Switch to GLES2

Closes #13

render/gles2/util.c

@@ -0,0 +1,38 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include <GLES2/gl2.h>
+#include <wlr/util/log.h>
+#include "render/gles2.h"
+
+const char *gles2_strerror(GLenum err) {
+	switch (err) {
+	case GL_INVALID_ENUM:
+		return "Invalid enum";
+	case GL_INVALID_VALUE:
+		return "Invalid value";
+	case GL_INVALID_OPERATION:
+		return "Invalid operation";
+	case GL_OUT_OF_MEMORY:
+		return "Out of memory";
+	case GL_INVALID_FRAMEBUFFER_OPERATION:
+		return "Invalid framebuffer operation";
+	default:
+		return "Unknown error";
+	}
+}
+
+bool _gles2_flush_errors(const char *file, int line) {
+	GLenum err;
+	bool failure = false;
+	while ((err = glGetError()) != GL_NO_ERROR) {
+		failure = true;
+		if (err == GL_OUT_OF_MEMORY) {
+			// The OpenGL context is now undefined
+			_wlr_log(L_ERROR, "[%s:%d] Fatal GL error: out of memory", file, line);
+			exit(1);
+		} else {
+			_wlr_log(L_ERROR, "[%s:%d] GL error %d %s", file, line, err, gles2_strerror(err));
+		}
+	}
+	return failure;
+}