From f61a916e4a4494b33adb651526bc52afd123c4c3 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 7 Sep 2020 23:36:05 +0900
Subject: [PATCH] shaderir/glsl: Bug fix: Calculate local variable indices
 correctly

Fixes #1339
---
 internal/shader/testdata/array2.expected.vs | 22 +++++++++++++++++++++
 internal/shader/testdata/array2.go          | 11 +++++++++++
 internal/shaderir/glsl/glsl.go              |  3 ++-
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 internal/shader/testdata/array2.expected.vs
 create mode 100644 internal/shader/testdata/array2.go

diff --git a/internal/shader/testdata/array2.expected.vs b/internal/shader/testdata/array2.expected.vs
new file mode 100644
index 000000000..1c89be5ea
--- /dev/null
+++ b/internal/shader/testdata/array2.expected.vs
@@ -0,0 +1,22 @@
+void F0(out vec2 l0[3]);
+
+void F0(out vec2 l0[3]) {
+	vec2 l1[2];
+	l1[0] = vec2(0);
+	l1[1] = vec2(0);
+	vec2 l2[3];
+	l2[0] = vec2(0);
+	l2[1] = vec2(0);
+	l2[2] = vec2(0);
+	{
+		vec2 l2[2];
+		l2[0] = vec2(0);
+		l2[1] = vec2(0);
+		l2[0] = l1[0];
+		l2[1] = l1[1];
+	}
+	l0[0] = l2[0];
+	l0[1] = l2[1];
+	l0[2] = l2[2];
+	return;
+}
diff --git a/internal/shader/testdata/array2.go b/internal/shader/testdata/array2.go
new file mode 100644
index 000000000..c5c3ce17d
--- /dev/null
+++ b/internal/shader/testdata/array2.go
@@ -0,0 +1,11 @@
+package main
+
+func Foo() [3]vec2 {
+	var a [2]vec2
+	{
+		var b [2]vec2
+		b = a
+	}
+	var c [3]vec2
+	return c
+}
diff --git a/internal/shaderir/glsl/glsl.go b/internal/shaderir/glsl/glsl.go
index 2855b0109..05ab4cc15 100644
--- a/internal/shaderir/glsl/glsl.go
+++ b/internal/shaderir/glsl/glsl.go
@@ -282,7 +282,8 @@ func descendantLocalVars(block, target *shaderir.Block) ([]shaderir.Type, bool)
 	for _, s := range block.Stmts {
 		for _, b := range s.Blocks {
 			if ts2, found := descendantLocalVars(b, target); found {
-				ts = append(ts, block.LocalVars...)
+				n := b.LocalVarIndexOffset - block.LocalVarIndexOffset
+				ts = append(ts, block.LocalVars[:n]...)
 				ts = append(ts, ts2...)
 				return ts, true
 			}