[Piglit] [PATCH v2 1/1] viewport-clamp: to test the viewport clamping

[Eleni Maria Stea]

A test to check the viewport clamping and to reproduce the following bug
on i965:

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108999

v2:
  - Renamed the test to something more relevant (Nanley Chery)
  - Fixed the description (Nanley Chery)
  - Used the piglit_build_simple_program function instead of my own code
  to compile and link the shaders (Nanley Chery)
---
 tests/general/CMakeLists.gl.txt |   1 +
 tests/general/viewport-clamp.c  | 116 ++++++++++++++++++++++++++++++++
 tests/opengl.py                 |   1 +
 3 files changed, 118 insertions(+)
 create mode 100644 tests/general/viewport-clamp.c

diff --git a/tests/general/CMakeLists.gl.txt b/tests/general/CMakeLists.gl.txt
index 83189fc42..a0da78bbe 100644
--- a/tests/general/CMakeLists.gl.txt
+++ b/tests/general/CMakeLists.gl.txt
@@ -132,5 +132,6 @@ piglit_add_executable (clear-accum clear-accum.c)
 piglit_add_executable (vs-point_size-zero vs-point_size-zero.c)
 piglit_add_executable (triangle-guardband-viewport triangle-guardband-viewport.c)
 piglit_add_executable (teximage-scale-bias teximage-scale-bias.c)
+piglit_add_executable (viewport-clamp viewport-clamp.c)
 
 # vim: ft=cmake:
diff --git a/tests/general/viewport-clamp.c b/tests/general/viewport-clamp.c
new file mode 100644
index 000000000..3ac353bbf
--- /dev/null
+++ b/tests/general/viewport-clamp.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author:
+ *    Eleni Maria Stea <estea at igalia.com>
+ */
+
+/* The purpose of this test is to validate the viewport clamping
+ * when the Y is flipped (0 on top). It can be used to reproduce this bug:
+ * https://bugs.freedesktop.org/show_bug.cgi?id=108999
+ * and test the fix: https://patchwork.freedesktop.org/series/53830/
+ */
+
+#include "piglit-util-gl.h"
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+config.supports_gl_compat_version = 20;
+config.window_width = 800;
+config.window_height = 600;
+config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGB;
+config.khr_no_error_support = PIGLIT_NO_ERRORS;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+static int piglit_error;
+static unsigned int vao, vbo;
+static unsigned int sdrprog;
+static const float varr[] = { -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1 };
+
+static const char *vsdr_src =
+	"attribute vec4 vertex;\n"
+	"void main()\n" "{\n" "gl_Position = vertex;\n" "}\n";
+
+static const char *fsdr_src =
+	"void main()\n"
+	"{\n" "gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n" "}\n";
+
+void
+piglit_init(int argc, char **argv)
+{
+	int status;
+
+	glGenBuffers(1, &vbo);
+	glBindBuffer(GL_ARRAY_BUFFER, vbo);
+	glBufferData(GL_ARRAY_BUFFER, sizeof varr, varr, GL_STATIC_DRAW);
+
+	glGenVertexArrays(1, &vao);
+	glBindVertexArray(vao);
+	glEnableVertexAttribArray(0);
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	glBindVertexArray(0);
+
+	sdrprog = piglit_build_simple_program(vsdr_src, fsdr_src);
+
+	glBindAttribLocation(sdrprog, 0, "vertex");
+	glLinkProgram(sdrprog);
+
+	glGetProgramiv(sdrprog, GL_LINK_STATUS, &status);
+	if (!status) {
+		fprintf(stderr, "failed to link program\n");
+		piglit_error = 1;
+		return;
+	}
+
+	glUseProgram(sdrprog);
+
+	if (glGetError() != GL_NO_ERROR)
+		piglit_error = 1;
+}
+
+enum piglit_result
+piglit_display(void)
+{
+	if (piglit_error)
+		return PIGLIT_FAIL;
+
+	glBindVertexArray(vao);
+
+	glViewport(2, 602, 262, 296);
+
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+
+	glViewport(0, 0, 800, 600);
+
+	glDrawArrays(GL_TRIANGLES, 0, 6);
+
+	glBindVertexArray(0);
+
+	if (glGetError() != GL_NO_ERROR)
+		return PIGLIT_FAIL;
+
+	piglit_swap_buffers();
+
+	return PIGLIT_PASS;
+}
diff --git a/tests/opengl.py b/tests/opengl.py
index d6cfa0986..500a874a9 100644
--- a/tests/opengl.py
+++ b/tests/opengl.py
@@ -878,6 +878,7 @@ with profile.test_list.group_manager(
     g(['incomplete-cubemap', 'format'], 'incomplete-cubemap-format')
     g(['gl-2.0-texture-units'])
     g(['gl-2.0-uniform-neg-location'])
+    g(['viewport-clamp'])
 
 with profile.test_list.group_manager(
         PiglitGLTest,
-- 
2.20.1