tgsi: add a utility for emulating some GL features

st/mesa will use this, but drivers can use it too.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Tested-by: Brian Paul <brianp@vmware.com>

3 files changed, 208 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/Makefile.sources b/src/gallium/auxiliary/Makefile.sources
index 1fa36416b8e..9df4e265b5b 100644
--- a/src/gallium/auxiliary/Makefile.sources
+++ b/src/gallium/auxiliary/Makefile.sources
@@ -137,6 +137,8 @@ C_SOURCES := \
 	tgsi/tgsi_dump.h \
 	tgsi/tgsi_exec.c \
 	tgsi/tgsi_exec.h \
+	tgsi/tgsi_emulate.c \
+	tgsi/tgsi_emulate.h \
 	tgsi/tgsi_info.c \
 	tgsi/tgsi_info.h \
 	tgsi/tgsi_iterate.c \
diff --git a/src/gallium/auxiliary/tgsi/tgsi_emulate.c b/src/gallium/auxiliary/tgsi/tgsi_emulate.c
new file mode 100644
index 00000000000..819087261b3
--- /dev/null
+++ b/src/gallium/auxiliary/tgsi/tgsi_emulate.c
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2015 Advanced Micro Devices, 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, 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 (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 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.
+ *
+ */
+
+#include "tgsi/tgsi_transform.h"
+#include "tgsi/tgsi_scan.h"
+#include "tgsi/tgsi_dump.h"
+#include "util/u_debug.h"
+
+#include "tgsi_emulate.h"
+
+struct tgsi_emulation_context {
+   struct tgsi_transform_context base;
+   struct tgsi_shader_info info;
+   unsigned flags;
+   bool first_instruction_emitted;
+};
+
+static inline struct tgsi_emulation_context *
+tgsi_emulation_context(struct tgsi_transform_context *tctx)
+{
+   return (struct tgsi_emulation_context *)tctx;
+}
+
+static void
+transform_decl(struct tgsi_transform_context *tctx,
+               struct tgsi_full_declaration *decl)
+{
+   struct tgsi_emulation_context *ctx = tgsi_emulation_context(tctx);
+
+   if (ctx->flags & TGSI_EMU_FORCE_PERSAMPLE_INTERP &&
+       decl->Declaration.File == TGSI_FILE_INPUT) {
+      assert(decl->Declaration.Interpolate);
+      decl->Interp.Location = TGSI_INTERPOLATE_LOC_SAMPLE;
+   }
+
+   tctx->emit_declaration(tctx, decl);
+}
+
+static void
+passthrough_edgeflag(struct tgsi_transform_context *tctx)
+{
+   struct tgsi_emulation_context *ctx = tgsi_emulation_context(tctx);
+   struct tgsi_full_declaration decl;
+   struct tgsi_full_instruction new_inst;
+
+   /* Input */
+   decl = tgsi_default_full_declaration();
+   decl.Declaration.File = TGSI_FILE_INPUT;
+   decl.Range.First = decl.Range.Last = ctx->info.num_inputs;
+   tctx->emit_declaration(tctx, &decl);
+
+   /* Output */
+   decl = tgsi_default_full_declaration();
+   decl.Declaration.File = TGSI_FILE_OUTPUT;
+   decl.Declaration.Semantic = true;
+   decl.Range.First = decl.Range.Last = ctx->info.num_outputs;
+   decl.Semantic.Name = TGSI_SEMANTIC_EDGEFLAG;
+   decl.Semantic.Index = 0;
+   tctx->emit_declaration(tctx, &decl);
+
+   /* MOV */
+   new_inst = tgsi_default_full_instruction();
+   new_inst.Instruction.Opcode = TGSI_OPCODE_MOV;
+
+   new_inst.Instruction.NumDstRegs = 1;
+   new_inst.Dst[0].Register.File  = TGSI_FILE_OUTPUT;
+   new_inst.Dst[0].Register.Index = ctx->info.num_outputs;
+   new_inst.Dst[0].Register.WriteMask = TGSI_WRITEMASK_XYZW;
+
+   new_inst.Instruction.NumSrcRegs = 1;
+   new_inst.Src[0].Register.File  = TGSI_FILE_INPUT;
+   new_inst.Src[0].Register.Index = ctx->info.num_inputs;
+   new_inst.Src[0].Register.SwizzleX = TGSI_SWIZZLE_X;
+   new_inst.Src[0].Register.SwizzleY = TGSI_SWIZZLE_X;
+   new_inst.Src[0].Register.SwizzleZ = TGSI_SWIZZLE_X;
+   new_inst.Src[0].Register.SwizzleW = TGSI_SWIZZLE_X;
+
+   tctx->emit_instruction(tctx, &new_inst);
+}
+
+static void
+transform_instr(struct tgsi_transform_context *tctx,
+		struct tgsi_full_instruction *inst)
+{
+   struct tgsi_emulation_context *ctx = tgsi_emulation_context(tctx);
+
+   /* Pass through edgeflags. */
+   if (!ctx->first_instruction_emitted) {
+      ctx->first_instruction_emitted = true;
+
+      if (ctx->flags & TGSI_EMU_PASSTHROUGH_EDGEFLAG)
+         passthrough_edgeflag(tctx);
+   }
+
+   /* Clamp color outputs. */
+   if (ctx->flags & TGSI_EMU_CLAMP_COLOR_OUTPUTS) {
+      for (int i = 0; i < inst->Instruction.NumDstRegs; i++) {
+         unsigned semantic;
+
+         if (inst->Dst[i].Register.File != TGSI_FILE_OUTPUT ||
+             inst->Dst[i].Register.Indirect)
+            continue;
+
+         semantic =
+            ctx->info.output_semantic_name[inst->Dst[i].Register.Index];
+
+         if (semantic == TGSI_SEMANTIC_COLOR ||
+             semantic == TGSI_SEMANTIC_BCOLOR)
+            inst->Instruction.Saturate = true;
+      }
+   }
+
+   tctx->emit_instruction(tctx, inst);
+}
+
+const struct tgsi_token *
+tgsi_emulate(const struct tgsi_token *tokens, unsigned flags)
+{
+   struct tgsi_emulation_context ctx;
+   struct tgsi_token *newtoks;
+   int newlen;
+
+   if (!(flags & (TGSI_EMU_CLAMP_COLOR_OUTPUTS |
+                  TGSI_EMU_PASSTHROUGH_EDGEFLAG |
+                  TGSI_EMU_FORCE_PERSAMPLE_INTERP)))
+      return NULL;
+
+   memset(&ctx, 0, sizeof(ctx));
+   ctx.flags = flags;
+   tgsi_scan_shader(tokens, &ctx.info);
+
+   if (flags & TGSI_EMU_FORCE_PERSAMPLE_INTERP)
+      ctx.base.transform_declaration = transform_decl;
+
+   if (flags & (TGSI_EMU_CLAMP_COLOR_OUTPUTS |
+                TGSI_EMU_PASSTHROUGH_EDGEFLAG))
+      ctx.base.transform_instruction = transform_instr;
+
+   newlen = tgsi_num_tokens(tokens) + 20;
+   newtoks = tgsi_alloc_tokens(newlen);
+   if (!newtoks)
+      return NULL;
+
+   tgsi_transform_shader(tokens, newtoks, newlen, &ctx.base);
+   return newtoks;
+}
diff --git a/src/gallium/auxiliary/tgsi/tgsi_emulate.h b/src/gallium/auxiliary/tgsi/tgsi_emulate.h
new file mode 100644
index 00000000000..425cec72ee1
--- /dev/null
+++ b/src/gallium/auxiliary/tgsi/tgsi_emulate.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2015 Advanced Micro Devices, 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, 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 (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 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.
+ *
+ */
+
+#ifndef TGSI_GL_EMULATION_H_
+#define TGSI_GL_EMULATION_H_
+
+#include "pipe/p_shader_tokens.h"
+
+#define TGSI_EMU_CLAMP_COLOR_OUTPUTS      (1 << 0)
+#define TGSI_EMU_PASSTHROUGH_EDGEFLAG     (1 << 1)
+#define TGSI_EMU_FORCE_PERSAMPLE_INTERP   (1 << 2)
+
+const struct tgsi_token *
+tgsi_emulate(const struct tgsi_token *tokens, unsigned flags);
+
+#endif /* TGSI_GL_EMULATION_H_ */