[Piglit] [PATCH] fbo-blending-formats: Correct precision of signed normalized types.

[Jose Fonseca]

Good catch. Thanks for all your reviews Brian!

Jose

----- Original Message -----
> On 12/06/2012 06:21 AM, jfonseca at vmware.com wrote:
> > From: José Fonseca<jfonseca at vmware.com>
> >
> > Signed types have less precision due to the sign bit.
> >
> > Without this it is impossible to devise an efficient way of lerping
> > signed normalized types that makes this test happy -- it would
> > require
> > 32bit float/int multiply and divides to get exact results.
> > ---
> >   tests/fbo/fbo-blending-formats.c |   46
> >   ++++++++++++++++++++++++++++----------
> >   1 file changed, 34 insertions(+), 12 deletions(-)
> >
> > diff --git a/tests/fbo/fbo-blending-formats.c
> > b/tests/fbo/fbo-blending-formats.c
> > index 3271429..7bc6686 100644
> > --- a/tests/fbo/fbo-blending-formats.c
> > +++ b/tests/fbo/fbo-blending-formats.c
> > @@ -61,6 +61,22 @@ static void blend(const float *rect, const float
> > *src, const float *dst, const f
> >   						  a>= 0.333 ? 0.333f : 0.0f) : \
> >   	 (a))
> >
> > +static int
> > +get_texture_bits(GLenum target, GLenum size_enum, GLenum
> > type_enum) {
> 
> Opening { on next line.
> 
> 
> > +	GLint size = 0;
> > +	glGetTexLevelParameteriv(target, 0, size_enum,&size);
> > +	if (!size) {
> > +		return size;
> > +	}
> > +	GLint type = GL_NONE;
> 
> Let's move this decl before the code for MSVC.
> 
> 
> > +	glGetTexLevelParameteriv(target, 0, type_enum,&type);
> > +	if (type == GL_SIGNED_NORMALIZED) {
> > +		/* One bit is lost for the sign */
> > +		size -= 1;
> > +	}
> > +	return size;
> > +}
> > +
> >   static enum piglit_result test_format(const struct format_desc
> >   *format)
> >   {
> >   	GLboolean pass = GL_TRUE;
> > @@ -128,18 +144,24 @@ static enum piglit_result test_format(const
> > struct format_desc *format)
> >   		     piglit_width, piglit_height, 0,
> >   		     GL_RGBA, GL_FLOAT, NULL);
> >
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_LUMINANCE_SIZE,&l);
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_ALPHA_SIZE,&a);
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_INTENSITY_SIZE,&i);
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_RED_SIZE,&r);
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_GREEN_SIZE,&g);
> > -	glGetTexLevelParameteriv(GL_TEXTURE_2D, 0,
> > -				 GL_TEXTURE_BLUE_SIZE,&b);
> > +	l = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_LUMINANCE_SIZE,
> > +			     GL_TEXTURE_LUMINANCE_TYPE);
> > +	a = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_ALPHA_SIZE,
> > +			     GL_TEXTURE_ALPHA_TYPE);
> > +	i = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_INTENSITY_SIZE,
> > +			     GL_TEXTURE_INTENSITY_TYPE);
> > +	r = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_RED_SIZE,
> > +			     GL_TEXTURE_RED_TYPE);
> > +	g = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_GREEN_SIZE,
> > +			     GL_TEXTURE_GREEN_TYPE);
> > +	b = get_texture_bits(GL_TEXTURE_2D,
> > +			     GL_TEXTURE_BLUE_SIZE,
> > +			     GL_TEXTURE_BLUE_TYPE);
> >
> >   	/* Compute expected result colors when reading back from a
> >   	texture/FBO */
> >           if (i) {
> 
> 
> Reviewed-by: Brian Paul <brianp at vmware.com>
>