WGL extensions

AUTHORS

@@ -21,6 +21,7 @@ Cary Cherng <ccherng@gmail.com>
 Cory Redmond <ace@ac3-servers.eu>
 David Porter <david@porter.me>
 Dmitry Bagdanov <dimbojob@gmail.com>
+Ethan Reesor <ethan.reesor@gmail.com>
 gonutz
 Hill <zhubicen@gmail.com>
 Jason A. Donenfeld <Jason@zx2c4.com>

gdi32.go

@@ -1066,6 +1066,7 @@ var (
 	deleteDC                *windows.LazyProc
 	deleteEnhMetaFile       *windows.LazyProc
 	deleteObject            *windows.LazyProc
+	describePixelFormat     *windows.LazyProc
 	ellipse                 *windows.LazyProc
 	endDoc                  *windows.LazyProc
 	endPage                 *windows.LazyProc
@@ -1146,6 +1147,7 @@ func init() {
 	deleteDC = libgdi32.NewProc("DeleteDC")
 	deleteEnhMetaFile = libgdi32.NewProc("DeleteEnhMetaFile")
 	deleteObject = libgdi32.NewProc("DeleteObject")
+	describePixelFormat = libgdi32.NewProc("DescribePixelFormat")
 	ellipse = libgdi32.NewProc("Ellipse")
 	endDoc = libgdi32.NewProc("EndDoc")
 	endPage = libgdi32.NewProc("EndPage")
@@ -1446,6 +1448,18 @@ func DeleteObject(hObject HGDIOBJ) bool {
 	return ret != 0
 }
 
+func DescribePixelFormat(hdc HDC, iPixelFormat int32, nBytes uint32, ppfd *PIXELFORMATDESCRIPTOR) bool {
+	ret, _, _ := syscall.Syscall6(describePixelFormat.Addr(), 4,
+		uintptr(hdc),
+		uintptr(iPixelFormat),
+		uintptr(nBytes),
+		uintptr(unsafe.Pointer(ppfd)),
+		0,
+		0)
+
+	return ret != 0
+}
+
 func Ellipse(hdc HDC, nLeftRect, nTopRect, nRightRect, nBottomRect int32) bool {
 	ret, _, _ := syscall.Syscall6(ellipse.Addr(), 5,
 		uintptr(hdc),

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sys v0.0.0-20201018230417-eeed37f84f13 h1:5jaG59Zhd+8ZXe8C+lgiAGqkOaZBruqrWclLkgAww34=
+golang.org/x/sys v0.0.0-20201018230417-eeed37f84f13/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

wglext.go

@@ -0,0 +1,114 @@
+// Copyright 2021 The win Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+package win
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// wglChoosePixelFormatARB
+const (
+	WGL_NUMBER_PIXEL_FORMATS_ARB    = 0x2000
+	WGL_DRAW_TO_WINDOW_ARB          = 0x2001
+	WGL_DRAW_TO_BITMAP_ARB          = 0x2002
+	WGL_ACCELERATION_ARB            = 0x2003
+	WGL_NEED_PALETTE_ARB            = 0x2004
+	WGL_NEED_SYSTEM_PALETTE_ARB     = 0x2005
+	WGL_SWAP_LAYER_BUFFERS_ARB      = 0x2006
+	WGL_SWAP_METHOD_ARB             = 0x2007
+	WGL_NUMBER_OVERLAYS_ARB         = 0x2008
+	WGL_NUMBER_UNDERLAYS_ARB        = 0x2009
+	WGL_TRANSPARENT_ARB             = 0x200A
+	WGL_TRANSPARENT_RED_VALUE_ARB   = 0x2037
+	WGL_TRANSPARENT_GREEN_VALUE_ARB = 0x2038
+	WGL_TRANSPARENT_BLUE_VALUE_ARB  = 0x2039
+	WGL_TRANSPARENT_ALPHA_VALUE_ARB = 0x203A
+	WGL_TRANSPARENT_INDEX_VALUE_ARB = 0x203B
+	WGL_SHARE_DEPTH_ARB             = 0x200C
+	WGL_SHARE_STENCIL_ARB           = 0x200D
+	WGL_SHARE_ACCUM_ARB             = 0x200E
+	WGL_SUPPORT_GDI_ARB             = 0x200F
+	WGL_SUPPORT_OPENGL_ARB          = 0x2010
+	WGL_DOUBLE_BUFFER_ARB           = 0x2011
+	WGL_STEREO_ARB                  = 0x2012
+	WGL_PIXEL_TYPE_ARB              = 0x2013
+	WGL_COLOR_BITS_ARB              = 0x2014
+	WGL_RED_BITS_ARB                = 0x2015
+	WGL_RED_SHIFT_ARB               = 0x2016
+	WGL_GREEN_BITS_ARB              = 0x2017
+	WGL_GREEN_SHIFT_ARB             = 0x2018
+	WGL_BLUE_BITS_ARB               = 0x2019
+	WGL_BLUE_SHIFT_ARB              = 0x201A
+	WGL_ALPHA_BITS_ARB              = 0x201B
+	WGL_ALPHA_SHIFT_ARB             = 0x201C
+	WGL_ACCUM_BITS_ARB              = 0x201D
+	WGL_ACCUM_RED_BITS_ARB          = 0x201E
+	WGL_ACCUM_GREEN_BITS_ARB        = 0x201F
+	WGL_ACCUM_BLUE_BITS_ARB         = 0x2020
+	WGL_ACCUM_ALPHA_BITS_ARB        = 0x2021
+	WGL_DEPTH_BITS_ARB              = 0x2022
+	WGL_STENCIL_BITS_ARB            = 0x2023
+	WGL_AUX_BUFFERS_ARB             = 0x2024
+	WGL_NO_ACCELERATION_ARB         = 0x2025
+	WGL_GENERIC_ACCELERATION_ARB    = 0x2026
+	WGL_FULL_ACCELERATION_ARB       = 0x2027
+	WGL_SWAP_EXCHANGE_ARB           = 0x2028
+	WGL_SWAP_COPY_ARB               = 0x2029
+	WGL_SWAP_UNDEFINED_ARB          = 0x202A
+	WGL_TYPE_RGBA_ARB               = 0x202B
+	WGL_TYPE_COLORINDEX_ARB         = 0x202C
+	WGL_SAMPLE_BUFFERS_ARB          = 0x2041
+	WGL_SAMPLES_ARB                 = 0x2042
+)
+
+// wglCreateContextAttribsARB
+const (
+	WGL_CONTEXT_DEBUG_BIT_ARB                 = 0x0001
+	WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB    = 0x0002
+	WGL_CONTEXT_MAJOR_VERSION_ARB             = 0x2091
+	WGL_CONTEXT_MINOR_VERSION_ARB             = 0x2092
+	WGL_CONTEXT_LAYER_PLANE_ARB               = 0x2093
+	WGL_CONTEXT_FLAGS_ARB                     = 0x2094
+	WGL_CONTEXT_PROFILE_MASK_ARB              = 0x9126
+	WGL_CONTEXT_CORE_PROFILE_BIT_ARB          = 0x0001
+	WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB = 0x0002
+)
+
+var wglChoosePixelFormatARB uintptr
+var wglCreateContextAttribsARB uintptr
+
+// InitWglExt initializes function pointers for WGL extensions. If it is called
+// without a current WGL context, all function pointers will be nil.
+func InitWglExt() {
+	wglChoosePixelFormatARB = WglGetProcAddress(syscall.StringBytePtr("wglChoosePixelFormatARB"))
+	wglCreateContextAttribsARB = WglGetProcAddress(syscall.StringBytePtr("wglCreateContextAttribsARB"))
+}
+
+func HasWglChoosePixelFormatARB() bool    { return wglChoosePixelFormatARB != 0 }
+func HasWglCreateContextAttribsARB() bool { return wglCreateContextAttribsARB != 0 }
+
+func WglChoosePixelFormatARB(hdc HDC, piAttribIList *int32, pfAttribFList *float32, nMaxFormats uint32, piFormats *int32, nNumFormats *uint32) bool {
+	ret, _, _ := syscall.Syscall6(wglChoosePixelFormatARB, 6,
+		uintptr(hdc),
+		uintptr(unsafe.Pointer(piAttribIList)),
+		uintptr(unsafe.Pointer(pfAttribFList)),
+		uintptr(nMaxFormats),
+		uintptr(unsafe.Pointer(piFormats)),
+		uintptr(unsafe.Pointer(nNumFormats)))
+
+	return ret != 0
+}
+
+func WglCreateContextAttribsARB(hdc HDC, hShareContext HGLRC, attribList *int32) HGLRC {
+	ret, _, _ := syscall.Syscall(wglCreateContextAttribsARB, 3,
+		uintptr(hdc),
+		uintptr(hShareContext),
+		uintptr(unsafe.Pointer(attribList)))
+
+	return HGLRC(ret)
+}