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stbi__bmp_load() might not return correct Channel 

Struct stbi__bmp_data in stbi__bmp_load() does not have initialize code for the: mr,mg,mb,ma, all_a as the code does in the beginning of " stbi__bmp_load()" function.
When I tried to load 24bit BMP image, the number of channels returned was 4. Image displayed wrongly.
When I done the same on the old stb_image (v1.33) image displayed correctly. On that code, the channel number returned was: 3.
After debugging, I found out that difference was in the use of the named struct. The values of the parameters above were not initialized for the 24bit BMP when calling "stbi__bmp_parse_header()" function.

Proposed solution:
I added an init() function to the struct, and called it just before we initialized the "info.all_a" in "stbi__bmp_load()" function.
Since the "stbi__bmp_parse_header()" is called only from  stbi__bmp_load(), I think my suggestion is safe.
pull/243/head
snagar 2016-02-11 21:35:48 +02:00
parent 955dfe991b
commit 56392668cb
1 changed files with 6 additions and 0 deletions
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6
stb_image.h
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@ -4603,6 +4603,11 @@ typedef struct
{
int bpp, offset, hsz;
unsigned int mr,mg,mb,ma, all_a;
// added by snagar.dev - missing initialization. Fix the channel value for 24bit BMP files
void init()
{
mr = mg = mb = ma = all_a = 0;
}
} stbi__bmp_data;
static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
@ -4699,6 +4704,7 @@ static stbi_uc *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int
int flip_vertically, pad, target;
stbi__bmp_data info;
info.init(); // added by saar
info.all_a = 255;
if (stbi__bmp_parse_header(s, &info) == NULL)
return NULL; // error code already set