From 13ae8f58727129c68f9294b75eba21355be255fe Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 19 Aug 2022 01:37:45 +0900
Subject: [PATCH] internal/shader: add type checks for the builtin function
 faceforward

Updates #2184
---
 internal/shader/expr.go        |  7 ++++-
 internal/shader/syntax_test.go | 56 ++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/internal/shader/expr.go b/internal/shader/expr.go
index fef0ee7cd..e6ec076f3 100644
--- a/internal/shader/expr.go
+++ b/internal/shader/expr.go
@@ -447,7 +447,7 @@ func (cs *compileState) parseExpr(block *block, fname string, expr ast.Expr, mar
 				})
 				return nil, nil, stmts, true
 
-			case shaderir.Clamp, shaderir.Mix, shaderir.Smoothstep:
+			case shaderir.Clamp, shaderir.Mix, shaderir.Smoothstep, shaderir.Faceforward:
 				// 3 arguments
 				if len(args) != 3 {
 					cs.addError(e.Pos(), fmt.Sprintf("number of %s's arguments must be 3 but %d", callee.BuiltinFunc, len(args)))
@@ -485,6 +485,11 @@ func (cs *compileState) parseExpr(block *block, fname string, expr ast.Expr, mar
 						cs.addError(e.Pos(), fmt.Sprintf("the first and the second arguments for %s must equal to the third argument %s or float but %s and %s", callee.BuiltinFunc, argts[2].String(), argts[0].String(), argts[1].String()))
 						return nil, nil, nil, false
 					}
+				default:
+					if !argts[0].Equal(&argts[1]) || !argts[0].Equal(&argts[2]) {
+						cs.addError(e.Pos(), fmt.Sprintf("all the argument types for %s must be the same but %s, %s, and %s", callee.BuiltinFunc, argts[0].String(), argts[1].String(), argts[2].String()))
+						return nil, nil, nil, false
+					}
 				}
 
 				switch callee.BuiltinFunc {
diff --git a/internal/shader/syntax_test.go b/internal/shader/syntax_test.go
index 607920a41..f8fd7c49c 100644
--- a/internal/shader/syntax_test.go
+++ b/internal/shader/syntax_test.go
@@ -1842,6 +1842,62 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	}
 }
 
+// Issue #2184
+func TestSyntaxBuiltinFuncTripleArgsType(t *testing.T) {
+	cases := []struct {
+		stmt string
+		err  bool
+	}{
+		{stmt: "a := {{.Func}}(); _ = a", err: true},
+		{stmt: "a := {{.Func}}(1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(false, false); _ = a", err: true},
+		{stmt: "a := {{.Func}}(1, 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(false, false, false); _ = a", err: true},
+		{stmt: "a := {{.Func}}(1, 1, 1); _ = a", err: false},
+		{stmt: "a := {{.Func}}(1.0, 1, 1); _ = a", err: false},
+		{stmt: "a := {{.Func}}(1, 1.0, 1); _ = a", err: false},
+		{stmt: "a := {{.Func}}(1, 1, 1.0); _ = a", err: false},
+		{stmt: "a := {{.Func}}(1, vec2(1), 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(1, 1, vec2(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(1, vec2(1), vec2(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec2(1), 1, 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec2(1), 1, vec2(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec2(1), vec2(1), 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec2(1), vec2(1), vec2(1)); _ = a", err: false},
+		{stmt: "a := {{.Func}}(vec2(1), vec2(1), vec3(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec3(1), 1, 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec3(1), 1, vec3(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec3(1), vec3(1), 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec3(1), vec3(1), vec3(1)); _ = a", err: false},
+		{stmt: "a := {{.Func}}(vec4(1), 1, 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec4(1), 1, vec4(1)); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec4(1), vec4(1), 1); _ = a", err: true},
+		{stmt: "a := {{.Func}}(vec4(1), vec4(1), vec4(1)); _ = a", err: false},
+		{stmt: "a := {{.Func}}(1, 1, 1, 1); _ = a", err: true},
+	}
+
+	funcs := []string{
+		"faceforward",
+	}
+	for _, c := range cases {
+		for _, f := range funcs {
+			stmt := strings.ReplaceAll(c.stmt, "{{.Func}}", f)
+			src := fmt.Sprintf(`package main
+
+func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
+	%s
+	return position
+}`, stmt)
+			_, err := compileToIR([]byte(src))
+			if err == nil && c.err {
+				t.Errorf("%s must return an error but does not", stmt)
+			} else if err != nil && !c.err {
+				t.Errorf("%s must not return nil but returned %v", stmt, err)
+			}
+		}
+	}
+}
+
 // Issue #2184
 func TestSyntaxBuiltinFuncClampType(t *testing.T) {
 	cases := []struct {