From ed824405fe215b978590c3a9757d9066ad73566c Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Sat, 9 Sep 2023 23:08:38 +0900
Subject: [PATCH] [qfcc] Support struct access to full algebra vectors

This makes them actually useable. Multi-vector expressions and variables
will be done soon.
---
 tools/qfcc/include/algebra.h     |  2 ++
 tools/qfcc/include/expr.h        |  2 ++
 tools/qfcc/source/algebra.c      |  4 ++--
 tools/qfcc/source/expr.c         |  4 +++-
 tools/qfcc/source/expr_algebra.c | 17 +++++++++++++++++
 tools/qfcc/test/algtypes.r       |  5 +++++
 6 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/tools/qfcc/include/algebra.h b/tools/qfcc/include/algebra.h
index 72030caf7..c62d6abfb 100644
--- a/tools/qfcc/include/algebra.h
+++ b/tools/qfcc/include/algebra.h
@@ -115,5 +115,7 @@ struct expr_s *algebra_dual (struct expr_s *e);
 struct expr_s *algebra_reverse (struct expr_s *e);
 struct expr_s *algebra_cast_expr (struct type_s *dstType, struct expr_s *e);
 struct expr_s *algebra_assign_expr (struct expr_s *dst, struct expr_s *src);
+struct expr_s *algebra_field_expr (struct expr_s *mvec,
+								   struct expr_s *field_name);
 
 #endif//__algebra_h
diff --git a/tools/qfcc/include/expr.h b/tools/qfcc/include/expr.h
index e079de644..6a5c3524f 100644
--- a/tools/qfcc/include/expr.h
+++ b/tools/qfcc/include/expr.h
@@ -633,6 +633,8 @@ expr_t *new_entity_expr (int entity_val);
 					(expr_t::e::field_val).
 */
 expr_t *new_field_expr (int field_val, struct type_s *type, struct def_s *def);
+struct symbol_s *get_struct_field (const struct type_s *t1, expr_t *e1,
+								   expr_t *e2);
 
 /** Create a new function constant expression node.
 
diff --git a/tools/qfcc/source/algebra.c b/tools/qfcc/source/algebra.c
index 829ede425..0014ee132 100644
--- a/tools/qfcc/source/algebra.c
+++ b/tools/qfcc/source/algebra.c
@@ -111,9 +111,9 @@ static const char *mvec_3d_names[] = {
 
 static const char *mvec_4d_names[] = {
 	"vec",
-	"bvecv",
+	"bvect",
 	"scalar",
-	"bvecm",
+	"bvecp",
 	"qvec",
 	"tvec",
 	0
diff --git a/tools/qfcc/source/expr.c b/tools/qfcc/source/expr.c
index fc4e76245..69ab2c0de 100644
--- a/tools/qfcc/source/expr.c
+++ b/tools/qfcc/source/expr.c
@@ -1463,7 +1463,7 @@ prepend_expr (expr_t *block, expr_t *e)
 	return block;
 }
 
-static symbol_t *
+symbol_t *
 get_struct_field (const type_t *t1, expr_t *e1, expr_t *e2)
 {
 	symtab_t   *strct = 0;
@@ -1587,6 +1587,8 @@ field_expr (expr_t *e1, expr_t *e2)
 				return new_offset_alias_expr (field->type, e1, field->s.offset);
 			}
 		}
+	} else if (is_algebra (t1)) {
+		return algebra_field_expr (e1, e2);
 	} else if (is_class (t1)) {
 		//Class instance variables aren't allowed and thus declaring one
 		//is treated as an error, so this is a follow-on error.
diff --git a/tools/qfcc/source/expr_algebra.c b/tools/qfcc/source/expr_algebra.c
index a3217e7ef..43aee6f4c 100644
--- a/tools/qfcc/source/expr_algebra.c
+++ b/tools/qfcc/source/expr_algebra.c
@@ -2242,3 +2242,20 @@ algebra_assign_expr (expr_t *dst, expr_t *src)
 	}
 	return block;
 }
+
+expr_t *
+algebra_field_expr (expr_t *mvec, expr_t *field_name)
+{
+	auto mvec_type = get_type (mvec);
+	auto algebra = algebra_get (mvec_type);
+
+	if (mvec_type->type == ev_invalid) {
+		auto mvec_struct = algebra->mvec_sym->type;
+		auto field = get_struct_field (mvec_struct, mvec, field_name);
+		if (!field) {
+			return mvec;
+		}
+		return new_offset_alias_expr (field->type, mvec, field->s.offset);
+	}
+	internal_error (mvec, "not implemented");
+}
diff --git a/tools/qfcc/test/algtypes.r b/tools/qfcc/test/algtypes.r
index 4c4f60572..68b937de7 100644
--- a/tools/qfcc/test/algtypes.r
+++ b/tools/qfcc/test/algtypes.r
@@ -48,5 +48,10 @@ main (void)
 		pga2 = (l1 • p)*l1;
 	}
 	printf ("%q\n", plane);
+	printf ("%g\n", pgaf1.scalar);
+	printf ("%q\n", pgaf1.vec);
+	printf ("%v %v\n", pgaf1.bvect, pgaf1.bvecp);
+	printf ("%q\n", pgaf1.tvec);
+	printf ("%g\n", (float)pgaf1.qvec);
 	return 0;		// to survive and prevail :)
 }