wimmel_gl: Use EGL instead of GLUT by default

That way we can create a context and make it current without creating a
window.

2 files changed, 55 insertions, 28 deletions

diff --git a/Makefile b/Makefile
index 310f1d9..a88cebe 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ wimmel_gl: wimmel_gl.o util.o
 
 
 wimmel_gl:
-	$(CC) -lglut `pkg-config --cflags --libs gtk+-2.0 glib-2.0` -o $@ $+
+	$(CC) `pkg-config --cflags --libs gtk+-2.0 glib-2.0 egl gl` -o $@ $+
 
 
 
diff --git a/wimmel_gl.c b/wimmel_gl.c
index 2a42109..dcf4c19 100644
--- a/wimmel_gl.c
+++ b/wimmel_gl.c
@@ -1,13 +1,20 @@
+#include <stdlib.h>
 #include <glib.h>
 #include <gdk-pixbuf/gdk-pixbuf.h>
 
 #define GL_GLEXT_PROTOTYPES
+#if 0
 #include <GL/glut.h>
+#else
+#include <EGL/egl.h>
+#endif
+
 #include <GL/gl.h>
 #include <GL/glext.h>
 
 #include "util.h"
 
+EGLDisplay dpy;
 GLuint vbo;
 GLint proj_uniform, tex_uniform, pixelsize_uniform,
       search_rect_uniform, barrier_uniform;
@@ -175,38 +182,31 @@ draw(void)
 
 }
 
-int
-main(int argc, char **argv)
+static void
+init_gl(void)
 {
 	GLuint fb, rb;
-	gint stride;
-	guchar *buffer;
-
-	g_type_init();
-
+#if 0
 	glutInit(&argc, argv);
-	if (argc <= 1)
-		return 1;
-
 	glutInitDisplayMode(GLUT_RGBA /*| GLUT_DEPTH */ | GLUT_DOUBLE);
-
-
-	pixbuf = gdk_pixbuf_new_from_file(argv[1], NULL);
-	if (!pixbuf)
-		return 1;
-
-	width  = gdk_pixbuf_get_width(pixbuf);
-	height = gdk_pixbuf_get_height(pixbuf);
-
-	x1 = atoi(argv[2]);
-	y1 = atoi(argv[3]);
-	mwidth = atoi(argv[4]);
-	mheight = atoi(argv[5]);
-
 	glutInitWindowSize(1,1);
 	int window = glutCreateWindow("wimmel");
 	glutDestroyWindow(window);
+#else
+	dpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
+	eglInitialize(dpy, NULL, NULL);
+	eglBindAPI(EGL_OPENGL_API);
+	EGLContext ctx = eglCreateContext(dpy, NULL, EGL_NO_CONTEXT, NULL);
+	if (ctx == NULL) {
+		fprintf(stderr, "failed to create context\n");
+		exit(EXIT_FAILURE);
+	}
 
+	if (!eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, ctx)) {
+		fprintf(stderr, "failed to make context current\n");
+		exit(EXIT_FAILURE);
+	}
+#endif
 	glGenFramebuffersEXT(1, &fb);
 	glGenRenderbuffersEXT(1, &rb);
 
@@ -223,14 +223,39 @@ main(int argc, char **argv)
 
 	if (glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT) !=
 	    GL_FRAMEBUFFER_COMPLETE_EXT) {
-		fprintf(stderr, "framebuffer not complete\n");
-		return 1;
+		fprintf(stderr, "Framebuffer not complete\n");
+		exit(EXIT_FAILURE);
 	}
+}
+
+int
+main(int argc, char **argv)
+{
+	gint stride;
+	guchar *buffer;
+
+	g_type_init();
+
+	if (argc <= 5)
+		return 1;
+
+	pixbuf = gdk_pixbuf_new_from_file(argv[1], NULL);
+	if (!pixbuf)
+		return 1;
+
+	width  = gdk_pixbuf_get_width(pixbuf);
+	height = gdk_pixbuf_get_height(pixbuf);
+
+	init_gl();
+
+	x1 = atoi(argv[2]);
+	y1 = atoi(argv[3]);
+	mwidth = atoi(argv[4]);
+	mheight = atoi(argv[5]);
 
 	init_shaders();
 	create_texture(pixbuf);
 	glViewport(0,0,width,height);
-
 	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 
 	draw();
@@ -264,5 +289,7 @@ main(int argc, char **argv)
 	free(buffer);
 	g_object_unref(pixbuf);
 
+	eglTerminate(dpy);
+
 	return 0;
 }