[Piglit] [PATCH 2/2] Transform feedback: test order of recorded vertices.
Paul Berry
stereotype441 at gmail.com
Wed Nov 2 15:10:12 PDT 2011
This patch adds a test to confirm that the order of vertices output by
transform feedback matches the order of vertices supplied to the GL
pipeline, even if some vertices take significantly longer to process
than others.
---
tests/all.tests | 5 +
.../spec/ext_transform_feedback/CMakeLists.gl.txt | 1 +
tests/spec/ext_transform_feedback/order.c | 315 ++++++++++++++++++++
3 files changed, 321 insertions(+), 0 deletions(-)
create mode 100644 tests/spec/ext_transform_feedback/order.c
diff --git a/tests/all.tests b/tests/all.tests
index 6ae9ab3..bfc4c1f 100644
--- a/tests/all.tests
+++ b/tests/all.tests
@@ -1319,6 +1319,11 @@ ext_transform_feedback['query-primitives_written-bufferrange-discard'] = PlainE
ext_transform_feedback['interleaved-attribs'] = PlainExecTest(['ext_transform_feedback-interleaved', '-auto'])
ext_transform_feedback['separate-attribs'] = PlainExecTest(['ext_transform_feedback-separate', '-auto'])
+for drawcall in ['arrays', 'elements']:
+ for mode in ['triangles', 'lines', 'points']:
+ test_name = 'order {0} {1}'.format(drawcall, mode)
+ ext_transform_feedback[test_name] = PlainExecTest(
+ 'ext_transform_feedback-{0} -auto'.format(test_name))
ext_transform_feedback['output-type float'] = PlainExecTest(['ext_transform_feedback-output-type', '-auto', 'float'])
ext_transform_feedback['output-type float[2]'] = PlainExecTest(['ext_transform_feedback-output-type', '-auto', 'float[2]'])
diff --git a/tests/spec/ext_transform_feedback/CMakeLists.gl.txt b/tests/spec/ext_transform_feedback/CMakeLists.gl.txt
index 81fa6a0..35c5dce 100644
--- a/tests/spec/ext_transform_feedback/CMakeLists.gl.txt
+++ b/tests/spec/ext_transform_feedback/CMakeLists.gl.txt
@@ -22,5 +22,6 @@ add_executable (ext_transform_feedback-position position.c)
add_executable (ext_transform_feedback-interleaved interleaved.c)
add_executable (ext_transform_feedback-separate separate.c)
add_executable (ext_transform_feedback-output-type output-type.c)
+add_executable (ext_transform_feedback-order order.c)
# vim: ft=cmake:
diff --git a/tests/spec/ext_transform_feedback/order.c b/tests/spec/ext_transform_feedback/order.c
new file mode 100644
index 0000000..5566247
--- /dev/null
+++ b/tests/spec/ext_transform_feedback/order.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright © 2011 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 order.c
+ *
+ * Confirm that the order of vertices output by transform feedback
+ * matches the order of vertices supplied to the GL pipeline.
+ *
+ * On OpenGL implementations that execute multiple vertex shader
+ * threads in parallel, it's possible that the threads won't complete
+ * in the same order that they were invoked. When this happens, it's
+ * critical that transform feedback records the vertices in the order
+ * that they were inserted into the GL pipeline, not the order of
+ * shader completion.
+ *
+ * This test verifies that transform feedback records vertices in the
+ * correct order by using a vertex shader whose execution time is
+ * dramatically different for different vertices.
+ *
+ * The test requries two command line arguments:
+ *
+ * - drawcall indicates which drawing function should be called. A
+ * value of "arrays" causes DrawArrays() to be used. A value of
+ * "elements" causes DrawElemeents() to be used. When
+ * DrawElements() is used, we supply an indices array that scrambles
+ * the order in which vertices are sent to the shader, and verify
+ * that the scrambling is reflected in the transform feedback
+ * output.
+ *
+ * - mode indiceates which drawing mode should be used. It may be
+ * "triangles", "lines", or "points".
+ */
+
+#include "piglit-util.h"
+
+#define NUM_POINTS 10002
+#define SHIFT_COUNT 64
+
+int piglit_width = 100;
+int piglit_height = 100;
+int piglit_window_mode = GLUT_DOUBLE | GLUT_RGB | GLUT_ALPHA;
+static GLenum draw_mode;
+static GLboolean use_draw_elements;
+static GLuint prog;
+static GLuint xfb_buf;
+static unsigned *verts;
+static unsigned *indices;
+
+/* This vertex shader computes the hailstone sequence, which is
+ * defined as:
+ *
+ * x[0] = starting_x
+ * x[n+1] = x[n]/2 if x[n] is even
+ * = 3*x[n]+1 if x[n] is odd
+ *
+ * The shader measures, for different values of starting_x, the
+ * minimum n such that x[n] = 1. This value is output in
+ * iteration_count. The shader outputs a copy of starting_x in
+ * starting_x_copy.
+ *
+ * To prevent an infinite loop, if starting_x is 0, it is changed to
+ * 1.
+ *
+ * In addition, to consume more execution time, the shader maintains a
+ * 31-bit shift register whose value starts at 1, and at each
+ * iteration of the algorithm, shifts it left, in circular fashion,
+ * shift_count times. shift_count can be adjusted as necessary to
+ * ensure that vertex shader threads complete out of order, but the
+ * entire test doesn't take too long to finish.
+ *
+ * All of this pointless mathematics serves one purpose: to ensure
+ * that different invocations of the vertex shader take dramatically
+ * different amounts of time to execute.
+ */
+static const char *vstext =
+ "#version 130\n"
+ "in uint starting_x;\n"
+ "flat out uint starting_x_copy;\n"
+ "flat out uint iteration_count;\n"
+ "flat out uint shift_reg_final;\n"
+ "uniform uint shift_count;\n"
+ "\n"
+ "void main()\n"
+ "{\n"
+ " gl_Position = vec4(0.0);\n"
+ " uint x = starting_x;\n"
+ " if (x == 0u)\n"
+ " x = 1u;\n"
+ " uint count = 0u;\n"
+ " uint shift_reg = 1u;\n"
+ " starting_x_copy = starting_x;\n"
+ " while (x != 1u) {\n"
+ " ++count;\n"
+ " if (x % 2u == 0u)\n"
+ " x /= 2u;\n"
+ " else\n"
+ " x = 3u * x + 1u;\n"
+ " uint i;\n"
+ " for (i = 0u; i < shift_count; ++i)\n"
+ " shift_reg = (shift_reg * 2u) % 0x7fffffffu;\n"
+ " }\n"
+ " iteration_count = count;\n"
+ " shift_reg_final = shift_reg;\n"
+ "}\n";
+
+static const char *varyings[] = {
+ "starting_x_copy", "iteration_count", "shift_reg_final"
+};
+
+static void
+initialize_shader_and_xfb()
+{
+ GLuint vs;
+
+ piglit_require_GLSL_version(130);
+ piglit_require_transform_feedback();
+ vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vstext);
+ prog = piglit_CreateProgram();
+ piglit_AttachShader(prog, vs);
+ piglit_TransformFeedbackVaryings(prog, 3, varyings,
+ GL_INTERLEAVED_ATTRIBS);
+ piglit_LinkProgram(prog);
+ if (!piglit_link_check_status(prog)) {
+ piglit_DeleteProgram(prog);
+ piglit_report_result(PIGLIT_FAIL);
+ }
+ glGenBuffers(1, &xfb_buf);
+ glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, xfb_buf);
+ glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER,
+ 3*NUM_POINTS*sizeof(unsigned), NULL, GL_STREAM_READ);
+ piglit_BindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, xfb_buf);
+ piglit_UseProgram(prog);
+ piglit_check_gl_error(0, PIGLIT_FAIL);
+}
+
+static void
+initialize_vertex_shader_inputs()
+{
+ GLint starting_x_index = glGetAttribLocation(prog, "starting_x");
+ unsigned i;
+
+ verts = malloc(NUM_POINTS*sizeof(unsigned));
+ indices = malloc(NUM_POINTS*sizeof(unsigned));
+
+ for (i = 0; i < NUM_POINTS; ++i)
+ verts[i] = i;
+ for (i = 0; i < NUM_POINTS/2; ++i) {
+ indices[i] = 2*i;
+ indices[i + NUM_POINTS/2] = 2*i+1;
+ }
+
+ piglit_Uniform1ui(piglit_GetUniformLocation(prog, "shift_count"),
+ SHIFT_COUNT);
+ glVertexAttribIPointer(starting_x_index, 1, GL_UNSIGNED_INT, sizeof(unsigned),
+ verts);
+ glEnableVertexAttribArray(starting_x_index);
+ piglit_check_gl_error(0, PIGLIT_FAIL);
+}
+
+/**
+ * Compute the value of iteration_count that we expect the vertex
+ * shader to output for the given starting_x.
+ */
+static unsigned
+compute_iteration_count(unsigned starting_x)
+{
+ unsigned count = 0;
+ unsigned x = starting_x;
+ if (x == 0)
+ x = 1;
+ while (x != 1) {
+ ++count;
+ if (x % 2 == 0)
+ x /= 2;
+ else
+ x = 3 * x + 1;
+ }
+ return count;
+}
+
+/**
+ * Compute the value of shift_reg_final that we expect the vertex
+ * shader to output for the given iteration_count.
+ */
+static unsigned
+compute_shift_reg_final(unsigned iteration_count)
+{
+ /* shift_reg starts at 1 and is shifted left
+ * SHIFT_COUNT*iteration_count times. After every 31 shifts,
+ * it resets to 1.
+ */
+ return ((unsigned) 1) << ((SHIFT_COUNT * iteration_count) % 31);
+}
+
+static void
+draw()
+{
+ glEnable(GL_RASTERIZER_DISCARD);
+ piglit_BeginTransformFeedback(draw_mode);
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+ if (use_draw_elements) {
+ glDrawElements(draw_mode, NUM_POINTS, GL_UNSIGNED_INT,
+ indices);
+ } else {
+ glDrawArrays(draw_mode, 0, NUM_POINTS);
+ }
+ piglit_EndTransformFeedback();
+ piglit_check_gl_error(0, PIGLIT_FAIL);
+}
+
+static void
+check_results_and_exit()
+{
+ unsigned *readback;
+ unsigned i;
+ GLboolean pass = GL_TRUE;
+
+ readback = glMapBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, GL_READ_ONLY);
+ piglit_check_gl_error(0, PIGLIT_FAIL);
+
+ for (i = 0; i < NUM_POINTS; ++i) {
+ unsigned expected_starting_x =
+ use_draw_elements ? indices[i] : i;
+ unsigned expected_iteration_count =
+ compute_iteration_count(expected_starting_x);
+ unsigned expected_shift_reg_final =
+ compute_shift_reg_final(expected_iteration_count);
+ if (readback[3*i] != expected_starting_x) {
+ printf("Order changed at vertex %u\n", i);
+ pass = GL_FALSE;
+ break;
+ }
+ if (readback[3*i+1] != expected_iteration_count) {
+ printf("Incorrect iteration_count at vertex %u\n", i);
+ pass = GL_FALSE;
+ break;
+ }
+ if (readback[3*i+2] != expected_shift_reg_final) {
+ printf("Incorrect shift_reg_final at vertex %u\n", i);
+ pass = GL_FALSE;
+ break;
+ }
+ }
+ glUnmapBuffer(GL_TRANSFORM_FEEDBACK_BUFFER);
+
+ piglit_report_result(pass ? PIGLIT_PASS : PIGLIT_FAIL);
+}
+
+static void
+print_usage_and_exit(char *prog_name)
+{
+ printf("Usage: %s <drawcall> <mode>\n"
+ " where <drawcall is one of:\n"
+ " arrays\n"
+ " elements\n"
+ " and <mode> is one of:\n"
+ " triangles\n"
+ " lines\n"
+ " points\n", prog_name);
+ exit(1);
+}
+
+void
+piglit_init(int argc, char **argv)
+{
+ /* Interpret command line args */
+ if (argc != 3)
+ print_usage_and_exit(argv[0]);
+ if (strcmp(argv[1], "arrays") == 0)
+ use_draw_elements = GL_FALSE;
+ else if (strcmp(argv[1], "elements") == 0)
+ use_draw_elements = GL_TRUE;
+ else
+ print_usage_and_exit(argv[0]);
+ if (strcmp(argv[2], "triangles") == 0)
+ draw_mode = GL_TRIANGLES;
+ else if (strcmp(argv[2], "lines") == 0)
+ draw_mode = GL_LINES;
+ else if (strcmp(argv[2], "points") == 0)
+ draw_mode = GL_POINTS;
+ else
+ print_usage_and_exit(argv[0]);
+
+ initialize_shader_and_xfb();
+ initialize_vertex_shader_inputs();
+ draw();
+ check_results_and_exit();
+}
+
+enum piglit_result piglit_display(void)
+{
+ /* Test should finish before we reach here. */
+ return PIGLIT_FAIL;
+}
--
1.7.6.4
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