From 5328426b4b04fa0473afa8b0f009037a9a890264 Mon Sep 17 00:00:00 2001
From: Cameron Cawley <ccawley2011@gmail.com>
Date: Thu, 25 Jun 2020 17:12:50 +0100
Subject: [PATCH] Support using the OpenGL3 renderer with SDL 1.2

---
 CMakeLists.txt                                |  2 +
 .../Rendering/Window/OpenGL3/SDL1.cpp         | 52 +++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 src/Backends/Rendering/Window/OpenGL3/SDL1.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 229b60b9..cc6cf6f0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -440,6 +440,8 @@ elseif(BACKEND_PLATFORM MATCHES "SDL2" AND BACKEND_RENDERER MATCHES "SDLTexture"
 elseif(BACKEND_PLATFORM MATCHES "SDL2" AND BACKEND_RENDERER MATCHES "SDLSurface")
 elseif(BACKEND_PLATFORM MATCHES "SDL2" AND BACKEND_RENDERER MATCHES "Software")
 	target_sources(CSE2 PRIVATE "src/Backends/Rendering/Window/Software/SDL2.cpp")
+elseif(BACKEND_PLATFORM MATCHES "SDL1" AND BACKEND_RENDERER MATCHES "OpenGL3")
+	target_sources(CSE2 PRIVATE "src/Backends/Rendering/Window/OpenGL3/SDL1.cpp")
 elseif(BACKEND_PLATFORM MATCHES "SDL1" AND BACKEND_RENDERER MATCHES "Software")
 	target_sources(CSE2 PRIVATE "src/Backends/Rendering/Window/Software/SDL1.cpp")
 elseif(BACKEND_PLATFORM MATCHES "GLFW3" AND BACKEND_RENDERER MATCHES "OpenGL3")
diff --git a/src/Backends/Rendering/Window/OpenGL3/SDL1.cpp b/src/Backends/Rendering/Window/OpenGL3/SDL1.cpp
new file mode 100644
index 00000000..44a7d867
--- /dev/null
+++ b/src/Backends/Rendering/Window/OpenGL3/SDL1.cpp
@@ -0,0 +1,52 @@
+#include "../OpenGL.h"
+
+#include <stddef.h>
+#include <string>
+
+#include <glad/glad.h>
+#include "SDL.h"
+
+#include "../../../Misc.h"
+
+bool WindowBackend_OpenGL_CreateWindow(const char *window_title, int *screen_width, int *screen_height, bool fullscreen)
+{
+	if (SDL_SetVideoMode(*screen_width, *screen_height, 0, SDL_RESIZABLE | SDL_OPENGL | (fullscreen ? SDL_FULLSCREEN : 0)) != NULL)
+	{
+		SDL_WM_SetCaption(window_title, NULL);
+
+		if (gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress))
+		{
+			// Check if the platform supports OpenGL 3.2
+			if (GLAD_GL_VERSION_3_2)
+			{
+				Backend_PostWindowCreation();
+
+				return true;
+			}
+			else
+			{
+				Backend_ShowMessageBox("Fatal error (OpenGL rendering backend)", "Your system does not support OpenGL 3.2");
+			}
+		}
+		else
+		{
+			Backend_ShowMessageBox("Fatal error (OpenGL rendering backend)", "Couldn't load OpenGL functions");
+		}
+	}
+	else
+	{
+		std::string error_message = std::string("Could not create window: ") + SDL_GetError();
+		Backend_ShowMessageBox("Fatal error (OpenGL rendering backend)", error_message.c_str());
+	}
+
+	return false;
+}
+
+void WindowBackend_OpenGL_DestroyWindow(void)
+{
+}
+
+void WindowBackend_OpenGL_Display(void)
+{
+	SDL_GL_SwapBuffers();
+}