/**************************************************************************
 * 
 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
 * 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, sub license, 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 (including the
 * next paragraph) 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 NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.
 * 
 **************************************************************************/

/**
 * Execute fragment shader using the TGSI interpreter.
 */

#include "sp_context.h"
#include "sp_state.h"
#include "sp_fs.h"
#include "sp_quad.h"

#include "pipe/p_state.h"
#include "pipe/p_defines.h"
#include "util/u_memory.h"
#include "tgsi/tgsi_exec.h"
#include "tgsi/tgsi_parse.h"


/**
 * Subclass of sp_fragment_shader
 */
struct sp_exec_fragment_shader
{
   struct sp_fragment_shader base;
   /* No other members for now */
};


/** cast wrapper */
static INLINE struct sp_exec_fragment_shader *
sp_exec_fragment_shader(const struct sp_fragment_shader *base)
{
   return (struct sp_exec_fragment_shader *) base;
}


/**
 * Compute quad X,Y,Z,W for the four fragments in a quad.
 *
 * This should really be part of the compiled shader.
 */
void
sp_setup_pos_vector(const struct tgsi_interp_coef *coef,
		    float x, float y,
		    struct tgsi_exec_vector *quadpos)
{
   uint chan;
   /* do X */
   quadpos->xyzw[0].f[0] = x;
   quadpos->xyzw[0].f[1] = x + 1;
   quadpos->xyzw[0].f[2] = x;
   quadpos->xyzw[0].f[3] = x + 1;

   /* do Y */
   quadpos->xyzw[1].f[0] = y;
   quadpos->xyzw[1].f[1] = y;
   quadpos->xyzw[1].f[2] = y + 1;
   quadpos->xyzw[1].f[3] = y + 1;

   /* do Z and W for all fragments in the quad */
   for (chan = 2; chan < 4; chan++) {
      const float dadx = coef->dadx[chan];
      const float dady = coef->dady[chan];
      const float a0 = coef->a0[chan] + dadx * x + dady * y;
      quadpos->xyzw[chan].f[0] = a0;
      quadpos->xyzw[chan].f[1] = a0 + dadx;
      quadpos->xyzw[chan].f[2] = a0 + dady;
      quadpos->xyzw[chan].f[3] = a0 + dadx + dady;
   }
}


static void
exec_prepare( const struct sp_fragment_shader *base,
	      struct tgsi_exec_machine *machine,
	      struct tgsi_sampler **samplers )
{
   /*
    * Bind tokens/shader to the interpreter's machine state.
    * Avoid redundant binding.
    */
   if (machine->Tokens != base->shader.tokens) {
      tgsi_exec_machine_bind_shader( machine,
                                     base->shader.tokens,
                                     PIPE_MAX_SAMPLERS,
                                     samplers );
   }
}


/* TODO: hide the machine struct in here somewhere, remove from this
 * interface:
 */
static unsigned 
exec_run( const struct sp_fragment_shader *base,
	  struct tgsi_exec_machine *machine,
	  struct quad_header *quad )
{
   /* Compute X, Y, Z, W vals for this quad */
   sp_setup_pos_vector(quad->posCoef, 
		       (float)quad->input.x0, (float)quad->input.y0, 
		       &machine->QuadPos);
   
   return tgsi_exec_machine_run( machine );
}


static void 
exec_delete( struct sp_fragment_shader *base )
{
   FREE((void *) base->shader.tokens);
   FREE(base);
}


struct sp_fragment_shader *
softpipe_create_fs_exec(struct softpipe_context *softpipe,
			const struct pipe_shader_state *templ)
{
   struct sp_exec_fragment_shader *shader;

   /* Decide whether we'll be codegenerating this shader and if so do
    * that now.
    */

   shader = CALLOC_STRUCT(sp_exec_fragment_shader);
   if (!shader)
      return NULL;

   /* we need to keep a local copy of the tokens */
   shader->base.shader.tokens = tgsi_dup_tokens(templ->tokens);
   shader->base.prepare = exec_prepare;
   shader->base.run = exec_run;
   shader->base.delete = exec_delete;

   return &shader->base;
}
