[Piglit] [PATCH 2/3] arb_internalformat_query: Verify that glGetInternalformativ does over-run the buffer

[Ian Romanick]

On 12/11/2012 04:13 PM, Eric Anholt wrote:
> Ian Romanick <idr at freedesktop.org> writes:
>> +/**
>> + * \file overrun.c
>> + * Verify that queries don't over-run the size of the supplied buffer.
>> + */
>> +
>> +#include "piglit-util-gl-common.h"
>> +
>> +PIGLIT_GL_TEST_CONFIG_BEGIN
>> +
>> +	config.supports_gl_compat_version = 10;
>> +	config.window_visual = PIGLIT_GL_VISUAL_RGB;
>> +
>> +PIGLIT_GL_TEST_CONFIG_END
>> +
>> +/* These are all the formats that are required to be color-renderable by the
>> + * OpenGL 3.0 spec.
>> + */
>
> Require gl compat version of 30 in that case?

I can do that.

>> +	/* Try GL_NUM_SAMPLE_COUNTS
>> +	 */
>> +	buffer[0] = ~num_sample_counts;
>
> I'd prefer an explicit magic value like 0xd0d0d0d0.  Yeah, the test
> wouldn't successfully test if there happened to be 0xd0d0d0d0 sample
> counts supported, but I think it's more obvious then what you're
> testing for.

Okay.

>> +	glGetInternalformativ(GL_RENDERBUFFER,
>> +			      format,
>> +			      GL_NUM_SAMPLE_COUNTS,
>> +			      0, buffer);
>> +	pass = piglit_check_gl_error(0)
>> +		&& pass;
>> +
>> +	if (buffer[0] != ~num_sample_counts) {
>> +		pass = false;
>> +		fprintf(stderr,
>> +			"pname = GL_NUM_SAMPLE_COUNTS, bufSize = 0 "
>> +			"over-ran the buffer.\n");
>> +	}
>> +
>> +	/* Try GL_SAMPLES
>> +	 */
>> +	memset(buffer, 0x7e, buffer_size_in_bytes);
>> +
>> +	glGetInternalformativ(GL_RENDERBUFFER,
>> +			      format,
>> +			      GL_SAMPLES,
>> +			      buffer_size_in_elements,
>> +			      buffer);
>> +	pass = piglit_check_gl_error(0)
>> +		&& pass;
>> +
>> +	for (i = 0; i < buffer_size_in_elements; i++) {
>> +		buffer[i] = ~buffer[i];
>> +		buffer_copy[i] = buffer[i];
>
> I'm confused, it looks like buffer_copy will have an inverted copy of
> the buffer data, but then we check an uninverted return value against
> it.

I call it once with the full size buffer.  I smash the data in the 
buffer.  I call it again with a buffer size of 1.  I verify that all of 
the data after the first element is still the smashed data.

> Also, worth checking that exactly NUM_SAMPLES values were actually
> written at this point?

I think the api-errors test should catch most errors when not enough 
data is written.  The test pre-fills the buffer with zero, and zero is 
an invalid value for the GL_SAMPLES query.

>> +	glGetInternalformativ(GL_RENDERBUFFER,
>> +			      format,
>> +			      GL_SAMPLES,
>> +			      1,
>> +			      buffer);
>> +	pass = piglit_check_gl_error(0)
>> +		&& pass;
>> +
>> +	for (i = 1; i < buffer_size_in_elements; i++) {
>> +		if (buffer[i] != buffer_copy[i]) {
>> +			fprintf(stderr,
>> +				"pname = GL_SAMPLES, bufSize = 1 "
>> +				"over-ran the buffer at element %u.\n",
>> +				i);
>> +			pass = false;
>> +		}
>> +	}