[Piglit] [PATCH 3/6] shader_runner: Allow "draw arrays" if no [vertex data] section.

[Paul Berry]

For some geometry shader tests, there's no need for any vertex shader
inputs at all--the geometry shader produces all the data itself.  To
allow tests like these, we need to be able to issue a "draw arrays"
command with any number of input vertices, even if there is no [vertex
data] section.

This patch disables shader_runner's "draw arrays" overflow checks in
the event that there is no [vertex data] section, so that the "draw
arrays" command can be used.  This is safe, since the lack of a
[vertex data] section means that no vertex attrib arrays are enabled,
so the shader won't try to access the vertex input data at all.
---
 tests/shaders/shader_runner.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tests/shaders/shader_runner.c b/tests/shaders/shader_runner.c
index be1bfef..492db06 100644
--- a/tests/shaders/shader_runner.c
+++ b/tests/shaders/shader_runner.c
@@ -95,6 +95,7 @@ const char *vertex_data_start = NULL;
 const char *vertex_data_end = NULL;
 GLuint prog;
 size_t num_vbo_rows = 0;
+bool vbo_present = false;
 bool link_ok = false;
 bool prog_in_use = false;
 GLchar *prog_err_info = NULL;
@@ -1710,7 +1711,8 @@ piglit_display(void)
 			if (first < 0) {
 				printf("draw arrays 'first' must be >= 0\n");
 				piglit_report_result(PIGLIT_FAIL);
-			} else if ((size_t) first >= num_vbo_rows) {
+			} else if (vbo_present &&
+				   (size_t) first >= num_vbo_rows) {
 				printf("draw arrays 'first' must be < %lu\n",
 				       (unsigned long) num_vbo_rows);
 				piglit_report_result(PIGLIT_FAIL);
@@ -1718,7 +1720,8 @@ piglit_display(void)
 			if (count <= 0) {
 				printf("draw arrays 'count' must be > 0\n");
 				piglit_report_result(PIGLIT_FAIL);
-			} else if (count > num_vbo_rows - (size_t) first) {
+			} else if (vbo_present &&
+				   count > num_vbo_rows - (size_t) first) {
 				printf("draw arrays cannot draw beyond %lu\n",
 				       (unsigned long) num_vbo_rows);
 				piglit_report_result(PIGLIT_FAIL);
@@ -1993,6 +1996,7 @@ piglit_init(int argc, char **argv)
 
 		num_vbo_rows = setup_vbo_from_text(prog, vertex_data_start,
 						   vertex_data_end);
+		vbo_present = true;
 	}
 	setup_ubos();
 }
-- 
1.8.3.4