[3/4] glsl-1.50/gs-max-output: new test for geometry shader amplification

Submitted by Nicolai Hähnle on Sept. 13, 2018, 6:10 p.m.

Details

Message ID 20180913181049.16397-4-nhaehnle@gmail.com
State New
Headers show
Series "Autumn cleaning: misc test case additions and fixes" ( rev: 1 ) in Piglit

Not browsing as part of any series.

Commit Message

Nicolai Hähnle Sept. 13, 2018, 6:10 p.m.
From: Nicolai Hähnle <nicolai.haehnle@amd.com>

Test the extremes of # of GS output vertices / components per GS input
primitive.

Existing tests only cover cases of high # of components per vertex, but
not cases of low # of components per vertex and high # of output vertices.
---
 tests/opengl.py                               |   1 +
 .../execution/geometry/CMakeLists.gl.txt      |   1 +
 .../execution/geometry/gs-max-output.cpp      | 549 ++++++++++++++++++
 3 files changed, 551 insertions(+)
 create mode 100644 tests/spec/glsl-1.50/execution/geometry/gs-max-output.cpp

Patch hide | download patch | download mbox

diff --git a/tests/opengl.py b/tests/opengl.py
index c599eb180..903a95809 100644
--- a/tests/opengl.py
+++ b/tests/opengl.py
@@ -1398,20 +1398,21 @@  with profile.test_list.group_manager(
        os.path.join('spec', 'glsl-1.50', 'minimum-maximums.txt')],
       'built-in constants',
       override_class=BuiltInConstantsTest)
     g(['built-in-constants',
        os.path.join('spec', 'glsl-1.50', 'minimum-maximums-compat.txt')],
       'built-in constants compatibility',
       override_class=BuiltInConstantsTest)
     g(['glsl-1.50-gs-emits-too-few-verts'], 'gs-emits-too-few-verts')
     g(['glsl-1.50-geometry-end-primitive-optional-with-points-out'],
       'gs-end-primitive-optional-with-points-out')
+    g(['glsl-1.50-gs-max-output', '-scan', '1', '20'], 'gs-max-output')
     g(['glsl-1.50-gs-max-output-components'], 'gs-max-output-components')
     g(['glsl-1.50-getshaderiv-may-return-GS'], 'getshaderiv-may-return-GS')
     g(['glsl-1.50-query-gs-prim-types'], 'query-gs-prim-types')
     g(['glsl-1.50-transform-feedback-type-and-size'],
       'transform-feedback-type-and-size')
     g(['glsl-1.50-transform-feedback-vertex-id'],
       'transform-feedback-vertex-id')
     g(['glsl-1.50-transform-feedback-builtins'], 'transform-feedback-builtins')
 
     for draw in ['', 'indexed']:
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 0d76adc06..c6d21f080 100644
--- a/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt
+++ b/tests/spec/glsl-1.50/execution/geometry/CMakeLists.gl.txt
@@ -13,14 +13,15 @@  piglit_add_executable (glsl-1.50-geometry-end-primitive end-primitive.c)
 piglit_add_executable (glsl-1.50-geometry-end-primitive-optional-with-points-out geometry-end-primitive-optional-with-points-out.c)
 piglit_add_executable (glsl-1.50-geometry-primitive-id-restart primitive-id-restart.c)
 piglit_add_executable (glsl-1.50-geometry-primitive-types primitive-types.c)
 piglit_add_executable (glsl-1.50-geometry-tri-strip-ordering-with-prim-restart tri-strip-ordering-with-prim-restart.c)
 piglit_add_executable (glsl-1.50-gs-emits-too-few-verts gs-emits-too-few-verts.c)
 piglit_add_executable (glsl-1.50-getshaderiv-may-return-GS getshaderiv-may-return-GS.c)
 piglit_add_executable (glsl-1.50-gs-mismatch-prim-type gs-mismatch-prim-type.c)
 piglit_add_executable (glsl-1.50-query-gs-prim-types query-gs-prim-types.c)
 piglit_add_executable (glsl-1.50-gs-input-layout-qualifiers gs-input-layout-qualifiers.c)
 piglit_add_executable (glsl-1.50-gs-output-layout-qualifiers gs-output-layout-qualifiers.c)
+piglit_add_executable (glsl-1.50-gs-max-output gs-max-output.cpp)
 piglit_add_executable (glsl-1.50-gs-max-output-components gs-max-output-components.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/gs-max-output.cpp b/tests/spec/glsl-1.50/execution/geometry/gs-max-output.cpp
new file mode 100644
index 000000000..eb9292655
--- /dev/null
+++ b/tests/spec/glsl-1.50/execution/geometry/gs-max-output.cpp
@@ -0,0 +1,549 @@ 
+/*
+ * Copyright (c) 2018 Advanced Micro Devices
+ *
+ * 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 gs-max-output.cpp
+ *
+ * Stress the limits of what a geometry shader can output using a generic
+ * geometry shader with points as input and output primitives, allowing
+ * arbitrary:
+ * - number of input instances (instanced draws)
+ * - number of input points per instance
+ * - number of invocations (GS instances)
+ * - number of output vertices per invocation
+ * - number of output components per vertex
+ */
+
+#include "piglit-util-gl.h"
+
+#include <map>
+#include <vector>
+
+#define WINDOW_SIZE 256
+
+PIGLIT_GL_TEST_CONFIG_BEGIN
+
+	config.supports_gl_compat_version = 32;
+	config.supports_gl_core_version = 32;
+	config.window_width = WINDOW_SIZE;
+	config.window_height = WINDOW_SIZE;
+	config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA;
+	config.khr_no_error_support = PIGLIT_NO_ERRORS;
+
+PIGLIT_GL_TEST_CONFIG_END
+
+#define PASTE(x) #x
+#define STR(x) PASTE(x)
+
+struct testcase {
+	unsigned num_instances; /* draw instances */
+	unsigned num_points; /* draw size / count */
+	unsigned num_invocations; /* GS invocations / instances */
+	unsigned num_outputs; /* # vertex ouput per GS invocation */
+	unsigned num_components; /* # extra components per GS output vertex */
+
+
+};
+
+struct fragmentshaderkey {
+	unsigned num_components;
+
+	bool operator<(const fragmentshaderkey &o) const {
+		return num_components < o.num_components;
+	}
+};
+
+struct geometryshaderkey {
+	unsigned num_invocations;
+	unsigned num_outputs;
+	unsigned num_components;
+
+	bool operator<(const geometryshaderkey &o) const {
+		if (num_invocations < o.num_invocations)
+			return true;
+		if (num_invocations > o.num_invocations)
+			return false;
+		if (num_outputs < o.num_outputs)
+			return true;
+		if (num_outputs > o.num_outputs)
+			return false;
+		return num_components < o.num_components;
+	}
+};
+
+static std::map<fragmentshaderkey, GLuint> fragmentshaders;
+static std::map<geometryshaderkey, GLuint> testprograms;
+
+static const struct testcase default_testcase = {
+	.num_instances = 1,
+	.num_points = 1,
+	.num_invocations = 1,
+	.num_outputs = 1,
+	.num_components = 0,
+};
+
+static GLuint vs_shader;
+static GLuint vao;
+static std::vector<testcase> testcases;
+static GLuint max_gs_invocations;
+static GLuint max_gs_out_vertices;
+static GLuint max_gs_total_out_components;
+static GLuint max_gs_out_components;
+static unsigned max_gs_out_vertices_real;
+
+static const char vs_text[] =
+	"#version 150\n"
+	"\n"
+	"uniform int u_verts_per_instance;\n"
+	"\n"
+	"out int vs_gs_id;\n"
+	"\n"
+	"void main() {\n"
+	"  vs_gs_id = gl_InstanceID * u_verts_per_instance + gl_VertexID;\n"
+	"}\n";
+
+/* Those numbers really don't matter much for what we're trying to do here. */
+#define GEN_SEQUENCE \
+	"int seq_next(int x) {\n" \
+	"  x = (x + 1) * 709900053;\n" \
+	"  x = x ^ (x >> 17);\n" \
+	"  return x;\n" \
+	"}\n"
+
+static const char gs_text[] =
+	"#version 150\n"
+	"#extension GL_ARB_gpu_shader5 : require\n"
+	"\n"
+	"#define NUM_INVOCATIONS %d\n"
+	"#define NUM_OUT_VERTICES %d\n"
+	"#define NUM_PAYLOAD_COMPONENTS %d\n"
+	"\n"
+	"layout(points, invocations = NUM_INVOCATIONS) in;\n"
+	"layout(points, max_vertices = NUM_OUT_VERTICES) out;\n"
+	"\n"
+	"in int vs_gs_id[];\n"
+	"#if NUM_PAYLOAD_COMPONENTS\n"
+	"flat out int gs_ps_data[NUM_PAYLOAD_COMPONENTS];\n"
+	"#endif\n"
+	"\n"
+	GEN_SEQUENCE
+	"\n"
+	"void main() {\n"
+	"  for (int i = 0; i < NUM_OUT_VERTICES; ++i) {\n"
+	"    int id = (vs_gs_id[0] * NUM_INVOCATIONS + gl_InvocationID) * NUM_OUT_VERTICES + i;\n"
+	"    int x = id %% " STR(WINDOW_SIZE) ";\n"
+	"    int y = id / " STR(WINDOW_SIZE) ";\n"
+	"    gl_Position.x = (float(x) + 0.5) / " STR(WINDOW_SIZE) " * 2.0 - 1.0;\n"
+	"    gl_Position.y = (float(y) + 0.5) / " STR(WINDOW_SIZE) " * 2.0 - 1.0;\n"
+	"    gl_Position.z = 0.0;\n"
+	"    gl_Position.w = 1.0;\n"
+	"\n"
+	"#if NUM_PAYLOAD_COMPONENTS\n"
+	"    int val = id;\n"
+	"    for (int j = 0; j < NUM_PAYLOAD_COMPONENTS; ++j) {\n"
+	"      gs_ps_data[j] = val;\n"
+	"      val = seq_next(val);\n"
+	"    }\n"
+	"#endif\n"
+	"\n"
+	"    EmitVertex();\n"
+	"  }\n"
+	"}\n";
+
+static const char fs_text[] =
+	"#version 150\n"
+	"\n"
+	"#define NUM_PAYLOAD_COMPONENTS %d\n"
+	"\n"
+	"#if NUM_PAYLOAD_COMPONENTS\n"
+	"flat in int gs_ps_data[NUM_PAYLOAD_COMPONENTS];\n"
+	"#endif\n"
+	"out vec4 out_color;\n"
+	"\n"
+	GEN_SEQUENCE
+	"\n"
+	"void main() {\n"
+	"#if NUM_PAYLOAD_COMPONENTS\n"
+	"  int id = int(gl_FragCoord.y) * " STR(WINDOW_SIZE) " + int(gl_FragCoord.x);\n"
+	"  int val = id;\n"
+	"  for (int j = 0; j < NUM_PAYLOAD_COMPONENTS; ++j) {\n"
+	"    if (val != gs_ps_data[j]) {\n"
+	"      out_color.x = 1.0;\n"
+	"      out_color.y = float(j) / (NUM_PAYLOAD_COMPONENTS - 1);\n"
+	"      out_color.z = float(val & 0xff) / 255;\n"
+	"      out_color.w = float(gs_ps_data[j] & 0xff) / 255;\n"
+	"      return;\n"
+	"    }\n"
+	"    val = seq_next(val);\n"
+	"  }\n"
+	"#endif\n"
+	"  out_color = vec4(0, 1, 0, 1);\n"
+	"}\n";
+
+static void
+print_testcase(const struct testcase *tc)
+{
+	printf("Case: instances = %u points = %u invocations = %u "
+	       "outputs = %u components = %u\n",
+	       tc->num_instances, tc->num_points, tc->num_invocations,
+	       tc->num_outputs, tc->num_components);
+}
+
+static void
+add_testcase(const struct testcase *tc)
+{
+	if (tc->num_instances > 64 * 1024 ||
+	    tc->num_points > 64 * 1024 ||
+	    tc->num_invocations > 64 * 1024 ||
+	    tc->num_outputs > 64 * 1024 ||
+	    tc->num_components > 64 * 1024) {
+		fprintf(stderr, "Excessive test case size. Are you sure?\n");
+		print_testcase(tc);
+		exit(1);
+	}
+
+	/* Check against implementation-defined limits. */
+	if (tc->num_outputs > (unsigned)max_gs_out_vertices) {
+		fprintf(stderr, "Too many output vertices (max: %d)\n",
+			max_gs_out_vertices);
+		print_testcase(tc);
+		exit(1);
+	}
+	if (tc->num_outputs * (4 + tc->num_components) > (unsigned)max_gs_total_out_components) {
+		fprintf(stderr, "Too many output components (max: %d)\n",
+			max_gs_total_out_components);
+		print_testcase(tc);
+		exit(1);
+	}
+	if (tc->num_invocations > (unsigned)max_gs_invocations) {
+		fprintf(stderr, "Too many GS invocations (max: %d)\n",
+			max_gs_invocations);
+		print_testcase(tc);
+		exit(1);
+	}
+
+	/* Compile GS shader and link program */
+	geometryshaderkey gskey;
+	gskey.num_invocations = tc->num_invocations;
+	gskey.num_outputs = tc->num_outputs;
+	gskey.num_components = tc->num_components;
+	if (testprograms.find(gskey) == testprograms.end()) {
+		char *text;
+
+		fragmentshaderkey fskey;
+		fskey.num_components = tc->num_components;
+		auto fsit = fragmentshaders.find(fskey);
+		if (fsit == fragmentshaders.end()) {
+			if (asprintf(&text, fs_text, tc->num_components) < 0)
+				abort();
+			GLuint fs_shader =
+				piglit_compile_shader_text(GL_FRAGMENT_SHADER, text);
+			free(text);
+
+			fsit = fragmentshaders.insert(std::make_pair(fskey, fs_shader)).first;
+		}
+
+		if (asprintf(&text, gs_text, tc->num_invocations, tc->num_outputs,
+			tc->num_components) < 0)
+			abort();
+		GLuint gs_shader =
+			piglit_compile_shader_text(GL_GEOMETRY_SHADER, text);
+		free(text);
+
+		GLuint prog =  glCreateProgram();
+		glAttachShader(prog, vs_shader);
+		glAttachShader(prog, gs_shader);
+		glAttachShader(prog, fsit->second);
+		glLinkProgram(prog);
+		if (!piglit_link_check_status(prog))
+			piglit_report_result(PIGLIT_FAIL);
+
+		glDeleteShader(gs_shader);
+
+		testprograms.insert(std::make_pair(gskey, prog));
+	}
+
+	testcases.push_back(*tc);
+}
+
+static bool
+run_testcase(const struct testcase *tc)
+{
+	print_testcase(tc);
+
+	glClearColor(0, 0, 0, 1);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	geometryshaderkey gskey;
+	gskey.num_invocations = tc->num_invocations;
+	gskey.num_outputs = tc->num_outputs;
+	gskey.num_components = tc->num_components;
+	auto progit = testprograms.find(gskey);
+	assert(progit != testprograms.end());
+
+	glUseProgram(progit->second);
+	glUniform1i(glGetUniformLocation(progit->second, "u_verts_per_instance"),
+		    tc->num_points);
+
+	glDrawArraysInstanced(GL_POINTS, 0, tc->num_points, tc->num_instances);
+
+	float expected[WINDOW_SIZE * WINDOW_SIZE * 4];
+	unsigned num_total =
+		tc->num_instances * tc->num_points * tc->num_invocations * tc->num_outputs;
+	memset(expected, 0, sizeof(expected));
+
+	for (unsigned i = 0; i < WINDOW_SIZE * WINDOW_SIZE; ++i) {
+		if (i < num_total)
+			expected[4 * i + 1] = 1.0;
+		expected[4 * i + 3] = 1.0;
+	}
+
+	return piglit_probe_image_rgba(0, 0, WINDOW_SIZE, WINDOW_SIZE, expected);
+}
+
+static void
+generate_testcases_max(const testcase &tc, bool explicit_instances, bool explicit_points)
+{
+	unsigned amplify = tc.num_invocations * tc.num_outputs;
+	double target_in_points = double(WINDOW_SIZE * WINDOW_SIZE) / amplify;
+
+	if (!explicit_instances) {
+		testcase tc1 = tc;
+		tc1.num_instances = MAX2(1, (unsigned)(target_in_points / tc1.num_points));
+		add_testcase(&tc1);
+	}
+
+	if (!explicit_points) {
+		testcase tc1 = tc;
+		tc1.num_points = MAX2(1, (unsigned)(target_in_points / tc1.num_instances));
+		add_testcase(&tc1);
+	}
+
+	if (!explicit_instances && !explicit_points) {
+		testcase tc1 = tc;
+		tc1.num_instances = MAX2(1, (unsigned)sqrt(target_in_points));
+		tc1.num_points = MAX2(1, (unsigned)(target_in_points / tc1.num_instances));
+		add_testcase(&tc1);
+	}
+
+	if (explicit_instances && explicit_points)
+		add_testcase(&tc);
+}
+
+void
+piglit_init(int argc, char **argv)
+{
+	bool explicit_instances = false;
+	bool explicit_points = false;
+	bool explicit_invocations = false;
+	bool explicit_outputs = false;
+	bool explicit_components = false;
+	bool scan_mode = false;
+	unsigned scan_seed = 0;
+	unsigned scan_count = 0;
+	struct testcase explicit_testcase;
+
+	memcpy(&explicit_testcase, &default_testcase, sizeof(explicit_testcase));
+
+	int i;
+	for (i = 1; i + 1 < argc; ++i) {
+		if (!strcmp(argv[i], "-instances")) {
+			explicit_testcase.num_instances = atoi(argv[i + 1]);
+			explicit_instances = true;
+			i++;
+		} else if (!strcmp(argv[i], "-points")) {
+			explicit_testcase.num_points = atoi(argv[i + 1]);
+			explicit_points = true;
+			i++;
+		} else if (!strcmp(argv[i], "-invocations")) {
+			explicit_testcase.num_invocations = atoi(argv[i + 1]);
+			explicit_invocations = true;
+			i++;
+		} else if (!strcmp(argv[i], "-outputs")) {
+			explicit_testcase.num_outputs = atoi(argv[i + 1]);
+			explicit_outputs = true;
+			i++;
+		} else if (!strcmp(argv[i], "-components")) {
+			explicit_testcase.num_components = atoi(argv[i + 1]);
+			explicit_components = true;
+			i++;
+		} else if (!strcmp(argv[i], "-scan")) {
+			if (i + 2 >= argc) {
+				fprintf(stderr, "-scan: too few arguments\n");
+				exit(1);
+			}
+			scan_seed = atoi(argv[i + 1]);
+			scan_count = atoi(argv[i + 2]);
+			scan_mode = true;
+			i += 2;
+		} else
+			break;
+	}
+	if (i < argc) {
+		fprintf(stderr, "Unknown argument: %s\n", argv[i]);
+		exit(1);
+	}
+
+	vs_shader = piglit_compile_shader_text(GL_VERTEX_SHADER, vs_text);
+	if (!piglit_check_gl_error(GL_NO_ERROR))
+		piglit_report_result(PIGLIT_FAIL);
+
+	/* Various other GL objects needed by the test */
+	glGenVertexArrays(1, &vao);
+	glBindVertexArray(vao);
+
+	glGetIntegerv(GL_MAX_GEOMETRY_OUTPUT_VERTICES, (GLint*)&max_gs_out_vertices);
+	glGetIntegerv(GL_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS,
+		      (GLint*)&max_gs_total_out_components);
+	glGetIntegerv(GL_MAX_GEOMETRY_OUTPUT_COMPONENTS,
+		      (GLint*)&max_gs_out_components);
+	glGetIntegerv(GL_MAX_GEOMETRY_SHADER_INVOCATIONS, (GLint*)&max_gs_invocations);
+	if (!piglit_check_gl_error(GL_NO_ERROR))
+		piglit_report_result(PIGLIT_FAIL);
+
+	max_gs_out_vertices_real = MIN2(max_gs_out_vertices,
+					max_gs_total_out_components / 4);
+
+	if (scan_mode) {
+		srand(scan_seed);
+
+		/* First, generate test cases that max out each of the dimensions */
+		testcase tc0 = explicit_testcase;
+		if (!explicit_invocations)
+			tc0.num_invocations = max_gs_invocations;
+
+		if (!explicit_outputs) {
+			testcase tc1 = tc0;
+
+			if (!explicit_components) {
+				tc1.num_outputs = max_gs_out_vertices_real;
+				tc1.num_components = MIN2(max_gs_total_out_components / tc1.num_outputs,
+							  max_gs_out_components) - 4;
+			} else {
+				tc1.num_outputs = MIN2(max_gs_total_out_components / (4 + tc1.num_components),
+						       max_gs_out_vertices_real);
+			}
+
+			generate_testcases_max(tc1, explicit_instances, explicit_points);
+		}
+
+		if (!explicit_components) {
+			testcase tc1 = tc0;
+
+			if (!explicit_outputs) {
+				tc1.num_components = max_gs_out_components - 4;
+				tc1.num_outputs = MIN2(max_gs_total_out_components / (4 + tc1.num_components),
+						       max_gs_out_vertices_real);
+			} else {
+				tc1.num_components = MIN2(max_gs_total_out_components / tc1.num_outputs,
+							  max_gs_out_components) - 4;
+			}
+
+			generate_testcases_max(tc1, explicit_instances, explicit_points);
+		}
+
+		if (explicit_outputs && explicit_components)
+			generate_testcases_max(tc0, explicit_instances, explicit_points);
+
+		/* Generate additional tests randomly */
+		while (testcases.size() < scan_count) {
+			testcase tc = explicit_testcase;
+
+			if (!explicit_outputs || !explicit_components) {
+				if (explicit_outputs || rand() & 1) {
+					unsigned max_components =
+						MIN2(max_gs_total_out_components / tc.num_outputs,
+						     max_gs_out_components) - 4;
+					tc.num_components = rand() % (max_components + 1);
+
+					if (!explicit_outputs) {
+						unsigned max_outputs =
+							MIN2(max_gs_total_out_components / (4 + tc.num_components),
+							     max_gs_out_vertices_real);
+						tc.num_outputs = 1 + rand() % max_outputs;
+					}
+				} else {
+					unsigned max_outputs =
+						MIN2(max_gs_total_out_components / (4 + tc.num_components),
+						     max_gs_out_vertices_real);
+					tc.num_outputs = 1 + rand() % max_outputs;
+
+					if (!explicit_components) {
+						unsigned max_components =
+							MIN2(max_gs_total_out_components / tc.num_outputs,
+							      max_gs_out_components) - 4;
+						tc.num_components = rand() % (max_components + 1);
+					}
+				}
+			}
+
+			if (!explicit_invocations)
+				tc.num_invocations = 1 + rand() % max_gs_invocations;
+
+			unsigned amplify = tc.num_invocations * tc.num_outputs;
+			unsigned target_in_points =
+				MAX2(1, (WINDOW_SIZE * WINDOW_SIZE + amplify - 1) / amplify);
+
+			switch (rand() % 4) {
+			case 0:
+				tc.num_points = 1 + rand() % target_in_points;
+				tc.num_instances = 1 + rand() % (1 + target_in_points / tc.num_points);
+				break;
+			case 1:
+				tc.num_instances = 1 + rand() % target_in_points;
+				tc.num_points = 1 + rand() % (1 + target_in_points / tc.num_instances);
+				break;
+			default: {
+				unsigned min = MAX2(1, sqrt(target_in_points) / 2);
+				unsigned max = MIN2(sqrt(target_in_points) * 3 / 2,
+						    target_in_points);
+				tc.num_instances = min + rand() % (max - min + 1);
+				tc.num_points = 1 + rand() % (1 + target_in_points / tc.num_instances);
+				break;
+			}
+			}
+
+			add_testcase(&tc);
+		}
+	} else {
+		add_testcase(&explicit_testcase);
+	}
+}
+
+enum piglit_result
+piglit_display(void)
+{
+	bool pass = true;
+
+	for (unsigned i = 0; i < testcases.size(); ++i) {
+		if (!run_testcase(&testcases[i]))
+			pass = false;
+	}
+
+	if (!piglit_check_gl_error(GL_NO_ERROR))
+		pass = false;
+
+	piglit_present_results();
+
+	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
+}