GP: implement Shadow FX (wip)

Initial implementation of effect to create a drop shadow of the strokes

source/blender/shader_fx/CMakeLists.txt

@@ -49,6 +49,7 @@ set(SRC
 	intern/FX_shader_light.c
 	intern/FX_shader_pixel.c
 	intern/FX_shader_rim.c
+	intern/FX_shader_shadow.c
 	intern/FX_shader_swirl.c
 	intern/FX_shader_wave.c
 

source/blender/shader_fx/FX_shader_types.h

@@ -38,6 +38,7 @@ extern ShaderFxTypeInfo shaderfx_Type_Flip;
 extern ShaderFxTypeInfo shaderfx_Type_Light;
 extern ShaderFxTypeInfo shaderfx_Type_Pixel;
 extern ShaderFxTypeInfo shaderfx_Type_Rim;
+extern ShaderFxTypeInfo shaderfx_Type_Shadow;
 extern ShaderFxTypeInfo shaderfx_Type_Swirl;
 extern ShaderFxTypeInfo shaderfx_Type_Wave;
 

source/blender/shader_fx/intern/FX_shader_shadow.c

@@ -0,0 +1,110 @@
+/*
+ * ***** 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.
+ *
+ * The Original Code is Copyright (C) 2018, Blender Foundation
+ * This is a new part of Blender
+ *
+ * Contributor(s): Antonio Vazquez
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ *
+ */
+
+/** \file blender/shader_fx/intern/FX_shader_shadow.c
+ *  \ingroup shader_fx
+ */
+
+#include <stdio.h>
+
+#include "DNA_scene_types.h"
+#include "DNA_object_types.h"
+#include "DNA_gpencil_types.h"
+
+#include "BLI_math_base.h"
+#include "BLI_utildefines.h"
+
+#include "BKE_library_query.h"
+#include "BKE_modifier.h"
+#include "BKE_shader_fx.h"
+
+#include "FX_shader_types.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_build.h"
+
+static void initData(ShaderFxData *md)
+{
+	ShadowShaderFxData *gpfx = (ShadowShaderFxData *)md;
+	gpfx->rotation = 0.0f;
+	ARRAY_SET_ITEMS(gpfx->offset, 15, 20);
+	ARRAY_SET_ITEMS(gpfx->scale, 1.0f, 1.0f);
+	ARRAY_SET_ITEMS(gpfx->shadow_rgba, 0.54f, 0.62f, 1.0f, 0.9f);
+
+	gpfx->amplitude = 10.0f;
+	gpfx->period = 20.0f;
+	gpfx->phase = 0.0f;
+	gpfx->orientation = 1;
+}
+
+static void copyData(const ShaderFxData *md, ShaderFxData *target)
+{
+	BKE_shaderfx_copyData_generic(md, target);
+}
+
+static void updateDepsgraph(ShaderFxData *fx, const ModifierUpdateDepsgraphContext *ctx)
+{
+	ShadowShaderFxData *fxd = (ShadowShaderFxData *)fx;
+	if (fxd->object != NULL) {
+		DEG_add_object_relation(ctx->node, fxd->object, DEG_OB_COMP_GEOMETRY, "Shadow ShaderFx");
+		DEG_add_object_relation(ctx->node, fxd->object, DEG_OB_COMP_TRANSFORM, "Shadow ShaderFx");
+	}
+	DEG_add_object_relation(ctx->node, ctx->object, DEG_OB_COMP_TRANSFORM, "Shadow ShaderFx");
+}
+
+static bool isDisabled(ShaderFxData *fx, int UNUSED(userRenderParams))
+{
+	ShadowShaderFxData *fxd = (ShadowShaderFxData *)fx;
+
+	return (!fxd->object) && (fxd->flag & FX_SHADOW_USE_OBJECT);
+}
+
+static void foreachObjectLink(
+	ShaderFxData *fx, Object *ob,
+	ShaderFxObjectWalkFunc walk, void *userData)
+{
+	ShadowShaderFxData *fxd = (ShadowShaderFxData *)fx;
+
+	walk(userData, ob, &fxd->object, IDWALK_CB_NOP);
+}
+
+ShaderFxTypeInfo shaderfx_Type_Shadow = {
+	/* name */              "Shadow",
+	/* structName */        "ShadowShaderFxData",
+	/* structSize */        sizeof(ShadowShaderFxData),
+	/* type */              eShaderFxType_GpencilType,
+	/* flags */             0,
+
+	/* copyData */          copyData,
+
+	/* initData */          initData,
+	/* freeData */          NULL,
+	/* isDisabled */        isDisabled,
+	/* updateDepsgraph */   updateDepsgraph,
+	/* dependsOnTime */     NULL,
+	/* foreachObjectLink */ foreachObjectLink,
+	/* foreachIDLink */     NULL,
+};

source/blender/shader_fx/intern/FX_shader_util.c

@@ -49,6 +49,7 @@ void shaderfx_type_init(ShaderFxTypeInfo *types[])
 	INIT_FX_TYPE(Light);
 	INIT_FX_TYPE(Pixel);
 	INIT_FX_TYPE(Rim);
+	INIT_FX_TYPE(Shadow);
 	INIT_FX_TYPE(Swirl);
 	INIT_FX_TYPE(Wave);
 #undef INIT_FX_TYPE