blend.c

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

      return;
   }

   if ( ! _mesa_validate_blend_equation( ctx, modeA, GL_TRUE ) ) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeA)");
      return;
   }


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

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

   if (ctx->Driver.BlendEquationSeparate)
      (*ctx->Driver.BlendEquationSeparate)( ctx, modeRGB, modeA );
}
#endif


/**
 * Set the blending color.
 *
 * \param red red color component.
 * \param green green color component.
 * \param blue blue color component.
 * \param alpha alpha color component.
 *
 * \sa glBlendColor().
 *
 * Clamps the parameters and updates gl_colorbuffer_attrib::BlendColor.  On a
 * change, flushes the vertices and notifies the driver via
 * dd_function_table::BlendColor callback.
 */
void GLAPIENTRY
_mesa_BlendColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
{
   GLfloat tmp[4];
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   tmp[0] = CLAMP( red,   0.0F, 1.0F );
   tmp[1] = CLAMP( green, 0.0F, 1.0F );
   tmp[2] = CLAMP( blue,  0.0F, 1.0F );
   tmp[3] = CLAMP( alpha, 0.0F, 1.0F );

   if (TEST_EQ_4V(tmp, ctx->Color.BlendColor))
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);
   COPY_4FV( ctx->Color.BlendColor, tmp );

   if (ctx->Driver.BlendColor)
      (*ctx->Driver.BlendColor)(ctx, tmp);
}


/**
 * Specify the alpha test function.
 *
 * \param func alpha comparison function.
 * \param ref reference value.
 *
 * Verifies the parameters and updates gl_colorbuffer_attrib. 
 * On a change, flushes the vertices and notifies the driver via
 * dd_function_table::AlphaFunc callback.
 */
void GLAPIENTRY
_mesa_AlphaFunc( GLenum func, GLclampf ref )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   switch (func) {
   case GL_NEVER:
   case GL_LESS:
   case GL_EQUAL:
   case GL_LEQUAL:
   case GL_GREATER:
   case GL_NOTEQUAL:
   case GL_GEQUAL:
   case GL_ALWAYS:
      ref = CLAMP(ref, 0.0F, 1.0F);

      if (ctx->Color.AlphaFunc == func && ctx->Color.AlphaRef == ref)
         return; /* no change */

      FLUSH_VERTICES(ctx, _NEW_COLOR);
      ctx->Color.AlphaFunc = func;
      ctx->Color.AlphaRef = ref;

      if (ctx->Driver.AlphaFunc)
         ctx->Driver.AlphaFunc(ctx, func, ref);
      return;

   default:
      _mesa_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
      return;
   }
}


/**
 * Specify a logic pixel operation for color index rendering.
 *
 * \param opcode operation.
 *
 * Verifies that \p opcode is a valid enum and updates
gl_colorbuffer_attrib::LogicOp.
 * On a change, flushes the vertices and notifies the driver via the
 * dd_function_table::LogicOpcode callback.
 */
void GLAPIENTRY
_mesa_LogicOp( GLenum opcode )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   switch (opcode) {
      case GL_CLEAR:
      case GL_SET:
      case GL_COPY:
      case GL_COPY_INVERTED:
      case GL_NOOP:
      case GL_INVERT:
      case GL_AND:
      case GL_NAND:
      case GL_OR:
      case GL_NOR:
      case GL_XOR:
      case GL_EQUIV:
      case GL_AND_REVERSE:
      case GL_AND_INVERTED:
      case GL_OR_REVERSE:
      case GL_OR_INVERTED:
	 break;
      default:
         _mesa_error( ctx, GL_INVALID_ENUM, "glLogicOp" );
	 return;
   }

   if (ctx->Color.LogicOp == opcode)
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);
   ctx->Color.LogicOp = opcode;

   if (ctx->Driver.LogicOpcode)
      ctx->Driver.LogicOpcode( ctx, opcode );
}

#if _HAVE_FULL_GL
void GLAPIENTRY
_mesa_IndexMask( GLuint mask )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (ctx->Color.IndexMask == mask)
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);
   ctx->Color.IndexMask = mask;

   if (ctx->Driver.IndexMask)
      ctx->Driver.IndexMask( ctx, mask );
}
#endif


/**
 * Enable or disable writing of frame buffer color components.
 *
 * \param red whether to mask writing of the red color component.
 * \param green whether to mask writing of the green color component.
 * \param blue whether to mask writing of the blue color component.
 * \param alpha whether to mask writing of the alpha color component.
 *
 * \sa glColorMask().
 *
 * Sets the appropriate value of gl_colorbuffer_attrib::ColorMask.  On a
 * change, flushes the vertices and notifies the driver via the
 * dd_function_table::ColorMask callback.
 */
void GLAPIENTRY
_mesa_ColorMask( GLboolean red, GLboolean green,
                 GLboolean blue, GLboolean alpha )
{
   GET_CURRENT_CONTEXT(ctx);
   GLubyte tmp[4];
   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glColorMask %d %d %d %d\n", red, green, blue, alpha);

   /* Shouldn't have any information about channel depth in core mesa
    * -- should probably store these as the native booleans:
    */
   tmp[RCOMP] = red    ? 0xff : 0x0;
   tmp[GCOMP] = green  ? 0xff : 0x0;
   tmp[BCOMP] = blue   ? 0xff : 0x0;
   tmp[ACOMP] = alpha  ? 0xff : 0x0;

   if (TEST_EQ_4UBV(tmp, ctx->Color.ColorMask))
      return;

   FLUSH_VERTICES(ctx, _NEW_COLOR);
   COPY_4UBV(ctx->Color.ColorMask, tmp);

   if (ctx->Driver.ColorMask)
      ctx->Driver.ColorMask( ctx, red, green, blue, alpha );
}


extern void GLAPIENTRY
_mesa_ClampColorARB(GLenum target, GLenum clamp)
{
   GET_CURRENT_CONTEXT(ctx);

   ASSERT_OUTSIDE_BEGIN_END(ctx);

   if (clamp != GL_TRUE && clamp != GL_FALSE && clamp != GL_FIXED_ONLY_ARB) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glClampColorARB(clamp)");
      return;
   }

   switch (target) {
   case GL_CLAMP_VERTEX_COLOR_ARB:
      ctx->Light.ClampVertexColor = clamp;
      break;
   case GL_CLAMP_FRAGMENT_COLOR_ARB:
      ctx->Color.ClampFragmentColor = clamp;
      break;
   case GL_CLAMP_READ_COLOR_ARB:
      ctx->Color.ClampReadColor = clamp;
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "glClampColorARB(target)");
      return;
   }
}




/**********************************************************************/
/** \name Initialization */
/*@{*/

/**
 * Initialization of the context's Color attribute group.
 *
 * \param ctx GL context.
 *
 * Initializes the related fields in the context color attribute group,
 * __GLcontextRec::Color.
 */
void _mesa_init_color( GLcontext * ctx )
{
   /* Color buffer group */
   ctx->Color.IndexMask = ~0u;
   ctx->Color.ColorMask[0] = 0xff;
   ctx->Color.ColorMask[1] = 0xff;
   ctx->Color.ColorMask[2] = 0xff;
   ctx->Color.ColorMask[3] = 0xff;
   ctx->Color.ClearIndex = 0;
   ASSIGN_4V( ctx->Color.ClearColor, 0, 0, 0, 0 );
   ctx->Color.AlphaEnabled = GL_FALSE;
   ctx->Color.AlphaFunc = GL_ALWAYS;
   ctx->Color.AlphaRef = 0;
   ctx->Color.BlendEnabled = GL_FALSE;
   ctx->Color.BlendSrcRGB = GL_ONE;
   ctx->Color.BlendDstRGB = GL_ZERO;
   ctx->Color.BlendSrcA = GL_ONE;
   ctx->Color.BlendDstA = GL_ZERO;
   ctx->Color.BlendEquationRGB = GL_FUNC_ADD;
   ctx->Color.BlendEquationA = GL_FUNC_ADD;
   ASSIGN_4V( ctx->Color.BlendColor, 0.0, 0.0, 0.0, 0.0 );
   ctx->Color.IndexLogicOpEnabled = GL_FALSE;
   ctx->Color.ColorLogicOpEnabled = GL_FALSE;
   ctx->Color._LogicOpEnabled = GL_FALSE;
   ctx->Color.LogicOp = GL_COPY;
   ctx->Color.DitherFlag = GL_TRUE;

   if (ctx->Visual.doubleBufferMode) {
      ctx->Color.DrawBuffer[0] = GL_BACK;
   }
   else {
      ctx->Color.DrawBuffer[0] = GL_FRONT;
   }

   ctx->Color.ClampFragmentColor = GL_FIXED_ONLY_ARB;
   ctx->Color.ClampReadColor = GL_FIXED_ONLY_ARB;
}

/*@}*/