X-Git-Url: https://git.ralfj.de/gltest.git/blobdiff_plain/aa4575e1aa768daff8ca10c7a8a06aa0603e998f..08f1ed05c2541efad748e78db01af569d84c3363:/eglbackend.cpp

diff --git a/eglbackend.cpp b/eglbackend.cpp
index 359d54a..ac7ab38 100644
--- a/eglbackend.cpp
+++ b/eglbackend.cpp
@@ -1,3 +1,21 @@
+/* gltest - small OpenGL tearing test program
+ * Copyright (C) 2012-2013 Ralf Jung <post@ralfj.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
 #include "eglbackend.h"
 
 #include <stdlib.h>
@@ -31,8 +49,7 @@ static void exitEglError(const char *what)
 	exit(1);
 }
 
-/* attributes for a double buffered visual in RGBA format with at least
-* 4 bits per color */
+// attributes for a  visual in RGBA format with at least 4 bits per color
 static const EGLint config_attribs[] = {
 	EGL_RED_SIZE,             4,
 	EGL_GREEN_SIZE,           4,
@@ -47,16 +64,16 @@ VisualID EGLBackend::initialize(Display *xDisplay)
 		// get connection and bind API
 		EGLint eglMajor, eglMinor;
 		display = eglGetDisplay(xDisplay);
-		if (display == EGL_NO_DISPLAY)                         
+		if (display == EGL_NO_DISPLAY)
 			exitEglError("Failed to get EGL display");
-		if (eglInitialize(display, &eglMajor, &eglMinor) == EGL_FALSE)                   
+		if (eglInitialize(display, &eglMajor, &eglMinor) == EGL_FALSE)
 			exitEglError("Failed to initialize EGL");
 		printf("Using EGL version %d.%d\n", eglMajor, eglMinor);
 		eglBindAPI(EGL_OPENGL_API);
 		// get an appropriate config
 		EGLConfig configs[1];
 		EGLint count;
-		if (eglChooseConfig(display, config_attribs, configs, 1, &count) == EGL_FALSE || count == 0)                            
+		if (eglChooseConfig(display, config_attribs, configs, 1, &count) == EGL_FALSE || count == 0)
 			exitEglError("Failed to choose config");
 		config = configs[0];
 	}
@@ -70,7 +87,7 @@ void EGLBackend::createContext(Window window)
 {
 	assert(display != EGL_NO_DISPLAY && context == EGL_NO_CONTEXT);
 	surface = eglCreateWindowSurface(display, config, window, NULL);
-	/* create an EGL context and use it with the surface */                                    
+	// create an EGL context and use it with the surface
 	context = eglCreateContext(display, config, EGL_NO_CONTEXT, NULL);
 	if (context == EGL_NO_CONTEXT)
 		exitEglError("Failed to create context");
@@ -94,11 +111,26 @@ EGLBackend::~EGLBackend()
 void EGLBackend::swapBuffers() const
 {
 	assert(context != EGL_NO_CONTEXT); // this implies the display is also initialized
-	eglSwapBuffers(display, surface);
+	if (eglSwapBuffers(display, surface) == EGL_FALSE)
+		exitEglError("Failed to swap buffers");
 }
 
 void EGLBackend::setSwapInterval(int i) const
 {
 	assert(context != EGL_NO_CONTEXT);
-	eglSwapInterval(display, i);
+	// check if swap interval value is supported
+	EGLint val;
+	eglGetConfigAttrib(display, config, EGL_MIN_SWAP_INTERVAL, &val);
+	if (i < val) {
+		fprintf(stderr, "Cannot set swap interval to %d, minimum supported value is %d\n", i, val);
+		exit(1);
+	}
+	eglGetConfigAttrib(display, config, EGL_MAX_SWAP_INTERVAL, &val);
+	if (i > val) {
+		fprintf(stderr, "Cannot set swap interval to %d, maximum supported value is %d\n", i, val);
+		exit(1);
+	}
+	// use it
+	if (eglSwapInterval(display, i) == EGL_FALSE)
+		exitEglError("Failed to set swap interval");
 }