xref: /xsrc/external/mit/MesaLib/dist/src/mesa/main/depth.c

/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 1999-2007  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.
 */


#include "glheader.h"

#include "context.h"
#include "depth.h"
#include "enums.h"
#include "macros.h"
#include "mtypes.h"
#include "state.h"


/**********************************************************************/
/*****                          API Functions                     *****/
/**********************************************************************/



void GLAPIENTRY
_mesa_ClearDepth( GLclampd depth )
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glClearDepth(%f)\n", depth);

   ctx->PopAttribState |= GL_DEPTH_BUFFER_BIT;
   ctx->Depth.Clear = CLAMP( depth, 0.0, 1.0 );
}


void GLAPIENTRY
_mesa_ClearDepthf( GLclampf depth )
{
   _mesa_ClearDepth(depth);
}


static ALWAYS_INLINE void
depth_func(struct gl_context *ctx, GLenum func, bool no_error)
{
   if (ctx->Depth.Func == func)
      return;

   if (!no_error) {
      switch (func) {
      case GL_LESS:    /* (default) pass if incoming z < stored z */
      case GL_GEQUAL:
      case GL_LEQUAL:
      case GL_GREATER:
      case GL_NOTEQUAL:
      case GL_EQUAL:
      case GL_ALWAYS:
      case GL_NEVER:
         break;
      default:
         _mesa_error(ctx, GL_INVALID_ENUM, "glDepth.Func");
         return;
      }
   }

   FLUSH_VERTICES(ctx, ctx->DriverFlags.NewDepth ? 0 : _NEW_DEPTH,
                  GL_DEPTH_BUFFER_BIT);
   ctx->NewDriverState |= ctx->DriverFlags.NewDepth;
   ctx->Depth.Func = func;
   _mesa_update_allow_draw_out_of_order(ctx);

   if (ctx->Driver.DepthFunc)
      ctx->Driver.DepthFunc(ctx, func);
}


void GLAPIENTRY
_mesa_DepthFunc_no_error(GLenum func)
{
   GET_CURRENT_CONTEXT(ctx);
   depth_func(ctx, func, true);
}


void GLAPIENTRY
_mesa_DepthFunc(GLenum func)
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glDepthFunc %s\n", _mesa_enum_to_string(func));

   depth_func(ctx, func, false);
}



void GLAPIENTRY
_mesa_DepthMask( GLboolean flag )
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glDepthMask %d\n", flag);

   /*
    * GL_TRUE indicates depth buffer writing is enabled (default)
    * GL_FALSE indicates depth buffer writing is disabled
    */
   if (ctx->Depth.Mask == flag)
      return;

   FLUSH_VERTICES(ctx, ctx->DriverFlags.NewDepth ? 0 : _NEW_DEPTH,
                  GL_DEPTH_BUFFER_BIT);
   ctx->NewDriverState |= ctx->DriverFlags.NewDepth;
   ctx->Depth.Mask = flag;
   _mesa_update_allow_draw_out_of_order(ctx);

   if (ctx->Driver.DepthMask)
      ctx->Driver.DepthMask( ctx, flag );
}



/**
 * Specified by the GL_EXT_depth_bounds_test extension.
 */
void GLAPIENTRY
_mesa_DepthBoundsEXT( GLclampd zmin, GLclampd zmax )
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glDepthBounds(%f, %f)\n", zmin, zmax);

   if (zmin > zmax) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glDepthBoundsEXT(zmin > zmax)");
      return;
   }

   zmin = SATURATE(zmin);
   zmax = SATURATE(zmax);

   if (ctx->Depth.BoundsMin == zmin && ctx->Depth.BoundsMax == zmax)
      return;

   FLUSH_VERTICES(ctx, ctx->DriverFlags.NewDepth ? 0 : _NEW_DEPTH,
                  GL_DEPTH_BUFFER_BIT);
   ctx->NewDriverState |= ctx->DriverFlags.NewDepth;
   ctx->Depth.BoundsMin = zmin;
   ctx->Depth.BoundsMax = zmax;
}


/**********************************************************************/
/*****                      Initialization                        *****/
/**********************************************************************/


/**
 * Initialize the depth buffer attribute group in the given context.
 */
void
_mesa_init_depth(struct gl_context *ctx)
{
   ctx->Depth.Test = GL_FALSE;
   ctx->Depth.Clear = 1.0;
   ctx->Depth.Func = GL_LESS;
   ctx->Depth.Mask = GL_TRUE;
}