Add test to verify transform feedback values of few builtin variables

Builtin variables tested are gl_Layer and gl_ViewportIndex. The test
case verifies a bug fix in Intel's i965 drivers. It can be later
extended to add testing for more builtin variables.

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>

3 files changed, 169 insertions, 0 deletions

diff --git a/tests/all.py b/tests/all.py
index de436965a..9feca214f 100644
--- a/tests/all.py
+++ b/tests/all.py
@@ -1396,6 +1396,7 @@ spec['glsl-1.50']['getshaderiv-may-return-GS'] = concurrent_test('glsl-1.50-gets
 spec['glsl-1.50']['query-gs-prim-types'] = concurrent_test('glsl-1.50-query-gs-prim-types')
 spec['glsl-1.50']['transform-feedback-type-and-size'] = concurrent_test('glsl-1.50-transform-feedback-type-and-size')
 spec['glsl-1.50']['transform-feedback-vertex-id'] = concurrent_test('glsl-1.50-transform-feedback-vertex-id')
+spec['glsl-1.50']['transform-feedback-builtins'] = concurrent_test('glsl-1.50-transform-feedback-builtins')
 for subtest in ['unnamed', 'named', 'array']:
     add_concurrent_test(
         spec['glsl-1.50'],
diff --git a/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt b/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt
index 2b5a282bd..b957f02ab 100644
--- a/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt
+++ b/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt
@@ -23,3 +23,4 @@ piglit_add_executable (glsl-1.50-gs-input-layout-qualifiers gs-input-layout-qual
 piglit_add_executable (glsl-1.50-gs-output-layout-qualifiers gs-output-layout-qualifiers.c)
 piglit_add_executable (glsl-1.50-transform-feedback-type-and-size transform-feedback-type-and-size.c)
 piglit_add_executable (glsl-1.50-transform-feedback-vertex-id transform-feedback-vertex-id.c)
+piglit_add_executable (glsl-1.50-transform-feedback-builtins transform-feedback-builtins.c)
diff --git a/tests/spec/glsl-1.50/execution/geometry/transform-feedback-builtins.c b/tests/spec/glsl-1.50/execution/geometry/transform-feedback-builtins.c
new file mode 100644
index 000000000..969bd92f4
--- /dev/null
+++ b/tests/spec/glsl-1.50/execution/geometry/transform-feedback-builtins.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright © 2014 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.
+ */
+
+/** \file transform-feedback-builtins.c
+ *
+ * Intel's i965 driver has a special internal handling for 'gl_Layer' and
+ * 'gl_ViewportIndex' builtin variables. This test verifies that transform
+ * feedback works fine for these builtin variables.
+ *
+ * Test creates a geometry shader which outputs the following builtin variables:
+ * - gl_Layer
+ * - gl_ViewportIndex
+ *
+ * Then it verifies that data captured by transform feedback is consistent with
+ * the assignments in geometry shader.
+ */
+
+#include "piglit-util-gl.h"
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+	config.supports_gl_compat_version = 32;
+	config.supports_gl_core_version = 32;
+PIGLIT_GL_TEST_CONFIG_END
+
+#define NUM_OUTPUT_INTS 3
+static const char *vstext =
+	"#version 150\n"
+	"void main()\n"
+	"{\n"
+        "  gl_Position = vec4(0.0);\n"
+	"}\n";
+
+static const char *gs_template =
+	"#version 150\n"
+	"%s"
+	"layout(triangles) in;\n"
+	"layout(triangle_strip, max_vertices = 3) out;\n"
+	"void main()\n"
+	"{\n"
+	"  for (int i = 0; i < 3; i++) {\n"
+	"    gl_Layer = 2 * i + 1;\n"
+	"%s"
+	"    EmitVertex();\n"
+	"  }\n"
+	"  EndPrimitive();\n"
+	"}\n";
+
+/**
+ * When below set of varyings are captured from the geometry shader
+ * above, the output should be a sequence of integers defined in this
+ * array.
+ */
+static const int expected[2][3] = {{1, 3, 5}, /* gl_Layer */
+				   {1, 2, 3}}; /* gl_ViewportIndex */
+
+static const char *varyings[] = {"gl_Layer", "gl_ViewportIndex"};
+
+void
+piglit_init(int argc, char **argv)
+{
+	int i, j, num_xfb_buffers;
+	GLuint prog, vao, xfb_buf[2];
+	const GLint *readback;
+	char *gstext;
+	bool pass = true;
+	bool test_gl_ViewportIndex =
+		piglit_is_extension_supported("GL_ARB_viewport_array");
+
+	num_xfb_buffers = ARRAY_SIZE(xfb_buf);
+
+	if (test_gl_ViewportIndex) {
+		asprintf(&gstext, gs_template,
+			 "#extension GL_ARB_viewport_array : require\n",
+			 "    gl_ViewportIndex = i + 1;\n");
+	} else {
+		printf("Skip testing 'gl_ViewportIndex'\n");
+		asprintf(&gstext, gs_template, "", "");
+		num_xfb_buffers -= 1;
+	}
+
+	prog = piglit_build_simple_program_unlinked_multiple_shaders(
+		GL_VERTEX_SHADER, vstext,
+		GL_GEOMETRY_SHADER, gstext,
+		0, NULL);
+
+	glTransformFeedbackVaryings(prog, num_xfb_buffers, varyings,
+				    GL_SEPARATE_ATTRIBS);
+
+	glLinkProgram(prog);
+	if (!piglit_link_check_status(prog)) {
+		glDeleteProgram(prog);
+		piglit_report_result(PIGLIT_FAIL);
+	}
+	glUseProgram(prog);
+
+	glGenVertexArrays(1, &vao);
+	glBindVertexArray(vao);
+
+	/* Setup transform feedback buffers */
+	glGenBuffers(num_xfb_buffers, xfb_buf);
+	for (i = 0; i < num_xfb_buffers; i++) {
+		glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, i, xfb_buf[i]);
+		glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER,
+			     NUM_OUTPUT_INTS * sizeof(GLint), NULL,
+			     GL_STATIC_READ);
+	}
+
+	glEnable(GL_RASTERIZER_DISCARD);
+
+	/* Do drawing */
+	glBeginTransformFeedback(GL_TRIANGLES);
+	glDrawArrays(GL_TRIANGLES, 0, 3);
+	glEndTransformFeedback();
+
+	/* Check if the correct data was written into the transform feedback
+	 * buffers.
+	 */
+	for (i = 0; i < num_xfb_buffers; i++) {
+		glBindBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, 0, xfb_buf[i], 0,
+				  NUM_OUTPUT_INTS * sizeof(GLint));
+		readback = glMapBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, 0,
+					    NUM_OUTPUT_INTS * sizeof(GLint),
+					    GL_MAP_READ_BIT);
+		for (j = 0; j < NUM_OUTPUT_INTS; j++) {
+			if (readback[j] != expected[i][j]) {
+				printf("Incorrect data for '%s' output %d."
+				       "  Expected %d, got %d.\n", varyings[i],
+				       j, expected[i][j], readback[j]);
+				pass = false;
+			}
+		}
+		glUnmapBuffer(GL_TRANSFORM_FEEDBACK_BUFFER);
+	}
+
+	glDeleteBuffers(num_xfb_buffers, xfb_buf);
+
+	/* Check for the errors */
+	pass = piglit_check_gl_error(GL_NO_ERROR) && pass;
+	piglit_report_result(pass ? PIGLIT_PASS : PIGLIT_FAIL);
+}
+
+enum piglit_result
+piglit_display(void)
+{
+	/* Unreached */
+	return PIGLIT_FAIL;
+}