s_context.c

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

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 *
 * Copyright (C) 1999-2008  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.
 *
 * Authors:
 *    Keith Whitwell <[e-mail]>
 *    Brian Paul
 */

#include "imports.h"
#include "bufferobj.h"
#include "context.h"
#include "colormac.h"
#include "mtypes.h"
#include "teximage.h"
#include "swrast.h"
#include "shader/prog_parameter.h"
#include "shader/prog_statevars.h"
#include "s_blend.h"
#include "s_context.h"
#include "s_lines.h"
#include "s_points.h"
#include "s_span.h"
#include "s_triangle.h"
#include "s_texfilter.h"


/**
 * Recompute the value of swrast->_RasterMask, etc. according to
 * the current context.  The _RasterMask field can be easily tested by
 * drivers to determine certain basic GL state (does the primitive need
 * stenciling, logic-op, fog, etc?).
 */
static void
_swrast_update_rasterflags( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   GLbitfield rasterMask = 0;

   if (ctx->Color.AlphaEnabled)           rasterMask |= ALPHATEST_BIT;
   if (ctx->Color.BlendEnabled)           rasterMask |= BLEND_BIT;
   if (ctx->Depth.Test)                   rasterMask |= DEPTH_BIT;
   if (swrast->_FogEnabled)               rasterMask |= FOG_BIT;
   if (ctx->Scissor.Enabled)              rasterMask |= CLIP_BIT;
   if (ctx->Stencil.Enabled)              rasterMask |= STENCIL_BIT;
   if (ctx->Visual.rgbMode) {
      const GLuint colorMask = *((GLuint *) &ctx->Color.ColorMask);
      if (colorMask != 0xffffffff)        rasterMask |= MASKING_BIT;
      if (ctx->Color._LogicOpEnabled)     rasterMask |= LOGIC_OP_BIT;
      if (ctx->Texture._EnabledUnits)     rasterMask |= TEXTURE_BIT;
   }
   else {
      if (ctx->Color.IndexMask != 0xffffffff) rasterMask |= MASKING_BIT;
      if (ctx->Color.IndexLogicOpEnabled)     rasterMask |= LOGIC_OP_BIT;
   }

   if (   ctx->Viewport.X < 0
       || ctx->Viewport.X + ctx->Viewport.Width > (GLint) ctx->DrawBuffer->Width
       || ctx->Viewport.Y < 0
       || ctx->Viewport.Y + ctx->Viewport.Height > (GLint) ctx->DrawBuffer->Height) {
      rasterMask |= CLIP_BIT;
   }

   if (ctx->Query.CurrentOcclusionObject)
      rasterMask |= OCCLUSION_BIT;


   /* If we're not drawing to exactly one color buffer set the
    * MULTI_DRAW_BIT flag.  Also set it if we're drawing to no
    * buffers or the RGBA or CI mask disables all writes.
    */
   if (ctx->DrawBuffer->_NumColorDrawBuffers != 1) {
      /* more than one color buffer designated for writing (or zero buffers) */
      rasterMask |= MULTI_DRAW_BIT;
   }
   else if (ctx->Visual.rgbMode && *((GLuint *) ctx->Color.ColorMask) == 0) {
      rasterMask |= MULTI_DRAW_BIT; /* all RGBA channels disabled */
   }
   else if (!ctx->Visual.rgbMode && ctx->Color.IndexMask==0) {
      rasterMask |= MULTI_DRAW_BIT; /* all color index bits disabled */
   }

   if (ctx->FragmentProgram._Current) {
      rasterMask |= FRAGPROG_BIT;
   }

   if (ctx->ATIFragmentShader._Enabled) {
      rasterMask |= ATIFRAGSHADER_BIT;
   }

#if CHAN_TYPE == GL_FLOAT
   if (ctx->Color.ClampFragmentColor == GL_TRUE) {
      rasterMask |= CLAMPING_BIT;
   }
#endif

   SWRAST_CONTEXT(ctx)->_RasterMask = rasterMask;
}


/**
 * Examine polygon cull state to compute the _BackfaceCullSign field.
 * _BackfaceCullSign will be 0 if no culling, -1 if culling back-faces,
 * and 1 if culling front-faces.  The Polygon FrontFace state also
 * factors in.
 */
static void
_swrast_update_polygon( GLcontext *ctx )
{
   GLfloat backface_sign;

   if (ctx->Polygon.CullFlag) {
      switch (ctx->Polygon.CullFaceMode) {
      case GL_BACK:
         backface_sign = -1.0;
	 break;
      case GL_FRONT:
         backface_sign = 1.0;
	 break;
      case GL_FRONT_AND_BACK:
         /* fallthrough */
      default:
	 backface_sign = 0.0;
      }
   }
   else {
      backface_sign = 0.0;
   }

   SWRAST_CONTEXT(ctx)->_BackfaceCullSign = backface_sign;

   /* This is for front/back-face determination, but not for culling */
   SWRAST_CONTEXT(ctx)->_BackfaceSign
      = (ctx->Polygon.FrontFace == GL_CW) ? -1.0 : 1.0;
}



/**
 * Update the _PreferPixelFog field to indicate if we need to compute
 * fog blend factors (from the fog coords) per-fragment.
 */
static void
_swrast_update_fog_hint( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   swrast->_PreferPixelFog = (!swrast->AllowVertexFog ||
                              ctx->FragmentProgram._Current ||
			      (ctx->Hint.Fog == GL_NICEST &&
			       swrast->AllowPixelFog));
}



/**
 * Update the swrast->_AnyTextureCombine flag.
 */
static void
_swrast_update_texture_env( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   GLuint i;
   swrast->_AnyTextureCombine = GL_FALSE;
   for (i = 0; i < ctx->Const.MaxTextureUnits; i++) {
      if (ctx->Texture.Unit[i].EnvMode == GL_COMBINE_EXT ||
          ctx->Texture.Unit[i].EnvMode == GL_COMBINE4_NV) {
         swrast->_AnyTextureCombine = GL_TRUE;
         return;
      }
   }
}


/**
 * Determine if we can defer texturing/shading until after Z/stencil
 * testing.  This potentially allows us to skip texturing/shading for
 * lots of fragments.
 */
static void
_swrast_update_deferred_texture(GLcontext *ctx)
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   if (ctx->Color.AlphaEnabled) {
      /* alpha test depends on post-texture/shader colors */
      swrast->_DeferredTexture = GL_FALSE;
   }
   else {
      const struct gl_fragment_program *fprog
         = ctx->FragmentProgram._Current;
      if (fprog && (fprog->Base.OutputsWritten & (1 << FRAG_RESULT_DEPR))) {
         /* Z comes from fragment program/shader */
         swrast->_DeferredTexture = GL_FALSE;
      }
      else if (ctx->Query.CurrentOcclusionObject) {
         /* occlusion query depends on shader discard/kill results */
         swrast->_DeferredTexture = GL_FALSE;
      }
      else {
         swrast->_DeferredTexture = GL_TRUE;
      }
   }
}


/**
 * Update swrast->_FogColor and swrast->_FogEnable values.
 */
static void
_swrast_update_fog_state( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const struct gl_fragment_program *fp = ctx->FragmentProgram._Current;

   /* determine if fog is needed, and if so, which fog mode */
   swrast->_FogEnabled = GL_FALSE;
   if (fp && fp->Base.Target == GL_FRAGMENT_PROGRAM_ARB) {
      if (fp->FogOption != GL_NONE) {
         swrast->_FogEnabled = GL_TRUE;
         swrast->_FogMode = fp->FogOption;
      }
   }
   else if (ctx->Fog.Enabled) {
      swrast->_FogEnabled = GL_TRUE;
      swrast->_FogMode = ctx->Fog.Mode;
   }
}


/**
 * Update state for running fragment programs.  Basically, load the
 * program parameters with current state values.
 */
static void
_swrast_update_fragment_program(GLcontext *ctx, GLbitfield newState)
{
   const struct gl_fragment_program *fp = ctx->FragmentProgram._Current;
   if (fp) {
#if 0
      /* XXX Need a way to trigger the initial loading of parameters
       * even when there's no recent state changes.
       */
      if (fp->Base.Parameters->StateFlags & newState)
#endif
         _mesa_load_state_parameters(ctx, fp->Base.Parameters);
   }
}



#define _SWRAST_NEW_DERIVED (_SWRAST_NEW_RASTERMASK |	\
			     _NEW_TEXTURE |		\
			     _NEW_HINT |		\
			     _NEW_POLYGON )

/* State referenced by _swrast_choose_triangle, _swrast_choose_line.
 */
#define _SWRAST_NEW_TRIANGLE (_SWRAST_NEW_DERIVED |		\
			      _NEW_RENDERMODE|			\
                              _NEW_POLYGON|			\
                              _NEW_DEPTH|			\
                              _NEW_STENCIL|			\
                              _NEW_COLOR|			\
                              _NEW_TEXTURE|			\
                              _SWRAST_NEW_RASTERMASK|		\
                              _NEW_LIGHT|			\
                              _NEW_FOG |			\
			      _DD_NEW_SEPARATE_SPECULAR)

#define _SWRAST_NEW_LINE (_SWRAST_NEW_DERIVED |		\
			  _NEW_RENDERMODE|		\
                          _NEW_LINE|			\
                          _NEW_TEXTURE|			\
                          _NEW_LIGHT|			\
                          _NEW_FOG|			\
                          _NEW_DEPTH |			\
                          _DD_NEW_SEPARATE_SPECULAR)

#define _SWRAST_NEW_POINT (_SWRAST_NEW_DERIVED |	\
			   _NEW_RENDERMODE |		\
			   _NEW_POINT |			\
			   _NEW_TEXTURE |		\
			   _NEW_LIGHT |			\
			   _NEW_FOG |			\
                           _DD_NEW_SEPARATE_SPECULAR)

#define _SWRAST_NEW_TEXTURE_SAMPLE_FUNC _NEW_TEXTURE

#define _SWRAST_NEW_TEXTURE_ENV_MODE _NEW_TEXTURE

#define _SWRAST_NEW_BLEND_FUNC _NEW_COLOR



/**
 * Stub for swrast->Triangle to select a true triangle function
 * after a state change.
 */
static void
_swrast_validate_triangle( GLcontext *ctx,
			   const SWvertex *v0,
                           const SWvertex *v1,
                           const SWvertex *v2 )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   _swrast_validate_derived( ctx );
   swrast->choose_triangle( ctx );
   ASSERT(swrast->Triangle);

   if (ctx->Texture._EnabledUnits == 0
       && NEED_SECONDARY_COLOR(ctx)
       && !ctx->FragmentProgram._Current) {
      /* separate specular color, but no texture */
      swrast->SpecTriangle = swrast->Triangle;
      swrast->Triangle = _swrast_add_spec_terms_triangle;
   }

   swrast->Triangle( ctx, v0, v1, v2 );
}

/**
 * Called via swrast->Line.  Examine current GL state and choose a software
 * line routine.  Then call it.
 */
static void
_swrast_validate_line( GLcontext *ctx, const SWvertex *v0, const SWvertex *v1 )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   _swrast_validate_derived( ctx );
   swrast->choose_line( ctx );
   ASSERT(swrast->Line);

   if (ctx->Texture._EnabledUnits == 0
       && NEED_SECONDARY_COLOR(ctx)
       && !ctx->FragmentProgram._Current) {
      swrast->SpecLine = swrast->Line;
      swrast->Line = _swrast_add_spec_terms_line;
   }

   swrast->Line( ctx, v0, v1 );
}

/**
 * Called via swrast->Point.  Examine current GL state and choose a software
 * point routine.  Then call it.
 */
static void
_swrast_validate_point( GLcontext *ctx, const SWvertex *v0 )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   _swrast_validate_derived( ctx );
   swrast->choose_point( ctx );

   if (ctx->Texture._EnabledUnits == 0
       && NEED_SECONDARY_COLOR(ctx)
       && !ctx->FragmentProgram._Current) {
      swrast->SpecPoint = swrast->Point;
      swrast->Point = _swrast_add_spec_terms_point;
   }

   swrast->Point( ctx, v0 );
}


/**
 * Called via swrast->BlendFunc.  Examine GL state to choose a blending
 * function, then call it.
 */
static void _ASMAPI
_swrast_validate_blend_func(GLcontext *ctx, GLuint n, const GLubyte mask[],
                            GLvoid *src, const GLvoid *dst,
                            GLenum chanType )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   _swrast_validate_derived( ctx ); /* why is this needed? */
   _swrast_choose_blend_func( ctx, chanType );

   swrast->BlendFunc( ctx, n, mask, src, dst, chanType );
}


/**
 * Make sure we have texture image data for all the textures we may need
 * for subsequent rendering.
 */
static void
_swrast_validate_texture_images(GLcontext *ctx)
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   GLuint u;

   if (!swrast->ValidateTextureImage || !ctx->Texture._EnabledUnits) {
      /* no textures enabled, or no way to validate images! */
      return;
   }

   for (u = 0; u < ctx->Const.MaxTextureImageUnits; u++) {
      if (ctx->Texture.Unit[u]._ReallyEnabled) {
         struct gl_texture_object *texObj = ctx->Texture.Unit[u]._Current;
         ASSERT(texObj);
         if (texObj) {
            GLuint numFaces = (texObj->Target == GL_TEXTURE_CUBE_MAP) ? 6 : 1;
            GLuint face;
            for (face = 0; face < numFaces; face++) {
               GLint lvl;
               for (lvl = texObj->BaseLevel; lvl <= texObj->_MaxLevel; lvl++) {
                  struct gl_texture_image *texImg = texObj->Image[face][lvl];
                  if (texImg && !texImg->Data) {
                     swrast->ValidateTextureImage(ctx, texObj, face, lvl);
                     ASSERT(texObj->Image[face][lvl]->Data);
                  }
               }
            }
         }
      }
   }
}


/**
 * Free the texture image data attached to all currently enabled
 * textures.  Meant to be called by device drivers when transitioning
 * from software to hardware rendering.
 */
void
_swrast_eject_texture_images(GLcontext *ctx)
{
   GLuint u;

   if (!ctx->Texture._EnabledUnits) {
      /* no textures enabled */
      return;
   }

   for (u = 0; u < ctx->Const.MaxTextureImageUnits; u++) {
      if (ctx->Texture.Unit[u]._ReallyEnabled) {
         struct gl_texture_object *texObj = ctx->Texture.Unit[u]._Current;
         ASSERT(texObj);
         if (texObj) {
            GLuint numFaces = (texObj->Target == GL_TEXTURE_CUBE_MAP) ? 6 : 1;
            GLuint face;
            for (face = 0; face < numFaces; face++) {
               GLint lvl;
               for (lvl = texObj->BaseLevel; lvl <= texObj->_MaxLevel; lvl++) {
                  struct gl_texture_image *texImg = texObj->Image[face][lvl];
                  if (texImg && texImg->Data) {
                     _mesa_free_texmemory(texImg->Data);
                     texImg->Data = NULL;
                  }
               }
            }