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/*
* 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"
#include "builtin_functions.h"
#include "main/mtypes.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_hidden;
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_linked_shader *shader)
{
/* gl_VertexID only exists in the vertex shader.
*/
if (shader->Stage != MESA_SHADER_VERTEX)
return false;
ir_function_signature *const main_sig =
_mesa_get_main_function_signature(shader->symbols);
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;
}