shader: Bug fix: Wrong type deduction with int(x)

Fixes #1298

internal/shader/expr.go

@@ -198,6 +198,12 @@ func (cs *compileState) parseExpr(block *block, expr ast.Expr) ([]shaderir.Expr,
 		if callee.Type == shaderir.BuiltinFuncExpr {
 			var t shaderir.Type
 			switch callee.BuiltinFunc {
+			case shaderir.BoolF:
+				t = shaderir.Type{Main: shaderir.Bool}
+			case shaderir.IntF:
+				t = shaderir.Type{Main: shaderir.Int}
+			case shaderir.FloatF:
+				t = shaderir.Type{Main: shaderir.Float}
 			case shaderir.Vec2F:
 				t = shaderir.Type{Main: shaderir.Vec2}
 			case shaderir.Vec3F:

internal/shader/testdata/issue1298.expected.vs

@@ -0,0 +1,8 @@
+void F0(in float l0, out int l1);
+
+void F0(in float l0, out int l1) {
+	int l2 = 0;
+	l2 = int(l0);
+	l1 = l2;
+	return;
+}

internal/shader/testdata/issue1298.go

@@ -0,0 +1,6 @@
+package main
+
+func Foo(f float) int {
+	x := int(f)
+	return x
+}