gpu/internal/convertshaders: move internal/cmd/convertshaders

The convert program is only used by the shaders from package gpu, and
we're about to make the backend package imported by the program internal
to package gpu. Move the converter below package gpu.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/internal/convertshaders/hlsl.go

@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// FXC is hlsl compiler that targets ShaderModel 5.x and lower.
+type FXC struct {
+	Bin     string
+	WorkDir WorkDir
+}
+
+func NewFXC() *FXC { return &FXC{Bin: "fxc.exe"} }
+
+// Compile compiles the input shader.
+func (fxc *FXC) Compile(path, variant string, input []byte, entryPoint string, profileVersion string) ([]byte, error) {
+	base := fxc.WorkDir.Path(filepath.Base(path), variant, profileVersion)
+	pathin := base + ".in"
+	pathout := base + ".out"
+	result := pathout
+
+	if err := fxc.WorkDir.WriteFile(pathin, input); err != nil {
+		return nil, fmt.Errorf("unable to write shader to disk: %w", err)
+	}
+
+	cmd := exec.Command(fxc.Bin)
+	if runtime.GOOS != "windows" {
+		cmd = exec.Command("wine", fxc.Bin)
+		if err := winepath(&pathin, &pathout); err != nil {
+			return nil, err
+		}
+	}
+
+	var profile string
+	switch filepath.Ext(path) {
+	case ".frag":
+		profile = "ps_" + profileVersion
+	case ".vert":
+		profile = "vs_" + profileVersion
+	default:
+		return nil, fmt.Errorf("unrecognized shader type %s", path)
+	}
+
+	cmd.Args = append(cmd.Args,
+		"/Fo", pathout,
+		"/T", profile,
+		"/E", entryPoint,
+		pathin,
+	)
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		info := ""
+		if runtime.GOOS != "windows" {
+			info = "If the fxc tool cannot be found, set WINEPATH to the Windows path for the Windows SDK.\n"
+		}
+		return nil, fmt.Errorf("%s\n%sfailed to run %v: %w", output, info, cmd.Args, err)
+	}
+
+	compiled, err := ioutil.ReadFile(result)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read output %q: %w", pathout, err)
+	}
+
+	return compiled, nil
+}
+
+// DXC is hlsl compiler that targets ShaderModel 6.0 and newer.
+type DXC struct {
+	Bin     string
+	WorkDir WorkDir
+}
+
+func NewDXC() *DXC { return &DXC{Bin: "dxc.exe"} }
+
+// Compile compiles the input shader.
+func (dxc *DXC) Compile(path, variant string, input []byte, entryPoint string, profile string) ([]byte, error) {
+	base := dxc.WorkDir.Path(filepath.Base(path), variant, profile)
+	pathin := base + ".in"
+	pathout := base + ".out"
+	result := pathout
+
+	if err := dxc.WorkDir.WriteFile(pathin, input); err != nil {
+		return nil, fmt.Errorf("unable to write shader to disk: %w", err)
+	}
+
+	cmd := exec.Command(dxc.Bin)
+	if runtime.GOOS != "windows" {
+		cmd = exec.Command("wine", dxc.Bin)
+		if err := winepath(&pathin, &pathout); err != nil {
+			return nil, err
+		}
+	}
+
+	cmd.Args = append(cmd.Args,
+		"-Fo", pathout,
+		"-T", profile,
+		"-E", entryPoint,
+		"-Qstrip_reflect",
+		pathin,
+	)
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		info := ""
+		if runtime.GOOS != "windows" {
+			info = "If the dxc tool cannot be found, set WINEPATH to the Windows path for the Windows SDK.\n"
+		}
+		return nil, fmt.Errorf("%s\n%sfailed to run %v: %w", output, info, cmd.Args, err)
+	}
+
+	compiled, err := ioutil.ReadFile(result)
+	if err != nil {
+		return nil, fmt.Errorf("unable to read output %q: %w", pathout, err)
+	}
+
+	return compiled, nil
+}
+
+// winepath uses the winepath tool to convert a paths to Windows format.
+// The returned path can be used as arguments for Windows command line tools.
+func winepath(paths ...*string) error {
+	for _, path := range paths {
+		out, err := exec.Command("winepath", "--windows", *path).Output()
+		if err != nil {
+			return fmt.Errorf("unable to run `winepath --windows %q`: %w", *path, err)
+		}
+		*path = strings.TrimSpace(string(out))
+	}
+	return nil
+}