mesa: Unconditionally enable floating-point textures

ARB_texture_float references US Patent #6,650,327 [1] which has a filing date
of June 16 1998.

According to [2], patents filed after 1995 expire 20 years from the filing
date, giving an expiration of June 17 2018.

[1] https://www.google.com/patents/US6650327
[2] https://en.wikipedia.org/wiki/Term_of_patent_in_the_United_States

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

configure.ac

@@ -763,21 +763,6 @@ esac
 
 AC_SUBST([LIB_EXT])
 
-dnl
-dnl potentially-infringing-but-nobody-knows-for-sure stuff
-dnl
-AC_ARG_ENABLE([texture-float],
-    [AS_HELP_STRING([--enable-texture-float],
-        [enable floating-point textures and renderbuffers @<:@default=disabled@:>@])],
-    [enable_texture_float="$enableval"],
-    [enable_texture_float=no]
-)
-if test "x$enable_texture_float" = xyes; then
-    AC_MSG_WARN([Floating-point textures enabled.])
-    AC_MSG_WARN([Please consult docs/patents.txt with your lawyer before building Mesa.])
-    DEFINES="$DEFINES -DTEXTURE_FLOAT_ENABLED"
-fi
-
 dnl
 dnl Arch/platform-specific settings
 dnl

docs/patents.txt

@@ -1,31 +0,0 @@
-ARB_texture_float:
-
-    Silicon Graphics, Inc. owns US Patent #6,650,327, issued November 18,
-    2003 [1].
-
-    SGI believes this patent contains necessary IP for graphics systems
-    implementing floating point rasterization and floating point
-    framebuffer capabilities described in ARB_texture_float extension, and
-    will discuss licensing on RAND terms, on an individual basis with
-    companies wishing to use this IP in the context of conformant OpenGL
-    implementations [2].
-
-    The source code to implement ARB_texture_float extension is included
-    and can be toggled on at compile time, for those who purchased a
-    license from SGI, or are in a country where the patent does not apply,
-    etc.
-
-    The software is provided "as is", without warranty of any kind, express
-    or implied, including but not limited to the warranties of
-    merchantability, fitness for a particular purpose and noninfringement.
-    In no event shall the authors or copyright holders be liable for any
-    claim, damages or other liability, whether in an action of contract,
-    tort or otherwise, arising from, out of or in connection with the
-    software or the use or other dealings in the software.
-
-    You should contact a lawyer or SGI's legal department if you want to
-    enable this extension.
-
-
-[1] https://patents.google.com/patent/US6650327B1
-[2] https://www.opengl.org/registry/specs/ARB/texture_float.txt

meson.build

@@ -60,10 +60,6 @@ with_tools = get_option('tools')
 if with_tools.contains('all')
   with_tools = ['freedreno', 'glsl', 'intel', 'nir', 'nouveau']
 endif
-if get_option('texture-float')
-  pre_args += '-DTEXTURE_FLOAT_ENABLED'
-  warning('Floating-point texture enabled. Please consult docs/patents.txt and your lawyer before building mesa.')
-endif
 
 dri_drivers_path = get_option('dri-drivers-path')
 if dri_drivers_path == ''

meson_options.txt

@@ -264,12 +264,6 @@ option(
   value : false,
   description : 'Build unit tests. Currently this will build *all* unit tests, which may build more than expected.'
 )
-option(
-  'texture-float',
-  type : 'boolean',
-  value : false,
-  description : 'Enable floating point textures and renderbuffers. This option may be patent encumbered, please read docs/patents.txt and consult with your lawyer before turning this on.'
-)
 option(
   'selinux',
   type : 'boolean',

scons/gallium.py

@@ -392,10 +392,6 @@ def generate(env):
         cppdefines += ['PIPE_SUBSYSTEM_WINDOWS_USER']
     if env['embedded']:
         cppdefines += ['PIPE_SUBSYSTEM_EMBEDDED']
-    if env['texture_float']:
-        print('warning: Floating-point textures enabled.')
-        print('warning: Please consult docs/patents.txt with your lawyer before building Mesa.')
-        cppdefines += ['TEXTURE_FLOAT_ENABLED']
     env.Append(CPPDEFINES = cppdefines)
 
     # C compiler options

src/gallium/auxiliary/util/u_format.c

@@ -242,16 +242,7 @@ util_format_is_supported(enum pipe_format format, unsigned bind)
       return FALSE;
    }
 
-#ifndef TEXTURE_FLOAT_ENABLED
-   if ((bind & PIPE_BIND_RENDER_TARGET) &&
-       format != PIPE_FORMAT_R9G9B9E5_FLOAT &&
-       format != PIPE_FORMAT_R11G11B10_FLOAT &&
-       util_format_is_float(format)) {
-      return FALSE;
-   }
-#else
    (void)bind;
-#endif
 
    return TRUE;
 }

src/mesa/main/extensions.c

@@ -129,9 +129,7 @@ _mesa_enable_sw_extensions(struct gl_context *ctx)
    ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
    ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
    ctx->Extensions.ARB_texture_filter_anisotropic = GL_TRUE;
-#ifdef TEXTURE_FLOAT_ENABLED
    ctx->Extensions.ARB_texture_float = GL_TRUE;
-#endif
    ctx->Extensions.ARB_texture_mirror_clamp_to_edge = GL_TRUE;
    ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
    ctx->Extensions.ARB_texture_rg = GL_TRUE;