On Thu, 2014-11-20 at 08:08 +0100, Iago Toral wrote: > On Wed, 2014-11-19 at 10:27 -0800, Ian Romanick wrote: > > On 11/19/2014 03:47 AM, Iago Toral Quiroga wrote: > > > Hi, > > > > > > I came across a GLSL test that checks that doing something like this in > > > a shader should fail: > > > > Is this one of the dEQP tests? > > Yes. > > > > float value = 1f; > > > > It seems like we have a test related to this in piglit somewhere... it > > looks like tests/shaders/glsl-floating-constant-120.shader_test uses > > that syntax, but it's not explicitly testing that feature. > > > > > However, this works fine in Mesa. Checking the spec I see: > > > > > > Floating-point constants are defined as follows. > > > floating-constant: > > > fractional-constant exponent-part(opt) floating-suffix(opt) > > > digit-sequence exponent-part floating-suffix(opt) > > > fractional-constant: > > > digit-sequence . digit-sequence > > > digit-sequence . > > > . digit-sequence > > > exponent-part: > > > e sign(opt) digit-sequence > > > E sign(opt) digit-sequence > > > sign: one of > > > + - > > > digit-sequence: > > > digit > > > digit-sequence digit > > > floating-suffix: one of > > > f F > > > > > > which suggests that the test is correct and Mesa has a bug. According to > > > the above rules, however, something like this is fine: > > > > > > float f = 1e2f; > > > > > > which I find kind of weird if the other case is not valid, so I wonder > > > if there is a bug in the spec or this is on purpose for some reason that > > > I am missing. > > > > > > Then, to make matters worse, I read this in opengl.org wiki [1]: > > > > > > "A numeric literal that uses a decimal is by default of type float. To > > > create a float literal from an integer value, use the suffix f or F as > > > in C/C++." > > > > > > which contradicts the spec and the test and is aligned with the current > > > way Mesa works. > > > > > > So: does anyone know what version is right? Could this be a bug in the > > > spec? and if it is not, do we want to change the behavior to follow the > > > spec as it is now? > > > > The $64,000 question: What do other GLSL compilers (including, perhaps, > > glslang) do? This seems like one of the cases where nobody is likely to > > follow the spec, and some application will depend on that. If that's > > the case, I'll submit a spec bug. > > Good point. I'll try to check a few cases and reply here. Thanks!
I did a quick test on AMD Radeon and nVidia proprietary drivers since I had these easily available. AMD fails to compile (so it follows the spec) but nVidia works (so same case as Mesa). This confirms your guess: different drivers are doing different things. Is this enough to file a spec bug? I imagine that the result on glslang won't change anything, but I can try to install it and test there too if you think that's interesting anyway. Iago _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev