.
// Usage:
// g3nshaders -in=<input_dir> -out<output_gofile> -v
// It is normally invoked by "go generate" inside the "shaders" directory
package main
import (
"bytes"
"flag"
"fmt"
"go/format"
"io/ioutil"
"log"
"os"
"path/filepath"
"strings"
"text/template"
)
// Program constants.
const (
PROGNAME = "g3nshaders"
VMAJOR = 0
VMINOR = 1
SHADEREXT = ".glsl"
DIR_INCLUDE = "include"
TYPE_VERTEX = "vertex"
TYPE_FRAGMENT = "fragment"
TYPE_GEOMETRY = "geometry"
)
//
// TEMPLATE is a Go template to generate the output file with the shaders' sources and
// maps describing the include and shader names and programs shaders.
//
const TEMPLATE = `// Code generated by G3NSHADERS. DO NOT EDIT.
// To regenerate this file install 'g3nshaders' and execute:
// 'go generate' in this folder.
package {{.Pkg}}
{{range .Includes}}
const include_{{.Name}}_source = ` + "`{{.Source}}`" + `
{{end}}
{{range .Shaders}}
const {{.Name}}_source = ` + "`{{.Source}}`" + `
{{end}}
// Maps include name with its source code
var includeMap = map[string]string {
{{range .Includes}}
"{{- .Name}}": include_{{.Name}}_source, {{end}}
}
// Maps shader name with its source code
var shaderMap = map[string]string {
{{range .Shaders}}
"{{- .Name}}": {{.Name}}_source, {{end}}
}
// Maps program name with Proginfo struct with shaders names
var programMap = map[string]ProgramInfo{
{{ range $progName, $progInfo := .Programs }}
"{{$progName}}": { "{{$progInfo.Vertex}}","{{$progInfo.Fragment}}","{{$progInfo.Geometry}}" }, {{end}}
}
`
// Command line options
var (
oVersion = flag.Bool("version", false, "Show version and exits")
oInp = flag.String("in", ".", "Input directory")
oOut = flag.String("out", "sources.go", "Go output file")
oPackage = flag.String("pkg", "shaders", "Package name")
oVerbose = flag.Bool("v", false, "Show files being processed")
)
// Valid shader types
var shaderTypes = map[string]bool{
TYPE_VERTEX: true,
TYPE_FRAGMENT: true,
TYPE_GEOMETRY: true,
}
// fileInfo describes a shader or include file name and source code
type fileInfo struct {
Name string // shader or include name
Source string // shader or include source code
Include bool // true if include, false otherwise
}
// progInfo describes all the shader names of an specific program
// If the program doesn't use the geometry shader it is set as an empty string
type progInfo struct {
Vertex string // vertex shader name
Fragment string // fragment shader name
Geometry string // geometry shader name
}
// templInfo contains all information needed for the template expansion
type templInfo struct {
Count int // number of shader files processed
Pkg string // name of the package for the generated output file
Includes []fileInfo // list of include files found
Shaders []fileInfo // list of shader files found
Programs map[string]progInfo // map of shader programs found
}
var templData templInfo // global template data
var logger *log.Logger // global logger
func main() {
// Parse command line parameters
flag.Usage = usage
flag.Parse()
// If requested, print version and exits
if *oVersion == true {
fmt.Fprintf(os.Stderr, "%s v%d.%d\n", PROGNAME, VMAJOR, VMINOR)
return
}
// Creates logger
logger = log.New(os.Stdout, "G3NSHADERS ", log.Ldate|log.Ltime)
// Initialize template data
templData.Pkg = *oPackage
templData.Programs = make(map[string]progInfo)
// Process the current directory and its subdirectories recursively
// appending information into templData
processDir(*oInp, false)
if templData.Count == 0 {
log.Print("No shader files found")
return
}
// Generates output file from TEMPLATE
generate(*oOut)
}
// processDir processes recursively all shaders files in the specified directory
func processDir(dir string, include bool) {
// Open directory to process
f, err := os.Open(dir)
if err != nil {
panic(err)
}
defer f.Close()
// Read all file entries from the directory
finfos, err := f.Readdir(0)
if err != nil {
panic(err)
}
// Process all directory entries.
for _, fi := range finfos {
if fi.IsDir() {
dirInclude := include
if fi.Name() == DIR_INCLUDE {
dirInclude = true
}
processDir(filepath.Join(dir, fi.Name()), dirInclude)
} else {
processFile(filepath.Join(dir, fi.Name()), include)
}
}
}
// processFile process one file checking if it has the shaders extension,
// otherwise it is ignored.
// If the include flag is true the file is an include file otherwise it
// it a shader
func processFile(file string, include bool) {
// Ignore file if it has not the shader extension
fext := filepath.Ext(file)
if fext != SHADEREXT {
return
}
if *oVerbose {
logger.Printf("Processing: %s", file)
}
// Get the file base name and its name with the extension
fbase := filepath.Base(file)
fname := fbase[:len(fbase)-len(fext)]
// If not in include directory, the file must be a shader program
// which name must have the format: <name>_<shader_type>
if !include {
parts := strings.Split(string(fname), "_")
if len(parts) < 2 {
logger.Print(" IGNORED: file does not have a valid shader name")
return
}
stype := parts[len(parts)-1]
if !shaderTypes[stype] {
logger.Print(" IGNORED: invalid shader type")
return
}
sname := strings.Join(parts[:len(parts)-1], "_")
pinfo, ok := templData.Programs[sname]
if !ok {
templData.Programs[sname] = pinfo
}
switch stype {
case TYPE_VERTEX:
pinfo.Vertex = fname
case TYPE_FRAGMENT:
pinfo.Fragment = fname
case TYPE_GEOMETRY:
pinfo.Geometry = fname
}
templData.Programs[sname] = pinfo
}
// Reads all file data
f, err := os.Open(file)
if err != nil {
panic(err)
}
defer f.Close()
data, err := ioutil.ReadAll(f)
if err != nil {
panic(err)
}
// Appends entry in Includes or Shaders
if include {
templData.Includes = append(templData.Includes, fileInfo{
Name: fname,
Source: string(data),
})
} else {
templData.Shaders = append(templData.Shaders, fileInfo{
Name: fname,
Source: string(data),
})
}
templData.Count++
}
// generate generates output go file with shaders sources from TEMPLATE
func generate(file string) {
if *oVerbose {
logger.Printf("Generating: %s", file)
}
// Parses the template
tmpl := template.New("tmpl")
tmpl, err := tmpl.Parse(TEMPLATE)
if err != nil {
panic(err)
}
// Expands template to buffer
var buf bytes.Buffer
err = tmpl.Execute(&buf, &templData)
if err != nil {
panic(err)
}
// Formats buffer as Go source
p, err := format.Source(buf.Bytes())
if err != nil {
panic(err)
}
// Writes formatted source to output file
f, err := os.Create(file)
if err != nil {
panic(err)
}
f.Write(p)
f.Close()
}
// usage shows the application usage
func usage() {
fmt.Fprintf(os.Stderr, "%s v%d.%d\n", PROGNAME, VMAJOR, VMINOR)
fmt.Fprintf(os.Stderr, "usage: %s [options]\n", strings.ToLower(PROGNAME))
flag.PrintDefaults()
os.Exit(2)
}