Changeset: 69 Add option for enabling OpenGL debug mode

1 files changed, 33 insertions, 2 deletions

diff --git a/source/30-game/main.cpp b/source/30-game/main.cpp
index c49fc0b..89f0e97 100644
--- a/source/30-game/main.cpp
+++ b/source/30-game/main.cpp
@@ -36,6 +36,10 @@ void GlfwErrorCallback(int error, const char* description) {
 	fprintf(stderr, "[GLFW] Error %d: %s\n", error, description);
 }
 
+void OpenGLDebugCallback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam​) {
+	fprintf(stderr, "GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n", (type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : ""), type, severity, message);
+}
+
 void GlfwFramebufferResizeCallback(GLFWwindow* window, int width, int height) {
 	AppConfig::mainWindowWidth = width;
 	AppConfig::mainWindowHeight = height;
@@ -102,6 +106,7 @@ fs::path GetEnvVar(const char* name, const char* backup) {
 int main(int argc, char* argv[]) {
 	using namespace Tags;
 
+	constexpr auto kOpenGLDebug = "opengl-debug";
 	constexpr auto kImGuiBackend = "imgui-backend";
 	constexpr auto kGameDataDir = "game-data-directory";
 	constexpr auto kGameAssetDir = "game-asset-directory";
@@ -109,6 +114,7 @@ int main(int argc, char* argv[]) {
 	cxxopts::Options options(std::string(AppConfig::kAppName), "");
 	// clang-format off
 	options.add_options()
+	(kOpenGLDebug, "Enable OpenGL debugging messages.")
 	(kImGuiBackend, "ImGui backend. Options: opengl2, opengl3. Leave empty to default.", cxxopts::value<std::string>())
 	(kGameAssetDir, "Directory in which assets are looked up from. Can be relative paths to the executable.", cxxopts::value<std::string>()->default_value("."))
 	(kGameDataDir, "Directory in which game data (such as saves and options) are saved to. Leave empty to use the default directory on each platform.", cxxopts::value<std::string>())
@@ -206,7 +212,7 @@ int main(int argc, char* argv[]) {
 
 	GlfwUserData glfwUserData;
 
-	GLFWwindow* window = glfwCreateWindow(1280, 720, "ImGui Command Palette Example", nullptr, nullptr);
+	GLFWwindow* window = glfwCreateWindow(1280, 720, "Project Brussel", nullptr, nullptr);
 	if (window == nullptr) {
 		return -2;
 	}
@@ -228,11 +234,36 @@ int main(int argc, char* argv[]) {
 	glfwMakeContextCurrent(window);
 	glfwSwapInterval(1);
 
-	// TODO setup opengl debug context
 	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
 		return -3;
 	}
 
+#if defined(BRUSSEL_DEV_ENV)
+	{
+		auto glVersionString = glGetString(GL_VERSION);
+
+		int glMajorVersion;
+		glGetIntegerv(GL_MAJOR_VERSION, &glMajorVersion);
+		int glMinorVersion;
+		glGetIntegerv(GL_MINOR_VERSION, &glMinorVersion);
+
+		printf("OpenGL version (via glGetString(GL_VERSION)): %s\n", glVersionString);
+		printf("OpenGL version (via glGetIntegerv() with GL_MAJOR_VERSION and GL_MINOR_VERSION): %d.%d\n", glMajorVersion, glMinorVersion);
+	}
+#endif
+
+	bool useOpenGLDebug = args[kOpenGLDebug].as<bool>();
+	if (useOpenGLDebug) {
+		printf("Using OpenGL debugging\n --%s", kOpenGLDebug);
+
+		// TODO check extension KHR_debug availability
+		// TODO conan glad is not including any extensions
+		// NOTE: KHR_debug is a core extension, which means it may be available in lower version even though the feature is added in 4.3
+		
+		glEnable(GL_DEBUG_OUTPUT);
+		glDebugMessageCallback(&OpenGLDebugCallback, 0);
+	}
+
 	IMGUI_CHECKVERSION();
 	auto ctx = ImGui::CreateContext();
 	auto& io = ImGui::GetIO();