glReadPixels

関数

フレームバッファの矩形領域のピクセルを読み出す。

DLLOPENGL32.dll呼出規約winapi

シグネチャ

// OPENGL32.dll
#include <windows.h>

void glReadPixels(
    INT x,
    INT y,
    INT width,
    INT height,
    DWORD format,
    DWORD type,
    void* pixels
);

パラメーター

名前	型	方向
x	INT	in
y	INT	in
width	INT	in
height	INT	in
format	DWORD	in
type	DWORD	in
pixels	void*	inout

戻り値の型: void

各言語での呼び出し定義

// OPENGL32.dll
#include <windows.h>

void glReadPixels(
    INT x,
    INT y,
    INT width,
    INT height,
    DWORD format,
    DWORD type,
    void* pixels
);

[DllImport("OPENGL32.dll", ExactSpelling = true)]
static extern void glReadPixels(
    int x,   // INT
    int y,   // INT
    int width,   // INT
    int height,   // INT
    uint format,   // DWORD
    uint type,   // DWORD
    IntPtr pixels   // void* in/out
);

<DllImport("OPENGL32.dll", ExactSpelling:=True)>
Public Shared Sub glReadPixels(
    x As Integer,   ' INT
    y As Integer,   ' INT
    width As Integer,   ' INT
    height As Integer,   ' INT
    format As UInteger,   ' DWORD
    type As UInteger,   ' DWORD
    pixels As IntPtr   ' void* in/out
)
End Sub

' x : INT
' y : INT
' width : INT
' height : INT
' format : DWORD
' type : DWORD
' pixels : void* in/out
Declare PtrSafe Sub glReadPixels Lib "opengl32" ( _
    ByVal x As Long, _
    ByVal y As Long, _
    ByVal width As Long, _
    ByVal height As Long, _
    ByVal format As Long, _
    ByVal type As Long, _
    ByVal pixels As LongPtr)
' VBA7前提(PtrSafe)。32bit Office では LongPtr→Long。Integer=16bit / Long=32bit / LongLong=64bit。

import ctypes
from ctypes import wintypes

glReadPixels = ctypes.windll.opengl32.glReadPixels
glReadPixels.restype = None
glReadPixels.argtypes = [
    ctypes.c_int,  # x : INT
    ctypes.c_int,  # y : INT
    ctypes.c_int,  # width : INT
    ctypes.c_int,  # height : INT
    wintypes.DWORD,  # format : DWORD
    wintypes.DWORD,  # type : DWORD
    ctypes.POINTER(None),  # pixels : void* in/out
]

require 'fiddle'
require 'fiddle/import'

lib = Fiddle.dlopen('OPENGL32.dll')
glReadPixels = Fiddle::Function.new(
  lib['glReadPixels'],
  [
    Fiddle::TYPE_INT,  # x : INT
    Fiddle::TYPE_INT,  # y : INT
    Fiddle::TYPE_INT,  # width : INT
    Fiddle::TYPE_INT,  # height : INT
    -Fiddle::TYPE_INT,  # format : DWORD
    -Fiddle::TYPE_INT,  # type : DWORD
    Fiddle::TYPE_VOIDP,  # pixels : void* in/out
  ],
  Fiddle::TYPE_VOID)

#[link(name = "opengl32")]
extern "system" {
    fn glReadPixels(
        x: i32,  // INT
        y: i32,  // INT
        width: i32,  // INT
        height: i32,  // INT
        format: u32,  // DWORD
        type: u32,  // DWORD
        pixels: *mut ()  // void* in/out
    );
}
// crates: windows-sys provides ready-made bindings for this API.

$sig = @"
[DllImport("OPENGL32.dll")]
public static extern void glReadPixels(int x, int y, int width, int height, uint format, uint type, IntPtr pixels);
"@
$api = Add-Type -MemberDefinition $sig -Name 'OPENGL32_glReadPixels' -Namespace Win32 -PassThru
# $api::glReadPixels(x, y, width, height, format, type, pixels)

#uselib "OPENGL32.dll"
#func global glReadPixels "glReadPixels" sptr, sptr, sptr, sptr, sptr, sptr, sptr
; glReadPixels x, y, width, height, format, type, pixels
; x : INT -> "sptr"
; y : INT -> "sptr"
; width : INT -> "sptr"
; height : INT -> "sptr"
; format : DWORD -> "sptr"
; type : DWORD -> "sptr"
; pixels : void* in/out -> "sptr"

#uselib "OPENGL32.dll"
#func global glReadPixels "glReadPixels" int, int, int, int, int, int, sptr
; glReadPixels x, y, width, height, format, type, pixels
; x : INT -> "int"
; y : INT -> "int"
; width : INT -> "int"
; height : INT -> "int"
; format : DWORD -> "int"
; type : DWORD -> "int"
; pixels : void* in/out -> "sptr"

; void glReadPixels(INT x, INT y, INT width, INT height, DWORD format, DWORD type, void* pixels)
#uselib "OPENGL32.dll"
#func global glReadPixels "glReadPixels" int, int, int, int, int, int, intptr
; glReadPixels x, y, width, height, format, type, pixels
; x : INT -> "int"
; y : INT -> "int"
; width : INT -> "int"
; height : INT -> "int"
; format : DWORD -> "int"
; type : DWORD -> "int"
; pixels : void* in/out -> "intptr"

import (
	"golang.org/x/sys/windows"
	"unsafe"
)

var (
	opengl32 = windows.NewLazySystemDLL("OPENGL32.dll")
	procglReadPixels = opengl32.NewProc("glReadPixels")
)

// x (INT), y (INT), width (INT), height (INT), format (DWORD), type (DWORD), pixels (void* in/out)
r1, _, err := procglReadPixels.Call(
	uintptr(x),
	uintptr(y),
	uintptr(width),
	uintptr(height),
	uintptr(format),
	uintptr(type),
	uintptr(pixels),
)
_ = err  // syscall.Errno (valid when the call sets last-error)
_ = r1   // void

procedure glReadPixels(
  x: Integer;   // INT
  y: Integer;   // INT
  width: Integer;   // INT
  height: Integer;   // INT
  format: DWORD;   // DWORD
  type: DWORD;   // DWORD
  pixels: Pointer   // void* in/out
); stdcall;
  external 'OPENGL32.dll' name 'glReadPixels';

result := DllCall("OPENGL32\glReadPixels"
    , "Int", x   ; INT
    , "Int", y   ; INT
    , "Int", width   ; INT
    , "Int", height   ; INT
    , "UInt", format   ; DWORD
    , "UInt", type   ; DWORD
    , "Ptr", pixels   ; void* in/out
    , "Int")   ; return: void

●glReadPixels(x, y, width, height, format, type, pixels) = DLL("OPENGL32.dll", "int glReadPixels(int, int, int, int, dword, dword, void*)")
# 呼び出し: glReadPixels(x, y, width, height, format, type, pixels)
# x : INT -> "int"
# y : INT -> "int"
# width : INT -> "int"
# height : INT -> "int"
# format : DWORD -> "dword"
# type : DWORD -> "dword"
# pixels : void* in/out -> "void*"
# なでしこ1は32bit・ANSI(Shift_JIS)。文字列=char*(ANSI)、ポインタ/ハンドル=void*(4byte)。