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brush: Convert SmudgeBucket from array to struct
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This will make the code slightly more readable.
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@jtojnar
jtojnar committed Aug 4, 2024
1 parent 0303431 commit cff0fe4
Showing 1 changed file with 86 additions and 68 deletions.
154 changes: 86 additions & 68 deletions mypaint-brush.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,13 +54,28 @@

#define GRID_SIZE 256.0

/* Named indices for the smudge bucket arrays */
enum {
SMUDGE_R, SMUDGE_G, SMUDGE_B, SMUDGE_A,
PREV_COL_R, PREV_COL_G, PREV_COL_B, PREV_COL_A,
PREV_COL_RECENTNESS,
SMUDGE_BUCKET_SIZE
};
#define SMUDGE_BUCKET_SIZE (sizeof(SmudgeBucket) / sizeof(float))

/**
* SmudgeBucket:
*
* Optionally used by MyPaintBrush.
*
* Usually used for brushes with multiple offset dabs, where each
* dab is assigned its own bucket containing a smudge state.
*/
typedef struct {
float smudge_r;
float smudge_g;
float smudge_b;
float smudge_a;
float prev_col_r;
float prev_col_g;
float prev_col_b;
float prev_col_a;
float prev_col_recentness;
float smudge_bucket_size;
} SmudgeBucket;

/* The Brush class stores two things:
b) settings: constant during a stroke (eg. size, spacing, dynamics, color selected by the user)
Expand Down Expand Up @@ -94,7 +109,7 @@ struct MyPaintBrush {
// smudge bucket array: part of the state, but stored separately.
// Usually used for brushes with multiple offset dabs, where each
// dab is assigned its own bucket containing a smudge state.
float *smudge_buckets;
SmudgeBucket *smudge_buckets;
int num_buckets;
int min_bucket_used;
int max_bucket_used;
Expand Down Expand Up @@ -158,7 +173,7 @@ brush_reset(MyPaintBrush *self)
int min_index = self->min_bucket_used;
if (min_index != -1) {
int max_index = self->max_bucket_used;
size_t num_bytes = (max_index - min_index + 1) * sizeof(self->smudge_buckets[0]) * SMUDGE_BUCKET_SIZE;
size_t num_bytes = (max_index - min_index + 1) * sizeof(self->smudge_buckets[0]);
memset(self->smudge_buckets + min_index, 0, num_bytes);
self->min_bucket_used = -1;
self->max_bucket_used = -1;
Expand Down Expand Up @@ -195,7 +210,7 @@ mypaint_brush_new_with_buckets(int num_smudge_buckets)
}

if (num_smudge_buckets > 0) {
float *bucket_array = malloc(num_smudge_buckets * SMUDGE_BUCKET_SIZE * sizeof(float));
SmudgeBucket *bucket_array = malloc(num_smudge_buckets * sizeof(SmudgeBucket));
if (!bucket_array) {
free(self);
return NULL;
Expand Down Expand Up @@ -460,16 +475,16 @@ mypaint_brush_set_smudge_bucket_state(
float prev_color_recentness)
{
if (self->num_buckets > bucket_index) {
float* bucket = &self->smudge_buckets[bucket_index];
bucket[SMUDGE_R] = r;
bucket[SMUDGE_G] = g;
bucket[SMUDGE_B] = b;
bucket[SMUDGE_A] = a;
bucket[PREV_COL_R] = prev_r;
bucket[PREV_COL_G] = prev_g;
bucket[PREV_COL_B] = prev_b;
bucket[PREV_COL_A] = prev_a;
bucket[PREV_COL_RECENTNESS] = prev_color_recentness;
SmudgeBucket* bucket = &self->smudge_buckets[bucket_index];
bucket->smudge_r = r;
bucket->smudge_g = g;
bucket->smudge_b = b;
bucket->smudge_a = a;
bucket->prev_col_r = prev_r;
bucket->prev_col_g = prev_g;
bucket->prev_col_b = prev_b;
bucket->prev_col_a = prev_a;
bucket->prev_col_recentness = prev_color_recentness;
return TRUE;
}
return FALSE;
Expand All @@ -492,16 +507,16 @@ mypaint_brush_get_smudge_bucket_state(
float* prev_color_recentness)
{
if (self->num_buckets > bucket_index) {
float* bucket = &self->smudge_buckets[bucket_index];
*r = bucket[SMUDGE_R];
*g = bucket[SMUDGE_G];
*b = bucket[SMUDGE_B];
*a = bucket[SMUDGE_A];
*prev_r = bucket[PREV_COL_R];
*prev_g = bucket[PREV_COL_G];
*prev_b = bucket[PREV_COL_B];
*prev_a = bucket[PREV_COL_A];
*prev_color_recentness = bucket[PREV_COL_RECENTNESS];
SmudgeBucket* bucket = &self->smudge_buckets[bucket_index];
*r = bucket->smudge_r;
*g = bucket->smudge_g;
*b = bucket->smudge_b;
*a = bucket->smudge_a;
*prev_r = bucket->prev_col_r;
*prev_g = bucket->prev_col_g;
*prev_b = bucket->prev_col_b;
*prev_a = bucket->prev_col_a;
*prev_color_recentness = bucket->prev_col_recentness;
return TRUE;
}
return FALSE;
Expand Down Expand Up @@ -903,9 +918,12 @@ void print_inputs(MyPaintBrush *self, float* inputs)
STATE(self, ACTUAL_ELLIPTICAL_DAB_ANGLE) = mod_arith(SETTING(self, ELLIPTICAL_DAB_ANGLE) - viewrotation + 180.0, 180.0) - 180.0;
}

float *fetch_smudge_bucket(MyPaintBrush *self) {
SmudgeBucket *fetch_smudge_bucket(MyPaintBrush *self) {
if (!self->smudge_buckets || !self->num_buckets) {
return &STATE(self, SMUDGE_RA);
float *smudge_state = &STATE(self, SMUDGE_RA);
// Not sure this can be done in general.
// static_assert (sizeof (SmudgeBucket) == sizeof(smudge_state) * SMUDGE_BUCKET_SIZE, "SmudgeBucket includes padding");
return (SmudgeBucket*) smudge_state;
}
const int bucket_index = CLAMP(roundf(SETTING(self, SMUDGE_BUCKET)), 0, self->num_buckets - 1);
if (self->min_bucket_used == -1 || self->min_bucket_used > bucket_index) {
Expand All @@ -914,12 +932,12 @@ void print_inputs(MyPaintBrush *self, float* inputs)
if (self->max_bucket_used < bucket_index) {
self->max_bucket_used = bucket_index;
}
return &self->smudge_buckets[bucket_index * SMUDGE_BUCKET_SIZE];
return &self->smudge_buckets[bucket_index];
}

gboolean
update_smudge_color(
const MyPaintBrush* self, MyPaintSurface* surface, float* const smudge_bucket, const float smudge_length, int px,
const MyPaintBrush* self, MyPaintSurface* surface, SmudgeBucket* const smudge_bucket, const float smudge_length, int px,
int py, const float radius, const float legacy_smudge, const float paint_factor)
{

Expand All @@ -934,16 +952,16 @@ void print_inputs(MyPaintBrush *self, float* inputs)
float r, g, b, a;
const float smudge_length_log = SETTING(self, SMUDGE_LENGTH_LOG);

const float recentness = smudge_bucket[PREV_COL_RECENTNESS] * update_factor;
smudge_bucket[PREV_COL_RECENTNESS] = recentness;
const float recentness = smudge_bucket->prev_col_recentness * update_factor;
smudge_bucket->prev_col_recentness = recentness;

const float margin = 0.0000000000000001;
if (recentness < MIN(1.0, powf(0.5 * update_factor, smudge_length_log) + margin)) {
if (recentness == 0.0) {
// first initialization of smudge color (initiate with color sampled from canvas)
update_factor = 0.0;
}
smudge_bucket[PREV_COL_RECENTNESS] = 1.0;
smudge_bucket->prev_col_recentness = 1.0;

const float radius_log = SETTING(self, SMUDGE_RADIUS_LOG);
const float smudge_radius = CLAMP(radius * expf(radius_log), ACTUAL_RADIUS_MIN, ACTUAL_RADIUS_MAX);
Expand All @@ -960,45 +978,45 @@ void print_inputs(MyPaintBrush *self, float* inputs)
if ((smudge_op_lim > 0.0 && a < smudge_op_lim) || (smudge_op_lim < 0.0 && a > -smudge_op_lim)) {
return TRUE; // signals the caller to return early
}
smudge_bucket[PREV_COL_R] = r;
smudge_bucket[PREV_COL_G] = g;
smudge_bucket[PREV_COL_B] = b;
smudge_bucket[PREV_COL_A] = a;
smudge_bucket->prev_col_r = r;
smudge_bucket->prev_col_g = g;
smudge_bucket->prev_col_b = b;
smudge_bucket->prev_col_a = a;
} else {
r = smudge_bucket[PREV_COL_R];
g = smudge_bucket[PREV_COL_G];
b = smudge_bucket[PREV_COL_B];
a = smudge_bucket[PREV_COL_A];
r = smudge_bucket->prev_col_r;
g = smudge_bucket->prev_col_g;
b = smudge_bucket->prev_col_b;
a = smudge_bucket->prev_col_a;
}

if (legacy_smudge) {
const float fac_old = update_factor;
const float fac_new = (1.0 - update_factor) * a;
smudge_bucket[SMUDGE_R] = fac_old * smudge_bucket[SMUDGE_R] + fac_new * r;
smudge_bucket[SMUDGE_G] = fac_old * smudge_bucket[SMUDGE_G] + fac_new * g;
smudge_bucket[SMUDGE_B] = fac_old * smudge_bucket[SMUDGE_B] + fac_new * b;
smudge_bucket[SMUDGE_A] = CLAMP((fac_old * smudge_bucket[SMUDGE_A] + fac_new), 0.0, 1.0);
smudge_bucket->smudge_r = fac_old * smudge_bucket->smudge_r + fac_new * r;
smudge_bucket->smudge_g = fac_old * smudge_bucket->smudge_g + fac_new * g;
smudge_bucket->smudge_b = fac_old * smudge_bucket->smudge_b + fac_new * b;
smudge_bucket->smudge_a = CLAMP((fac_old * smudge_bucket->smudge_a + fac_new), 0.0, 1.0);
} else if (a > WGM_EPSILON * 10) {
float prev_smudge_color[4] = {smudge_bucket[SMUDGE_R], smudge_bucket[SMUDGE_G], smudge_bucket[SMUDGE_B],
smudge_bucket[SMUDGE_A]};
float prev_smudge_color[4] = {smudge_bucket->smudge_r, smudge_bucket->smudge_g, smudge_bucket->smudge_b,
smudge_bucket->smudge_a};
float sampled_color[4] = {r, g, b, a};

float* smudge_new = mix_colors(prev_smudge_color, sampled_color, update_factor, paint_factor);
smudge_bucket[SMUDGE_R] = smudge_new[SMUDGE_R];
smudge_bucket[SMUDGE_G] = smudge_new[SMUDGE_G];
smudge_bucket[SMUDGE_B] = smudge_new[SMUDGE_B];
smudge_bucket[SMUDGE_A] = smudge_new[SMUDGE_A];
smudge_bucket->smudge_r = smudge_new[0];
smudge_bucket->smudge_g = smudge_new[1];
smudge_bucket->smudge_b = smudge_new[2];
smudge_bucket->smudge_a = smudge_new[3];
} else {
// To avoid color noise from spectral mixing with a low alpha,
// we'll just decrease the alpha of the existing smudge color.
smudge_bucket[SMUDGE_A] = (smudge_bucket[SMUDGE_A] + a) / 2;
smudge_bucket->smudge_a = (smudge_bucket->smudge_a + a) / 2;
}
return FALSE; // signals the caller to not return early (the default)
}

float
apply_smudge(
const float* const smudge_bucket, const float smudge_value, const gboolean legacy_smudge,
const SmudgeBucket* const smudge_bucket, const float smudge_value, const gboolean legacy_smudge,
const float paint_factor, float* color_r, float* color_g, float* color_b)
{
float smudge_factor = MIN(1.0, smudge_value);
Expand All @@ -1007,22 +1025,22 @@ void print_inputs(MyPaintBrush *self, float* inputs)
// dab will do erasing towards that transparency level.
// see also ../doc/smudge_math.png
const float eraser_target_alpha =
CLAMP((1.0 - smudge_factor) + smudge_factor * smudge_bucket[SMUDGE_A], 0.0, 1.0);
CLAMP((1.0 - smudge_factor) + smudge_factor * smudge_bucket->smudge_a, 0.0, 1.0);

if (eraser_target_alpha > 0) {
if (legacy_smudge) {
const float col_factor = 1.0 - smudge_factor;
*color_r = (smudge_factor * smudge_bucket[SMUDGE_R] + col_factor * *color_r) / eraser_target_alpha;
*color_g = (smudge_factor * smudge_bucket[SMUDGE_G] + col_factor * *color_g) / eraser_target_alpha;
*color_b = (smudge_factor * smudge_bucket[SMUDGE_B] + col_factor * *color_b) / eraser_target_alpha;
*color_r = (smudge_factor * smudge_bucket->smudge_r + col_factor * *color_r) / eraser_target_alpha;
*color_g = (smudge_factor * smudge_bucket->smudge_g + col_factor * *color_g) / eraser_target_alpha;
*color_b = (smudge_factor * smudge_bucket->smudge_b + col_factor * *color_b) / eraser_target_alpha;
} else {
float smudge_color[4] = {smudge_bucket[SMUDGE_R], smudge_bucket[SMUDGE_G], smudge_bucket[SMUDGE_B],
smudge_bucket[SMUDGE_A]};
float smudge_color[4] = {smudge_bucket->smudge_r, smudge_bucket->smudge_g, smudge_bucket->smudge_b,
smudge_bucket->smudge_a};
float brush_color[4] = {*color_r, *color_g, *color_b, 1.0};
float* color_new = mix_colors(smudge_color, brush_color, smudge_factor, paint_factor);
*color_r = color_new[SMUDGE_R];
*color_g = color_new[SMUDGE_G];
*color_b = color_new[SMUDGE_B];
*color_r = color_new[0];
*color_g = color_new[1];
*color_b = color_new[2];
}
} else {
// we are only erasing; the color does (should) not matter
Expand Down Expand Up @@ -1123,7 +1141,7 @@ gboolean prepare_and_draw_dab (MyPaintBrush *self, MyPaintSurface * surface, gbo
const float smudge_length = SETTING(self, SMUDGE_LENGTH);
if (smudge_length < 1.0 && // default smudge length is 0.5, so the smudge factor is checked as well
(SETTING(self, SMUDGE) != 0.0 || !mypaint_mapping_is_constant(self->settings[MYPAINT_BRUSH_SETTING_SMUDGE]))) {
float* const bucket = fetch_smudge_bucket(self);
SmudgeBucket* const bucket = fetch_smudge_bucket(self);
gboolean return_early = update_smudge_color(
self, surface, bucket, smudge_length, ROUND(x), ROUND(y), radius, legacy_smudge, paint_factor);
if (return_early) {
Expand All @@ -1135,7 +1153,7 @@ gboolean prepare_and_draw_dab (MyPaintBrush *self, MyPaintSurface * surface, gbo
const float smudge_value = SETTING(self, SMUDGE);

if (smudge_value > 0.0) {
float* const bucket = fetch_smudge_bucket(self);
SmudgeBucket* const bucket = fetch_smudge_bucket(self);
eraser_target_alpha =
apply_smudge(bucket, smudge_value, legacy_smudge, paint_factor, &color_h, &color_s, &color_v);
}
Expand Down

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