blend.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/**
 * \file blend.c
 * Blending operations.
 */

/*
 * Mesa 3-D graphics library
 * Version:  6.5.1
 *
 * 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
 * BRIAN PAUL 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.
 */



#include "glheader.h"
#include "blend.h"
#include "colormac.h"
#include "context.h"
#include "enums.h"
#include "macros.h"
#include "mtypes.h"


/**
 * Specify the blending operation.
 *
 * \param sfactor source factor operator.
 * \param dfactor destination factor operator.
 *
 * \sa glBlendFunc, glBlendFuncSeparateEXT
 *
 * Swizzles the inputs and calls \c glBlendFuncSeparateEXT.  This is done
 * using the \c CurrentDispatch table in the context, so this same function
 * can be used while compiling display lists.  Therefore, there is no need
 * for the display list code to save and restore this function.
 */
void GLAPIENTRY
_mesa_BlendFunc( GLenum sfactor, GLenum dfactor )
{
   GET_CURRENT_CONTEXT(ctx);

   (*ctx->CurrentDispatch->BlendFuncSeparateEXT)( sfactor, dfactor,
						  sfactor, dfactor );
}


/**
 * Process GL_EXT_blend_func_separate().
 *
 * \param sfactorRGB RGB source factor operator.
 * \param dfactorRGB RGB destination factor operator.
 * \param sfactorA alpha source factor operator.
 * \param dfactorA alpha destination factor operator.
 *
 * Verifies the parameters and updates gl_colorbuffer_attrib.
 * On a change, flush the vertices and notify the driver via
 * dd_function_table::BlendFuncSeparate.
 */
void GLAPIENTRY
_mesa_BlendFuncSeparateEXT( GLenum sfactorRGB, GLenum dfactorRGB,
                            GLenum sfactorA, GLenum dfactorA )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
      _mesa_debug(ctx, "glBlendFuncSeparate %s %s %s %s\n",
                  _mesa_lookup_enum_by_nr(sfactorRGB),
                  _mesa_lookup_enum_by_nr(dfactorRGB),
                  _mesa_lookup_enum_by_nr(sfactorA),
                  _mesa_lookup_enum_by_nr(dfactorA));

   switch (sfactorRGB) {
      case GL_SRC_COLOR:
      case GL_ONE_MINUS_SRC_COLOR:
         if (!ctx->Extensions.NV_blend_square) {
            _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (sfactorRGB)");
            return;
         }
         /* fall-through */
      case GL_ZERO:
      case GL_ONE:
      case GL_DST_COLOR:
      case GL_ONE_MINUS_DST_COLOR:
      case GL_SRC_ALPHA:
      case GL_ONE_MINUS_SRC_ALPHA:
      case GL_DST_ALPHA:
      case GL_ONE_MINUS_DST_ALPHA:
      case GL_SRC_ALPHA_SATURATE:
      case GL_CONSTANT_COLOR:
      case GL_ONE_MINUS_CONSTANT_COLOR:
      case GL_CONSTANT_ALPHA:
      case GL_ONE_MINUS_CONSTANT_ALPHA:
         break;
      default:
         _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (sfactorRGB)");
         return;
   }

   switch (dfactorRGB) {
      case GL_DST_COLOR:
      case GL_ONE_MINUS_DST_COLOR:
         if (!ctx->Extensions.NV_blend_square) {
            _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (dfactorRGB)");
            return;
         }
         /* fall-through */
      case GL_ZERO:
      case GL_ONE:
      case GL_SRC_COLOR:
      case GL_ONE_MINUS_SRC_COLOR:
      case GL_SRC_ALPHA:
      case GL_ONE_MINUS_SRC_ALPHA:
      case GL_DST_ALPHA:
      case GL_ONE_MINUS_DST_ALPHA:
      case GL_CONSTANT_COLOR:
      case GL_ONE_MINUS_CONSTANT_COLOR:
      case GL_CONSTANT_ALPHA:
      case GL_ONE_MINUS_CONSTANT_ALPHA:
         break;
      default:
         _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (dfactorRGB)");
         return;
   }

   switch (sfactorA) {
      case GL_SRC_COLOR:
      case GL_ONE_MINUS_SRC_COLOR:
         if (!ctx->Extensions.NV_blend_square) {
            _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (sfactorA)");
            return;
         }
         /* fall-through */
      case GL_ZERO:
      case GL_ONE:
      case GL_DST_COLOR:
      case GL_ONE_MINUS_DST_COLOR:
      case GL_SRC_ALPHA:
      case GL_ONE_MINUS_SRC_ALPHA:
      case GL_DST_ALPHA:
      case GL_ONE_MINUS_DST_ALPHA:
      case GL_SRC_ALPHA_SATURATE:
      case GL_CONSTANT_COLOR:
      case GL_ONE_MINUS_CONSTANT_COLOR:
      case GL_CONSTANT_ALPHA:
      case GL_ONE_MINUS_CONSTANT_ALPHA:
         break;
      default:
         _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (sfactorA)");
         return;
   }

   switch (dfactorA) {
      case GL_DST_COLOR:
      case GL_ONE_MINUS_DST_COLOR:
         if (!ctx->Extensions.NV_blend_square) {
            _mesa_error(ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (dfactorA)");
            return;
         }
         /* fall-through */
      case GL_ZERO:
      case GL_ONE:
      case GL_SRC_COLOR:
      case GL_ONE_MINUS_SRC_COLOR:
      case GL_SRC_ALPHA:
      case GL_ONE_MINUS_SRC_ALPHA:
      case GL_DST_ALPHA:
      case GL_ONE_MINUS_DST_ALPHA:
      case GL_CONSTANT_COLOR:
      case GL_ONE_MINUS_CONSTANT_COLOR:
      case GL_CONSTANT_ALPHA:
      case GL_ONE_MINUS_CONSTANT_ALPHA:
         break;
      default:
         _mesa_error( ctx, GL_INVALID_ENUM, "glBlendFunc or glBlendFuncSeparate (dfactorA)" );
         return;
   }

   if (ctx->Color.BlendSrcRGB == sfactorRGB &&
       ctx->Color.BlendDstRGB == dfactorRGB &&
       ctx->Color.BlendSrcA == sfactorA &&
       ctx->Color.BlendDstA == dfactorA)
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);

   ctx->Color.BlendSrcRGB = sfactorRGB;
   ctx->Color.BlendDstRGB = dfactorRGB;
   ctx->Color.BlendSrcA = sfactorA;
   ctx->Color.BlendDstA = dfactorA;

   if (ctx->Driver.BlendFuncSeparate) {
      (*ctx->Driver.BlendFuncSeparate)( ctx, sfactorRGB, dfactorRGB,
					sfactorA, dfactorA );
   }
}


#if _HAVE_FULL_GL

static GLboolean
_mesa_validate_blend_equation( GLcontext *ctx,
			       GLenum mode, GLboolean is_separate )
{
   switch (mode) {
      case GL_FUNC_ADD:
         break;
      case GL_MIN:
      case GL_MAX:
         if (!ctx->Extensions.EXT_blend_minmax &&
             !ctx->Extensions.ARB_imaging) {
            return GL_FALSE;
         }
         break;
      /* glBlendEquationSeparate cannot take GL_LOGIC_OP as a parameter.
       */
      case GL_LOGIC_OP:
         if (!ctx->Extensions.EXT_blend_logic_op || is_separate) {
            return GL_FALSE;
         }
         break;
      case GL_FUNC_SUBTRACT:
      case GL_FUNC_REVERSE_SUBTRACT:
         if (!ctx->Extensions.EXT_blend_subtract &&
             !ctx->Extensions.ARB_imaging) {
            return GL_FALSE;
         }
         break;
      default:
         return GL_FALSE;
   }

   return GL_TRUE;
}


/* This is really an extension function! */
void GLAPIENTRY
_mesa_BlendEquation( GLenum mode )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
      _mesa_debug(ctx, "glBlendEquation %s\n",
                  _mesa_lookup_enum_by_nr(mode));

   if ( ! _mesa_validate_blend_equation( ctx, mode, GL_FALSE ) ) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquation");
      return;
   }

   if ( (ctx->Color.BlendEquationRGB == mode) &&
	(ctx->Color.BlendEquationA == mode) )
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);
   ctx->Color.BlendEquationRGB = mode;
   ctx->Color.BlendEquationA = mode;

   if (ctx->Driver.BlendEquationSeparate)
      (*ctx->Driver.BlendEquationSeparate)( ctx, mode, mode );
}


void GLAPIENTRY
_mesa_BlendEquationSeparateEXT( GLenum modeRGB, GLenum modeA )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
      _mesa_debug(ctx, "glBlendEquationSeparateEXT %s %s\n",
                  _mesa_lookup_enum_by_nr(modeRGB),
                  _mesa_lookup_enum_by_nr(modeA));

   if ( (modeRGB != modeA) && !ctx->Extensions.EXT_blend_equation_separate ) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
		  "glBlendEquationSeparateEXT not supported by driver");
      return;
   }

   if ( ! _mesa_validate_blend_equation( ctx, modeRGB, GL_TRUE ) ) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeRGB)");