gallium/util: new polygon stipple utility helper

The polygon stipple fallback does not have to be implemented in the
draw module (it doesn't need window coords, etc).  Drivers can use
this utility and avoid sw vertex fallbacks if pstipple is enabled.
Note: this is WIP and not used by any driver yet.

2 files changed, 490 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_pstipple.c b/src/gallium/auxiliary/util/u_pstipple.c
new file mode 100644
index 00000000000..f79a6938d1d
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_pstipple.c
@@ -0,0 +1,434 @@
+/**************************************************************************
+ * 
+ * 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"
+
+/** 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 */
+   transfer = pipe_get_transfer(pipe, tex, 0, 0,
+                                PIPE_TRANSFER_WRITE, 0, 0, 32, 32);
+   data = pipe->transfer_map(pipe, 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);
+   pipe->transfer_destroy(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;
+   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;
+};
+
+
+/**
+ * TGSI declaration transform callback.
+ * Look for a free sampler, a free input attrib, and two free temp regs.
+ */
+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;
+
+   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.
+ * Replace writes to result.color w/ a temp reg.
+ * Upon END instruction, insert texture sampling code for antialiasing.
+ */
+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 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 reg */
+      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 = TGSI_INTERPOLATE_LINEAR;
+         decl.Declaration.Semantic = 1;
+         decl.Semantic.Name = TGSI_SEMANTIC_POSITION;
+         decl.Semantic.Index = 0;
+         decl.Range.First = 
+            decl.Range.Last = wincoordInput;
+         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;
+
+   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;
+   }
+
+   memset(&transform, 0, sizeof(transform));
+   transform.wincoordInput = -1;
+   transform.maxInput = -1;
+   transform.texTemp = -1;
+   transform.firstInstruction = TRUE;
+   transform.base.transform_instruction = pstip_transform_inst;
+   transform.base.transform_declaration = pstip_transform_decl;
+   transform.base.transform_immediate = pstip_transform_immed;
+
+   tgsi_transform_shader(fs->tokens,
+                         (struct tgsi_token *) new_fs->tokens,
+                         newLen, &transform.base);
+
+#if 0 /* DEBUG */
+   tgsi_dump(fs->tokens, 0);
+   tgsi_dump(pstip_fs.tokens, 0);
+#endif
+
+   assert(transform.freeSampler < PIPE_MAX_SAMPLERS);
+   *samplerUnitOut = transform.freeSampler;
+
+   return new_fs;
+}
+
diff --git a/src/gallium/auxiliary/util/u_pstipple.h b/src/gallium/auxiliary/util/u_pstipple.h
new file mode 100644
index 00000000000..1c2f5f48af4
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_pstipple.h
@@ -0,0 +1,56 @@
+/**************************************************************************
+ * 
+ * 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.
+ * 
+ **************************************************************************/
+
+#ifndef U_PSTIPPLE_H
+#define U_PSTIPPLE_H
+
+#include "pipe/p_compiler.h"
+
+struct pipe_context;
+struct pipe_resource;
+struct pipe_shader_state;
+
+
+extern struct pipe_resource *
+util_pstipple_create_stipple_texture(struct pipe_context *pipe,
+                                     const uint32_t pattern[32]);
+
+extern struct pipe_sampler_view *
+util_pstipple_create_sampler_view(struct pipe_context *pipe,
+                                  struct pipe_resource *tex);
+
+extern void *
+util_pstipple_create_sampler(struct pipe_context *pipe);
+
+extern struct pipe_shader_state *
+util_pstipple_create_fragment_shader(struct pipe_context *pipe,
+                                     struct pipe_shader_state *fs,
+                                     unsigned *samplerUnitOut);
+
+
+#endif