/**************************************************************************
 *
 * Copyright 2007-2009 VMware, Inc.
 * 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 VMWARE 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.
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 **************************************************************************/

/*
 * Rasterization for binned triangles within a tile
 */

#include "util/u_math.h"
#include "lp_debug.h"
#include "lp_rast_priv.h"
#include "lp_tile_soa.h"


/**
 * Add a 4x4 block of pixels to the block list.
 * All pixels are known to be inside the triangle's bounds.
 */
static void
block_full_4( struct lp_rasterizer_task *rast_task, int x, int y )
{
   const unsigned i = rast_task->nr_blocks;
   assert(x % 4 == 0);
   assert(y % 4 == 0);
   rast_task->blocks[i].x = x;
   rast_task->blocks[i].y = y;
   rast_task->blocks[i].mask = ~0;
   rast_task->nr_blocks++;
}


/**
 * Add a 16x16 block of pixels to the block list.
 * All pixels are known to be inside the triangle's bounds.
 */
static void
block_full_16( struct lp_rasterizer_task *rast_task, int x, int y )
{
   unsigned ix, iy;
   assert(x % 16 == 0);
   assert(y % 16 == 0);
   for (iy = 0; iy < 16; iy += 4)
      for (ix = 0; ix < 16; ix += 4)
	 block_full_4(rast_task, x + ix, y + iy);
}


/**
 * Evaluate each pixel in a 4x4 block to determine if it lies within
 * the triangle's bounds.
 * Generate a mask of in/out flags and add the block to the blocks list.
 */
static void
do_block_4( struct lp_rasterizer_task *rast_task,
	    const struct lp_rast_triangle *tri,
	    int x, int y,
	    int c1,
	    int c2,
	    int c3 )
{
   int i;
   unsigned mask = 0;

   assert(x % 4 == 0);
   assert(y % 4 == 0);

   for (i = 0; i < 16; i++) {
      int any_negative = ((c1 + tri->step[0][i]) | 
                          (c2 + tri->step[1][i]) | 
                          (c3 + tri->step[2][i])) >> 31;
      mask |= (~any_negative) & (1 << i);
   }
   
   /* As we do trivial reject already, masks should rarely be all zero:
    */
   if (mask) {
      const unsigned i = rast_task->nr_blocks;
      rast_task->blocks[i].x = x;
      rast_task->blocks[i].y = y;
      rast_task->blocks[i].mask = mask;
      rast_task->nr_blocks++;
   }
}


/**
 * Evaluate a 16x16 block of pixels to determine which 4x4 subblocks are in/out
 * of the triangle's bounds.
 */
static void
do_block_16( struct lp_rasterizer_task *rast_task,
             const struct lp_rast_triangle *tri,
             int x, int y,
             int c1,
             int c2,
             int c3 )
{
   int ix, iy, i = 0;

   int ei1 = tri->ei1 * 4;
   int ei2 = tri->ei2 * 4;
   int ei3 = tri->ei3 * 4;

   int eo1 = tri->eo1 * 4;
   int eo2 = tri->eo2 * 4;
   int eo3 = tri->eo3 * 4;

   assert(x % 16 == 0);
   assert(y % 16 == 0);

   for (iy = 0; iy < 16; iy+=4) {
      for (ix = 0; ix < 16; ix+=4, i++) {
	 int cx1 = c1 + (tri->step[0][i] * 4);
	 int cx2 = c2 + (tri->step[1][i] * 4);
	 int cx3 = c3 + (tri->step[2][i] * 4);
	 
	 if (cx1 + eo1 < 0 ||
	     cx2 + eo2 < 0 ||
	     cx3 + eo3 < 0) {
            /* the block is completely outside the triangle - nop */
	 }
	 else if (cx1 + ei1 > 0 &&
		  cx2 + ei2 > 0 &&
		  cx3 + ei3 > 0) {
            /* the block is completely inside the triangle */
	    block_full_4(rast_task, x+ix, y+iy);
	 }
	 else {
            /* the block is partially in/out of the triangle */
	    do_block_4(rast_task, tri, x+ix, y+iy, cx1, cx2, cx3);
	 }
      }
   }
}


/**
 * Scan the tile in chunks and figure out which pixels to rasterize
 * for this triangle.
 */
void
lp_rast_triangle( struct lp_rasterizer *rast,
                  unsigned thread_index,
                  const union lp_rast_cmd_arg arg )
{
   struct lp_rasterizer_task *rast_task = &rast->tasks[thread_index];
   const struct lp_rast_triangle *tri = arg.triangle;

   int x = rast_task->x;
   int y = rast_task->y;
   int ix, iy;
   unsigned i = 0;

   int c1 = tri->c1 + tri->dx12 * y - tri->dy12 * x;
   int c2 = tri->c2 + tri->dx23 * y - tri->dy23 * x;
   int c3 = tri->c3 + tri->dx31 * y - tri->dy31 * x;

   int ei1 = tri->ei1 * 16;
   int ei2 = tri->ei2 * 16;
   int ei3 = tri->ei3 * 16;

   int eo1 = tri->eo1 * 16;
   int eo2 = tri->eo2 * 16;
   int eo3 = tri->eo3 * 16;

   assert(Elements(rast_task->blocks) == (TILE_SIZE * TILE_SIZE) / (4*4));

   LP_DBG(DEBUG_RAST, "lp_rast_triangle\n");

   rast_task->nr_blocks = 0;

   /* Walk over the tile to build a list of 4x4 pixel blocks which will
    * be filled/shaded.  We do this at two granularities: 16x16 blocks
    * and then 4x4 blocks.
    */
   for (iy = 0; iy < TILE_SIZE; iy += 16) {
      for (ix = 0; ix < TILE_SIZE; ix += 16, i++) {
	 int cx1 = c1 + (tri->step[0][i] * 16);
	 int cx2 = c2 + (tri->step[1][i] * 16);
	 int cx3 = c3 + (tri->step[2][i] * 16);
	 
	 if (cx1 + eo1 < 0 ||
	     cx2 + eo2 < 0 ||
	     cx3 + eo3 < 0) {
            /* the block is completely outside the triangle - nop */
	 }
	 else if (cx1 + ei1 > 0 &&
		  cx2 + ei2 > 0 &&
		  cx3 + ei3 > 0) {
            /* the block is completely inside the triangle */
	    block_full_16(rast_task, x+ix, y+iy);
	 }
	 else {
            /* the block is partially in/out of the triangle */
	    do_block_16(rast_task, tri, x+ix, y+iy, cx1, cx2, cx3);
	 }
      }
   }

   assert(rast_task->nr_blocks <= Elements(rast_task->blocks));

   /* Shade the 4x4 pixel blocks */
   for (i = 0; i < rast_task->nr_blocks; i++) 
      lp_rast_shade_quads(rast,
                          thread_index,
                          &tri->inputs, 
			  rast_task->blocks[i].x,
			  rast_task->blocks[i].y,
			  rast_task->blocks[i].mask);
}