internal/graphicsdriver/opengl/gl: reladn: refactoring

This is a reland of a1ad87a262

internal/graphicsdriver/opengl/context_gl.go

@@ -290,8 +290,8 @@ func (c *context) newShader(shaderType uint32, source string) (shader, error) {
 	if s == 0 {
 		return 0, fmt.Errorf("opengl: glCreateShader failed: shader type: %d", shaderType)
 	}
-	cSources, free := gl.Strs(source + "\x00")
+	cSources, free := gl.CStr(source)
-	gl.ShaderSource(uint32(s), 1, cSources, nil)
+	gl.ShaderSource(uint32(s), 1, &cSources, nil)
 	free()
 	gl.CompileShader(s)
 
@@ -325,8 +325,8 @@ func (c *context) newProgram(shaders []shader, attributes []string) (program, er
 	}
 
 	for i, name := range attributes {
-		l, free := gl.Strs(name + "\x00")
+		l, free := gl.CStr(name)
-		gl.BindAttribLocation(p, uint32(i), *l)
+		gl.BindAttribLocation(p, uint32(i), l)
 		free()
 	}
 
@@ -360,8 +360,8 @@ func (c *context) deleteProgram(p program) {
 }
 
 func (c *context) getUniformLocationImpl(p program, location string) uniformLocation {
-	l, free := gl.Strs(location + "\x00")
+	l, free := gl.CStr(location)
-	uniform := uniformLocation(gl.GetUniformLocation(uint32(p), *l))
+	uniform := uniformLocation(gl.GetUniformLocation(uint32(p), l))
 	free()
 	return uniform
 }

internal/graphicsdriver/opengl/gl/conversions_cgo.go

@@ -17,27 +17,14 @@ func GoStr(cstr *byte) string {
 	return C.GoString((*C.char)(unsafe.Pointer(cstr)))
 }
 
-// Strs takes a list of Go strings (with or without null-termination) and
+// CStr takes a Go string (with or without null-termination)
-// returns their C counterpart.
+// and returns the C counterpart.
 //
-// The returned free function must be called once you are done using the strings
+// The returned free function must be called once you are done using the string
 // in order to free the memory.
-//
+func CStr(str string) (cstr *byte, free func()) {
-// If no strings are provided as a parameter this function will panic.
+	cs := C.CString(str)
-func Strs(strs ...string) (cstrs **byte, free func()) {
+	return (*byte)(unsafe.Pointer(cs)), func() {
-	if len(strs) == 0 {
+		C.free(unsafe.Pointer(cs))
-		panic("gl: expected at least 1 string at Strs")
-	}
-
-	css := make([]*byte, 0, len(strs))
-	for _, str := range strs {
-		cs := C.CString(str)
-		css = append(css, (*byte)(unsafe.Pointer(cs)))
-	}
-
-	return (**byte)(&css[0]), func() {
-		for _, cs := range css {
-			C.free(unsafe.Pointer(cs))
-		}
 	}
 }

internal/graphicsdriver/opengl/gl/conversions_nocgo.go

@@ -26,31 +26,18 @@ func GoStr(cstr *byte) string {
 	return ""
 }
 
-// Strs takes a list of Go strings (with or without null-termination) and
+// CStr takes a Go string (with or without null-termination)
-// returns their C counterpart.
+// and returns the C counterpart.
 //
-// The returned free function must be called once you are done using the strings
+// The returned free function must be called once you are done using the string
 // in order to free the memory.
-//
+func CStr(str string) (cstr *byte, free func()) {
-// If no strings are provided as a parameter this function will panic.
+	bs := []byte(str)
-func Strs(strs ...string) (cstrs **byte, free func()) {
+	if len(bs) == 0 || bs[len(bs)-1] != 0 {
-	if len(strs) == 0 {
+		bs = append(bs, 0)
-		panic("gl: expected at least 1 string at Strs")
 	}
-
+	return &bs[0], func() {
-	pinned := make([][]byte, 0, len(strs))
+		runtime.KeepAlive(bs)
-	ptrs := make([]*byte, 0, len(strs))
+		bs = nil
-	for _, str := range strs {
-		bs := []byte(str)
-		if len(bs) == 0 || bs[len(bs)-1] != 0 {
-			bs = append(bs, 0)
-		}
-		pinned = append(pinned, bs)
-		ptrs = append(ptrs, &bs[0])
-	}
-
-	return &ptrs[0], func() {
-		runtime.KeepAlive(pinned)
-		pinned = nil
 	}
 }