From 332bcb62fa8099b39ae83fb09a254fdc3d8f6b7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Thu, 11 May 2023 12:44:49 +0200
Subject: [PATCH] It makes no sense to call isPixelFormatSrgb() on a
 depth/stencil format.

Doing so usually points to some error in user code, so directly disallow
it, instead of returning false. Such behavior is consistent with
pixelFormatChannelCount() and other helper APIs.
---
 src/Magnum/PixelFormat.cpp          |  3 ++-
 src/Magnum/PixelFormat.h            |  3 ++-
 src/Magnum/Test/PixelFormatTest.cpp | 12 +++++++-----
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/Magnum/PixelFormat.cpp b/src/Magnum/PixelFormat.cpp
index 40afec253..52d5fa2dc 100644
--- a/src/Magnum/PixelFormat.cpp
+++ b/src/Magnum/PixelFormat.cpp
@@ -352,6 +352,7 @@ bool isPixelFormatSrgb(const PixelFormat format) {
         case PixelFormat::RG32F:
         case PixelFormat::RGB32F:
         case PixelFormat::RGBA32F:
+            return false;
         case PixelFormat::Depth16Unorm:
         case PixelFormat::Depth24Unorm:
         case PixelFormat::Depth32F:
@@ -359,7 +360,7 @@ bool isPixelFormatSrgb(const PixelFormat format) {
         case PixelFormat::Depth16UnormStencil8UI:
         case PixelFormat::Depth24UnormStencil8UI:
         case PixelFormat::Depth32FStencil8UI:
-            return false;
+            CORRADE_ASSERT_UNREACHABLE("isPixelFormatSrgb(): can't determine colorspace of" << format, {});
     }
     #ifdef CORRADE_TARGET_GCC
     #pragma GCC diagnostic pop
diff --git a/src/Magnum/PixelFormat.h b/src/Magnum/PixelFormat.h
index e80005996..70f9b1406 100644
--- a/src/Magnum/PixelFormat.h
+++ b/src/Magnum/PixelFormat.h
@@ -814,7 +814,8 @@ MAGNUM_EXPORT UnsignedInt pixelFormatChannelCount(PixelFormat format);
 @m_since_latest
 
 Returns @cpp true @ce for `*Srgb` formats, @cpp false @ce otherwise. Expects
-that the pixel format is *not* implementation-specific.
+that the pixel format is *not* implementation-specific and not a
+depth/stencil format.
 @see @ref isPixelFormatImplementationSpecific()
 */
 MAGNUM_EXPORT bool isPixelFormatSrgb(PixelFormat format);
diff --git a/src/Magnum/Test/PixelFormatTest.cpp b/src/Magnum/Test/PixelFormatTest.cpp
index e11b9149e..f4c0e9b92 100644
--- a/src/Magnum/Test/PixelFormatTest.cpp
+++ b/src/Magnum/Test/PixelFormatTest.cpp
@@ -50,7 +50,7 @@ struct PixelFormatTest: TestSuite::Tester {
 
     void isSrgb();
     void isSrgbInvalid();
-    void isSrgbImplementationSpecific();
+    void isSrgbDepthStencilImplementationSpecific();
 
     void isDepthOrStencil();
     void isDepthOrStencilInvalid();
@@ -100,7 +100,7 @@ PixelFormatTest::PixelFormatTest() {
 
               &PixelFormatTest::isSrgb,
               &PixelFormatTest::isSrgbInvalid,
-              &PixelFormatTest::isSrgbImplementationSpecific,
+              &PixelFormatTest::isSrgbDepthStencilImplementationSpecific,
 
               &PixelFormatTest::isDepthOrStencil,
               &PixelFormatTest::isDepthOrStencilInvalid,
@@ -319,8 +319,8 @@ void PixelFormatTest::channelFormatCountDepthStencilImplementationSpecific() {
 
 void PixelFormatTest::isSrgb() {
     CORRADE_VERIFY(isPixelFormatSrgb(PixelFormat::RG8Srgb));
+    CORRADE_VERIFY(!isPixelFormatSrgb(PixelFormat::RG8Snorm));
     CORRADE_VERIFY(!isPixelFormatSrgb(PixelFormat::RGB16F));
-    CORRADE_VERIFY(!isPixelFormatSrgb(PixelFormat::Stencil8UI));
 }
 
 void PixelFormatTest::isSrgbInvalid() {
@@ -335,14 +335,16 @@ void PixelFormatTest::isSrgbInvalid() {
         "isPixelFormatSrgb(): invalid format PixelFormat(0xdead)\n");
 }
 
-void PixelFormatTest::isSrgbImplementationSpecific() {
+void PixelFormatTest::isSrgbDepthStencilImplementationSpecific() {
     CORRADE_SKIP_IF_NO_ASSERT();
 
     std::ostringstream out;
     Error redirectError{&out};
     isPixelFormatSrgb(pixelFormatWrap(0xdead));
+    isPixelFormatSrgb(PixelFormat::Depth16Unorm);
     CORRADE_COMPARE(out.str(),
-        "isPixelFormatSrgb(): can't determine colorspace of an implementation-specific format 0xdead\n");
+        "isPixelFormatSrgb(): can't determine colorspace of an implementation-specific format 0xdead\n"
+        "isPixelFormatSrgb(): can't determine colorspace of PixelFormat::Depth16Unorm\n");
 }
 
 void PixelFormatTest::isDepthOrStencil() {