Move OpenGL extension query into renderer backend

src/renderer_gl/opengl_capabilities.cpp

@@ -344,6 +344,31 @@ pp::foundation::Result<OpenGlRuntimeInfo> query_opengl_runtime_info(
     });
 }
 
+pp::foundation::Result<std::vector<std::string>> query_opengl_extensions(
+    OpenGlExtensionQueryDispatch dispatch)
+{
+    if (dispatch.get_integer == nullptr || dispatch.get_string_indexed == nullptr) {
+        return pp::foundation::Result<std::vector<std::string>>::failure(
+            pp::foundation::Status::invalid_argument("OpenGL extension query callbacks must not be null"));
+    }
+
+    std::int32_t extension_count = 0;
+    dispatch.get_integer(extension_count_query(), &extension_count);
+    if (extension_count <= 0) {
+        return pp::foundation::Result<std::vector<std::string>>::success({});
+    }
+
+    std::vector<std::string> extensions;
+    extensions.reserve(static_cast<std::size_t>(extension_count));
+    for (std::int32_t index = 0; index < extension_count; ++index) {
+        const char* extension = dispatch.get_string_indexed(
+            extension_string_name(),
+            static_cast<std::uint32_t>(index));
+        extensions.emplace_back(extension != nullptr ? extension : "");
+    }
+    return pp::foundation::Result<std::vector<std::string>>::success(std::move(extensions));
+}
+
 OpenGlDefaultClear panopainter_default_clear() noexcept
 {
     return OpenGlDefaultClear {

src/renderer_gl/opengl_capabilities.h

@@ -5,7 +5,9 @@
 #include <array>
 #include <cstdint>
 #include <span>
+#include <string>
 #include <string_view>
+#include <vector>
 
 namespace pp::renderer::gl {
 
@@ -459,11 +461,17 @@ struct OpenGlRuntimeInfo {
 };
 
 using OpenGlStringQueryFn = const char* (*)(std::uint32_t name) noexcept;
+using OpenGlIndexedStringQueryFn = const char* (*)(std::uint32_t name, std::uint32_t index) noexcept;
 
 struct OpenGlRuntimeInfoDispatch {
     OpenGlStringQueryFn get_string = nullptr;
 };
 
+struct OpenGlExtensionQueryDispatch {
+    OpenGlGetIntegerFn get_integer = nullptr;
+    OpenGlIndexedStringQueryFn get_string_indexed = nullptr;
+};
+
 struct OpenGlDefaultClear {
     std::array<float, 4> color {};
     std::uint32_t mask = 0;
@@ -690,6 +698,8 @@ struct OpenGlMeshDeleteDispatch {
     OpenGlStateRestoreDispatch dispatch) noexcept;
 [[nodiscard]] pp::foundation::Result<OpenGlRuntimeInfo> query_opengl_runtime_info(
     OpenGlRuntimeInfoDispatch dispatch) noexcept;
+[[nodiscard]] pp::foundation::Result<std::vector<std::string>> query_opengl_extensions(
+    OpenGlExtensionQueryDispatch dispatch);
 [[nodiscard]] OpenGlDefaultClear panopainter_default_clear() noexcept;
 [[nodiscard]] pp::foundation::Status clear_panopainter_default_target(OpenGlClearDispatch dispatch) noexcept;
 [[nodiscard]] pp::foundation::Status apply_opengl_viewport(