diff options
Diffstat (limited to 'mesalib/src/glsl/lower_vertex_id.cpp')
-rw-r--r-- | mesalib/src/glsl/lower_vertex_id.cpp | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/mesalib/src/glsl/lower_vertex_id.cpp b/mesalib/src/glsl/lower_vertex_id.cpp new file mode 100644 index 000000000..fc90bc8e6 --- /dev/null +++ b/mesalib/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; +} |