TL;DR: I want to create a standalone application that has image resources (with alpha channel) embedded. What is the modern/standard way of doing this and extracting the data?
I am currently writing an application in C that uses OpenGL as the graphics engine (I chose it for the faster development time compared to Vulkan, even though I really want to learn Vulkan as well) and in this app I use Signed Distance Fields to render my text. This requires a Font Atlas with an alpha channel to draw the characters from.
I want to be able to embed this Font Atlas (currently it is a .PNG file) in the executable. There are other image resources as well, but I am mentioning this scenario to show why I really need the alpha channel.
I used the Win32 API to do the following:
Get current module.
HMODULE getCurrentModule()
{
HMODULE hModule = NULL;
GetModuleHandleEx(
GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
(LPCTSTR)getCurrentModule,
&hModule);
return hModule;
}
Embed Text files for the shaders.
std::string loadShaderFromResource(int shaderID)
{
// Load resource from executable.
HRSRC shaderResource = FindResource(getCurrentModule(), MAKEINTRESOURCE(shaderID), MAKEINTRESOURCE(TEXTFILE));
HGLOBAL resourceData = LoadResource(getCurrentModule(), shaderResource);
DWORD resourceSize = SizeofResource(getCurrentModule(), shaderResource);
char* resourceFinal = (char*)LockResource(resourceData);
std::string shaderSource;
shaderSource.assign(resourceFinal, resourceSize);
return shaderSource;
}
My resource.h file.
It is a bit messy, but I am including it to provide as much info as possible.
/*=======================================================================================================================================*/
/* Setup by Visual Studio. */
/*=======================================================================================================================================*/
// Next default values for new objects
//
#ifdef APSTUDIO_INVOKED
#ifndef APSTUDIO_READONLY_SYMBOLS
#define _APS_NEXT_RESOURCE_VALUE 116
#define _APS_NEXT_COMMAND_VALUE 40003
#define _APS_NEXT_CONTROL_VALUE 1001
#define _APS_NEXT_SYMED_VALUE 101
#endif
#endif
/*=======================================================================================================================================*/
/* Resources. */
/*=======================================================================================================================================*/
//-------------------------------------------------------------------------------------------------
// Resource Types
#define TEXTFILE 255
#define PNG 254
//-------------------------------------------------------------------------------------------------
// Shaders
#define BASIC_SHADER 253
#define STATIC_SHADER 252
#define TEXTURE_SHADER 251
//-------------------------------------------------------------------------------------------------
// ImGui images.
#define COMPONENT_PNG 250
#define DRAW_CIRCUIT_BUCKETS 249
#define DRAW_MCC_PNG 248
//-------------------------------------------------------------------------------------------------
// OpenGL Textures.
#define CIRCUIT_TREE_PNG 247
//-------------------------------------------------------------------------------------------------
// OpenGL Fonts.
#define ARIAL_SDF_FNT 246
#define ARIAL_SDF_PNG 245
#define ARIAL_SDF_BMP 244
#define ARIAL_SDF_MIN_FNT 243
#define ARIAL_SDF_MIN_PNG 242
//-------------------------------------------------------------------------------------------------
// Application icon.
#define IDI_ICON1 116 // Exe icon.
#define ICON_BMP 115 // GLFW icon.
#define PANDA 114
//-------------------------------------------------------------------------------------------------
/*=======================================================================================================================================*/
/* Includes. */
/*=======================================================================================================================================*/
// Windows api for the exe.
#include <Windows.h>
#include <string>
/*=======================================================================================================================================*/
/* Data. */
/*=======================================================================================================================================*/
// Struct that stores the bitmap data.
struct Bitmap {
void* pixelData;
int width = 0;
int height = 0;
};
/*=======================================================================================================================================*/
/* Functions. */
/*=======================================================================================================================================*/
// Load the current module.
HMODULE getCurrentModule();
// Load shader from resource.
std::string loadShaderFromResource(int shaderID);
// Loading bitmaps.
Bitmap loadBitmapFromResource(int bitmapID);
unsigned int loadBitmapToGL(Bitmap bitmap);
/*=======================================================================================================================================*/
/* EOF. */
/*=======================================================================================================================================*/
My resource.rc file.
// Microsoft Visual C generated resource script.
//
#include "resource.h"
#define APSTUDIO_READONLY_SYMBOLS
/////////////////////////////////////////////////////////////////////////////
//
// Generated from the TEXTINCLUDE 2 resource.
//
#include "winres.h"
/////////////////////////////////////////////////////////////////////////////
#undef APSTUDIO_READONLY_SYMBOLS
/////////////////////////////////////////////////////////////////////////////
// English (United States) resources
#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
#pragma code_page(1252)
#ifdef APSTUDIO_INVOKED
/////////////////////////////////////////////////////////////////////////////
//
// TEXTINCLUDE
//
1 TEXTINCLUDE
BEGIN
"resource.h\0"
END
2 TEXTINCLUDE
BEGIN
"#include ""winres.h""\r\n"
"\0"
END
3 TEXTINCLUDE
BEGIN
"\r\n"
"\0"
END
#endif // APSTUDIO_INVOKED
/*=======================================================================================================================================*/
/* Resources. */
/*=======================================================================================================================================*/
//-------------------------------------------------------------------------------------------------
// Resource ID Resource Type Resource Path
//-------------------------------------------------------------------------------------------------
// Application icon.
IDI_ICON1 ICON "Icons\\circuitIcon128.ico"
ICON_BMP BITMAP "Icons\\circuitIcon.bmp"
PANDA BITMAP "Icons\\panda.bmp"
//-------------------------------------------------------------------------------------------------
// Shaders.
BASIC_SHADER TEXTFILE "Shaders\\basicShader.shader"
STATIC_SHADER TEXTFILE "Shaders\\staticShader.shader"
TEXTURE_SHADER TEXTFILE "Shaders\\textureShader.shader"
//-------------------------------------------------------------------------------------------------
// ImGui images.
COMPONENT_PNG PNG "Icons\\component.png"
DRAW_CIRCUIT_BUCKETS_PNG PNG "Icons\\Draw_Circuit_Buckets.png"
DRAW_MCC_PNG PNG "Icons\\Draw_MCC.png"
//-------------------------------------------------------------------------------------------------
// OpenGL Textures.
CIRCUIT_TREE_PNG PNG "Textures\\circuitTree.png"
//-------------------------------------------------------------------------------------------------
// OpenGL Fonts.
ARIAL_SDF_FNT TEXTFILE "Fonts\\Arial_SDF.fnt"
ARIAL_SDF_PNG PNG "Fonts\\Arial_SDF_PNG.png"
ARIAL_SDF_BMP BITMAP "Fonts\\Arial_SDF_BMP_32.bmp"
ARIAL_SDF_MIN_FNT TEXTFILE "Fonts\\Arial_SDF_Min.fnt"
ARIAL_SDF_MIN_PNG PNG "Fonts\\Arial_SDF_Min.png"
//-------------------------------------------------------------------------------------------------
#endif // English (United States) resources
//=================================================================================================
#ifndef APSTUDIO_INVOKED
/////////////////////////////////////////////////////////////////////////////
//
// Generated from the TEXTINCLUDE 3 resource.
//
/////////////////////////////////////////////////////////////////////////////
#endif // not APSTUDIO_INVOKED
/*=======================================================================================================================================*/
/* EOF. */
/*=======================================================================================================================================*/
I noticed that most of the forums regarding the Win32 API and this type of question is very, very old. Is it still used? Is there a more modern way of doing it? I saw some people using CMake.
Edit 1
I tried adding the following, as suggested by @Barmak with some edits:
HBITMAP loadImageFromResource(int resourceID)
{
HBITMAP hbitmap = NULL;
ULONG_PTR token;
Gdiplus::GdiplusStartupInput tmp;
Gdiplus::GdiplusStartup(&token, &tmp, NULL);
if (auto hres = FindResource(getCurrentModule(), MAKEINTRESOURCE(resourceID), RT_RCDATA))
if (auto size = SizeofResource(getCurrentModule(), hres))
if (auto data = LockResource(LoadResource(getCurrentModule(), hres)))
if (auto stream = SHCreateMemStream((BYTE*)data, size))
{
Gdiplus::Bitmap bmp(stream);
stream->Release();
bmp.GetHBITMAP(Gdiplus::Color::Transparent, &hbitmap);
}
Gdiplus::GdiplusShutdown(token);
return hbitmap;
}
However, when viewing hbitmap in debug mode it shows 0xffffffffa00513d7 {unused=???} and does not work.
resource.h:
#define ICON_PNG 240 // GLFW icon.
resource.rc:
ICON_PNG RCDATA "Icons\\circuitImage.png"
Edit 2
I made a simple mistake. I added these lines to the function:
BITMAP bitmap;
GetObject(hbitmap, sizeof(BITMAP), &bitmap);
And now it works by returing a BITMAP instead of HBITMAP. However, it is upside down and some of the coloring seems off when using it with glfwSetWindowIcon(). It works perfectly in other places!
BITMAP loadImageFromResource(int resourceID)
{
HBITMAP hbitmap = NULL;
ULONG_PTR token;
Gdiplus::GdiplusStartupInput tmp;
Gdiplus::GdiplusStartup(&token, &tmp, NULL);
if (auto hres = FindResource(getCurrentModule(), MAKEINTRESOURCE(resourceID), RT_RCDATA))
if (auto size = SizeofResource(getCurrentModule(), hres))
if (auto data = LockResource(LoadResource(getCurrentModule(), hres)))
if (auto stream = SHCreateMemStream((BYTE*)data, size))
{
Gdiplus::Bitmap bmp(stream);
stream->Release();
bmp.GetHBITMAP(Gdiplus::Color::Transparent, &hbitmap);
}
Gdiplus::GdiplusShutdown(token);
BITMAP bitmap;
GetObject(hbitmap, sizeof(BITMAP), &bitmap);
return bitmap;
}
CodePudding user response：
Credit: Barmak Shemirani
First, store the .PNG file by adding these lines to:
resource.h
#define ICON_PNG 240 // GLFW icon.
resource.rc
ICON_PNG RCDATA "Icons\\circuitImage.png"
Then load the .PNG as a bitmap like this:
BITMAP loadImageFromResource(int resourceID)
{
HBITMAP hbitmap = NULL;
ULONG_PTR token;
Gdiplus::GdiplusStartupInput tmp;
Gdiplus::GdiplusStartup(&token, &tmp, NULL);
if (auto hres = FindResource(getCurrentModule(), MAKEINTRESOURCE(resourceID), RT_RCDATA))
if (auto size = SizeofResource(getCurrentModule(), hres))
if (auto data = LockResource(LoadResource(getCurrentModule(), hres)))
if (auto stream = SHCreateMemStream((BYTE*)data, size))
{
Gdiplus::Bitmap bmp(stream);
stream->Release();
bmp.GetHBITMAP(Gdiplus::Color::Transparent, &hbitmap);
}
Gdiplus::GdiplusShutdown(token);
BITMAP bitmap;
if(!hbitmap) return NULL;
GetObject(hbitmap, sizeof(BITMAP), &bitmap);
return bitmap;
}
By calling it like this:
BITMAP image = loadImageFromResource(ICON_PNG);
Edit 1
I used this function to load the bitmap into OpenGL:
unsigned int loadBitmapToGL(BITMAP bitmap)
{
unsigned int textureID = 0;
glCreateTextures(GL_TEXTURE_2D, 1, &textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bitmap.bmWidth, bitmap.bmHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, (const void*)bitmap.bmBits);
return textureID;
}
Also added if(!hbitmap) return NULL; as suggested by Barmak.