[Mesa-dev] [PATCH 05/13] glsl: Add a lowering pass for gl_VertexID
Kenneth Graunke
kenneth at whitecape.org
Fri Aug 8 00:31:09 PDT 2014
From: Ian Romanick <ian.d.romanick at intel.com>
Converts gl_VertexID to (gl_VertexIDMESA + gl_BaseVertex). gl_VertexIDMESA
is backed by SYSTEM_VALUE_VERTEX_ID_ZERO_BASE, and gl_BaseVertex is backed
by SYSTEM_VALUE_BASE_VERTEX.
v2: Put the enum in struct gl_constants and propoerly resolve the scope
in C++ code. Fix suggested by Marek.
v3: Reabase on Matt's foreach_in_list changes (was using foreach_list).
v4 (Ken): Use a systemvalue instead of a uniform because
STATE_BASE_VERTEX has been removed.
v5: Use a boolean to select lowering, and only allow one lowering
method. Suggested by Ken.
v6 (Ken): Replace strcmp against literal "gl_BaseVertex"/"gl_VertexID"
with SYSTEM_VALUE enum checks, for efficiency.
Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/glsl/Makefile.sources | 1 +
src/glsl/ir_optimization.h | 2 +
src/glsl/linker.cpp | 3 +
src/glsl/lower_vertex_id.cpp | 144 +++++++++++++++++++++++++++++++++++++++++++
src/mesa/main/context.c | 6 ++
src/mesa/main/mtypes.h | 9 +++
6 files changed, 165 insertions(+)
create mode 100644 src/glsl/lower_vertex_id.cpp
I suppose this is Signed-off-by [v4, v6] and Reviewed-by [v5]...
diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
index 2131dda..cb8d5a6 100644
--- a/src/glsl/Makefile.sources
+++ b/src/glsl/Makefile.sources
@@ -76,6 +76,7 @@ LIBGLSL_FILES = \
$(GLSL_SRCDIR)/lower_vec_index_to_swizzle.cpp \
$(GLSL_SRCDIR)/lower_vector.cpp \
$(GLSL_SRCDIR)/lower_vector_insert.cpp \
+ $(GLSL_SRCDIR)/lower_vertex_id.cpp \
$(GLSL_SRCDIR)/lower_output_reads.cpp \
$(GLSL_SRCDIR)/lower_ubo_reference.cpp \
$(GLSL_SRCDIR)/opt_algebraic.cpp \
diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h
index b83c225..2892dc2 100644
--- a/src/glsl/ir_optimization.h
+++ b/src/glsl/ir_optimization.h
@@ -125,6 +125,8 @@ bool optimize_redundant_jumps(exec_list *instructions);
bool optimize_split_arrays(exec_list *instructions, bool linked);
bool lower_offset_arrays(exec_list *instructions);
+bool lower_vertex_id(gl_shader *shader);
+
ir_rvalue *
compare_index_block(exec_list *instructions, ir_variable *index,
unsigned base, unsigned components, void *mem_ctx);
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index ae6c91a..aadc47d 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1737,6 +1737,9 @@ link_intrastage_shaders(void *mem_ctx,
}
}
+ if (ctx->Const.VertexID_is_zero_based)
+ lower_vertex_id(linked);
+
/* Make a pass over all variable declarations to ensure that arrays with
* unspecified sizes have a size specified. The size is inferred from the
* max_array_access field.
diff --git a/src/glsl/lower_vertex_id.cpp b/src/glsl/lower_vertex_id.cpp
new file mode 100644
index 0000000..fc90bc8
--- /dev/null
+++ b/src/glsl/lower_vertex_id.cpp
@@ -0,0 +1,144 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * 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.
+ */
+
+/**
+ * \file lower_vertex_id.cpp
+ *
+ * There exists hardware, such as i965, that does not implement the OpenGL
+ * semantic for gl_VertexID. Instead, that hardware does not include the
+ * value of basevertex in the gl_VertexID value. To implement the OpenGL
+ * semantic, we'll have to convert gl_Vertex_ID to
+ * gl_VertexIDMESA+gl_BaseVertexMESA.
+ */
+
+#include "glsl_symbol_table.h"
+#include "ir_hierarchical_visitor.h"
+#include "ir.h"
+#include "ir_builder.h"
+#include "linker.h"
+#include "program/prog_statevars.h"
+
+namespace {
+
+class lower_vertex_id_visitor : public ir_hierarchical_visitor {
+public:
+ explicit lower_vertex_id_visitor(ir_function_signature *main_sig,
+ exec_list *ir_list)
+ : progress(false), VertexID(NULL), gl_VertexID(NULL),
+ gl_BaseVertex(NULL), main_sig(main_sig), ir_list(ir_list)
+ {
+ foreach_in_list(ir_instruction, ir, ir_list) {
+ ir_variable *const var = ir->as_variable();
+
+ if (var != NULL && var->data.mode == ir_var_system_value &&
+ var->data.location == SYSTEM_VALUE_BASE_VERTEX) {
+ gl_BaseVertex = var;
+ break;
+ }
+ }
+ }
+
+ virtual ir_visitor_status visit(ir_dereference_variable *);
+
+ bool progress;
+
+private:
+ ir_variable *VertexID;
+ ir_variable *gl_VertexID;
+ ir_variable *gl_BaseVertex;
+
+ ir_function_signature *main_sig;
+ exec_list *ir_list;
+};
+
+} /* anonymous namespace */
+
+ir_visitor_status
+lower_vertex_id_visitor::visit(ir_dereference_variable *ir)
+{
+ if (ir->var->data.mode != ir_var_system_value ||
+ ir->var->data.location != SYSTEM_VALUE_VERTEX_ID)
+ return visit_continue;
+
+ if (VertexID == NULL) {
+ const glsl_type *const int_t = glsl_type::int_type;
+ void *const mem_ctx = ralloc_parent(ir);
+
+ VertexID = new(mem_ctx) ir_variable(int_t, "__VertexID",
+ ir_var_temporary);
+ ir_list->push_head(VertexID);
+
+ gl_VertexID = new(mem_ctx) ir_variable(int_t, "gl_VertexIDMESA",
+ ir_var_system_value);
+ gl_VertexID->data.how_declared = ir_var_declared_implicitly;
+ gl_VertexID->data.read_only = true;
+ gl_VertexID->data.location = SYSTEM_VALUE_VERTEX_ID_ZERO_BASE;
+ gl_VertexID->data.explicit_location = true;
+ gl_VertexID->data.explicit_index = 0;
+ ir_list->push_head(gl_VertexID);
+
+ if (gl_BaseVertex == NULL) {
+ gl_BaseVertex = new(mem_ctx) ir_variable(int_t, "gl_BaseVertex",
+ ir_var_system_value);
+ gl_BaseVertex->data.how_declared = ir_var_declared_implicitly;
+ gl_BaseVertex->data.read_only = true;
+ gl_BaseVertex->data.location = SYSTEM_VALUE_BASE_VERTEX;
+ gl_BaseVertex->data.explicit_location = true;
+ gl_BaseVertex->data.explicit_index = 0;
+ ir_list->push_head(gl_BaseVertex);
+ }
+
+ ir_instruction *const inst =
+ ir_builder::assign(VertexID,
+ ir_builder::add(gl_VertexID, gl_BaseVertex));
+
+ main_sig->body.push_head(inst);
+ }
+
+ ir->var = VertexID;
+ progress = true;
+
+ return visit_continue;
+}
+
+bool
+lower_vertex_id(gl_shader *shader)
+{
+ /* gl_VertexID only exists in the vertex shader.
+ */
+ if (shader->Stage != MESA_SHADER_VERTEX)
+ return false;
+
+ ir_function_signature *const main_sig =
+ link_get_main_function_signature(shader);
+ if (main_sig == NULL) {
+ assert(main_sig != NULL);
+ return false;
+ }
+
+ lower_vertex_id_visitor v(main_sig, shader->ir);
+
+ v.run(shader->ir);
+
+ return v.progress;
+}
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index 50aae8b..c59b757 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -622,6 +622,12 @@ _mesa_init_constants(struct gl_context *ctx)
ctx->Const.MaxProgramMatrices = MAX_PROGRAM_MATRICES;
ctx->Const.MaxProgramMatrixStackDepth = MAX_PROGRAM_MATRIX_STACK_DEPTH;
+ /* Assume that if GLSL 1.30+ (or GLSL ES 3.00+) is supported that
+ * gl_VertexID is implemented using a native hardware register with OpenGL
+ * semantics.
+ */
+ ctx->Const.VertexID_is_zero_based = false;
+
/* CheckArrayBounds is overriden by drivers/x11 for X server */
ctx->Const.CheckArrayBounds = GL_FALSE;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 99037c6..4f15369 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3477,6 +3477,15 @@ struct gl_constants
GLboolean NativeIntegers;
/**
+ * Does VertexID count from zero or from base vertex?
+ *
+ * \note
+ * If desktop GLSL 1.30 or GLSL ES 3.00 are not supported, this field is
+ * ignored and need not be set.
+ */
+ bool VertexID_is_zero_based;
+
+ /**
* If the driver supports real 32-bit integers, what integer value should be
* used for boolean true in uniform uploads? (Usually 1 or ~0.)
*/
--
2.0.2
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