[Piglit] [PATCH v2] winsys-framework Default to showing window

[Arthur Huillet]

Thanks :)

Reviewed by: Arthur Huillet <ahuillet at nvidia.com>

On Tue, 17 Nov 2015 11:33:31 -0800
Alex Goins <agoins at nvidia.com> wrote:

> From: agoins <agoins at nvidia.com>
> 
> winsys-framework incorrectly assumed that it will always have ownership of the
> pixels in its own buffers. If using the default framebuffer (i.e., when Piglit
> is not running in FBO mode,) ownership will not be acquired unless the window is
> mapped.
> 
> While this is not typically a problem because buffers are separate, NVIDIA's
> Unified Back Buffer feature makes all windows share a back buffer while still
> conforming to the OpenGL spec. If Piglit does not establish pixel ownership, its
> output will be clobbered by other windows.
> 
> While this problem could be easily fixed by specifying PIGLIT_FORCE_WINDOW=1 or
> -fbo, the current default takes advantage of undefined behavior in the OpenGL
> spec. A better solution would be to replace PIGLIT_FORCE_WINDOW with
> PIGLIT_NO_WINDOW, a flag that allows tests to be run without mapping a window or
> using an FBO. The default behavior, the, would be to map a window. Really,
> though, if users want to test with offscreen rendering, they should use FBOs
> with flag -fbo.
> 
> More information on pixel ownership here:
> https://www.opengl.org/documentation/specs/version1.1/glspec1.1/node94.html
> ---
>  .../piglit-framework-gl/piglit_winsys_framework.c    | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/tests/util/piglit-framework-gl/piglit_winsys_framework.c b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
> index c80e972..ff3428a 100644
> --- a/tests/util/piglit-framework-gl/piglit_winsys_framework.c
> +++ b/tests/util/piglit-framework-gl/piglit_winsys_framework.c
> @@ -53,18 +53,18 @@ run_test(struct piglit_gl_framework *gl_fw,
>           int argc, char *argv[])
>  {
>  	struct piglit_winsys_framework *winsys_fw = piglit_winsys_framework(gl_fw);
> -	bool force_window = false;
> -	const char *env_force_window = getenv("PIGLIT_FORCE_WINDOW");
> +	bool no_window = false;
> +	const char *env_no_window = getenv("PIGLIT_NO_WINDOW");
>  
>  
> -	if (env_force_window != NULL) {
> -		if (strcmp(env_force_window, "0") == 0) {
> -			force_window = false;
> -		} else if (strcmp(env_force_window, "1") == 0) {
> -			force_window = true;
> +	if (env_no_window != NULL) {
> +		if (strcmp(env_no_window, "0") == 0) {
> +			no_window = false;
> +		} else if (strcmp(env_no_window, "1") == 0) {
> +			no_window = true;
>  		} else {
> -			fprintf(stderr, "PIGLIT_FORCE_WINDOW has invalid"
> -				" value: %s\n", env_force_window);
> +			fprintf(stderr, "PIGLIT_NO_WINDOW has invalid"
> +				" value: %s\n", env_no_window);
>  			abort();
>  		}
>  	}
> @@ -73,7 +73,7 @@ run_test(struct piglit_gl_framework *gl_fw,
>  		gl_fw->test_config->init(argc, argv);
>  
>  	if (!gl_fw->test_config->requires_displayed_window &&
> -	    piglit_automatic && !force_window) {
> +	    piglit_automatic && no_window) {
>  		enum piglit_result result = PIGLIT_PASS;
>  		if (gl_fw->test_config->display)
>  			result = gl_fw->test_config->display();
> -- 
> 1.9.1
> 
> 
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-- 
Greetings, 
A. Huillet