Move OpenGL framebuffer diagnostics

docs/modernization/build-inventory.md

@@ -129,7 +129,8 @@ Known local toolchain state:
   GLES float/half-float extensions, WebGL exclusion behavior, and the
   upload-type mapping used by legacy `Texture2D` and `RTT` creation. It also
   validates image channel-count to OpenGL texture format mapping, including
-  invalid channel counts rejected by `Texture2D::create(Image)`.
+  invalid channel counts rejected by `Texture2D::create(Image)`, and
+  framebuffer status naming used by `RTT` diagnostics.
 - `windows-msvc-vcpkg-headless` validates manifest install/configure/build/test
   for the current headless component matrix; see DEBT-0007 for remaining app
   and platform triplet migration.

docs/modernization/roadmap.md

@@ -389,9 +389,10 @@ catalog now consumed by the legacy OpenGL app initialization path.
 OpenGL capability detection for framebuffer fetch, map-buffer alignment, and
 float texture support. It also owns the OpenGL texture upload-type mapping used
 by legacy `Texture2D` and `RTT` creation, plus image channel-count to texture
-format mapping for `Texture2D` image uploads. The legacy app delegates
+format mapping for `Texture2D` image uploads and framebuffer status naming for
-extension and upload-format interpretation to that backend library, but the
+`RTT` diagnostics. The legacy app delegates extension, upload-format, and
-existing renderer classes are not yet fully behind the renderer interfaces.
+framebuffer diagnostic interpretation to that backend library, but the existing
+renderer classes are not yet fully behind the renderer interfaces.
 
 Implementation tasks:
 
@@ -631,7 +632,8 @@ Results:
   and Android arm64 configure/build, covering framebuffer fetch, map-buffer
   alignment, desktop GL core float support, GLES float/half-float extensions,
   WebGL exclusion behavior, upload types for RGBA8/RGBA16F/RGBA32F internal
-  formats, and image channel-count format mapping including invalid counts.
+  formats, image channel-count format mapping including invalid counts, and
+  framebuffer status names.
 - PowerShell analyze automation returns JSON summaries and includes the shader
   validation target.
 - `windows-msvc-vcpkg-headless` configured through the Visual Studio bundled

src/renderer_gl/opengl_capabilities.cpp

@@ -17,6 +17,14 @@ constexpr std::uint32_t gl_rgb8 = 0x8051U;
 constexpr std::uint32_t gl_rgba8 = 0x8058U;
 constexpr std::uint32_t gl_rgba32f = 0x8814U;
 constexpr std::uint32_t gl_rgba16f = 0x881AU;
+constexpr std::uint32_t gl_framebuffer_complete = 0x8CD5U;
+constexpr std::uint32_t gl_framebuffer_incomplete_attachment = 0x8CD6U;
+constexpr std::uint32_t gl_framebuffer_incomplete_missing_attachment = 0x8CD7U;
+constexpr std::uint32_t gl_framebuffer_incomplete_draw_buffer = 0x8CDBU;
+constexpr std::uint32_t gl_framebuffer_incomplete_read_buffer = 0x8CDCU;
+constexpr std::uint32_t gl_framebuffer_unsupported = 0x8CDDU;
+constexpr std::uint32_t gl_framebuffer_undefined = 0x8219U;
+constexpr std::uint32_t gl_framebuffer_incomplete_multisample = 0x8D56U;
 
 [[nodiscard]] bool contains(std::string_view text, std::string_view needle) noexcept
 {
@@ -92,4 +100,28 @@ OpenGlPixelFormat texture_format_for_channel_count(std::uint32_t channel_count)
     }
 }
 
+const char* framebuffer_status_name(std::uint32_t status) noexcept
+{
+    switch (status) {
+    case gl_framebuffer_complete:
+        return "GL_FRAMEBUFFER_COMPLETE";
+    case gl_framebuffer_undefined:
+        return "GL_FRAMEBUFFER_UNDEFINED";
+    case gl_framebuffer_incomplete_attachment:
+        return "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT";
+    case gl_framebuffer_incomplete_missing_attachment:
+        return "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT";
+    case gl_framebuffer_incomplete_draw_buffer:
+        return "GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER";
+    case gl_framebuffer_incomplete_read_buffer:
+        return "GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER";
+    case gl_framebuffer_unsupported:
+        return "GL_FRAMEBUFFER_UNSUPPORTED";
+    case gl_framebuffer_incomplete_multisample:
+        return "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE";
+    default:
+        return "UNKNOWN";
+    }
+}
+
 }

src/renderer_gl/opengl_capabilities.h

@@ -32,5 +32,6 @@ struct OpenGlPixelFormat {
 
 [[nodiscard]] std::uint32_t texture_upload_type_for_internal_format(std::uint32_t internal_format) noexcept;
 [[nodiscard]] OpenGlPixelFormat texture_format_for_channel_count(std::uint32_t channel_count) noexcept;
+[[nodiscard]] const char* framebuffer_status_name(std::uint32_t status) noexcept;
 
 }

src/rtt.cpp

@@ -244,22 +244,11 @@ bool RTT::create(int width, int height, int tex/* = -1*/, GLint internal_format,
             glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, rboID);
         }
 
-        auto err2str = [](GLenum err) {
-            switch (err)
-            {
-            case GL_FRAMEBUFFER_UNDEFINED: return "GL_FRAMEBUFFER_UNDEFINED";
-            case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: return "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT";
-            case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: return "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT";
-            case GL_FRAMEBUFFER_UNSUPPORTED: return "GL_FRAMEBUFFER_UNSUPPORTED";
-            case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE: return "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE";
-            default: return "UNKNOWN";
-            }
-        };
-
         // Check FBO status
         status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
         if (status != GL_FRAMEBUFFER_COMPLETE)
-            LOG("RTT::create failed because: %s", err2str(status));
+            LOG("RTT::create failed because: %s",
+                pp::renderer::gl::framebuffer_status_name(static_cast<std::uint32_t>(status)));
 
         // Switch back to window-system-provided framebuffer
         glBindFramebuffer(GL_FRAMEBUFFER, oldFboID);

tests/renderer_gl/capabilities_tests.cpp

@@ -114,6 +114,25 @@ void maps_image_channel_count_to_texture_format(pp::tests::Harness& h)
     PP_EXPECT(h, invalid.pixel_format == 0U);
 }
 
+void names_framebuffer_status_codes(pp::tests::Harness& h)
+{
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CD5U) == std::string_view("GL_FRAMEBUFFER_COMPLETE"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8219U) == std::string_view("GL_FRAMEBUFFER_UNDEFINED"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CD6U)
+                     == std::string_view("GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CD7U)
+                     == std::string_view("GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CDBU)
+                     == std::string_view("GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CDCU)
+                     == std::string_view("GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8CDDU)
+                     == std::string_view("GL_FRAMEBUFFER_UNSUPPORTED"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0x8D56U)
+                     == std::string_view("GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE"));
+    PP_EXPECT(h, pp::renderer::gl::framebuffer_status_name(0U) == std::string_view("UNKNOWN"));
+}
+
 }
 
 int main()
@@ -125,5 +144,6 @@ int main()
     harness.run("ignores_gles_texture_extensions_for_webgl_runtime", ignores_gles_texture_extensions_for_webgl_runtime);
     harness.run("selects_texture_upload_type_from_internal_format", selects_texture_upload_type_from_internal_format);
     harness.run("maps_image_channel_count_to_texture_format", maps_image_channel_count_to_texture_format);
+    harness.run("names_framebuffer_status_codes", names_framebuffer_status_codes);
     return harness.finish();
 }