--- /dev/null
+/*
+ * 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;
+}
projects / mesa.git / commitdiff