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Adapting SDL_stbimage.h interface for SDL3
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@DanielGibson
DanielGibson committed Jan 29, 2025
1 parent 655914c commit 8f61610
Showing 1 changed file with 78 additions and 32 deletions.
110 changes: 78 additions & 32 deletions SDL_stbimage.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,9 +76,31 @@
#ifndef SDL__STBIMAGE_H
#define SDL__STBIMAGE_H

// if you really think you need <SDL2/SDL.h> here instead.. feel free to change it,
// but the cool kids have path/to/include/SDL2/ in their compilers include path.
#include <SDL.h>
// for SDL3, you either can #define SDL_STBIMG_SDL3 yourself
// OR #include <SDL3/SDL.h> yourself before this header
// (the following lines handle for the second case)
#if defined(SDL_VERSION_ATLEAST)
#if SDL_VERSION_ATLEAST(3, 0, 0))
#define SDL_STBIMG_SDL3
#endif
#endif

#if defined(SDL_STBIMG_SDL3)
// in SDL3 this is the official way to include SDL.h
#include <SDL3/SDL.h>
#else // SDL2 and SDL1.2
// if you really think you need <SDL2/SDL.h> here instead.. feel free to change it,
// but the cool kids have path/to/include/SDL2/ in their compilers include path.
// (meaning, that's how was supposed to be done for SDL2 and what sdl2-config supports)
#include <SDL.h>

// allow using bool. In C++ it's a builtin type
// in SDL3 SDL_stdinc.h (through SDL.h) makes sure it's available
#ifndef __cpluscplus
#include <stdbool.h>
#endif

#endif

#ifndef SDL_STBIMG_ALLOW_STDIO
#define STBI_NO_STDIO // don't need STDIO, will use SDL_RWops to open files
Expand All @@ -104,24 +126,27 @@ SDL_STBIMG_DEF SDL_Surface* STBIMG_Load(const char* file);
// Returns NULL on error, use SDL_GetError() to get more information.
SDL_STBIMG_DEF SDL_Surface* STBIMG_LoadFromMemory(const unsigned char* buffer, int length);

// loads an image file into a RGB(A) SDL_Surface from a seekable SDL_RWops (src)
// if you set freesrc to non-zero, SDL_RWclose(src) will be executed after reading.
// Returns NULL on error, use SDL_GetError() to get more information.
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_RWops* src, int freesrc);

// loads an image file into a RGB(A) SDL_Surface from a seekable SDL_IOStream/SDL_RWops (src)
// if you set freesrc to true, SDL_CloseIO(src)/SDL_RWclose(src) will be executed after reading.
// Returns NULL on error, use SDL_GetError() to get more information.
#ifdef SDL_STBIMG_SDL3
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_IOStream* src, bool freesrc);
#else // SDL2 or SDL1.2
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_RWops* src, bool freesrc);
#endif

// Creates an SDL_Surface* using the raw RGB(A) pixelData with given width/height
// (this doesn't use stb_image and is just a simple SDL_CreateSurfaceFrom()-wrapper)
// ! It must be byte-wise 24bit RGB ("888", bytesPerPixel=3) !
// ! or byte-wise 32bit RGBA ("8888", bytesPerPixel=4) data !
// If freeWithSurface is SDL_TRUE, SDL_FreeSurface() will free the pixelData
// If freeWithSurface is true, SDL_FreeSurface() will free the pixelData
// you passed with SDL_free() - NOTE that you should only do that if pixelData
// was allocated with SDL_malloc(), SDL_calloc() or SDL_realloc()!
// Returns NULL on error (in that case pixelData won't be freed!),
// use SDL_GetError() to get more information.
SDL_STBIMG_DEF SDL_Surface* STBIMG_CreateSurface(unsigned char* pixelData, int width, int height,
int bytesPerPixel, SDL_bool freeWithSurface);

int bytesPerPixel, bool freeWithSurface);

#if SDL_MAJOR_VERSION > 1
// loads the image file at the given path into a RGB(A) SDL_Texture
Expand All @@ -134,11 +159,16 @@ STBIMG_LoadTexture(SDL_Renderer* renderer, const char* file);
SDL_STBIMG_DEF SDL_Texture*
STBIMG_LoadTextureFromMemory(SDL_Renderer* renderer, const unsigned char* buffer, int length);

// loads an image file into a RGB(A) SDL_Texture from a seekable SDL_RWops (src)
// if you set freesrc to non-zero, SDL_RWclose(src) will be executed after reading.
// loads an image file into a RGB(A) SDL_Texture from a seekable SDL_IOStream/SDL_RWops (src)
// if you set freesrc to true, SDL_CloseIO(src)/SDL_RWclose(src) will be executed after reading.
// Returns NULL on error, use SDL_GetError() to get more information.
#ifdef SDL_STBIMG_SDL3
SDL_STBIMG_DEF SDL_Texture*
STBIMG_LoadTexture_RW(SDL_Renderer* renderer, SDL_IOStream* src, bool freesrc);
#else // SDL2
SDL_STBIMG_DEF SDL_Texture*
STBIMG_LoadTexture_RW(SDL_Renderer* renderer, SDL_RWops* src, int freesrc);
STBIMG_LoadTexture_RW(SDL_Renderer* renderer, SDL_RWops* src, bool freesrc);
#endif

// Creates an SDL_Texture* using the raw RGB(A) pixelData with given width/height
// (this doesn't use stb_image and is just a simple SDL_CreateSurfaceFrom()-wrapper)
Expand All @@ -152,19 +182,27 @@ STBIMG_CreateTexture(SDL_Renderer* renderer, const unsigned char* pixelData,


typedef struct {
#ifdef SDL_STBIMG_SDL3
SDL_IOStream* src;
#else
SDL_RWops* src;
#endif
stbi_io_callbacks stb_cbs;
int atEOF; // defaults to 0; 1: reached EOF or error on read, 2: error on seek
} STBIMG_stbio_RWops;

// creates stbi_io_callbacks and userdata to use stbi_*_from_callbacks() directly,
// especially useful to use SDL_RWops with stb_image, without using SDL_Surface
// especially useful to use SDL_IOStream/SDL_RWops with stb_image, without using SDL_Surface
// src must be readable and seekable!
// Returns SDL_FALSE on error (SDL_GetError() will give you info), else SDL_TRUE
// Returns false on error (SDL_GetError() will give you info), else true
// NOTE: If you want to use src twice (e.g. for info and load), remember to rewind
// it by seeking back to its initial position and resetting out->atEOF to 0
// inbetween the uses!
SDL_STBIMG_DEF SDL_bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbio_RWops* out);
#ifdef SDL_STBIMG_SDL3
SDL_STBIMG_DEF bool STBIMG_stbi_callback_from_RW(SDL_IOStream* src, STBIMG_stbio_RWops* out);
#else
SDL_STBIMG_DEF bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbio_RWops* out);
#endif

#if 0 // Use STBIMG_stbi_callback_from_RW() like this:
SDL_RWops* src = ...; // wherever it's from
Expand Down Expand Up @@ -201,18 +239,26 @@ SDL_STBIMG_DEF SDL_bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbi


#if SDL_MAJOR_VERSION > 1
// loads an image file into a RGB(A) SDL_Surface from a SDL_RWops (src)
// - without using SDL_RWseek(), for streams that don't support or are slow
// loads an image file into a RGB(A) SDL_Surface from a SDL_RWops/SDL_IOStream (src)
// - without using SDL_RWseek()/SDL_SeekIO, for streams that don't support or are slow
// at seeking. It reads everything into a buffer and calls STBIMG_LoadFromMemory()
// You should probably only use this if you *really* have performance problems
// because of seeking or your src doesn't support SDL_RWseek(), but SDL_RWsize()
// src must at least support SDL_RWread() and SDL_RWsize()
// if you set freesrc to non-zero, SDL_RWclose(src) will be executed after reading.
// because of seeking or your src doesn't support SDL_RWseek()/SDL_SeekIO, but SDL_RWsize()/SDL_GetIOSize
// src must at least support SDL_RWread()/SDL_ReadIO() and SDL_RWsize()/SDL_GetIOSize
// if you set freesrc to true, SDL_RWclose(src)/SDL_CloseIO(src) will be executed after reading.
// Returns NULL on error, use SDL_GetError() to get more information.
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW_noSeek(SDL_RWops* src, int freesrc);
#ifdef SDL_STBIMG_SDL3
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW_noSeek(SDL_IOStream* src, bool freesrc);
#else
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW_noSeek(SDL_RWops* src, bool freesrc);
#endif

// the same for textures (you should probably not use this one, either..)
SDL_STBIMG_DEF SDL_Texture* STBIMG_LoadTexture_RW_noSeek(SDL_Renderer* renderer, SDL_RWops* src, int freesrc);
#ifdef SDL_STBIMG_SDL3
SDL_STBIMG_DEF SDL_Texture* STBIMG_LoadTexture_RW_noSeek(SDL_Renderer* renderer, SDL_IOStream* src, bool freesrc);
#else
SDL_STBIMG_DEF SDL_Texture* STBIMG_LoadTexture_RW_noSeek(SDL_Renderer* renderer, SDL_RWops* src, bool freesrc);
#endif
#endif // SDL_MAJOR_VERSION > 1

#ifdef __cplusplus
Expand Down Expand Up @@ -386,12 +432,12 @@ static int STBIMG__io_eof(void* user)
}


SDL_STBIMG_DEF SDL_bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbio_RWops* out)
SDL_STBIMG_DEF bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbio_RWops* out)
{
if(out == NULL)
{
SDL_SetError("STBIMG_stbi_callback_from_RW(): out must not be NULL!");
return SDL_FALSE;
return false;
}

// make sure out is at least initialized to something deterministic
Expand All @@ -400,7 +446,7 @@ SDL_STBIMG_DEF SDL_bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbi
if(src == NULL)
{
SDL_SetError("STBIMG_stbi_callback_from_RW(): src must not be NULL!");
return SDL_FALSE;
return false;
}

out->src = src;
Expand All @@ -409,11 +455,11 @@ SDL_STBIMG_DEF SDL_bool STBIMG_stbi_callback_from_RW(SDL_RWops* src, STBIMG_stbi
out->stb_cbs.skip = STBIMG__io_skip;
out->stb_cbs.eof = STBIMG__io_eof;

return SDL_TRUE;
return true;
}


SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_RWops* src, int freesrc)
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_RWops* src, bool freesrc)
{
STBIMG__image img = {0};
int bppToUse = 0;
Expand Down Expand Up @@ -496,7 +542,7 @@ SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW(SDL_RWops* src, int freesrc)
}

#if SDL_MAJOR_VERSION > 1
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW_noSeek(SDL_RWops* src, int freesrc)
SDL_STBIMG_DEF SDL_Surface* STBIMG_Load_RW_noSeek(SDL_RWops* src, bool freesrc)
{
unsigned char* buf = NULL;
Sint64 fileSize = 0;
Expand Down Expand Up @@ -560,7 +606,7 @@ SDL_STBIMG_DEF SDL_Surface* STBIMG_Load(const char* file)
}


SDL_STBIMG_DEF SDL_Surface* STBIMG_CreateSurface(unsigned char* pixelData, int width, int height, int bytesPerPixel, SDL_bool freeWithSurface)
SDL_STBIMG_DEF SDL_Surface* STBIMG_CreateSurface(unsigned char* pixelData, int width, int height, int bytesPerPixel, bool freeWithSurface)
{
STBIMG__image img;

Expand Down Expand Up @@ -617,7 +663,7 @@ STBIMG_LoadTextureFromMemory(SDL_Renderer *renderer, const unsigned char* buffer
}

SDL_STBIMG_DEF SDL_Texture*
STBIMG_LoadTexture_RW(SDL_Renderer* renderer, SDL_RWops* src, int freesrc)
STBIMG_LoadTexture_RW(SDL_Renderer* renderer, SDL_RWops* src, bool freesrc)
{
return STBIMG__SurfToTex(renderer, STBIMG_Load_RW(src, freesrc));
}
Expand All @@ -631,7 +677,7 @@ STBIMG_CreateTexture(SDL_Renderer* renderer, const unsigned char* pixelData,
}

SDL_STBIMG_DEF SDL_Texture*
STBIMG_LoadTexture_RW_noSeek(SDL_Renderer* renderer, SDL_RWops* src, int freesrc)
STBIMG_LoadTexture_RW_noSeek(SDL_Renderer* renderer, SDL_RWops* src, bool freesrc)
{
return STBIMG__SurfToTex(renderer, STBIMG_Load_RW_noSeek(src, freesrc));
}
Expand Down

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