text: /**
   * \file blend.h
   * Blending functions operations.
   */
  
  /*
   * Mesa 3-D graphics library
   *
   * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * 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.
   */
  
  
  
  #ifndef BLEND_H
  #define BLEND_H
  
  
  #include "glheader.h"
  #include "context.h"
  #include "formats.h"
  #include "extensions.h"
  
  #include "state_tracker/st_context.h"
  
  struct gl_context;
  struct gl_framebuffer;
  
  extern GLboolean
  _mesa_get_clamp_fragment_color(const struct gl_context *ctx,
                                 const struct gl_framebuffer *drawFb);
  
  extern GLboolean
  _mesa_get_clamp_vertex_color(const struct gl_context *ctx,
                               const struct gl_framebuffer *drawFb);
  
  extern GLboolean
  _mesa_get_clamp_read_color(const struct gl_context *ctx,
                             const struct gl_framebuffer *readFb);
  
  extern void
  _mesa_update_clamp_fragment_color(struct gl_context *ctx,
                                    const struct gl_framebuffer *drawFb);
  
  extern void
  _mesa_update_clamp_vertex_color(struct gl_context *ctx,
                                  const struct gl_framebuffer *drawFb);
  
  extern void  
  _mesa_init_color( struct gl_context * ctx );
  
  
  static inline enum gl_advanced_blend_mode
  _mesa_get_advanced_blend_sh_constant(GLbitfield blend_enabled,
                                       enum gl_advanced_blend_mode mode)
  {
     return blend_enabled ? mode : BLEND_NONE;
  }
  
  static inline bool
  _mesa_advanded_blend_sh_constant_changed(struct gl_context *ctx,
                                           GLbitfield new_blend_enabled,
                                           enum gl_advanced_blend_mode new_mode)
  {
     return _mesa_get_advanced_blend_sh_constant(new_blend_enabled, new_mode) !=
            _mesa_get_advanced_blend_sh_constant(ctx->Color.BlendEnabled,
                                                 ctx->Color._AdvancedBlendMode);
  }
  
  static inline void
  _mesa_flush_vertices_for_blend_state(struct gl_context *ctx)
  {
     FLUSH_VERTICES(ctx, 0, GL_COLOR_BUFFER_BIT);
     ctx->NewDriverState |= ST_NEW_BLEND;
  }
  
  static inline void
  _mesa_flush_vertices_for_blend_adv(struct gl_context *ctx,
                                     GLbitfield new_blend_enabled,
                                     enum gl_advanced_blend_mode new_mode)
  {
     /* The advanced blend mode needs _NEW_COLOR to update the state constant. */
     if (_mesa_has_KHR_blend_equation_advanced(ctx) &&
         _mesa_advanded_blend_sh_constant_changed(ctx, new_blend_enabled,
                                                  new_mode)) {
        FLUSH_VERTICES(ctx, _NEW_COLOR, GL_COLOR_BUFFER_BIT);
        ctx->NewDriverState |= ST_NEW_BLEND;
        return;
     }
     _mesa_flush_vertices_for_blend_state(ctx);
  }
  
  static inline GLbitfield
  _mesa_replicate_colormask(GLbitfield mask0, unsigned num_buffers)
  {
     GLbitfield mask = mask0;
  
     for (unsigned i = 1; i < num_buffers; i++)
        mask |= mask0 << (i * 4);
     return mask;
  }
  
  #endif
  