util: Add util functionality for GL4.1 support

[mesa.git] / src / gallium / auxiliary / tgsi / tgsi_vpos.c

diff --git a/src/gallium/auxiliary/tgsi/tgsi_vpos.c b/src/gallium/auxiliary/tgsi/tgsi_vpos.c
new file mode 100644 (file)
index 0000000..daae4f4
--- /dev/null
+++ b/src/gallium/auxiliary/tgsi/tgsi_vpos.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2018 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 THE AUTHORS 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.
+ */
+
+
+/**
+ * TGSI utility transforms the shader to write imm(0, 0, 0, 1) to vertex
+ * position
+ */
+
+#include "util/u_debug.h"
+#include "util/u_math.h"
+#include "tgsi_vpos.h"
+#include "tgsi_transform.h"
+#include "tgsi_dump.h"
+#include "pipe/p_state.h"
+
+
+struct write_vpos_context
+{
+   struct tgsi_transform_context base;
+   unsigned imm_index;
+};
+
+
+static inline struct write_vpos_context *
+write_vpos_context(struct tgsi_transform_context *ctx)
+{
+   return (struct write_vpos_context *) ctx;
+}
+
+
+/**
+ * TGSI transform prolog callback.
+ */
+static void
+write_vpos_prolog(struct tgsi_transform_context *ctx)
+{
+   struct write_vpos_context *vc = write_vpos_context(ctx);
+   struct tgsi_full_instruction inst;
+
+   tgsi_transform_immediate_decl(ctx, 0.0, 0.0, 0.0, 1.0);
+   tgsi_transform_output_decl(ctx, 0,
+                             TGSI_SEMANTIC_POSITION, 0,
+                             0);
+   inst = tgsi_default_full_instruction();
+   inst.Instruction.Opcode = TGSI_OPCODE_MOV;
+   inst.Instruction.NumDstRegs = 1;
+   tgsi_transform_dst_reg(&inst.Dst[0], TGSI_FILE_OUTPUT,
+                          0, TGSI_WRITEMASK_XYZW);
+   inst.Instruction.NumSrcRegs = 1;
+   tgsi_transform_src_reg(&inst.Src[0], TGSI_FILE_IMMEDIATE,
+                          vc->imm_index, TGSI_SWIZZLE_X,
+                          TGSI_SWIZZLE_Y, TGSI_SWIZZLE_Z, TGSI_SWIZZLE_W);
+   ctx->emit_instruction(ctx, &inst);
+}
+
+
+/**
+ * TGSI utility writes imm(0, 0, 0, 1) to vertex position
+ */
+struct tgsi_token *
+tgsi_write_vpos(const struct tgsi_token *tokens_in,
+                unsigned num_immediates)
+{
+   struct write_vpos_context transform;
+   const uint num_new_tokens = 1000; /* should be enough */
+   const uint new_len = tgsi_num_tokens(tokens_in) + num_new_tokens;
+   struct tgsi_token *new_tokens;
+
+   /* setup transformation context */
+   memset(&transform, 0, sizeof(transform));
+   transform.base.prolog = write_vpos_prolog;
+
+   transform.imm_index = num_immediates;
+
+   /* allocate new tokens buffer */
+   new_tokens = tgsi_alloc_tokens(new_len);
+   if (!new_tokens)
+      return NULL;
+
+   /* transform the shader */
+   tgsi_transform_shader(tokens_in, new_tokens, new_len, &transform.base);
+
+   return new_tokens;
+}
+
+