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cogl-pipeline: Store the uniform overrides in an array instead of list

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Previously the uniform overrides were stored in a linked list. Now
they are stored in a g_malloc'd array. The values are still tightly
packed so that there is only a value for each uniform that has a
corresponding bit in override_mask. The allocated size of the array
always exactly corresponds to the number of bits set in the
override_mask. This means that when a new uniform value is set on a
pipeline it will have to grow the array and copy the old values
in. The assumption is that setting a value for a new uniform is much
less frequent then setting a value for an existing uniform so it makes
more sense to optimise the latter.

The advantage of using an array is that we can quickly jump to right
boxed value given a uniform location by doing a population count in
the bitmask for the number of bits less than the given uniform
location. This can be done in O(1) time whereas the old approach using
a list would scale by the number of bits set.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
This commit is contained in:
Neil Roberts 2011-11-04 17:56:44 +00:00
parent f23b12a886
commit 4a7cd0d2ac
4 changed files with 76 additions and 111 deletions
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26
cogl/cogl-pipeline-private.h
View File

@ -339,32 +339,18 @@ typedef struct
CoglWinding front_winding;
} CoglPipelineCullFaceState;
typedef struct _CoglPipelineUniformOverride CoglPipelineUniformOverride;
COGL_SLIST_HEAD (CoglPipelineUniformOverrideList,
CoglPipelineUniformOverride);
struct _CoglPipelineUniformOverride
{
COGL_SLIST_ENTRY (CoglPipelineUniformOverride) list_node;
/* We don't need to store the location of the uniform here because
it is implicit from the order in the list */
/* One of these overrides can effectively remove a uniform by
setting the boxed value type to none. In that case no attempt
will be made to upload the value */
CoglBoxedValue value;
};
typedef struct
{
CoglBitmask override_mask;
/* This is an array of values. Only the uniforms that have a bit set
in override_mask have a corresponding value here. The uniform's
location is implicit from the order in this array */
CoglBoxedValue *override_values;
/* Uniforms that have been modified since this pipeline was last
flushed */
CoglBitmask changed_mask;
CoglPipelineUniformOverrideList override_list;
} CoglPipelineUniformsState;
typedef struct

11
cogl/cogl-pipeline-progend-glsl.c
View File

@ -559,7 +559,8 @@ typedef struct
unsigned long *uniform_differences;
int n_differences;
CoglContext *ctx;
CoglPipelineUniformOverride *override;
const CoglBoxedValue *values;
int value_index;
} FlushUniformsClosure;
static gboolean
@ -609,13 +610,13 @@ flush_uniform_cb (int uniform_num, void *user_data)
if (uniform_location != -1)
_cogl_boxed_value_set_uniform (data->ctx,
uniform_location,
&data->override->value);
data->values + data->value_index);
data->n_differences--;
COGL_FLAGS_SET (data->uniform_differences, uniform_num, FALSE);
}
data->override = COGL_SLIST_NEXT (data->override, list_node);
data->value_index++;
return data->n_differences > 0;
}
@ -698,8 +699,8 @@ _cogl_pipeline_progend_glsl_flush_uniforms (CoglPipeline *pipeline,
const CoglPipelineUniformsState *parent_uniforms_state =
&pipeline->big_state->uniforms_state;
data.override =
COGL_SLIST_FIRST (&parent_uniforms_state->override_list);
data.values = parent_uniforms_state->override_values;
data.value_index = 0;
_cogl_bitmask_foreach (&parent_uniforms_state->override_mask,
flush_uniform_cb,

104
cogl/cogl-pipeline-state.c
View File

@ -240,8 +240,9 @@ _cogl_pipeline_user_shader_equal (CoglPipeline *authority0,
typedef struct
{
const CoglBoxedValue **values;
const CoglPipelineUniformOverride *override_values;
const CoglBoxedValue **dst_values;
const CoglBoxedValue *src_values;
int override_count;
} GetUniformsClosure;
static gboolean
@ -249,10 +250,10 @@ get_uniforms_cb (int uniform_num, void *user_data)
{
GetUniformsClosure *data = user_data;
if (data->values[uniform_num] == NULL)
data->values[uniform_num] = &data->override_values->value;
if (data->dst_values[uniform_num] == NULL)
data->dst_values[uniform_num] = data->src_values + data->override_count;
data->override_values = COGL_SLIST_NEXT (data->override_values, list_node);
data->override_count++;
return TRUE;
}
@ -268,14 +269,15 @@ _cogl_pipeline_get_all_uniform_values (CoglPipeline *pipeline,
memset (values, 0,
sizeof (const CoglBoxedValue *) * ctx->n_uniform_names);
data.values = values;
data.dst_values = values;
do
{
const CoglPipelineUniformsState *uniforms_state =
&pipeline->big_state->uniforms_state;
data.override_values = COGL_SLIST_FIRST (&uniforms_state->override_list);
data.override_count = 0;
data.src_values = uniforms_state->override_values;
if ((pipeline->differences & COGL_PIPELINE_STATE_UNIFORMS))
_cogl_bitmask_foreach (&uniforms_state->override_mask,
@ -1398,44 +1400,13 @@ cogl_pipeline_set_point_size (CoglPipeline *pipeline,
_cogl_pipeline_point_size_equal);
}
typedef struct
{
int location;
CoglPipelineUniformOverride *previous_override;
CoglPipelineUniformOverride *found_override;
CoglPipelineUniformOverride *it;
} FindUniformOverrideClosure;
static gboolean
find_uniform_override_cb (int it_location,
void *user_data)
{
FindUniformOverrideClosure *data = user_data;
if (it_location < data->location)
{
data->previous_override = data->it;
data->it = COGL_SLIST_NEXT (data->it, list_node);
return TRUE;
}
else
{
if (it_location == data->location)
data->found_override = data->it;
return FALSE;
}
}
static CoglBoxedValue *
_cogl_pipeline_override_uniform (CoglPipeline *pipeline,
int location)
{
CoglPipelineState state = COGL_PIPELINE_STATE_UNIFORMS;
CoglPipelineUniformsState *uniforms_state;
FindUniformOverrideClosure find_data;
CoglPipelineUniformOverride *override;
int override_index;
_COGL_GET_CONTEXT (ctx, NULL);
@ -1452,36 +1423,53 @@ _cogl_pipeline_override_uniform (CoglPipeline *pipeline,
uniforms_state = &pipeline->big_state->uniforms_state;
find_data.previous_override = NULL;
find_data.found_override = NULL;
find_data.it = COGL_SLIST_FIRST (&uniforms_state->override_list);
find_data.location = location;
_cogl_bitmask_foreach (&uniforms_state->override_mask,
find_uniform_override_cb,
&find_data);
/* Count the number of bits that are set below this location. That
should give us the position where our new value should lie */
override_index = _cogl_bitmask_popcount_upto (&uniforms_state->override_mask,
location);
_cogl_bitmask_set (&uniforms_state->changed_mask, location, TRUE);
/* If this pipeline already has an override for this value then we
can just use it directly */
if (find_data.found_override)
return &find_data.found_override->value;
if (_cogl_bitmask_get (&uniforms_state->override_mask, location))
return uniforms_state->override_values + override_index;
/* We need to add a new override */
override = g_slice_new (CoglPipelineUniformOverride);
_cogl_boxed_value_init (&override->value);
/* We need to create a new override value in the right position
within the array. This is pretty inefficient but the hope is that
it will be much more common to modify an existing uniform rather
than modify a new one so it is more important to optimise the
former case. */
if (find_data.previous_override)
COGL_SLIST_INSERT_AFTER (find_data.previous_override, override, list_node);
if (uniforms_state->override_values == NULL)
{
g_assert (override_index == 0);
uniforms_state->override_values = g_new (CoglBoxedValue, 1);
}
else
COGL_SLIST_INSERT_HEAD (&uniforms_state->override_list,
override,
list_node);
{
/* We need to grow the array and copy in the old values */
CoglBoxedValue *old_values = uniforms_state->override_values;
int old_size = _cogl_bitmask_popcount (&uniforms_state->override_mask);
uniforms_state->override_values = g_new (CoglBoxedValue, old_size + 1);
/* Copy in the old values leaving a gap for the new value */
memcpy (uniforms_state->override_values,
old_values,
sizeof (CoglBoxedValue) * override_index);
memcpy (uniforms_state->override_values,
old_values + override_index + 1,
sizeof (CoglBoxedValue) * (old_size - override_index));
g_free (old_values);
}
_cogl_boxed_value_init (uniforms_state->override_values + override_index);
_cogl_bitmask_set (&uniforms_state->override_mask, location, TRUE);
return &override->value;
return uniforms_state->override_values + override_index;
}
void

46
cogl/cogl-pipeline.c
View File

@ -224,7 +224,7 @@ _cogl_pipeline_init_default_pipeline (void)
_cogl_bitmask_init (&uniforms_state->override_mask);
_cogl_bitmask_init (&uniforms_state->changed_mask);
COGL_SLIST_INIT (&uniforms_state->override_list);
uniforms_state->override_values = NULL;
ctx->default_pipeline = _cogl_pipeline_object_new (pipeline);
}
@ -467,16 +467,12 @@ _cogl_pipeline_free (CoglPipeline *pipeline)
{
CoglPipelineUniformsState *uniforms_state
= &pipeline->big_state->uniforms_state;
CoglPipelineUniformOverride *override, *tmp;
int n_overrides = _cogl_bitmask_popcount (&uniforms_state->override_mask);
int i;
COGL_SLIST_FOREACH_SAFE (override,
&uniforms_state->override_list,
list_node,
tmp)
{
_cogl_boxed_value_destroy (&override->value);
g_slice_free (CoglPipelineUniformOverride, override);
}
for (i = 0; i < n_overrides; i++)
_cogl_boxed_value_destroy (uniforms_state->override_values + i);
g_free (uniforms_state->override_values);
_cogl_bitmask_destroy (&uniforms_state->override_mask);
_cogl_bitmask_destroy (&uniforms_state->changed_mask);
@ -953,27 +949,21 @@ _cogl_pipeline_copy_differences (CoglPipeline *dest,
if (differences & COGL_PIPELINE_STATE_UNIFORMS)
{
CoglPipelineUniformOverride *prev = NULL;
CoglPipelineUniformOverride *override;
int n_overrides =
_cogl_bitmask_popcount (&src->big_state->uniforms_state.override_mask);
int i;
COGL_SLIST_INIT (&big_state->uniforms_state.override_list);
big_state->uniforms_state.override_values =
g_malloc (n_overrides * sizeof (CoglBoxedValue));
COGL_SLIST_FOREACH (override,
&src->big_state->uniforms_state.override_list,
list_node)
for (i = 0; i < n_overrides; i++)
{
CoglPipelineUniformOverride *new_override =
g_slice_new (CoglPipelineUniformOverride);
_cogl_boxed_value_copy (&new_override->value,
&override->value);
if (prev)
COGL_SLIST_INSERT_AFTER (prev, new_override, list_node);
else
COGL_SLIST_INSERT_HEAD (&big_state->uniforms_state.override_list,
new_override,
list_node);
CoglBoxedValue *dst_bv =
big_state->uniforms_state.override_values + i;
const CoglBoxedValue *src_bv =
src->big_state->uniforms_state.override_values + i;
prev = new_override;
_cogl_boxed_value_copy (dst_bv, src_bv);
}
_cogl_bitmask_init (&big_state->uniforms_state.override_mask);
@ -1073,7 +1063,7 @@ _cogl_pipeline_init_multi_property_sparse_state (CoglPipeline *pipeline,
&pipeline->big_state->uniforms_state;
_cogl_bitmask_init (&uniforms_state->override_mask);
_cogl_bitmask_init (&uniforms_state->changed_mask);
COGL_SLIST_INIT (&uniforms_state->override_list);
uniforms_state->override_values = NULL;
}
}
}