[Piglit] [PATCH] egl: doesn't allow egl to create a forward-compatible context with req ver < 3

[asimiklit.work at gmail.com]

From: Andrii Simiklit <andrii.simiklit at globallogic.com>

EGL_KHR_create_context spec says:
	   "The default values for EGL_CONTEXT_MAJOR_VERSION_KHR and
        EGL_CONTEXT_MINOR_VERSION_KHR are 1 and 0 respectively."

		requesting a forward-compatible context for OpenGL
        versions less than 3.0 will generate an error.

	 "* If an OpenGL context is requested and the values for attributes
        EGL_CONTEXT_MAJOR_VERSION_KHR and EGL_CONTEXT_MINOR_VERSION_KHR,
        when considered together with the value for attribute
        EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR, specify an OpenGL
        version and feature set that are not defined, than an
        EGL_BAD_MATCH error is generated.

        The defined versions of OpenGL at the time of writing are OpenGL
        1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 2.0, 2.1, 3.0, 3.1, 3.2, 4.0, 4.1,
        4.2, and 4.3. Feature deprecation was introduced with OpenGL
        3.0, so forward-compatible contexts may only be requested for
        OpenGL 3.0 and above. Thus, examples of invalid combinations of
        attributes include:

          - Major version < 1 or > 4
          - Major version == 1 and minor version < 0 or > 5
          - Major version == 2 and minor version < 0 or > 1
          - Major version == 3 and minor version < 0 or > 2
          - Major version == 4 and minor version < 0 or > 3
          - Forward-compatible flag set and major version < 3

        Because the purpose of forward-compatible contexts is to allow
        application development on a specific OpenGL version with the
        knowledge that the app will run on a future version, context
        creation will fail if
        EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR is set and the
        context version returned cannot implement exactly the requested
        version."

Additionally this patch checks and an independence of the attributes order in list.

Signed-off-by: Andrii Simiklit <andrii.simiklit at globallogic.com>
---
 .../valid-flag-forward-compatible-gl.c        | 70 +++++++++++++++----
 1 file changed, 57 insertions(+), 13 deletions(-)

diff --git a/tests/egl/spec/egl_khr_create_context/valid-flag-forward-compatible-gl.c b/tests/egl/spec/egl_khr_create_context/valid-flag-forward-compatible-gl.c
index 42feb54d6..ea00ef595 100644
--- a/tests/egl/spec/egl_khr_create_context/valid-flag-forward-compatible-gl.c
+++ b/tests/egl/spec/egl_khr_create_context/valid-flag-forward-compatible-gl.c
@@ -23,16 +23,30 @@
 #include "piglit-util-egl.h"
 #include "common.h"
 
-int gl_version;
+int gl_version = 0;
 
-static bool try_flag(int flag)
+static bool try_flag(int req_version, int flag)
 {
-	const EGLint attribs[] = {
-		EGL_CONTEXT_FLAGS_KHR, flag,
-		EGL_NONE
-	};
+	bool oresult = true;
+	const unsigned vidx = req_version < 0 ? 0 : (req_version == 0) ? 1 : 2;
+	const bool is_forward_compatible =
+			(0 != (flag & EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR));
 
-	ctx = eglCreateContext(egl_dpy, cfg, EGL_NO_CONTEXT, attribs);
+	const EGLint attribs[][5] = {
+		/*------------req_version-before-case------------*/
+		{ EGL_CONTEXT_MAJOR_VERSION_KHR, abs(req_version),
+		  EGL_CONTEXT_FLAGS_KHR, flag,
+		  EGL_NONE },
+		/*------------no-req_version-case----------------*/
+		{ EGL_CONTEXT_FLAGS_KHR, flag,
+		  EGL_NONE },
+		/*------------req_version-after-case-------------*/
+		{ EGL_CONTEXT_FLAGS_KHR, flag,
+		  EGL_CONTEXT_MAJOR_VERSION_KHR, abs(req_version),
+		  EGL_NONE }
+	};
+	assert(vidx < 3);
+	ctx = eglCreateContext(egl_dpy, cfg, EGL_NO_CONTEXT, attribs[vidx]);
 	if (ctx != NULL) {
 		/* Get GL version in order to know whether we can test
 		 * EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR.
@@ -47,6 +61,18 @@ static bool try_flag(int flag)
 
 			gl_version = piglit_get_gl_version();
 		}
+		if (abs(req_version) < 3 && is_forward_compatible) {
+			/* The EGL_KHR_create_context spec says:
+			 *
+		    *   requesting a forward-compatible context for OpenGL
+          *   versions less than 3.0 will generate an error
+			 *
+			 *   The default values for EGL_CONTEXT_MAJOR_VERSION_KHR and
+          *   EGL_CONTEXT_MINOR_VERSION_KHR are 1 and 0 respectively.
+		    */
+			piglit_report_result(PIGLIT_FAIL);
+		 	oresult = false;
+		}
 		eglDestroyContext(egl_dpy, ctx);
 	} else if (!piglit_check_egl_error(EGL_BAD_MATCH)) {
 		/* The EGL_KHR_create_context spec says:
@@ -60,12 +86,13 @@ static bool try_flag(int flag)
 		piglit_report_result(PIGLIT_FAIL);
 	}
 
-	return true;
+	return oresult;
 }
 
 int main(int argc, char **argv)
 {
 	bool pass = true;
+	int req_version;
 
 	if (!EGL_KHR_create_context_setup(EGL_OPENGL_BIT)) {
 		fprintf(stderr, "Desktop GL not available.\n");
@@ -77,11 +104,28 @@ int main(int argc, char **argv)
 	 *
 	 *    "The default value of EGL_CONTEXT_FLAGS_KHR is zero."
 	 */
-	pass = pass && try_flag(0);
-	if (gl_version >= 30) {
-		pass = pass && try_flag(EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR);
-	} else {
-		piglit_report_result(PIGLIT_SKIP);
+	for(req_version = 0; req_version < 4 && pass; ++req_version) {
+		pass = pass && try_flag(req_version, 0);
+		if (gl_version >= 30) {
+			pass = pass && try_flag(req_version,
+									EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR);
+		} else {
+			piglit_report_result(PIGLIT_SKIP);
+			break;
+		}
+	}
+	/* The sign of a req_version is used to specifay EGL_CONTEXT_MAJOR_VERSION_KHR
+	 * flag before or after of EGL_CONTEXT_FLAGS_KHR
+	 **/
+	for(req_version = 0; req_version > -4 && pass; --req_version) {
+		pass = pass && try_flag(req_version, 0);
+		if (gl_version >= 30) {
+			pass = pass && try_flag(req_version,
+									EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR);
+		} else {
+			piglit_report_result(PIGLIT_SKIP);
+			break;
+		}
 	}
 
 	EGL_KHR_create_context_teardown();
-- 
2.17.1