[core] Refactor OpenGL extension loading mechanism

Previously, we initialized global variables that held pointers to the extension functions. While this seemed to work, the spec doesn't guarantee that the function pointers are identical for different OpenGL contexts. Therefore, we are now making them a member variable of the Context object.

1 files changed, 55 insertions, 0 deletions

diff --git a/src/mbgl/gl/debugging_extension.cpp b/src/mbgl/gl/debugging_extension.cpp
new file mode 100644
index 0000000000..5afa4f50fc
--- /dev/null
+++ b/src/mbgl/gl/debugging_extension.cpp
@@ -0,0 +1,55 @@
+#include <mbgl/gl/debugging_extension.hpp>
+#include <mbgl/util/logging.hpp>
+
+namespace mbgl {
+namespace gl {
+namespace extension {
+
+void Debugging::DebugCallback(GLenum source,
+                              GLenum type,
+                              GLuint id,
+                              GLenum severity,
+                              GLsizei /* length */,
+                              const GLchar* message,
+                              const void* /* userParam */) {
+    std::string strSource;
+    switch (source) {
+        case GL_DEBUG_SOURCE_API: strSource = "DEBUG_SOURCE_API"; break;
+        case GL_DEBUG_SOURCE_WINDOW_SYSTEM: strSource = "DEBUG_SOURCE_WINDOW_SYSTEM"; break;
+        case GL_DEBUG_SOURCE_SHADER_COMPILER: strSource = "DEBUG_SOURCE_SHADER_COMPILER"; break;
+        case GL_DEBUG_SOURCE_THIRD_PARTY: strSource = "DEBUG_SOURCE_THIRD_PARTY"; break;
+        case GL_DEBUG_SOURCE_APPLICATION: strSource = "DEBUG_SOURCE_APPLICATION"; break;
+        case GL_DEBUG_SOURCE_OTHER: strSource = "DEBUG_SOURCE_OTHER"; break;
+        default: strSource = "(unknown)"; break;
+    }
+
+    std::string strType;
+    switch (type) {
+        case GL_DEBUG_TYPE_ERROR: strType = "DEBUG_TYPE_ERROR"; break;
+        case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR: strType = "DEBUG_TYPE_DEPRECATED_BEHAVIOR"; break;
+        case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR: strType = "DEBUG_TYPE_UNDEFINED_BEHAVIOR"; break;
+        case GL_DEBUG_TYPE_PERFORMANCE: strType = "DEBUG_TYPE_PERFORMANCE"; break;
+        case GL_DEBUG_TYPE_PORTABILITY: strType = "DEBUG_TYPE_PORTABILITY"; break;
+        case GL_DEBUG_TYPE_OTHER: strType = "DEBUG_TYPE_OTHER"; break;
+        case GL_DEBUG_TYPE_MARKER: strType = "DEBUG_TYPE_MARKER"; break;
+        case GL_DEBUG_TYPE_PUSH_GROUP: strType = "DEBUG_TYPE_OTHER"; break;
+        case GL_DEBUG_TYPE_POP_GROUP: strType = "DEBUG_TYPE_POP_GROUP"; break;
+        default: strSource = "(unknown)"; break;
+    }
+
+    std::string strSeverity;
+    mbgl::EventSeverity evtSeverity;
+    switch (severity) {
+        case GL_DEBUG_SEVERITY_HIGH: strSeverity = "DEBUG_SEVERITY_HIGH"; evtSeverity = mbgl::EventSeverity::Error; break;
+        case GL_DEBUG_SEVERITY_MEDIUM: strSeverity = "DEBUG_SEVERITY_MEDIUM"; evtSeverity = mbgl::EventSeverity::Warning; break;
+        case GL_DEBUG_SEVERITY_LOW: strSeverity = "DEBUG_SEVERITY_LOW"; evtSeverity = mbgl::EventSeverity::Info; break;
+        case GL_DEBUG_SEVERITY_NOTIFICATION: strSeverity = "DEBUG_SEVERITY_NOTIFICATION"; evtSeverity = mbgl::EventSeverity::Debug; break;
+        default: strSource = "(unknown)"; evtSeverity = mbgl::EventSeverity::Debug; break;
+    }
+
+    mbgl::Log::Record(evtSeverity, mbgl::Event::OpenGL, "GL_%s GL_%s %u GL_%s - %s", strSource.c_str(), strType.c_str(), id, strSeverity.c_str(), message);
+}
+
+} // namespace extension
+} // namespace gl
+} // namespace mbgl