From e3163ca8a315aeb3f9986cd3d181ada77954b6df Mon Sep 17 00:00:00 2001
From: outfrost <kotlet.bahn@gmail.com>
Date: Tue, 22 Jan 2019 22:24:00 +0100
Subject: [PATCH] Add vsync via EXT_swap_control

---
 Makefile |  2 +-
 main.c   | 30 +++++++++++++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 9486be4..3dfa87d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 compileargs ::= -g -Wall -Wextra -Wpedantic
 linkargs ::=
-libraries ::= -L/usr/local/lib -lGL -lglut -lassimp
+libraries ::= -L/usr/local/lib -lGL -lGLEW -lglut -lassimp
 # Prefix all object file names with the compilation directory
 objects ::= $(addprefix out/, \
               main.o debugutil.o glut_janitor.o render.o \
diff --git a/main.c b/main.c
index 32f2c85..28b3c4d 100644
--- a/main.c
+++ b/main.c
@@ -1,4 +1,6 @@
+#include <GL/glxew.h>
 #include <GL/glut.h>
+#include <stdio.h>
 
 #include "debugutil.h"
 #include "glut_janitor.h"
@@ -8,14 +10,40 @@
 
 int main(int argc, char** argv) {
 	glutInit(&argc, argv);
+	// glutInitContextVersion(4,5); TODO establish correct context
 	
 	glutInitWindowSize(800, 600);
 	
-	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGBA | GLUT_DEPTH);
+	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
 	glutCreateWindow(NULL);
 	
 	glutSetWindowTitle(getGlInfoString());
 	
+	GLenum glewInitStatus = glewInit();
+	if (glewInitStatus != GLEW_OK) {
+		fprintf(stderr, "GLEW init failed: %s\n", glewGetErrorString(glewInitStatus));
+		return 1;
+	}
+	printf("GLEW %s\n", glewGetString(GLEW_VERSION));
+	
+	if (GLXEW_EXT_swap_control) {
+		Display* display = glXGetCurrentDisplay();
+		GLXDrawable drawable = glXGetCurrentDrawable();
+		if (drawable) {
+			glXSwapIntervalEXT(display, drawable, 1);
+		}
+		else {
+			fprintf(stderr, "Drawable is not here\n");
+		}
+	}
+	else if (GLXEW_MESA_swap_control) {
+		glXSwapIntervalMESA(1);
+		printf("Swap interval %d\n", glXGetSwapIntervalMESA());
+	}
+	else {
+		fprintf(stderr, "Could not enable vsync\n");
+	}
+	
 	glutDisplayFunc(renderScene);
 	glutReshapeFunc(resizeStage);
 	//glutKeyboardFunc(key_pressed);
-- 
2.44.0