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HTML5: fix various crashes with image files #923

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Merged
Shchvova merged 2 commits into from
Jun 11, 2026
Merged

HTML5: fix various crashes with image files #923

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f45abe2
Fix file extension getting and handling
XeduR Apr 17, 2026
3d38249
HTML5: Fix crashes when loading invalid or corrupted images
XeduR Jun 8, 2026
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7 changes: 6 additions & 1 deletion librtt/Display/Rtt_TextureFactory.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -278,7 +278,12 @@ TextureFactory::FindOrCreate(
if ( result.IsNull() )
{
PlatformBitmap *bitmap = CreateBitmap( filePath.GetString(), flags, isMask );
result = CreateAndAdd( key, bitmap, true, isRetina );

// Guards the NULL bitmap Linux returns on a failed load; no-op on emscripten (returns an empty bitmap).
if ( bitmap )
{
result = CreateAndAdd( key, bitmap, true, isRetina );
}
}

return result;
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32 changes: 27 additions & 5 deletions platform/emscripten/Rtt_EmscriptenBitmap.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@
#include "Core/Rtt_Types.h"
#include "Rtt_BitmapUtils.h"
#include <SDL2/SDL.h>
#include <cctype>
#include <cstring>

#if defined(EMSCRIPTEN)
#include "emscripten/emscripten.h" // for native alert and etc
Expand Down Expand Up @@ -171,14 +173,24 @@ namespace Rtt
{
Rtt_ASSERT(fData == NULL);

// get file ext
int n = strlen(path);
if (n < 5)
if (path == NULL)
{
return false;
}

std::string ext = path + n - 4;
// Extract extension after the last dot. Case-insensitive to accept .JPG, .PNG, etc.
const char *dot = strrchr(path, '.');
if (dot == NULL || dot[1] == '\0')
{
return false;
}

std::string ext(dot);
for (size_t i = 0; i < ext.size(); i++)
{
ext[i] = (char)tolower((unsigned char)ext[i]);
}

if (ext == ".bmp")
{
fData = bitmapUtil::loadBMP(path, fWidth, fHeight, fFormat);
Expand All @@ -198,11 +210,16 @@ namespace Rtt
{
fFormat = kRGBA;
}
else
{
fWidth = 0;
fHeight = 0;
}
fclose(f);
}
}
else
if (ext == ".jpg")
if (ext == ".jpg" || ext == ".jpeg")
{
FILE* f = fopen(path, "rb");
if (f)
Expand Down Expand Up @@ -230,6 +247,11 @@ namespace Rtt
}
free(img);
}
else
{
fWidth = 0;
fHeight = 0;
}
fclose(f);
return fData != NULL;
}
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7 changes: 0 additions & 7 deletions platform/emscripten/Rtt_EmscriptenPlatform.cpp
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Expand Up @@ -294,13 +294,6 @@ namespace Rtt
}
}

if (result && result->GetFormat() == PlatformBitmap::kUndefined)
{
// failed to load bitmap
Rtt_DELETE(result);
result = NULL;
}

return result;
}

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10 changes: 9 additions & 1 deletion platform/shared/Rtt_BitmapUtils.cpp
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Expand Up @@ -26,6 +26,12 @@ namespace bitmapUtil
};
typedef struct JpegErrorMgr* jpegErrorMgr;

// Replace libpng's default error handler, which crashes on emscripten, with a clean longjmp.
void pngErrorHandler(png_structp png_ptr, png_const_charp)
{
longjmp(png_jmpbuf(png_ptr), 1);
}

void jpgErrorHandler(j_common_ptr cinfo)
{
char jpegLastErrorMsg[JMSG_LENGTH_MAX];
Expand Down Expand Up @@ -246,7 +252,7 @@ namespace bitmapUtil

uint8_t* loadPNG(FILE* fp, int& w, int& h)
{
png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
png_structp png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, pngErrorHandler, NULL);
if (png == NULL)
{
return NULL;
Expand All @@ -255,11 +261,13 @@ namespace bitmapUtil
png_infop info = png_create_info_struct(png);
if (info == NULL)
{
png_destroy_read_struct(&png, NULL, NULL);
return NULL;
}

if (setjmp(png_jmpbuf(png)))
{
png_destroy_read_struct(&png, &info, NULL);
return NULL;
}

Expand Down