mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
54 lines
1.4 KiB
Go
54 lines
1.4 KiB
Go
// SPDX-License-Identifier: MIT
|
|
|
|
package gl
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"strings"
|
|
"unsafe"
|
|
)
|
|
|
|
// Ptr takes a slice or pointer (to a singular scalar value or the first
|
|
// element of an array or slice) and returns its GL-compatible address.
|
|
//
|
|
// For example:
|
|
//
|
|
// var data []uint8
|
|
// ...
|
|
// gl.TexImage2D(gl.TEXTURE_2D, ..., gl.UNSIGNED_BYTE, gl.Ptr(&data[0]))
|
|
func Ptr(data interface{}) unsafe.Pointer {
|
|
if data == nil {
|
|
return unsafe.Pointer(nil)
|
|
}
|
|
var addr unsafe.Pointer
|
|
switch v := data.(type) {
|
|
case *uint8:
|
|
addr = unsafe.Pointer(v)
|
|
case *uint16:
|
|
addr = unsafe.Pointer(v)
|
|
case *float32:
|
|
addr = unsafe.Pointer(v)
|
|
case []uint8:
|
|
addr = unsafe.Pointer(&v[0])
|
|
case []uint16:
|
|
addr = unsafe.Pointer(&v[0])
|
|
case []float32:
|
|
addr = unsafe.Pointer(&v[0])
|
|
default:
|
|
panic(fmt.Errorf("unsupported type %T; must be a slice or pointer to a singular scalar value or the first element of an array or slice", v))
|
|
}
|
|
return addr
|
|
}
|
|
|
|
// Str takes a null-terminated Go string and returns its GL-compatible address.
|
|
// This function reaches into Go string storage in an unsafe way so the caller
|
|
// must ensure the string is not garbage collected.
|
|
func Str(str string) *uint8 {
|
|
if !strings.HasSuffix(str, "\x00") {
|
|
panic("str argument missing null terminator: " + str)
|
|
}
|
|
header := (*reflect.StringHeader)(unsafe.Pointer(&str))
|
|
return (*uint8)(unsafe.Pointer(header.Data))
|
|
}
|