[Piglit] [PATCH] glx: Fix glx-swap-exchange

[Brian Paul]

On 08/07/2017 11:21 AM, Thomas Hellstrom wrote:
> Fix the following problems with this test:
>
> 1) The spec is not referring to glXChooseVisual attributes, only to
> glXChooseFBConfig attributes. So use glXChooseFBConfig.
>
> 2) Make sure we have an alpha channel.
>
> 3) Call piglit_dispatch_default_init before issuing GL commands.
>
> 4) Restrict the test to the RGB channels. At least temporary. The spec says
> the front buffer contents should become the new back buffer contents but
> I'm not 100% sure all implementations actually support front buffer alpha.

I think the expectation has always been that the front and back color 
buffers have the same color depth for all channels.


> We might need to revisit this.
>
> Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
> ---
>   tests/glx/glx-swap-exchange.c | 74 +++++++++++++++++++++++++++----------------
>   1 file changed, 46 insertions(+), 28 deletions(-)
>
> diff --git a/tests/glx/glx-swap-exchange.c b/tests/glx/glx-swap-exchange.c
> index 3f045f8..137140f 100644
> --- a/tests/glx/glx-swap-exchange.c
> +++ b/tests/glx/glx-swap-exchange.c
> @@ -1,5 +1,6 @@
>   /*
>    * Copyright © 2010 Intel Corporation
> + * Copyright © 2010 VMWare Inc.

2017?


>    *
>    * Permission is hereby granted, free of charge, to any person obtaining a
>    * copy of this software and associated documentation files (the "Software"),
> @@ -22,6 +23,7 @@
>    *
>    * Authors:
>    *    Eric Anholt <eric at anholt.net>
> + *    Thomas Hellstrom <thellstrom at vmware.com>
>    *
>    */
>
> @@ -36,60 +38,63 @@
>
>   int piglit_width = 50, piglit_height = 50;
>   static Display *dpy;
> -static Window win;
> -static XVisualInfo *visinfo;
> +static GLXFBConfig *config;
> +static GLXContext ctx;
> +static GLXWindow gwin;
>
>   enum piglit_result
>   draw(Display *dpy)
>   {
>   	GLboolean pass = GL_TRUE;
> -	float green[] = {0.0, 1.0, 0.0, 0.0};
> -	GLXContext ctx;
> +	float green[] = {0.0, 1.0, 0.0, 0.3};

const, while you're there?


>
> -	ctx = piglit_get_glx_context(dpy, visinfo);
> -	glXMakeCurrent(dpy, win, ctx);
> -
> -	/* Clear background to gray */
> -	glClearColor(0.0, 1.0, 0.0, 0.0);
> +	glXMakeContextCurrent(dpy, gwin, gwin, ctx);
> +	glClearColor(0.0, 1.0, 0.0, 0.3);
> +	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
>   	glClear(GL_COLOR_BUFFER_BIT);
> -	glXSwapBuffers(dpy, win);
> -	glClearColor(1.0, 0.0, 0.0, 0.0);
> +	glXSwapBuffers(dpy, gwin);
> +	glClearColor(1.0, 0.0, 0.0, 0.5);
>   	glClear(GL_COLOR_BUFFER_BIT);
> -	glXSwapBuffers(dpy, win);
> -
> -	pass = piglit_probe_pixel_rgba(0, 0, green);
> +	glXSwapBuffers(dpy, gwin);
>
> -	glXSwapBuffers(dpy, win);
> +	/*
> +	 * Spec says the front buffer contents should be the new back buffer,
> +	 * but are front buffer contents required to have alpha?
> +	 * Ignore the alpha channel for now.
> +	 */
> +	pass = piglit_probe_pixel_rgb(0, 0, green);

Maybe we could test the alpha channel too, but print/return a warning if 
it's incorrect.


>
>   	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
>   }
>
>
> -XVisualInfo *
> -piglit_get_swap_exchange_visual(Display *dpy)
> +static GLXFBConfig *
> +piglit_get_swap_exchange_config(Display *dpy)
>   {
> -	XVisualInfo *visinfo;
> +	GLXFBConfig *fbc;
> +	int nele;
>   	int attrib[] = {
> -		GLX_RGBA,
> -		GLX_RED_SIZE, 1,
> -		GLX_GREEN_SIZE, 1,
> -		GLX_BLUE_SIZE, 1,
> -		GLX_DOUBLEBUFFER,
> +		GLX_RENDER_TYPE, GLX_RGBA_BIT,
> +		GLX_RED_SIZE, 8,
> +		GLX_GREEN_SIZE, 8,
> +		GLX_BLUE_SIZE, 8,
> +		GLX_ALPHA_SIZE, 8,
>   		GLX_SWAP_METHOD_OML, GLX_SWAP_EXCHANGE_OML,
> +		GLX_DOUBLEBUFFER, True,
>   		None
>   	};
>   	int screen = DefaultScreen(dpy);
>
> -	visinfo = glXChooseVisual(dpy, screen, attrib);
> -	if (visinfo == NULL) {
> +	fbc = glXChooseFBConfig(dpy, screen, attrib, &nele);
> +	if (fbc == NULL) {
>   		fprintf(stderr,
>   			"Couldn't get a GLX_SWAP_EXCHANGE_OML, RGBA, "
> -			"double-buffered visual\n");
> +			"double-buffered fbconfig\n");
>   		piglit_report_result(PIGLIT_SKIP);
>   		exit(1);
>   	}
>
> -	return visinfo;
> +	return fbc;
>   }
>
>   int
> @@ -97,6 +102,8 @@ main(int argc, char **argv)
>   {
>   	int i;
>   	const char *glx_extension_list;
> +	Window win;
> +	XVisualInfo *visinfo;
>
>   	for(i = 1; i < argc; ++i) {
>   		if (!strcmp(argv[i], "-auto"))
> @@ -117,10 +124,21 @@ main(int argc, char **argv)
>   		piglit_report_result(PIGLIT_SKIP);
>   	}
>
> -	visinfo = piglit_get_swap_exchange_visual(dpy);
> +	config = piglit_get_swap_exchange_config(dpy);
> +	visinfo = glXGetVisualFromFBConfig(dpy, config[0]);
> +	if (!visinfo) {
> +		printf("Error: couldn't create a visual from fbconfig.\n");
> +		piglit_report_result(PIGLIT_FAIL);
> +	}
> +
>   	win = piglit_get_glx_window(dpy, visinfo);
> +	XFree(visinfo);
>
>   	XMapWindow(dpy, win);
> +	gwin = glXCreateWindow(dpy, config[0], win, NULL);
> +	ctx = glXCreateNewContext(dpy, config[0], GLX_RGBA_TYPE, 0, GL_TRUE);
> +	glXMakeContextCurrent(dpy, gwin, gwin, ctx);
> +	piglit_dispatch_default_init(PIGLIT_DISPATCH_GL);
>
>   	piglit_glx_event_loop(dpy, draw);
>
>

Looks good otherwise.

Reviewed-by: Brian Paul <brianp at vmware.com>