tests: Test whether a simple EGL main loop uses too many buffers

This adds a test that tries to simulate a simple game loop that would
be like this:

while (1) {
        draw_something();
        eglSwapBuffers();
}

In this case the test is relying on eglSwapBuffers to throttle to a
sensible frame rate.

The test then verifies that only 2 EGL buffers are used. This is done
via a new request and event in the wayland-test protocol.

Currently this causes 3 buffers to be created because the release
event generated by the swap buffers is not processed by Mesa until it
blocks for the frame complete event in the next swap buffers call, but
that is too late.

This can be fixed in Mesa by issuing a sync request after the swap
buffers and blocking on it before deciding whether to allocate a new
buffer.

1 files changed, 128 insertions, 0 deletions

diff --git a/tests/buffer-count-test.c b/tests/buffer-count-test.c
new file mode 100644
index 00000000..ad2bceeb
--- /dev/null
+++ b/tests/buffer-count-test.c
@@ -0,0 +1,128 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and
+ * its documentation for any purpose is hereby granted without fee, provided
+ * that the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of the copyright holders not be used in
+ * advertising or publicity pertaining to distribution of the software
+ * without specific, written prior permission.  The copyright holders make
+ * no representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+ * CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "weston-test-client-helper.h"
+#include <stdio.h>
+#include <poll.h>
+#include <time.h>
+
+#include <EGL/egl.h>
+#include <wayland-egl.h>
+#include <GLES2/gl2.h>
+
+struct test_data {
+	struct client *client;
+
+	EGLDisplay egl_dpy;
+	EGLContext egl_ctx;
+	EGLConfig egl_conf;
+	EGLSurface egl_surface;
+};
+
+static void
+init_egl(struct test_data *test_data)
+{
+	struct wl_egl_window *native_window;
+	struct surface *surface = test_data->client->surface;
+
+	static const EGLint context_attribs[] = {
+		EGL_CONTEXT_CLIENT_VERSION, 2,
+		EGL_NONE
+	};
+
+	EGLint config_attribs[] = {
+		EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
+		EGL_RED_SIZE, 1,
+		EGL_GREEN_SIZE, 1,
+		EGL_BLUE_SIZE, 1,
+		EGL_ALPHA_SIZE, 0,
+		EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
+		EGL_NONE
+	};
+
+	EGLint major, minor, n;
+	EGLBoolean ret;
+
+	test_data->egl_dpy = eglGetDisplay((EGLNativeDisplayType)
+					   test_data->client->wl_display);
+	assert(test_data->egl_dpy);
+
+	ret = eglInitialize(test_data->egl_dpy, &major, &minor);
+	assert(ret == EGL_TRUE);
+	ret = eglBindAPI(EGL_OPENGL_ES_API);
+	assert(ret == EGL_TRUE);
+
+	ret = eglChooseConfig(test_data->egl_dpy, config_attribs,
+			      &test_data->egl_conf, 1, &n);
+	assert(ret && n == 1);
+
+	test_data->egl_ctx = eglCreateContext(test_data->egl_dpy,
+					      test_data->egl_conf,
+					      EGL_NO_CONTEXT, context_attribs);
+	assert(test_data->egl_ctx);
+
+	native_window =
+		wl_egl_window_create(surface->wl_surface,
+				     surface->width,
+				     surface->height);
+	test_data->egl_surface =
+		eglCreateWindowSurface(test_data->egl_dpy,
+				       test_data->egl_conf,
+				       (EGLNativeWindowType) native_window,
+				       NULL);
+
+	ret = eglMakeCurrent(test_data->egl_dpy, test_data->egl_surface,
+			     test_data->egl_surface, test_data->egl_ctx);
+	assert(ret == EGL_TRUE);
+}
+
+TEST(test_buffer_count)
+{
+	struct test_data test_data;
+	uint32_t buffer_count;
+	int i;
+
+	test_data.client = client_create(10, 10, 10, 10);
+	init_egl(&test_data);
+
+	/* This is meant to represent a typical game loop which is
+	 * expecting eglSwapBuffers to block and throttle the
+	 * rendering to a sensible frame rate. Therefore it doesn't
+	 * expect to have to install a frame callback itself. I'd
+	 * imagine this is what a typical SDL game would end up
+	 * doing */
+
+	for (i = 0; i < 10; i++) {
+		glClear(GL_COLOR_BUFFER_BIT);
+		eglSwapBuffers(test_data.egl_dpy, test_data.egl_surface);
+	}
+
+	buffer_count = get_n_egl_buffers(test_data.client);
+
+	printf("buffers used = %i\n", buffer_count);
+
+	/* The implementation should only end up creating two buffers
+	 * and cycling between them */
+	assert(buffer_count == 2);
+}