/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenkernel/intern/brush.c
 *  \ingroup bke
 */

#include "MEM_guardedalloc.h"

#include "DNA_brush_types.h"
#include "DNA_scene_types.h"
#include "DNA_object_types.h"

#include "BLI_math.h"
#include "BLI_blenlib.h"
#include "BLI_rand.h"

#include "BKE_brush.h"
#include "BKE_colortools.h"
#include "BKE_global.h"
#include "BKE_library.h"
#include "BKE_library_query.h"
#include "BKE_library_remap.h"
#include "BKE_main.h"
#include "BKE_paint.h"
#include "BKE_texture.h"
#include "BKE_icons.h"

#include "IMB_colormanagement.h"
#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"

#include "RE_render_ext.h" /* externtex */

static RNG *brush_rng;

void BKE_brush_system_init(void)
{
	brush_rng = BLI_rng_new(0);
	BLI_rng_srandom(brush_rng, 31415682);
}

void BKE_brush_system_exit(void)
{
	BLI_rng_free(brush_rng);
}


static void brush_defaults(Brush *brush)
{
	brush->blend = 0;
	brush->flag = 0;

	brush->ob_mode = OB_MODE_ALL_PAINT;

	/* BRUSH SCULPT TOOL SETTINGS */
	brush->weight = 1.0f; /* weight of brush 0 - 1.0 */
	brush->size = 35; /* radius of the brush in pixels */
	brush->alpha = 0.5f; /* brush strength/intensity probably variable should be renamed? */
	brush->autosmooth_factor = 0.0f;
	brush->crease_pinch_factor = 0.5f;
	brush->sculpt_plane = SCULPT_DISP_DIR_AREA;
	brush->plane_offset = 0.0f; /* how far above or below the plane that is found by averaging the faces */
	brush->plane_trim = 0.5f;
	brush->clone.alpha = 0.5f;
	brush->normal_weight = 0.0f;
	brush->fill_threshold = 0.2f;
	brush->flag |= BRUSH_ALPHA_PRESSURE;

	/* BRUSH PAINT TOOL SETTINGS */
	brush->rgb[0] = 1.0f; /* default rgb color of the brush when painting - white */
	brush->rgb[1] = 1.0f;
	brush->rgb[2] = 1.0f;

	zero_v3(brush->secondary_rgb);

	/* BRUSH STROKE SETTINGS */
	brush->flag |= (BRUSH_SPACE | BRUSH_SPACE_ATTEN);
	brush->spacing = 10; /* how far each brush dot should be spaced as a percentage of brush diameter */

	brush->smooth_stroke_radius = 75;
	brush->smooth_stroke_factor = 0.9f;

	brush->rate = 0.1f; /* time delay between dots of paint or sculpting when doing airbrush mode */

	brush->jitter = 0.0f;

	/* BRUSH TEXTURE SETTINGS */
	BKE_texture_mtex_default(&brush->mtex);
	BKE_texture_mtex_default(&brush->mask_mtex);

	brush->texture_sample_bias = 0; /* value to added to texture samples */
	brush->texture_overlay_alpha = 33;
	brush->mask_overlay_alpha = 33;
	brush->cursor_overlay_alpha = 33;
	brush->overlay_flags = 0;

	/* brush appearance  */

	brush->add_col[0] = 1.00; /* add mode color is light red */
	brush->add_col[1] = 0.39;
	brush->add_col[2] = 0.39;

	brush->sub_col[0] = 0.39; /* subtract mode color is light blue */
	brush->sub_col[1] = 0.39;
	brush->sub_col[2] = 1.00;

	brush->stencil_pos[0] = 256;
	brush->stencil_pos[1] = 256;

	brush->stencil_dimension[0] = 256;
	brush->stencil_dimension[1] = 256;
}

/* Datablock add/copy/free/make_local */

void BKE_brush_init(Brush *brush)
{
	BLI_assert(MEMCMP_STRUCT_OFS_IS_ZERO(brush, id));

	/* enable fake user by default */
	id_fake_user_set(&brush->id);

	brush_defaults(brush);

	brush->sculpt_tool = SCULPT_TOOL_DRAW; /* sculpting defaults to the draw tool for new brushes */

	/* the default alpha falloff curve */
	BKE_brush_curve_preset(brush, CURVE_PRESET_SMOOTH);
}

/**
 * \note Resulting brush will have two users: one as a fake user, another is assumed to be used by the caller.
 */
Brush *BKE_brush_add(Main *bmain, const char *name, const eObjectMode ob_mode)
{
	Brush *brush;

	brush = BKE_libblock_alloc(bmain, ID_BR, name, 0);

	BKE_brush_init(brush);

	brush->ob_mode = ob_mode;

	return brush;
}

struct Brush *BKE_brush_first_search(struct Main *bmain, const eObjectMode ob_mode)
{
	Brush *brush;

	for (brush = bmain->brush.first; brush; brush = brush->id.next) {
		if (brush->ob_mode & ob_mode)
			return brush;
	}
	return NULL;
}

/**
 * Only copy internal data of Brush ID from source to already allocated/initialized destination.
 * You probably nerver want to use that directly, use id_copy or BKE_id_copy_ex for typical needs.
 *
 * WARNING! This function will not handle ID user count!
 *
 * \param flag  Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
 */
void BKE_brush_copy_data(Main *UNUSED(bmain), Brush *brush_dst, const Brush *brush_src, const int flag)
{
	if (brush_src->icon_imbuf) {
		brush_dst->icon_imbuf = IMB_dupImBuf(brush_src->icon_imbuf);
	}

	if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
		BKE_previewimg_id_copy(&brush_dst->id, &brush_src->id);
	}
	else {
		brush_dst->preview = NULL;
	}

	brush_dst->curve = curvemapping_copy(brush_src->curve);

	/* enable fake user by default */
	id_fake_user_set(&brush_dst->id);
}

Brush *BKE_brush_copy(Main *bmain, const Brush *brush)
{
	Brush *brush_copy;
	BKE_id_copy_ex(bmain, &brush->id, (ID **)&brush_copy, 0, false);
	return brush_copy;
}

/** Free (or release) any data used by this brush (does not free the brush itself). */
void BKE_brush_free(Brush *brush)
{
	if (brush->icon_imbuf) {
		IMB_freeImBuf(brush->icon_imbuf);
	}

	curvemapping_free(brush->curve);

	MEM_SAFE_FREE(brush->gradient);

	BKE_previewimg_free(&(brush->preview));
}

void BKE_brush_make_local(Main *bmain, Brush *brush, const bool lib_local)
{
	bool is_local = false, is_lib = false;

	/* - only lib users: do nothing (unless force_local is set)
	 * - only local users: set flag
	 * - mixed: make copy
	 */

	if (!ID_IS_LINKED(brush)) {
		return;
	}

	if (brush->clone.image) {
		/* Special case: ima always local immediately. Clone image should only have one user anyway. */
		id_make_local(bmain, &brush->clone.image->id, false, false);
	}

	BKE_library_ID_test_usages(bmain, brush, &is_local, &is_lib);

	if (lib_local || is_local) {
		if (!is_lib) {
			id_clear_lib_data(bmain, &brush->id);
			BKE_id_expand_local(bmain, &brush->id);

			/* enable fake user by default */
			id_fake_user_set(&brush->id);
		}
		else {
			Brush *brush_new = BKE_brush_copy(bmain, brush);  /* Ensures FAKE_USER is set */

			brush_new->id.us = 0;

			/* setting newid is mandatory for complex make_lib_local logic... */
			ID_NEW_SET(brush, brush_new);

			if (!lib_local) {
				BKE_libblock_remap(bmain, brush, brush_new, ID_REMAP_SKIP_INDIRECT_USAGE);
			}
		}
	}
}

void BKE_brush_debug_print_state(Brush *br)
{
	/* create a fake brush and set it to the defaults */
	Brush def = {{NULL}};
	brush_defaults(&def);

#define BR_TEST(field, t)					\
	if (br->field != def.field)				\
		printf("br->" #field " = %" #t ";\n", br->field)

#define BR_TEST_FLAG(_f)							\
	if ((br->flag & _f) && !(def.flag & _f))		\
		printf("br->flag |= " #_f ";\n");			\
	else if (!(br->flag & _f) && (def.flag & _f))	\
		printf("br->flag &= ~" #_f ";\n")

#define BR_TEST_FLAG_OVERLAY(_f)							\
	if ((br->overlay_flags & _f) && !(def.overlay_flags & _f))		\
		printf("br->overlay_flags |= " #_f ";\n");			\
	else if (!(br->overlay_flags & _f) && (def.overlay_flags & _f))	\
		printf("br->overlay_flags &= ~" #_f ";\n")

	/* print out any non-default brush state */
	BR_TEST(normal_weight, f);

	BR_TEST(blend, d);
	BR_TEST(size, d);

	/* br->flag */
	BR_TEST_FLAG(BRUSH_AIRBRUSH);
	BR_TEST_FLAG(BRUSH_ALPHA_PRESSURE);
	BR_TEST_FLAG(BRUSH_SIZE_PRESSURE);
	BR_TEST_FLAG(BRUSH_JITTER_PRESSURE);
	BR_TEST_FLAG(BRUSH_SPACING_PRESSURE);
	BR_TEST_FLAG(BRUSH_ANCHORED);
	BR_TEST_FLAG(BRUSH_DIR_IN);
	BR_TEST_FLAG(BRUSH_SPACE);
	BR_TEST_FLAG(BRUSH_SMOOTH_STROKE);
	BR_TEST_FLAG(BRUSH_PERSISTENT);
	BR_TEST_FLAG(BRUSH_ACCUMULATE);
	BR_TEST_FLAG(BRUSH_LOCK_ALPHA);
	BR_TEST_FLAG(BRUSH_ORIGINAL_NORMAL);
	BR_TEST_FLAG(BRUSH_OFFSET_PRESSURE);
	BR_TEST_FLAG(BRUSH_SPACE_ATTEN);
	BR_TEST_FLAG(BRUSH_ADAPTIVE_SPACE);
	BR_TEST_FLAG(BRUSH_LOCK_SIZE);
	BR_TEST_FLAG(BRUSH_EDGE_TO_EDGE);
	BR_TEST_FLAG(BRUSH_DRAG_DOT);
	BR_TEST_FLAG(BRUSH_INVERSE_SMOOTH_PRESSURE);
	BR_TEST_FLAG(BRUSH_PLANE_TRIM);
	BR_TEST_FLAG(BRUSH_FRONTFACE);
	BR_TEST_FLAG(BRUSH_CUSTOM_ICON);

	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_CURSOR);
	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_PRIMARY);
	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_SECONDARY);
	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_CURSOR_OVERRIDE_ON_STROKE);
	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_PRIMARY_OVERRIDE_ON_STROKE);
	BR_TEST_FLAG_OVERLAY(BRUSH_OVERLAY_SECONDARY_OVERRIDE_ON_STROKE);

	BR_TEST(jitter, f);
	BR_TEST(spacing, d);
	BR_TEST(smooth_stroke_radius, d);
	BR_TEST(smooth_stroke_factor, f);
	BR_TEST(rate, f);

	BR_TEST(alpha, f);

	BR_TEST(sculpt_plane, d);

	BR_TEST(plane_offset, f);

	BR_TEST(autosmooth_factor, f);

	BR_TEST(crease_pinch_factor, f);

	BR_TEST(plane_trim, f);

	BR_TEST(texture_sample_bias, f);
	BR_TEST(texture_overlay_alpha, d);

	BR_TEST(add_col[0], f);
	BR_TEST(add_col[1], f);
	BR_TEST(add_col[2], f);
	BR_TEST(sub_col[0], f);
	BR_TEST(sub_col[1], f);
	BR_TEST(sub_col[2], f);

	printf("\n");

#undef BR_TEST
#undef BR_TEST_FLAG
}

void BKE_brush_sculpt_reset(Brush *br)
{
	/* enable this to see any non-default
	 * settings used by a brush: */
	// BKE_brush_debug_print_state(br);

	brush_defaults(br);
	BKE_brush_curve_preset(br, CURVE_PRESET_SMOOTH);

	switch (br->sculpt_tool) {
		case SCULPT_TOOL_CLAY:
			br->flag |= BRUSH_FRONTFACE;
			break;
		case SCULPT_TOOL_CREASE:
			br->flag |= BRUSH_DIR_IN;
			br->alpha = 0.25;
			break;
		case SCULPT_TOOL_FILL:
			br->add_col[1] = 1;
			br->sub_col[0] = 0.25;
			br->sub_col[1] = 1;
			break;
		case SCULPT_TOOL_FLATTEN:
			br->add_col[1] = 1;
			br->sub_col[0] = 0.25;
			br->sub_col[1] = 1;
			break;
		case SCULPT_TOOL_INFLATE:
			br->add_col[0] = 0.750000;
			br->add_col[1] = 0.750000;
			br->add_col[2] = 0.750000;
			br->sub_col[0] = 0.250000;
			br->sub_col[1] = 0.250000;
			br->sub_col[2] = 0.250000;
			break;
		case SCULPT_TOOL_NUDGE:
			br->add_col[0] = 0.250000;
			br->add_col[1] = 1.000000;
			br->add_col[2] = 0.250000;
			break;
		case SCULPT_TOOL_PINCH:
			br->add_col[0] = 0.750000;
			br->add_col[1] = 0.750000;
			br->add_col[2] = 0.750000;
			br->sub_col[0] = 0.250000;
			br->sub_col[1] = 0.250000;
			br->sub_col[2] = 0.250000;
			break;
		case SCULPT_TOOL_SCRAPE:
			br->add_col[1] = 1.000000;
			br->sub_col[0] = 0.250000;
			br->sub_col[1] = 1.000000;
			break;
		case SCULPT_TOOL_ROTATE:
			br->alpha = 1.0;
			break;
		case SCULPT_TOOL_SMOOTH:
			br->flag &= ~BRUSH_SPACE_ATTEN;
			br->spacing = 5;
			br->add_col[0] = 0.750000;
			br->add_col[1] = 0.750000;
			br->add_col[2] = 0.750000;
			break;
		case SCULPT_TOOL_GRAB:
		case SCULPT_TOOL_SNAKE_HOOK:
		case SCULPT_TOOL_THUMB:
			br->size = 75;
			br->flag &= ~BRUSH_ALPHA_PRESSURE;
			br->flag &= ~BRUSH_SPACE;
			br->flag &= ~BRUSH_SPACE_ATTEN;
			br->add_col[0] = 0.250000;
			br->add_col[1] = 1.000000;
			br->add_col[2] = 0.250000;
			break;
		default:
			break;
	}
}

/**
 * Library Operations
 */
void BKE_brush_curve_preset(Brush *b, eCurveMappingPreset preset)
{
	CurveMap *cm = NULL;

	if (!b->curve)
		b->curve = curvemapping_add(1, 0, 0, 1, 1);

	cm = b->curve->cm;
	cm->flag &= ~CUMA_EXTEND_EXTRAPOLATE;

	b->curve->preset = preset;
	curvemap_reset(cm, &b->curve->clipr, b->curve->preset, CURVEMAP_SLOPE_NEGATIVE);
	curvemapping_changed(b->curve, false);
}

/* Generic texture sampler for 3D painting systems. point has to be either in
 * region space mouse coordinates, or 3d world coordinates for 3D mapping.
 *
 * rgba outputs straight alpha. */
float BKE_brush_sample_tex_3D(const Scene *scene, const Brush *br,
                              const float point[3],
                              float rgba[4], const int thread,
                              struct ImagePool *pool)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	const MTex *mtex = &br->mtex;
	float intensity = 1.0;
	bool hasrgb = false;

	if (!mtex->tex) {
		intensity = 1;
	}
	else if (mtex->brush_map_mode == MTEX_MAP_MODE_3D) {
		/* Get strength by feeding the vertex
		 * location directly into a texture */
		hasrgb = externtex(mtex, point, &intensity,
		                   rgba, rgba + 1, rgba + 2, rgba + 3, thread, pool, false, false);
	}
	else if (mtex->brush_map_mode == MTEX_MAP_MODE_STENCIL) {
		float rotation = -mtex->rot;
		float point_2d[2] = {point[0], point[1]};
		float x, y;
		float co[3];

		x = point_2d[0] - br->stencil_pos[0];
		y = point_2d[1] - br->stencil_pos[1];

		if (rotation > 0.001f || rotation < -0.001f) {
			const float angle    = atan2f(y, x) + rotation;
			const float flen     = sqrtf(x * x + y * y);

			x = flen * cosf(angle);
			y = flen * sinf(angle);
		}

		if (fabsf(x) > br->stencil_dimension[0] || fabsf(y) > br->stencil_dimension[1]) {
			zero_v4(rgba);
			return 0.0f;
		}
		x /= (br->stencil_dimension[0]);
		y /= (br->stencil_dimension[1]);

		co[0] = x;
		co[1] = y;
		co[2] = 0.0f;

		hasrgb = externtex(mtex, co, &intensity,
		                   rgba, rgba + 1, rgba + 2, rgba + 3, thread, pool, false, false);
	}
	else {
		float rotation = -mtex->rot;
		float point_2d[2] = {point[0], point[1]};
		float x = 0.0f, y = 0.0f; /* Quite warnings */
		float invradius = 1.0f; /* Quite warnings */
		float co[3];

		if (mtex->brush_map_mode == MTEX_MAP_MODE_VIEW) {
			/* keep coordinates relative to mouse */

			rotation += ups->brush_rotation;

			x = point_2d[0] - ups->tex_mouse[0];
			y = point_2d[1] - ups->tex_mouse[1];

			/* use pressure adjusted size for fixed mode */
			invradius = 1.0f / ups->pixel_radius;
		}
		else if (mtex->brush_map_mode == MTEX_MAP_MODE_TILED) {
			/* leave the coordinates relative to the screen */

			/* use unadjusted size for tiled mode */
			invradius = 1.0f / BKE_brush_size_get(scene, br);

			x = point_2d[0];
			y = point_2d[1];
		}
		else if (mtex->brush_map_mode == MTEX_MAP_MODE_RANDOM) {
			rotation += ups->brush_rotation;
			/* these contain a random coordinate */
			x = point_2d[0] - ups->tex_mouse[0];
			y = point_2d[1] - ups->tex_mouse[1];

			invradius = 1.0f / ups->pixel_radius;
		}

		x *= invradius;
		y *= invradius;

		/* it is probably worth optimizing for those cases where
		 * the texture is not rotated by skipping the calls to
		 * atan2, sqrtf, sin, and cos. */
		if (rotation > 0.001f || rotation < -0.001f) {
			const float angle    = atan2f(y, x) + rotation;
			const float flen     = sqrtf(x * x + y * y);

			x = flen * cosf(angle);
			y = flen * sinf(angle);
		}

		co[0] = x;
		co[1] = y;
		co[2] = 0.0f;

		hasrgb = externtex(mtex, co, &intensity,
		                   rgba, rgba + 1, rgba + 2, rgba + 3, thread, pool, false, false);
	}

	intensity += br->texture_sample_bias;

	if (!hasrgb) {
		rgba[0] = intensity;
		rgba[1] = intensity;
		rgba[2] = intensity;
		rgba[3] = 1.0f;
	}
	/* For consistency, sampling always returns color in linear space */
	else if (ups->do_linear_conversion) {
		IMB_colormanagement_colorspace_to_scene_linear_v3(rgba, ups->colorspace);
	}

	return intensity;
}

float BKE_brush_sample_masktex(const Scene *scene, Brush *br,
                               const float point[2],
                               const int thread,
                               struct ImagePool *pool)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	MTex *mtex = &br->mask_mtex;
	float rgba[4], intensity;

	if (!mtex->tex) {
		return 1.0f;
	}
	if (mtex->brush_map_mode == MTEX_MAP_MODE_STENCIL) {
		float rotation = -mtex->rot;
		float point_2d[2] = {point[0], point[1]};
		float x, y;
		float co[3];

		x = point_2d[0] - br->mask_stencil_pos[0];
		y = point_2d[1] - br->mask_stencil_pos[1];

		if (rotation > 0.001f || rotation < -0.001f) {
			const float angle    = atan2f(y, x) + rotation;
			const float flen     = sqrtf(x * x + y * y);

			x = flen * cosf(angle);
			y = flen * sinf(angle);
		}

		if (fabsf(x) > br->mask_stencil_dimension[0] || fabsf(y) > br->mask_stencil_dimension[1]) {
			zero_v4(rgba);
			return 0.0f;
		}
		x /= (br->mask_stencil_dimension[0]);
		y /= (br->mask_stencil_dimension[1]);

		co[0] = x;
		co[1] = y;
		co[2] = 0.0f;

		externtex(mtex, co, &intensity,
		          rgba, rgba + 1, rgba + 2, rgba + 3, thread, pool, false, false);
	}
	else {
		float rotation = -mtex->rot;
		float point_2d[2] = {point[0], point[1]};
		float x = 0.0f, y = 0.0f; /* Quite warnings */
		float invradius = 1.0f; /* Quite warnings */
		float co[3];

		if (mtex->brush_map_mode == MTEX_MAP_MODE_VIEW) {
			/* keep coordinates relative to mouse */

			rotation += ups->brush_rotation_sec;

			x = point_2d[0] - ups->mask_tex_mouse[0];
			y = point_2d[1] - ups->mask_tex_mouse[1];

			/* use pressure adjusted size for fixed mode */
			invradius = 1.0f / ups->pixel_radius;
		}
		else if (mtex->brush_map_mode == MTEX_MAP_MODE_TILED) {
			/* leave the coordinates relative to the screen */

			/* use unadjusted size for tiled mode */
			invradius = 1.0f / BKE_brush_size_get(scene, br);

			x = point_2d[0];
			y = point_2d[1];
		}
		else if (mtex->brush_map_mode == MTEX_MAP_MODE_RANDOM) {
			rotation += ups->brush_rotation_sec;
			/* these contain a random coordinate */
			x = point_2d[0] - ups->mask_tex_mouse[0];
			y = point_2d[1] - ups->mask_tex_mouse[1];

			invradius = 1.0f / ups->pixel_radius;
		}

		x *= invradius;
		y *= invradius;

		/* it is probably worth optimizing for those cases where
		 * the texture is not rotated by skipping the calls to
		 * atan2, sqrtf, sin, and cos. */
		if (rotation > 0.001f || rotation < -0.001f) {
			const float angle    = atan2f(y, x) + rotation;
			const float flen     = sqrtf(x * x + y * y);

			x = flen * cosf(angle);
			y = flen * sinf(angle);
		}

		co[0] = x;
		co[1] = y;
		co[2] = 0.0f;

		externtex(mtex, co, &intensity,
		          rgba, rgba + 1, rgba + 2, rgba + 3, thread, pool, false, false);
	}

	CLAMP(intensity, 0.0f, 1.0f);

	switch (br->mask_pressure) {
		case BRUSH_MASK_PRESSURE_CUTOFF:
			intensity  = ((1.0f - intensity) < ups->size_pressure_value) ? 1.0f : 0.0f;
			break;
		case BRUSH_MASK_PRESSURE_RAMP:
			intensity = ups->size_pressure_value + intensity * (1.0f - ups->size_pressure_value);
			break;
		default:
			break;
	}

	return intensity;
}

/* Unified Size / Strength / Color */

/* XXX: be careful about setting size and unprojected radius
 * because they depend on one another
 * these functions do not set the other corresponding value
 * this can lead to odd behavior if size and unprojected
 * radius become inconsistent.
 * the biggest problem is that it isn't possible to change
 * unprojected radius because a view context is not
 * available.  my usual solution to this is to use the
 * ratio of change of the size to change the unprojected
 * radius.  Not completely convinced that is correct.
 * In any case, a better solution is needed to prevent
 * inconsistency. */


const float *BKE_brush_color_get(const struct Scene *scene, const struct Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	return (ups->flag & UNIFIED_PAINT_COLOR) ? ups->rgb : brush->rgb;
}

const float *BKE_brush_secondary_color_get(const struct Scene *scene, const struct Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	return (ups->flag & UNIFIED_PAINT_COLOR) ? ups->secondary_rgb : brush->secondary_rgb;
}

void BKE_brush_color_set(struct Scene *scene, struct Brush *brush, const float color[3])
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	if (ups->flag & UNIFIED_PAINT_COLOR)
		copy_v3_v3(ups->rgb, color);
	else
		copy_v3_v3(brush->rgb, color);
}

void BKE_brush_size_set(Scene *scene, Brush *brush, int size)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	/* make sure range is sane */
	CLAMP(size, 1, MAX_BRUSH_PIXEL_RADIUS);

	if (ups->flag & UNIFIED_PAINT_SIZE)
		ups->size = size;
	else
		brush->size = size;
}

int BKE_brush_size_get(const Scene *scene, const Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;
	int size = (ups->flag & UNIFIED_PAINT_SIZE) ? ups->size : brush->size;

	return size;
}

bool BKE_brush_use_locked_size(const Scene *scene, const Brush *brush)
{
	const short us_flag = scene->toolsettings->unified_paint_settings.flag;

	return (us_flag & UNIFIED_PAINT_SIZE) ?
	       (us_flag & UNIFIED_PAINT_BRUSH_LOCK_SIZE) :
	       (brush->flag & BRUSH_LOCK_SIZE);
}

bool BKE_brush_use_size_pressure(const Scene *scene, const Brush *brush)
{
	const short us_flag = scene->toolsettings->unified_paint_settings.flag;

	return (us_flag & UNIFIED_PAINT_SIZE) ?
	       (us_flag & UNIFIED_PAINT_BRUSH_SIZE_PRESSURE) :
	       (brush->flag & BRUSH_SIZE_PRESSURE);
}

bool BKE_brush_use_alpha_pressure(const Scene *scene, const Brush *brush)
{
	const short us_flag = scene->toolsettings->unified_paint_settings.flag;

	return (us_flag & UNIFIED_PAINT_ALPHA) ?
	       (us_flag & UNIFIED_PAINT_BRUSH_ALPHA_PRESSURE) :
	       (brush->flag & BRUSH_ALPHA_PRESSURE);
}

bool BKE_brush_sculpt_has_secondary_color(const Brush *brush)
{
	return ELEM(
	        brush->sculpt_tool, SCULPT_TOOL_BLOB, SCULPT_TOOL_DRAW,
	        SCULPT_TOOL_INFLATE, SCULPT_TOOL_CLAY, SCULPT_TOOL_CLAY_STRIPS,
	        SCULPT_TOOL_PINCH, SCULPT_TOOL_CREASE, SCULPT_TOOL_LAYER,
	        SCULPT_TOOL_FLATTEN, SCULPT_TOOL_FILL, SCULPT_TOOL_SCRAPE,
	        SCULPT_TOOL_MASK);
}

void BKE_brush_unprojected_radius_set(Scene *scene, Brush *brush, float unprojected_radius)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	if (ups->flag & UNIFIED_PAINT_SIZE)
		ups->unprojected_radius = unprojected_radius;
	else
		brush->unprojected_radius = unprojected_radius;
}

float BKE_brush_unprojected_radius_get(const Scene *scene, const Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	return (ups->flag & UNIFIED_PAINT_SIZE) ?
	       ups->unprojected_radius :
	       brush->unprojected_radius;
}

void BKE_brush_alpha_set(Scene *scene, Brush *brush, float alpha)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	if (ups->flag & UNIFIED_PAINT_ALPHA)
		ups->alpha = alpha;
	else
		brush->alpha = alpha;
}

float BKE_brush_alpha_get(const Scene *scene, const Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	return (ups->flag & UNIFIED_PAINT_ALPHA) ? ups->alpha : brush->alpha;
}

float BKE_brush_weight_get(const Scene *scene, const Brush *brush)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	return (ups->flag & UNIFIED_PAINT_WEIGHT) ? ups->weight : brush->weight;
}

void BKE_brush_weight_set(const Scene *scene, Brush *brush, float value)
{
	UnifiedPaintSettings *ups = &scene->toolsettings->unified_paint_settings;

	if (ups->flag & UNIFIED_PAINT_WEIGHT)
		ups->weight = value;
	else
		brush->weight = value;
}

/* scale unprojected radius to reflect a change in the brush's 2D size */
void BKE_brush_scale_unprojected_radius(float *unprojected_radius,
                                        int new_brush_size,
                                        int old_brush_size)
{
	float scale = new_brush_size;
	/* avoid division by zero */
	if (old_brush_size != 0)
		scale /= (float)old_brush_size;
	(*unprojected_radius) *= scale;
}

/* scale brush size to reflect a change in the brush's unprojected radius */
void BKE_brush_scale_size(
        int *r_brush_size,
        float new_unprojected_radius,
        float old_unprojected_radius)
{
	float scale = new_unprojected_radius;
	/* avoid division by zero */
	if (old_unprojected_radius != 0)
		scale /= new_unprojected_radius;
	(*r_brush_size) = (int)((float)(*r_brush_size) * scale);
}

void BKE_brush_jitter_pos(const Scene *scene, Brush *brush, const float pos[2], float jitterpos[2])
{
	float rand_pos[2];
	float spread;
	int diameter;

	do {
		rand_pos[0] = BLI_rng_get_float(brush_rng) - 0.5f;
		rand_pos[1] = BLI_rng_get_float(brush_rng) - 0.5f;
	} while (len_squared_v2(rand_pos) > SQUARE(0.5f));


	if (brush->flag & BRUSH_ABSOLUTE_JITTER) {
		diameter = 2 * brush->jitter_absolute;
		spread = 1.0;
	}
	else {
		diameter = 2 * BKE_brush_size_get(scene, brush);
		spread = brush->jitter;
	}
	/* find random position within a circle of diameter 1 */
	jitterpos[0] = pos[0] + 2 * rand_pos[0] * diameter * spread;
	jitterpos[1] = pos[1] + 2 * rand_pos[1] * diameter * spread;
}

void BKE_brush_randomize_texture_coords(UnifiedPaintSettings *ups, bool mask)
{
	/* we multiply with brush radius as an optimization for the brush
	 * texture sampling functions */
	if (mask) {
		ups->mask_tex_mouse[0] = BLI_rng_get_float(brush_rng) * ups->pixel_radius;
		ups->mask_tex_mouse[1] = BLI_rng_get_float(brush_rng) * ups->pixel_radius;
	}
	else {
		ups->tex_mouse[0] = BLI_rng_get_float(brush_rng) * ups->pixel_radius;
		ups->tex_mouse[1] = BLI_rng_get_float(brush_rng) * ups->pixel_radius;
	}
}

/* Uses the brush curve control to find a strength value */
float BKE_brush_curve_strength(const Brush *br, float p, const float len)
{
	float strength;

	if (p >= len) return 0;
	else p = p / len;

	strength = curvemapping_evaluateF(br->curve, 0, p);

	return strength;
}


/* Uses the brush curve control to find a strength value between 0 and 1 */
float BKE_brush_curve_strength_clamped(Brush *br, float p, const float len)
{
	float strength = BKE_brush_curve_strength(br, p, len);

	CLAMP(strength, 0.0f, 1.0f);

	return strength;
}

/* TODO: should probably be unified with BrushPainter stuff? */
unsigned int *BKE_brush_gen_texture_cache(Brush *br, int half_side, bool use_secondary)
{
	unsigned int *texcache = NULL;
	MTex *mtex = (use_secondary) ? &br->mask_mtex : &br->mtex;
	float intensity;
	float rgba[4];
	int ix, iy;
	int side = half_side * 2;

	if (mtex->tex) {
		float x, y, step = 2.0 / side, co[3];

		texcache = MEM_callocN(sizeof(int) * side * side, "Brush texture cache");

		/* do normalized cannonical view coords for texture */
		for (y = -1.0, iy = 0; iy < side; iy++, y += step) {
			for (x = -1.0, ix = 0; ix < side; ix++, x += step) {
				co[0] = x;
				co[1] = y;
				co[2] = 0.0f;

				/* This is copied from displace modifier code */
				/* TODO(sergey): brush are always cacheing with CM enabled for now. */
				externtex(mtex, co, &intensity,
				          rgba, rgba + 1, rgba + 2, rgba + 3, 0, NULL, false, false);

				((char *)texcache)[(iy * side + ix) * 4] =
				((char *)texcache)[(iy * side + ix) * 4 + 1] =
				((char *)texcache)[(iy * side + ix) * 4 + 2] =
				((char *)texcache)[(iy * side + ix) * 4 + 3] = (char)(intensity * 255.0f);
			}
		}
	}

	return texcache;
}


/**** Radial Control ****/
struct ImBuf *BKE_brush_gen_radial_control_imbuf(Brush *br, bool secondary)
{
	ImBuf *im = MEM_callocN(sizeof(ImBuf), "radial control texture");
	unsigned int *texcache;
	int side = 128;
	int half = side / 2;
	int i, j;

	curvemapping_initialize(br->curve);
	texcache = BKE_brush_gen_texture_cache(br, half, secondary);
	im->rect_float = MEM_callocN(sizeof(float) * side * side, "radial control rect");
	im->x = im->y = side;

	for (i = 0; i < side; ++i) {
		for (j = 0; j < side; ++j) {
			float magn = sqrtf(pow2f(i - half) + pow2f(j - half));
			im->rect_float[i * side + j] = BKE_brush_curve_strength_clamped(br, magn, half);
		}
	}

	/* Modulate curve with texture */
	if (texcache) {
		for (i = 0; i < side; ++i) {
			for (j = 0; j < side; ++j) {
				const int col = texcache[i * side + j];
				im->rect_float[i * side + j] *=
				        (((char *)&col)[0] + ((char *)&col)[1] + ((char *)&col)[2]) / 3.0f / 255.0f;
			}
		}

		MEM_freeN(texcache);
	}

	return im;
}