[Piglit] [PATCH] glsl-1.40: Add a test for vertex shaders that don't write gl_Position.

[Ian Romanick]

On 03/19/2012 11:05 PM, Eric Anholt wrote:
> Transform feedback is used to get a testable output, and it's this
> possibility of using vertex shader execution without rasterization
> that led to the change in the spec.

It was transform feedback and geometry shaders.  You could have a vertex 
shader that calculates control point data, and a geometry shader that 
tessellates the patch and generates its own gl_Position.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> ---
>   tests/all.tests                        |    1 +
>   tests/spec/CMakeLists.txt              |    1 +
>   tests/spec/glsl-1.40/CMakeLists.gl.txt |   18 +++++
>   tests/spec/glsl-1.40/CMakeLists.txt    |    1 +
>   tests/spec/glsl-1.40/tf-no-position.c  |  126 ++++++++++++++++++++++++++++++++
>   5 files changed, 147 insertions(+), 0 deletions(-)
>   create mode 100644 tests/spec/glsl-1.40/CMakeLists.gl.txt
>   create mode 100644 tests/spec/glsl-1.40/CMakeLists.txt
>   create mode 100644 tests/spec/glsl-1.40/tf-no-position.c
>
> diff --git a/tests/all.tests b/tests/all.tests
> index 77a0f6a..f446c7b 100644
> --- a/tests/all.tests
> +++ b/tests/all.tests
> @@ -989,6 +989,7 @@ add_shader_test_dir(spec['glsl-1.40'],
>   	            os.path.join(testsDir, 'spec', 'glsl-1.40'),
>   		    recursive=True)
>   spec['glsl-1.40']['execution']['textureSize'] = Group()
> +spec['glsl-1.40']['execution']['tf-no-position'] = concurrent_test('glsl-1.40-tf-no-position')
>
>   textureSize_samplers_140 = textureSize_samplers_130 + ['sampler2DRect', 'isampler2DRect', 'sampler2DRectShadow', 'samplerBuffer', 'isamplerBuffer', 'usamplerBuffer']
>   for stage in ['vs', 'fs']:
> diff --git a/tests/spec/CMakeLists.txt b/tests/spec/CMakeLists.txt
> index 93f0681..29dcf0f 100644
> --- a/tests/spec/CMakeLists.txt
> +++ b/tests/spec/CMakeLists.txt
> @@ -37,6 +37,7 @@ add_subdirectory (arb_copy_buffer)
>   add_subdirectory (glsl-1.10)
>   add_subdirectory (glsl-1.20)
>   add_subdirectory (glsl-1.30)
> +add_subdirectory (glsl-1.40)
>   add_subdirectory (gl-2.0)
>   add_subdirectory (gl-2.1)
>   add_subdirectory (gl-3.0)
> diff --git a/tests/spec/glsl-1.40/CMakeLists.gl.txt b/tests/spec/glsl-1.40/CMakeLists.gl.txt
> new file mode 100644
> index 0000000..0d57dbc
> --- /dev/null
> +++ b/tests/spec/glsl-1.40/CMakeLists.gl.txt
> @@ -0,0 +1,18 @@
> +include_directories(
> +	${GLEXT_INCLUDE_DIR}
> +	${OPENGL_INCLUDE_PATH}
> +	${GLUT_INCLUDE_DIR}
> +	${piglit_SOURCE_DIR}/tests/spec/arb_color_buffer_float
> +	${piglit_SOURCE_DIR}/tests/util
> +)
> +
> +link_libraries (
> +	piglitutil
> +	${OPENGL_gl_LIBRARY}
> +	${OPENGL_glu_LIBRARY}
> +	${GLUT_glut_LIBRARY}
> +)
> +
> +add_executable (glsl-1.40-tf-no-position tf-no-position.c)
> +
> +# vim: ft=cmake:
> diff --git a/tests/spec/glsl-1.40/CMakeLists.txt b/tests/spec/glsl-1.40/CMakeLists.txt
> new file mode 100644
> index 0000000..144a306
> --- /dev/null
> +++ b/tests/spec/glsl-1.40/CMakeLists.txt
> @@ -0,0 +1 @@
> +piglit_include_target_api()
> diff --git a/tests/spec/glsl-1.40/tf-no-position.c b/tests/spec/glsl-1.40/tf-no-position.c
> new file mode 100644
> index 0000000..821f524
> --- /dev/null
> +++ b/tests/spec/glsl-1.40/tf-no-position.c
> @@ -0,0 +1,126 @@
> +/*
> + * Copyright © 2012 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 tf-no-position.c
> + *
> + * Verify that we can render without specifying a gl_Position, by
> + * using EXT_transform_feedback to get results.
> + */
> +
> +#include "piglit-util.h"
> +
> +#define BUFFER_SIZE 4
> +
> +int piglit_width = 10;
> +int piglit_height = 10;
> +int piglit_window_mode = GLUT_DOUBLE | GLUT_RGB | GLUT_ALPHA;
> +
> +static const char *vs_source =
> +	"#version 140\n"
> +	"in uint i;\n"
> +	"flat out uint o;\n"
> +	"\n"
> +	"void main()\n"
> +	"{\n"
> +	"	o = i;\n"
> +	"}\n";
> +
> +enum piglit_result piglit_display(void)
> +{
> +	return PIGLIT_FAIL; /* UNREACHED */
> +}
> +
> +void piglit_init(int argc, char **argv)
> +{
> +	GLuint vs;
> +	GLuint *readback;
> +	GLuint buffer[BUFFER_SIZE];
> +	GLuint expected[BUFFER_SIZE];
> +	int i;
> +	bool pass = true;
> +	GLint input_index;
> +	GLuint prog;
> +	GLuint xfb_buf;
> +	GLuint verts[4] = { 0, 1, 2, 3 };
> +	const char *varying = "o";
> +
> +	piglit_require_GLSL_version(140);
> +	piglit_require_gl_version(30);
> +	piglit_require_transform_feedback();
> +	vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vs_source);
> +	if (!vs)
> +		piglit_report_result(PIGLIT_FAIL);
> +
> +	prog = piglit_CreateProgram();
> +	piglit_AttachShader(prog, vs);
> +	piglit_TransformFeedbackVaryings(prog, 1,&varying,
> +					 GL_INTERLEAVED_ATTRIBS);
> +	piglit_LinkProgram(prog);
> +	if (!piglit_link_check_status(prog))
> +		piglit_report_result(PIGLIT_FAIL);
> +	glGenBuffers(1,&xfb_buf);
> +	if (!piglit_check_gl_error(0))
> +		piglit_report_result(PIGLIT_FAIL);
> +
> +	input_index = glGetAttribLocation(prog, "i");
> +
> +	piglit_UseProgram(prog);
> +
> +	glBindBuffer(GL_ARRAY_BUFFER, 0);
> +	glVertexAttribIPointer(input_index, 1, GL_UNSIGNED_INT,
> +			       sizeof(GLuint),&verts);
> +	glEnableVertexAttribArray(input_index);
> +	pass = piglit_check_gl_error(0)&&  pass;
> +
> +	glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, xfb_buf);
> +	memset(buffer, 0xd0, sizeof(buffer));
> +	glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, sizeof(buffer), buffer,
> +		     GL_STREAM_READ);
> +	piglit_BindBufferRange(GL_TRANSFORM_FEEDBACK_BUFFER, 0, xfb_buf,
> +			       0,
> +			       sizeof(buffer));
> +	piglit_BeginTransformFeedback(GL_POINTS);
> +	glDrawArrays(GL_POINTS, 0, ARRAY_SIZE(verts));
> +	piglit_EndTransformFeedback();
> +
> +	readback = glMapBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, GL_READ_ONLY);
> +
> +	/* Check output */
> +	for (i = 0; i<  BUFFER_SIZE; ++i) {
> +		if (verts[i] != readback[i]) {
> +			printf("readback[%u]: %u, expected: %u\n", i,
> +			       readback[i], expected[i]);
> +			pass = false;
> +		}
> +	}
> +
> +	/* Note that rasterization occurred, but the results were
> +	 * undefined due to gl_Position not being written.  We do want
> +	 * to have rasterization occur (as opposed to just transform
> +	 * feedback) just to make sure the GPU didn't wedge or
> +	 * anything.
> +	 */
> +
> +	piglit_report_result(pass ? PIGLIT_PASS : PIGLIT_FAIL);
> +}