Re: [Tinycc-devel] Found an issue when compiling raylib with TCC

[Michael Matz]

Hello,

On Mon, 28 May 2018, Ray wrote:

> Just found an issue when compiling with TCC, it seems that TCC is not
> casting some int values correctly to float when dividing, I mean:

Which version of TCC?  (mob branch or anything else?)

> Following code fails on calculating correct float coordinates:
>
> // sourceRec.x, sourceRec.y are floats
> // texture.width, texture.height are int
> rlTexCoord2f(sourceRec.x/texture.width, sourceRec.y/texture.height);
>
> Same code works perfectly with MinGW, GCC, MSVC, Clang...
>
> Also tried: 
>
> rlTexCoord2f(sourceRec.x/(float)texture.width,
> sourceRec.y/(float)texture.height);
>
> Instead I had to do:
>
> float width = (float)texture.width;
> float height = (float)texture.height;
>
> rlTexCoord2f(sourceRec.x/width, sourceRec.y/height);
>
> More info about this issue: https://github.com/raysan5/raylib/issues/553

I can't find a test which reproduces a problem with current mob branch. 
I tried:

% cat x.c
#include <stdio.h>

void get2f (float a, float b)
{
  printf("%f %f\n", a, b);
}

struct F2 {
    float x,y;
};
struct I2 {
    int width, height;
};

int main()
{
  struct F2 a = {5.5f, 42.3f};
  struct I2 b = {1024, 768};
  get2f(a.x/(float)b.width, a.y/(float)b.height);
  return 0;
}
% tcc x.c && ./a.out
0.005371 0.055078

(which is the correct result)  It also works without the explicit casts to 
float in the divisions, and it works when the initialization of a and b 
are done via assignments, not in the initializer.  So I fear you'll have 
to get us a self-contained testcase showing a problem (or confirm that 
it's no problem anymore with mob branch).


Ciao,
Michael.