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/**************************************************************************

 *

 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.

 * Copyright 2010 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 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.

 *

 **************************************************************************/

/**

 * Polygon stipple helper module.  Drivers/GPUs which don't support polygon

 * stipple natively can use this module to simulate it.

 *

 * Basically, modify fragment shader to sample the 32x32 stipple pattern

 * texture and do a fragment kill for the 'off' bits.

 *

 * This was originally a 'draw' module stage, but since we don't need

 * vertex window coords or anything, it can be a stand-alone utility module.

 *

 * Authors:  Brian Paul

 */

#include "pipe/p_context.h"

#include "pipe/p_defines.h"

#include "pipe/p_shader_tokens.h"

#include "util/u_inlines.h"

#include "util/u_format.h"

#include "util/u_memory.h"

#include "util/u_pstipple.h"

#include "util/u_sampler.h"

#include "tgsi/tgsi_transform.h"

#include "tgsi/tgsi_dump.h"

#include "tgsi/tgsi_scan.h"

/** Approx number of new tokens for instructions in pstip_transform_inst() */

#define NUM_NEW_TOKENS 50

static void

util_pstipple_update_stipple_texture(struct pipe_context *pipe,

                                     struct pipe_resource *tex,

                                     const uint32_t pattern[32])

{

   static const uint bit31 = 1 << 31;

   struct pipe_transfer *transfer;

   ubyte *data;

   int i, j;

   /* map texture memory */

   data = pipe_transfer_map(pipe, tex, 0, 0,

                            PIPE_TRANSFER_WRITE, 0, 0, 32, 32, &transfer);

   /*

    * Load alpha texture.

    * Note: 0 means keep the fragment, 255 means kill it.

    * We'll negate the texel value and use KILP which kills if value

    * is negative.

    */

   for (i = 0; i < 32; i++) {

      for (j = 0; j < 32; j++) {

         if (pattern[i] & (bit31 >> j)) {

            /* fragment "on" */

            data[i * transfer->stride + j] = 0;

         }

         else {

            /* fragment "off" */

            data[i * transfer->stride + j] = 255;

         }

      }

   }

   /* unmap */

   pipe->transfer_unmap(pipe, transfer);

}

/**

 * Create a 32x32 alpha8 texture that encodes the given stipple pattern.

 */

struct pipe_resource *

util_pstipple_create_stipple_texture(struct pipe_context *pipe,

                                     const uint32_t pattern[32])

{

   struct pipe_screen *screen = pipe->screen;

   struct pipe_resource templat, *tex;

   memset(&templat, 0, sizeof(templat));

   templat.target = PIPE_TEXTURE_2D;

   templat.format = PIPE_FORMAT_A8_UNORM;

   templat.last_level = 0;

   templat.width0 = 32;

   templat.height0 = 32;

   templat.depth0 = 1;

   templat.array_size = 1;

   templat.bind = PIPE_BIND_SAMPLER_VIEW;

   tex = screen->resource_create(screen, &templat);

   if (tex)

      util_pstipple_update_stipple_texture(pipe, tex, pattern);

   return tex;

}

/**

 * Create sampler view to sample the stipple texture.

 */

struct pipe_sampler_view *

util_pstipple_create_sampler_view(struct pipe_context *pipe,

                                  struct pipe_resource *tex)

{

   struct pipe_sampler_view templat, *sv;

   u_sampler_view_default_template(&templat, tex, tex->format);

   sv = pipe->create_sampler_view(pipe, tex, &templat);

   return sv;

}

/**

 * Create the sampler CSO that'll be used for stippling.

 */

void *

util_pstipple_create_sampler(struct pipe_context *pipe)

{

   struct pipe_sampler_state templat;

   void *s;

   memset(&templat, 0, sizeof(templat));

   templat.wrap_s = PIPE_TEX_WRAP_REPEAT;

   templat.wrap_t = PIPE_TEX_WRAP_REPEAT;

   templat.wrap_r = PIPE_TEX_WRAP_REPEAT;

   templat.min_mip_filter = PIPE_TEX_MIPFILTER_NONE;

   templat.min_img_filter = PIPE_TEX_FILTER_NEAREST;

   templat.mag_img_filter = PIPE_TEX_FILTER_NEAREST;

   templat.normalized_coords = 1;

   templat.min_lod = 0.0f;

   templat.max_lod = 0.0f;

   s = pipe->create_sampler_state(pipe, &templat);

   return s;

}

/**

 * Subclass of tgsi_transform_context, used for transforming the

 * user's fragment shader to add the extra texture sample and fragment kill

 * instructions.

 */

struct pstip_transform_context {

   struct tgsi_transform_context base;

   struct tgsi_shader_info info;

   uint tempsUsed;  /**< bitmask */

   int wincoordInput;

   int maxInput;

   uint samplersUsed;  /**< bitfield of samplers used */

   int freeSampler;  /** an available sampler for the pstipple */

   int texTemp;  /**< temp registers */

   int numImmed;

   boolean firstInstruction;

   uint coordOrigin;

};

/**

 * TGSI declaration transform callback.

 * Track samplers used, temps used, inputs used.

 */

static void

pstip_transform_decl(struct tgsi_transform_context *ctx,

                     struct tgsi_full_declaration *decl)

{

   struct pstip_transform_context *pctx =

      (struct pstip_transform_context *) ctx;

   /* XXX we can use tgsi_shader_info instead of some of this */

   if (decl->Declaration.File == TGSI_FILE_SAMPLER) {

      uint i;

      for (i = decl->Range.First; i <= decl->Range.Last; i++) {

         pctx->samplersUsed |= 1 << i;

      }

   }

   else if (decl->Declaration.File == TGSI_FILE_INPUT) {

      pctx->maxInput = MAX2(pctx->maxInput, (int) decl->Range.Last);

      if (decl->Semantic.Name == TGSI_SEMANTIC_POSITION)

         pctx->wincoordInput = (int) decl->Range.First;

   }

   else if (decl->Declaration.File == TGSI_FILE_TEMPORARY) {

      uint i;

      for (i = decl->Range.First; i <= decl->Range.Last; i++) {

         pctx->tempsUsed |= (1 << i);

      }

   }

   ctx->emit_declaration(ctx, decl);

}

static void

pstip_transform_immed(struct tgsi_transform_context *ctx,

                      struct tgsi_full_immediate *immed)

{

   struct pstip_transform_context *pctx =

      (struct pstip_transform_context *) ctx;

   pctx->numImmed++;

}

/**

 * Find the lowest zero bit in the given word, or -1 if bitfield is all ones.

 */

static int

free_bit(uint bitfield)

{

   return ffs(~bitfield) - 1;

}

/**

 * TGSI instruction transform callback.

 * Before the first instruction, insert our new code to sample the

 * stipple texture (using the fragment coord register) then kill the

 * fragment if the stipple texture bit is off.

 *

 * Insert:

 *   declare new registers

 *   MUL texTemp, INPUT[wincoord], 1/32;

 *   TEX texTemp, texTemp, sampler;

 *   KIL -texTemp;   # if -texTemp < 0, KILL fragment

 *   [...original code...]

 */

static void

pstip_transform_inst(struct tgsi_transform_context *ctx,

                     struct tgsi_full_instruction *inst)

{

   struct pstip_transform_context *pctx =

      (struct pstip_transform_context *) ctx;

   if (pctx->firstInstruction) {

      /* emit our new declarations before the first instruction */

      struct tgsi_full_declaration decl;

      struct tgsi_full_instruction newInst;

      uint i;

      int wincoordInput;

      /* find free texture sampler */

      pctx->freeSampler = free_bit(pctx->samplersUsed);

      if (pctx->freeSampler >= PIPE_MAX_SAMPLERS)

         pctx->freeSampler = PIPE_MAX_SAMPLERS - 1;

      if (pctx->wincoordInput < 0)

         wincoordInput = pctx->maxInput + 1;

      else

         wincoordInput = pctx->wincoordInput;

      /* find one free temp register */

      for (i = 0; i < 32; i++) {

         if ((pctx->tempsUsed & (1 << i)) == 0) {

            /* found a free temp */

            if (pctx->texTemp < 0)

               pctx->texTemp  = i;

            else

               break;

         }

      }

      assert(pctx->texTemp >= 0);

      if (pctx->wincoordInput < 0) {

         /* declare new position input reg */

         decl = tgsi_default_full_declaration();

         decl.Declaration.File = TGSI_FILE_INPUT;

         decl.Declaration.Interpolate = 1;

         decl.Declaration.Semantic = 1;

         decl.Semantic.Name = TGSI_SEMANTIC_POSITION;

         decl.Semantic.Index = 0;

         decl.Range.First =

            decl.Range.Last = wincoordInput;

         decl.Interp.Interpolate = TGSI_INTERPOLATE_LINEAR;

         ctx->emit_declaration(ctx, &decl);

      }

      /* declare new sampler */

      decl = tgsi_default_full_declaration();

      decl.Declaration.File = TGSI_FILE_SAMPLER;

      decl.Range.First =

      decl.Range.Last = pctx->freeSampler;

      ctx->emit_declaration(ctx, &decl);

      /* declare new temp regs */

      decl = tgsi_default_full_declaration();

      decl.Declaration.File = TGSI_FILE_TEMPORARY;

      decl.Range.First =

      decl.Range.Last = pctx->texTemp;

      ctx->emit_declaration(ctx, &decl);

      /* emit immediate = {1/32, 1/32, 1, 1}

       * The index/position of this immediate will be pctx->numImmed

       */

      {

         static const float value[4] = { 1.0/32, 1.0/32, 1.0, 1.0 };

         struct tgsi_full_immediate immed;

         uint size = 4;

         immed = tgsi_default_full_immediate();

         immed.Immediate.NrTokens = 1 + size; /* one for the token itself */

         immed.u[0].Float = value[0];

         immed.u[1].Float = value[1];

         immed.u[2].Float = value[2];

         immed.u[3].Float = value[3];

         ctx->emit_immediate(ctx, &immed);

      }

      pctx->firstInstruction = FALSE;

      /*

       * Insert new MUL/TEX/KILP instructions at start of program

       * Take gl_FragCoord, divide by 32 (stipple size), sample the

       * texture and kill fragment if needed.

       *

       * We'd like to use non-normalized texcoords to index into a RECT

       * texture, but we can only use REPEAT wrap mode with normalized

       * texcoords.  Darn.

       */

      /* XXX invert wincoord if origin isn't lower-left... */

      /* MUL texTemp, INPUT[wincoord], 1/32; */

      newInst = tgsi_default_full_instruction();

      newInst.Instruction.Opcode = TGSI_OPCODE_MUL;

      newInst.Instruction.NumDstRegs = 1;

      newInst.Dst[0].Register.File = TGSI_FILE_TEMPORARY;

      newInst.Dst[0].Register.Index = pctx->texTemp;

      newInst.Instruction.NumSrcRegs = 2;

      newInst.Src[0].Register.File = TGSI_FILE_INPUT;

      newInst.Src[0].Register.Index = wincoordInput;

      newInst.Src[1].Register.File = TGSI_FILE_IMMEDIATE;

      newInst.Src[1].Register.Index = pctx->numImmed;

      ctx->emit_instruction(ctx, &newInst);

      /* TEX texTemp, texTemp, sampler; */

      newInst = tgsi_default_full_instruction();

      newInst.Instruction.Opcode = TGSI_OPCODE_TEX;

      newInst.Instruction.NumDstRegs = 1;

      newInst.Dst[0].Register.File = TGSI_FILE_TEMPORARY;

      newInst.Dst[0].Register.Index = pctx->texTemp;

      newInst.Instruction.NumSrcRegs = 2;

      newInst.Instruction.Texture = TRUE;

      newInst.Texture.Texture = TGSI_TEXTURE_2D;

      newInst.Src[0].Register.File = TGSI_FILE_TEMPORARY;

      newInst.Src[0].Register.Index = pctx->texTemp;

      newInst.Src[1].Register.File = TGSI_FILE_SAMPLER;

      newInst.Src[1].Register.Index = pctx->freeSampler;

      ctx->emit_instruction(ctx, &newInst);

      /* KIL -texTemp;   # if -texTemp < 0, KILL fragment */

      newInst = tgsi_default_full_instruction();

      newInst.Instruction.Opcode = TGSI_OPCODE_KIL;

      newInst.Instruction.NumDstRegs = 0;

      newInst.Instruction.NumSrcRegs = 1;

      newInst.Src[0].Register.File = TGSI_FILE_TEMPORARY;

      newInst.Src[0].Register.Index = pctx->texTemp;

      newInst.Src[0].Register.Negate = 1;

      ctx->emit_instruction(ctx, &newInst);

   }

   /* emit this instruction */

   ctx->emit_instruction(ctx, inst);

}

/**

 * Given a fragment shader, return a new fragment shader which

 * samples a stipple texture and executes KILL.

 */

struct pipe_shader_state *

util_pstipple_create_fragment_shader(struct pipe_context *pipe,

                                     struct pipe_shader_state *fs,

                                     unsigned *samplerUnitOut)

{

   struct pipe_shader_state *new_fs;

   struct pstip_transform_context transform;

   const uint newLen = tgsi_num_tokens(fs->tokens) + NUM_NEW_TOKENS;

   unsigned i;

   new_fs = MALLOC(sizeof(*new_fs));

   if (!new_fs)

      return NULL;

   new_fs->tokens = tgsi_alloc_tokens(newLen);

   if (!new_fs->tokens) {

      FREE(new_fs);

      return NULL;

   }

   /* Setup shader transformation info/context.

    */

   memset(&transform, 0, sizeof(transform));

   transform.wincoordInput = -1;

   transform.maxInput = -1;

   transform.texTemp = -1;

   transform.firstInstruction = TRUE;

   transform.coordOrigin = TGSI_FS_COORD_ORIGIN_UPPER_LEFT;

   transform.base.transform_instruction = pstip_transform_inst;

   transform.base.transform_declaration = pstip_transform_decl;

   transform.base.transform_immediate = pstip_transform_immed;

   tgsi_scan_shader(fs->tokens, &transform.info);

   /* find fragment coordinate origin property */

   for (i = 0; i < transform.info.num_properties; i++) {

      if (transform.info.properties[i].name == TGSI_PROPERTY_FS_COORD_ORIGIN)

         transform.coordOrigin = transform.info.properties[i].data[0];

   }

   tgsi_transform_shader(fs->tokens,

                         (struct tgsi_token *) new_fs->tokens,

                         newLen, &transform.base);

#if 0 /* DEBUG */

   tgsi_dump(fs->tokens, 0);

   tgsi_dump(new_fs->tokens, 0);

#endif

   assert(transform.freeSampler < PIPE_MAX_SAMPLERS);

   *samplerUnitOut = transform.freeSampler;

   return new_fs;

}