/*
 * 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.
 */

/**
 * \file vbo_context.h
 * \brief VBO builder module datatypes and definitions.
 * \author Keith Whitwell
 */


/**
 * \mainpage The VBO builder module
 *
 * This module hooks into the GL dispatch table and catches all vertex
 * building and drawing commands, such as glVertex3f, glBegin and
 * glDrawArrays.  The module stores all incoming vertex data as arrays
 * in GL vertex buffer objects (VBOs), and translates all drawing
 * commands into calls to a driver supplied DrawPrimitives() callback.
 *
 * The module captures both immediate mode and display list drawing,
 * and manages the allocation, reference counting and deallocation of
 * vertex buffer objects itself.
 * 
 * The DrawPrimitives() callback can be either implemented by the
 * driver itself or hooked to the tnl module's _tnl_draw_primitives()
 * function for hardware without tnl capablilties or during fallbacks.
 */


#ifndef _VBO_CONTEXT_H
#define _VBO_CONTEXT_H

#include "vbo.h"
#include "vbo_attrib.h"
#include "vbo_exec.h"
#include "vbo_save.h"


/** Used to signal when transitioning from one kind of drawing method
 * to another.
 */
enum draw_method
{
   DRAW_NONE,          /**< Initial value only */
   DRAW_BEGIN_END,
   DRAW_DISPLAY_LIST,
   DRAW_ARRAYS
};


struct vbo_context {
   struct gl_client_array currval[VBO_ATTRIB_MAX];
   
   /** Map VERT_ATTRIB_x to VBO_ATTRIB_y */
   GLuint map_vp_none[VERT_ATTRIB_MAX];
   GLuint map_vp_arb[VERT_ATTRIB_MAX];

   struct vbo_exec_context exec;
   struct vbo_save_context save;

   /* Callback into the driver.  This must always succeed, the driver
    * is responsible for initiating any fallback actions required:
    */
   vbo_draw_func draw_prims;

   enum draw_method last_draw_method;
};


static inline struct vbo_context *vbo_context(struct gl_context *ctx) 
{
   return ctx->vbo_context;
}


/**
 * Return VP_x token to indicate whether we're running fixed-function
 * vertex transformation, an NV vertex program or ARB vertex program/shader.
 */
static inline enum vp_mode
get_program_mode( struct gl_context *ctx )
{
   if (!ctx->VertexProgram._Current)
      return VP_NONE;
   else if (ctx->VertexProgram._Current == ctx->VertexProgram._TnlProgram)
      return VP_NONE;
   else
      return VP_ARB;
}


/**
 * This is called by glBegin, glDrawArrays and glDrawElements (and
 * variations of those calls).  When we transition from immediate mode
 * drawing to array drawing we need to invalidate the array state.
 *
 * glBegin/End builds vertex arrays.  Those arrays may look identical
 * to glDrawArrays arrays except that the position of the elements may
 * be different.  For example, arrays of (position3v, normal3f) vs. arrays
 * of (normal3f, position3f).  So we need to make sure we notify drivers
 * that arrays may be changing.
 */
static inline void
vbo_draw_method(struct vbo_context *vbo, enum draw_method method)
{
   if (vbo->last_draw_method != method) {
      struct gl_context *ctx = vbo->exec.ctx;

      switch (method) {
      case DRAW_ARRAYS:
         ctx->Array._DrawArrays = vbo->exec.array.inputs;
         break;
      case DRAW_BEGIN_END:
         ctx->Array._DrawArrays = vbo->exec.vtx.inputs;
         break;
      case DRAW_DISPLAY_LIST:
         ctx->Array._DrawArrays = vbo->save.inputs;
         break;
      default:
         ASSERT(0);
      }

      ctx->NewDriverState |= ctx->DriverFlags.NewArray;
      vbo->last_draw_method = method;
   }
}

/**
 * Return if format is integer. The immediate mode commands only emit floats
 * for non-integer types, thus everything else is integer.
 */
static inline GLboolean
vbo_attrtype_to_integer_flag(GLenum format)
{
   switch (format) {
   case GL_FLOAT:
      return GL_FALSE;
   case GL_INT:
   case GL_UNSIGNED_INT:
      return GL_TRUE;
   default:
      ASSERT(0);
      return GL_FALSE;
   }
}


/**
 * Return default component values for the given format.
 * The return type is an array of floats, because that's how we declare
 * the vertex storage despite the fact we sometimes store integers in there.
 */
static inline const GLfloat *
vbo_get_default_vals_as_float(GLenum format)
{
   static const GLfloat default_float[4] = { 0, 0, 0, 1 };
   static const GLint default_int[4] = { 0, 0, 0, 1 };

   switch (format) {
   case GL_FLOAT:
      return default_float;
   case GL_INT:
   case GL_UNSIGNED_INT:
      return (const GLfloat*)default_int;
   default:
      ASSERT(0);
      return NULL;
   }
}

#endif
