mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-14 15:07:26 +01:00
102 lines
2.7 KiB
Go
102 lines
2.7 KiB
Go
// SPDX-License-Identifier: MIT
|
|
|
|
// +build !js
|
|
// +build !windows
|
|
|
|
package gl
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"strings"
|
|
"unsafe"
|
|
)
|
|
|
|
// #include <stdlib.h>
|
|
import "C"
|
|
|
|
// 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))
|
|
}
|
|
|
|
// GoStr takes a null-terminated string returned by OpenGL and constructs a
|
|
// corresponding Go string.
|
|
func GoStr(cstr *uint8) string {
|
|
return C.GoString((*C.char)(unsafe.Pointer(cstr)))
|
|
}
|
|
|
|
// Strs takes a list of Go strings (with or without null-termination) and
|
|
// returns their C counterpart.
|
|
//
|
|
// The returned free function must be called once you are done using the strings
|
|
// in order to free the memory.
|
|
//
|
|
// If no strings are provided as a parameter this function will panic.
|
|
func Strs(strs ...string) (cstrs **uint8, free func()) {
|
|
if len(strs) == 0 {
|
|
panic("Strs: expected at least 1 string")
|
|
}
|
|
|
|
// Allocate a contiguous array large enough to hold all the strings' contents.
|
|
n := 0
|
|
for i := range strs {
|
|
n += len(strs[i])
|
|
}
|
|
data := C.malloc(C.size_t(n))
|
|
|
|
// Copy all the strings into data.
|
|
dataSlice := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
|
|
Data: uintptr(data),
|
|
Len: n,
|
|
Cap: n,
|
|
}))
|
|
css := make([]*uint8, len(strs)) // Populated with pointers to each string.
|
|
offset := 0
|
|
for i := range strs {
|
|
copy(dataSlice[offset:offset+len(strs[i])], strs[i][:]) // Copy strs[i] into proper data location.
|
|
css[i] = (*uint8)(unsafe.Pointer(&dataSlice[offset])) // Set a pointer to it.
|
|
offset += len(strs[i])
|
|
}
|
|
|
|
return (**uint8)(&css[0]), func() { C.free(data) }
|
|
}
|