New Grease Pencil object for 2D animation

This commit merge the full development done in greasepencil-object branch and include mainly the following features.

- New grease pencil object.
- New drawing engine.
- New grease pencil modes Draw/Sculpt/Edit and Weight Paint.
- New brushes for grease pencil.
- New modifiers for grease pencil.
- New shaders FX.
- New material system (replace old palettes and colors).
- Split of annotations (old grease pencil) and new grease pencil object.
- UI adapted to blender 2.8.

You can get more info here:

https://code.blender.org/2017/12/drawing-2d-animation-in-blender-2-8/
https://code.blender.org/2018/07/grease-pencil-status-update/

This is the result of nearly two years of development and I want thanks firstly the other members of the grease pencil team: Daniel M. Lara, Matias Mendiola and Joshua Leung for their support, ideas and to keep working in the project all the time, without them this project had been impossible.

Also, I want thanks other Blender developers for their help, advices and to be there always to help me, and specially to Clément Foucault, Dalai Felinto, Pablo Vázquez and Campbell Barton.

5 files changed, 209 insertions, 4 deletions

diff --git a/source/blender/draw/intern/DRW_render.h b/source/blender/draw/intern/DRW_render.h
index 0db16ab5472..abba8d3ce91 100644
--- a/source/blender/draw/intern/DRW_render.h
+++ b/source/blender/draw/intern/DRW_render.h
@@ -136,6 +136,7 @@ typedef char DRWViewportEmptyList;
 
 
 
+
 typedef struct DrawEngineDataSize {
 	int fbl_len;
 	int txl_len;
diff --git a/source/blender/draw/intern/draw_cache.c b/source/blender/draw/intern/draw_cache.c
index bdfa3211f7c..ac84a847a1b 100644
--- a/source/blender/draw/intern/draw_cache.c
+++ b/source/blender/draw/intern/draw_cache.c
@@ -107,6 +107,7 @@ static struct DRWShapeCache {
 	GPUBatch *drw_particle_cross;
 	GPUBatch *drw_particle_circle;
 	GPUBatch *drw_particle_axis;
+	GPUBatch *drw_gpencil_axes;
 } SHC = {NULL};
 
 void DRW_shape_cache_free(void)
@@ -551,12 +552,67 @@ GPUBatch *DRW_cache_screenspace_circle_get(void)
 #undef CIRCLE_RESOL
 }
 
-/** \} */
+/* Grease Pencil object */
+GPUBatch *DRW_cache_gpencil_axes_get(void)
+{
+	if (!SHC.drw_gpencil_axes) {
+		int axis;
+		float v1[3] = { 0.0f, 0.0f, 0.0f };
+		float v2[3] = { 0.0f, 0.0f, 0.0f };
+
+		/* cube data */
+		const GLfloat verts[8][3] = {
+			{ -0.25f, -0.25f, -0.25f },
+			{ -0.25f, -0.25f,  0.25f },
+			{ -0.25f,  0.25f, -0.25f },
+			{ -0.25f,  0.25f,  0.25f },
+			{ 0.25f, -0.25f, -0.25f },
+			{ 0.25f, -0.25f,  0.25f },
+			{ 0.25f,  0.25f, -0.25f },
+			{ 0.25f,  0.25f,  0.25f }
+		};
+
+		const GLubyte indices[24] = { 0, 1, 1, 3, 3, 2, 2, 0, 0, 4, 4, 5, 5, 7, 7, 6, 6, 4, 1, 5, 3, 7, 2, 6 };
+
+		/* Position Only 3D format */
+		static GPUVertFormat format = { 0 };
+		static uint pos_id;
+		if (format.attr_len == 0) {
+			pos_id = GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+		}
+
+		GPUVertBuf *vbo =  GPU_vertbuf_create_with_format(&format);
+
+		/* alloc 30 elements for cube and 3 axis */
+		GPU_vertbuf_data_alloc(vbo, ARRAY_SIZE(indices) + 6);
+
+		/* draw axis */
+		for (axis = 0; axis < 3; axis++) {
+			v1[axis] = 1.0f;
+			v2[axis] = -1.0f;
+
+			GPU_vertbuf_attr_set(vbo, pos_id, axis * 2, v1);
+			GPU_vertbuf_attr_set(vbo, pos_id, axis * 2 + 1, v2);
+
+			/* reset v1 & v2 to zero for next axis */
+			v1[axis] = v2[axis] = 0.0f;
+		}
+
+		/* draw cube */
+		for (int i = 0; i < 24; ++i) {
+			GPU_vertbuf_attr_set(vbo, pos_id, i + 6, verts[indices[i]]);
+		}
+
+		SHC.drw_gpencil_axes = GPU_batch_create(GPU_PRIM_LINES, vbo, NULL);
+	}
+	return SHC.drw_gpencil_axes;
+}
+
 
 /* -------------------------------------------------------------------- */
 
 /** \name Common Object API
- * \{ */
+* \{ */
 
 GPUBatch *DRW_cache_object_wire_outline_get(Object *ob)
 {
diff --git a/source/blender/draw/intern/draw_cache.h b/source/blender/draw/intern/draw_cache.h
index 129c0252f30..7d0996b3059 100644
--- a/source/blender/draw/intern/draw_cache.h
+++ b/source/blender/draw/intern/draw_cache.h
@@ -82,6 +82,9 @@ struct GPUBatch *DRW_cache_field_vortex_get(void);
 struct GPUBatch *DRW_cache_field_tube_limit_get(void);
 struct GPUBatch *DRW_cache_field_cone_limit_get(void);
 
+/* Grease Pencil */
+struct GPUBatch *DRW_cache_gpencil_axes_get(void);
+
 /* Lamps */
 struct GPUBatch *DRW_cache_lamp_get(void);
 struct GPUBatch *DRW_cache_lamp_shadows_get(void);
diff --git a/source/blender/draw/intern/draw_cache_impl.h b/source/blender/draw/intern/draw_cache_impl.h
index eeb7b1c41ee..d4dbe5db80d 100644
--- a/source/blender/draw/intern/draw_cache_impl.h
+++ b/source/blender/draw/intern/draw_cache_impl.h
@@ -41,6 +41,7 @@ struct Curve;
 struct Lattice;
 struct Mesh;
 struct MetaBall;
+struct bGPdata;
 
 /* Expose via BKE callbacks */
 void DRW_mball_batch_cache_dirty(struct MetaBall *mb, int mode);
@@ -58,6 +59,9 @@ void DRW_lattice_batch_cache_free(struct Lattice *lt);
 void DRW_particle_batch_cache_dirty(struct ParticleSystem *psys, int mode);
 void DRW_particle_batch_cache_free(struct ParticleSystem *psys);
 
+void DRW_gpencil_batch_cache_dirty(struct bGPdata *gpd);
+void DRW_gpencil_batch_cache_free(struct bGPdata *gpd);
+
 /* Curve */
 struct GPUBatch *DRW_curve_batch_cache_get_wire_edge(struct Curve *cu, struct CurveCache *ob_curve_cache);
 struct GPUBatch *DRW_curve_batch_cache_get_normal_edge(
diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 714edc23719..e6e20934283 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -48,6 +48,7 @@
 
 #include "ED_space_api.h"
 #include "ED_screen.h"
+#include "ED_gpencil.h"
 #include "ED_particle.h"
 #include "ED_view3d.h"
 
@@ -1222,10 +1223,17 @@ static void drw_engines_enable_from_mode(int mode)
 			break;
 		case CTX_MODE_OBJECT:
 			break;
+		case CTX_MODE_GPENCIL_PAINT:
+		case CTX_MODE_GPENCIL_EDIT:
+		case CTX_MODE_GPENCIL_SCULPT:
+		case CTX_MODE_GPENCIL_WEIGHT:
+			break;
 		default:
 			BLI_assert(!"Draw mode invalid");
 			break;
 	}
+	/* grease pencil */
+	use_drw_engine(&draw_engine_gpencil_type);
 }
 
 static void drw_engines_enable_from_overlays(int overlay_flag)
@@ -1258,6 +1266,10 @@ static void drw_engines_enable(ViewLayer *view_layer, RenderEngineType *engine_t
 		drw_engines_enable_from_object_mode();
 		drw_engines_enable_from_mode(mode);
 	}
+	else {
+		/* if gpencil must draw the strokes, but not the object */
+		drw_engines_enable_from_mode(mode);
+	}
 }
 
 static void drw_engines_disable(void)
@@ -1377,6 +1389,7 @@ void DRW_draw_render_loop_ex(
 	Scene *scene = DEG_get_evaluated_scene(depsgraph);
 	ViewLayer *view_layer = DEG_get_evaluated_view_layer(depsgraph);
 	RegionView3D *rv3d = ar->regiondata;
+	bool do_annotations = (((v3d->flag2 & V3D_SHOW_ANNOTATION) != 0) && ((v3d->flag2 & V3D_RENDER_OVERRIDE) == 0));
 
 	DST.draw_ctx.evil_C = evil_C;
 	DST.viewport = viewport;
@@ -1471,6 +1484,17 @@ void DRW_draw_render_loop_ex(
 
 	drw_engines_draw_scene();
 
+	/* annotations - temporary drawing buffer (3d space) */
+	/* XXX: Or should we use a proper draw/overlay engine for this case? */
+	if (((v3d->flag2 & V3D_RENDER_OVERRIDE) == 0) &&
+	    (do_annotations))
+	{
+		glDisable(GL_DEPTH_TEST);
+		/* XXX: as scene->gpd is not copied for COW yet */
+		ED_gpencil_draw_view3d_annotations(DEG_get_input_scene(depsgraph), depsgraph, v3d, ar, true);
+		glEnable(GL_DEPTH_TEST);
+	}
+
 	DRW_draw_callbacks_post_scene();
 	if (DST.draw_ctx.evil_C) {
 		ED_region_draw_cb_draw(DST.draw_ctx.evil_C, DST.draw_ctx.ar, REGION_DRAW_POST_VIEW);
@@ -1495,6 +1519,17 @@ void DRW_draw_render_loop_ex(
 
 		DRW_draw_region_info();
 
+		/* annotations - temporary drawing buffer (screenspace) */
+		/* XXX: Or should we use a proper draw/overlay engine for this case? */
+		if (((v3d->flag2 & V3D_RENDER_OVERRIDE) == 0) &&
+		    (do_annotations))
+		{
+			glDisable(GL_DEPTH_TEST);
+			/* XXX: as scene->gpd is not copied for COW yet */
+			ED_gpencil_draw_view3d_annotations(DEG_get_input_scene(depsgraph), depsgraph, v3d, ar, false);
+			glEnable(GL_DEPTH_TEST);
+		}
+
 		if ((v3d->flag2 & V3D_RENDER_OVERRIDE) == 0) {
 			/* Draw 2D after region info so we can draw on top of the camera passepartout overlay.
 			 * 'DRW_draw_region_info' sets the projection in pixel-space. */
@@ -1583,6 +1618,105 @@ void DRW_draw_render_loop_offscreen(
 	GPU_offscreen_bind(ofs, false);
 }
 
+/* helper to check if exit object type to render */
+static bool DRW_render_check_object_type(struct Depsgraph *depsgraph, short obtype)
+{
+	DEG_OBJECT_ITER_FOR_RENDER_ENGINE_BEGIN(depsgraph, ob)
+	{
+		if ((ob->type == obtype) && (DRW_check_object_visible_within_active_context(ob))) {
+			return true;
+		}
+	}
+	DEG_OBJECT_ITER_FOR_RENDER_ENGINE_END
+
+	return false;
+}
+
+static void DRW_render_gpencil_to_image(RenderEngine *engine, struct Depsgraph *depsgraph, struct RenderLayer *render_layer, const rcti *rect)
+{
+	if (draw_engine_gpencil_type.render_to_image) {
+		if (DRW_render_check_object_type(depsgraph, OB_GPENCIL)) {
+			ViewportEngineData *gpdata = drw_viewport_engine_data_ensure(&draw_engine_gpencil_type);
+			draw_engine_gpencil_type.render_to_image(gpdata, engine, render_layer, rect);
+		}
+	}
+}
+
+void DRW_render_gpencil(struct RenderEngine *engine, struct Depsgraph *depsgraph)
+{
+	/* This function is only valid for Cycles
+	 * Eevee done all work in the Eevee render directly.
+	 * Maybe it can be done equal for both engines?
+	*/
+	if (STREQ(engine->type->name, "Eevee")) {
+		return;
+	}
+
+	Scene *scene = DEG_get_evaluated_scene(depsgraph);
+	ViewLayer *view_layer = DEG_get_evaluated_view_layer(depsgraph);
+	RenderEngineType *engine_type = engine->type;
+	RenderData *r = &scene->r;
+	Render *render = engine->re;
+	/* Changing Context */
+	/* GPXX Review this context */
+	DRW_opengl_context_enable();
+	/* Reset before using it. */
+	drw_state_prepare_clean_for_draw(&DST);
+	DST.options.is_image_render = true;
+	DST.options.is_scene_render = true;
+	DST.options.draw_background = scene->r.alphamode == R_ADDSKY;
+	DST.buffer_finish_called = true;
+
+	DST.draw_ctx = (DRWContextState) {
+		.scene = scene, .view_layer = view_layer,
+		.engine_type = engine_type,
+		.depsgraph = depsgraph, .object_mode = OB_MODE_OBJECT,
+	};
+	drw_context_state_init();
+
+	DST.viewport = GPU_viewport_create();
+	const int size[2] = { (r->size * r->xsch) / 100, (r->size * r->ysch) / 100 };
+	GPU_viewport_size_set(DST.viewport, size);
+
+	drw_viewport_var_init();
+
+	/* set default viewport */
+	gpuPushAttrib(GPU_ENABLE_BIT | GPU_VIEWPORT_BIT);
+	glDisable(GL_SCISSOR_TEST);
+	glViewport(0, 0, size[0], size[1]);
+
+	/* Main rendering. */
+	rctf view_rect;
+	rcti render_rect;
+	RE_GetViewPlane(render, &view_rect, &render_rect);
+	if (BLI_rcti_is_empty(&render_rect)) {
+		BLI_rcti_init(&render_rect, 0, size[0], 0, size[1]);
+	}
+
+	RenderResult *render_result = RE_engine_get_result(engine);
+	RenderLayer *render_layer = render_result->layers.first;
+
+	DRW_render_gpencil_to_image(engine, depsgraph, render_layer, &render_rect);
+
+	/* Force cache to reset. */
+	drw_viewport_cache_resize();
+	GPU_viewport_free(DST.viewport);
+	DRW_state_reset();
+
+	glDisable(GL_DEPTH_TEST);
+
+	/* Restore Drawing area. */
+	gpuPopAttrib();
+	glEnable(GL_SCISSOR_TEST);
+	GPU_framebuffer_restore();
+
+	/* Changing Context */
+	/* GPXX Review this context */
+	DRW_opengl_context_disable();
+
+	DST.buffer_finish_called = false;
+}
+
 void DRW_render_to_image(RenderEngine *engine, struct Depsgraph *depsgraph)
 {
 	Scene *scene = DEG_get_evaluated_scene(depsgraph);
@@ -1663,6 +1797,8 @@ void DRW_render_to_image(RenderEngine *engine, struct Depsgraph *depsgraph)
 	{
 		RE_SetActiveRenderView(render, render_view->name);
 		engine_type->draw_engine->render_to_image(data, engine, render_layer, &render_rect);
+		/* grease pencil: render result is merged in the previous render result. */
+		DRW_render_gpencil_to_image(engine, depsgraph, render_layer, &render_rect);
 		DST.buffer_finish_called = false;
 	}
 
@@ -1671,8 +1807,6 @@ void DRW_render_to_image(RenderEngine *engine, struct Depsgraph *depsgraph)
 	/* Force cache to reset. */
 	drw_viewport_cache_resize();
 
-	/* TODO grease pencil */
-
 	GPU_viewport_free(DST.viewport);
 	GPU_framebuffer_restore();
 
@@ -2286,6 +2420,7 @@ void DRW_engines_register(void)
 	DRW_engine_register(&draw_engine_particle_type);
 	DRW_engine_register(&draw_engine_pose_type);
 	DRW_engine_register(&draw_engine_sculpt_type);
+	DRW_engine_register(&draw_engine_gpencil_type);
 
 	/* setup callbacks */
 	{
@@ -2304,6 +2439,9 @@ void DRW_engines_register(void)
 		/* BKE: particle.c */
 		extern void *BKE_particle_batch_cache_dirty_cb;
 		extern void *BKE_particle_batch_cache_free_cb;
+		/* BKE: gpencil.c */
+		extern void *BKE_gpencil_batch_cache_dirty_cb;
+		extern void *BKE_gpencil_batch_cache_free_cb;
 
 		BKE_mball_batch_cache_dirty_cb = DRW_mball_batch_cache_dirty;
 		BKE_mball_batch_cache_free_cb = DRW_mball_batch_cache_free;
@@ -2319,6 +2457,9 @@ void DRW_engines_register(void)
 
 		BKE_particle_batch_cache_dirty_cb = DRW_particle_batch_cache_dirty;
 		BKE_particle_batch_cache_free_cb = DRW_particle_batch_cache_free;
+
+		BKE_gpencil_batch_cache_dirty_cb = DRW_gpencil_batch_cache_dirty;
+		BKE_gpencil_batch_cache_free_cb = DRW_gpencil_batch_cache_free;
 	}
 }