opengl_demo.patch

diff --git a/apps/opengl_demo/Makefile b/apps/opengl_demo/Makefile
index 8c75fa5..a9fc30f 100644
--- a/apps/opengl_demo/Makefile
+++ b/apps/opengl_demo/Makefile
@@ -26,12 +26,14 @@ ifeq ($(UNAME),Darwin)
   # These are for OS X:
   DTX_FONT       = /Library/Fonts/Arial.ttf
   OPENGL_LIBS    = -lglfw3 -framework OpenGL -framework GLUT
+  GENERATOR_LIBS = -lHalide -lz -lcurses
 
 else
 
   # These are for Ubuntu Linux
   DTX_FONT       = /usr/share/fonts/truetype/dejavu/DejaVuSans.ttf
-  OPENGL_LIBS    = -lglfw -lGL -lglut -lX11 -lpthread -ldl
+  OPENGL_LIBS    = `pkg-config glfw3 --libs` -lGL -lglut -lX11 -lpthread -ldl -lXxf86vm -lXinerama -lXcursor -lXrandr
+  GENERATOR_LIBS = -lHalide -lz -lcurses -Wl,--rpath=$(HALIDE_LIB_PATH)
 
 endif
 
@@ -45,7 +47,7 @@ CXXFLAGS       = -std=c++11 -g -DDTX_FONT=\"$(DTX_FONT)\" $(HALIDE_INC_PATH)
 .PHONY: run clean
 
 default:	run
-	
+
 run:	build/opengl_demo
 	build/opengl_demo image.png
 
diff --git a/apps/opengl_demo/glfw_helpers.cpp b/apps/opengl_demo/glfw_helpers.cpp
index 80484e9..e605e36 100644
--- a/apps/opengl_demo/glfw_helpers.cpp
+++ b/apps/opengl_demo/glfw_helpers.cpp
@@ -1,7 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <GLFW/glfw3.h>
-
+#include <unistd.h>
 #include "glfw_helpers.h"
 
 using namespace GlfwHelpers;
@@ -26,6 +26,12 @@ static void key_callback(GLFWwindow *window, int key, int scancode, int action,
         glfwSetWindowShouldClose(window, GL_TRUE);
 }
 
+static bool first_focus = false;
+static void focus_callback(GLFWwindow *window, int)
+{
+    first_focus = true;
+}
+
 struct info GlfwHelpers::setup(int width, int height)
 {
     struct info info;
@@ -36,8 +42,13 @@ struct info GlfwHelpers::setup(int width, int height)
     window = glfwCreateWindow(width, height, "opengl_halide_test", NULL, NULL);
     if (!window) die("couldn't create window!");
     glfwSetKeyCallback(window, key_callback);
+    glfwSetWindowFocusCallback(window, focus_callback);
     glfwMakeContextCurrent(window);
 
+    while (!first_focus) {
+        glfwWaitEvents();
+    }
+
     int framebuffer_width, framebuffer_height;
     glfwGetFramebufferSize(window, &framebuffer_width, &framebuffer_height);
     info.dpi_scale = float(framebuffer_width) / float(width);
diff --git a/apps/opengl_demo/opengl_helpers.cpp b/apps/opengl_demo/opengl_helpers.cpp
index a162000..8d9c577 100644
--- a/apps/opengl_demo/opengl_helpers.cpp
+++ b/apps/opengl_demo/opengl_helpers.cpp
@@ -10,6 +10,7 @@ void OpenGLHelpers::setup(float dpi_scale)
 {
     const int scaled_font_size = font_size * dpi_scale;
     dtx_use_font(dtx_open_font(DTX_FONT, scaled_font_size), scaled_font_size);
+    glClear(GL_COLOR_BUFFER_BIT);
 }
 
 GLuint OpenGLHelpers::create_texture(int width, int height, const uint8_t *data)

Forget the unistd thing, forgot to delete that