From dc68bc6c13b09ea2088142b90080a0049d492715 Mon Sep 17 00:00:00 2001
From: Kyle Bayes <kylebayes@google.com>
Date: Wed, 1 May 2024 09:38:25 -0700
Subject: [PATCH] Add another unit test for caching PNG decoded images
 verifying that when a PNG file is updated the stale cached asset is not used.

PiperOrigin-RevId: 629748520
Change-Id: I6935a3d172ac1459602d3d82ac548adeb08a7b11
---
 test/user/user_api_test.cc         | 66 +++++++++++++++++++++++++++++-
 test/user/user_objects_test.cc     | 26 ++++++------
 test/xml/xml_native_reader_test.cc | 25 +++++------
 3 files changed, 88 insertions(+), 29 deletions(-)

diff --git a/test/user/user_api_test.cc b/test/user/user_api_test.cc
index 4c9af8ab..52a0a8ad 100644
--- a/test/user/user_api_test.cc
+++ b/test/user/user_api_test.cc
@@ -148,7 +148,8 @@ TEST_F(PluginTest, RecompileCompare) {
 }
 
 // ------------------- test cache with modified assets -------------------------
-TEST_F(PluginTest, RecompileCompareCache) {
+
+TEST_F(PluginTest, RecompileCompareObjCache) {
   static constexpr char xml[] = R"(
   <mujoco>
     <asset>
@@ -200,7 +201,70 @@ TEST_F(PluginTest, RecompileCompareCache) {
   mj_deleteVFS(vfs.get());
 }
 
+TEST_F(PluginTest, RecompileComparePngCache) {
+  static constexpr char xml[] = R"(
+  <mujoco>
+    <asset>
+      <texture content_type="image/png" file="tex.png" type="2d"/>
+      <material name="material" texture="tex"/>
+    </asset>
+
+    <worldbody>
+      <geom type="plane" material="material" size="4 4 4"/>
+    </worldbody>
+  </mujoco>
+)";
+
+  // tiny RGB 2 x 3 PNG file
+  static constexpr unsigned char tex1[] = {
+    0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+    0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x02,
+    0x08, 0x02, 0x00, 0x00, 0x00, 0x12, 0x16, 0xf1, 0x4d, 0x00, 0x00, 0x00,
+    0x1c, 0x49, 0x44, 0x41, 0x54, 0x08, 0xd7, 0x63, 0x78, 0xc1, 0xc0, 0xc0,
+    0xc0, 0xf0, 0xbf, 0xb8, 0xb8, 0x98, 0x81, 0xe1, 0x3f, 0xc3, 0xff, 0xff,
+    0xff, 0xc5, 0xc4, 0xc4, 0x00, 0x46, 0xd7, 0x07, 0x7f, 0xd2, 0x52, 0xa1,
+    0x41, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60,
+    0x82
+  };
+
+  // previous PNG file, but rotated by 180 degrees
+  static constexpr unsigned char tex2[] = {
+    0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+    0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x02,
+    0x08, 0x02, 0x00, 0x00, 0x00, 0x12, 0x16, 0xf1, 0x4d, 0x00, 0x00, 0x00,
+    0x1c, 0x49, 0x44, 0x41, 0x54, 0x08, 0xd7, 0x63, 0x10, 0x13, 0x13, 0xfb,
+    0xff, 0xff, 0x3f, 0xc3, 0x7f, 0x06, 0x96, 0xd8, 0xd8, 0x58, 0x46, 0x46,
+    0x86, 0x17, 0x0c, 0x0c, 0x00, 0x49, 0x22, 0x06, 0x44, 0xe4, 0x91, 0xb8,
+    0x83, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60,
+    0x82
+  };
+
+
+  auto vfs = std::make_unique<mjVFS>();
+  mj_defaultVFS(vfs.get());
+  mj_addBufferVFS(vfs.get(), "tex.png", tex1, sizeof(tex1));
+
+  std::array<char, 1024> error;
+
+  // load model once
+  mjModel* m = LoadModelFromString(xml, error.data(), error.size(), vfs.get());
+  EXPECT_EQ(m->ntexdata, 18);  // w x h x rgb = 3 x 2 x 3
+  mjtByte byte = m->tex_rgb[0];
+  mj_deleteModel(m);
+
+  // update tex.png, load again
+  mj_deleteFileVFS(vfs.get(), "tex.png");
+  mj_addBufferVFS(vfs.get(), "tex.png", tex2, sizeof(tex2));
+  m = LoadModelFromString(xml, error.data(), error.size(), vfs.get());
+  EXPECT_NE(m->tex_rgb[0], byte);
+  EXPECT_EQ(m->tex_rgb[15], byte);  // first pixel is now last pixel
+  mj_deleteModel(m);
+
+  mj_deleteVFS(vfs.get());
+}
+
 // -------------------------------- test attach --------------------------------
+
 static constexpr char xml_child[] = R"(
   <mujoco>
     <default>
diff --git a/test/user/user_objects_test.cc b/test/user/user_objects_test.cc
index 5441ea9f..93043166 100644
--- a/test/user/user_objects_test.cc
+++ b/test/user/user_objects_test.cc
@@ -342,20 +342,18 @@ TEST_F(ContentTypeTest, TextureLoadPng) {
   </mujoco>
   )";
 
-  // credit: https://www.mjt.me.uk/posts/smallest-png/
-  static constexpr unsigned char tiny[] =
-      { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0x00,
-        0x00, 0x00, 0x0D, 0x49, 0x48, 0x44, 0x52, 0x00, 0x00,
-        0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x03, 0x00,
-        0x00, 0x00, 0x66, 0xBC, 0x3A, 0x25, 0x00, 0x00, 0x00,
-        0x03, 0x50, 0x4C, 0x54, 0x45, 0xB5, 0xD0, 0xD0, 0x63,
-        0x04, 0x16, 0xEA, 0x00, 0x00, 0x00, 0x1F, 0x49, 0x44,
-        0x41, 0x54, 0x68, 0x81, 0xED, 0xC1, 0x01, 0x0D, 0x00,
-        0x00, 0x00, 0xC2, 0xA0, 0xF7, 0x4F, 0x6D, 0x0E, 0x37,
-        0xA0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0xBE, 0x0D, 0x21, 0x00, 0x00, 0x01, 0x9A, 0x60, 0xE1,
-        0xD5, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44,
-        0xAE, 0x42, 0x60, 0x82 };
+  // tiny RGB 2 x 3 PNG file
+  static constexpr unsigned char tiny[] = {
+    0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+    0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x02,
+    0x08, 0x02, 0x00, 0x00, 0x00, 0x12, 0x16, 0xf1, 0x4d, 0x00, 0x00, 0x00,
+    0x1c, 0x49, 0x44, 0x41, 0x54, 0x08, 0xd7, 0x63, 0x78, 0xc1, 0xc0, 0xc0,
+    0xc0, 0xf0, 0xbf, 0xb8, 0xb8, 0x98, 0x81, 0xe1, 0x3f, 0xc3, 0xff, 0xff,
+    0xff, 0xc5, 0xc4, 0xc4, 0x00, 0x46, 0xd7, 0x07, 0x7f, 0xd2, 0x52, 0xa1,
+    0x41, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60,
+    0x82
+  };
+
   size_t tiny_sz = sizeof(tiny);
 
   char error[1024];
diff --git a/test/xml/xml_native_reader_test.cc b/test/xml/xml_native_reader_test.cc
index 0a210378..5658be39 100644
--- a/test/xml/xml_native_reader_test.cc
+++ b/test/xml/xml_native_reader_test.cc
@@ -490,20 +490,17 @@ TEST_F(XMLReaderTest, InvalidDefaultClassName) {
 
 // ------------------------ test including -------------------------------------
 
-// credit: https://www.mjt.me.uk/posts/smallest-png/
-static constexpr unsigned char kTinyPng[] =
-    { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0x00,
-      0x00, 0x00, 0x0D, 0x49, 0x48, 0x44, 0x52, 0x00, 0x00,
-      0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x03, 0x00,
-      0x00, 0x00, 0x66, 0xBC, 0x3A, 0x25, 0x00, 0x00, 0x00,
-      0x03, 0x50, 0x4C, 0x54, 0x45, 0xB5, 0xD0, 0xD0, 0x63,
-      0x04, 0x16, 0xEA, 0x00, 0x00, 0x00, 0x1F, 0x49, 0x44,
-      0x41, 0x54, 0x68, 0x81, 0xED, 0xC1, 0x01, 0x0D, 0x00,
-      0x00, 0x00, 0xC2, 0xA0, 0xF7, 0x4F, 0x6D, 0x0E, 0x37,
-      0xA0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-      0xBE, 0x0D, 0x21, 0x00, 0x00, 0x01, 0x9A, 0x60, 0xE1,
-      0xD5, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44,
-      0xAE, 0x42, 0x60, 0x82 };
+// tiny RGB 2 x 3 PNG file
+static constexpr unsigned char kTinyPng[] = {
+  0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+  0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x02,
+  0x08, 0x02, 0x00, 0x00, 0x00, 0x12, 0x16, 0xf1, 0x4d, 0x00, 0x00, 0x00,
+  0x1c, 0x49, 0x44, 0x41, 0x54, 0x08, 0xd7, 0x63, 0x78, 0xc1, 0xc0, 0xc0,
+  0xc0, 0xf0, 0xbf, 0xb8, 0xb8, 0x98, 0x81, 0xe1, 0x3f, 0xc3, 0xff, 0xff,
+  0xff, 0xc5, 0xc4, 0xc4, 0x00, 0x46, 0xd7, 0x07, 0x7f, 0xd2, 0x52, 0xa1,
+  0x41, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60,
+  0x82
+};
 
 TEST_F(XMLReaderTest, IncludeTest) {
   static constexpr char xml[] = R"(