Workbench: Added the basics for the OverlayMode

Implemented the face orientation overlay for testing.
Overlay mode is only drawn when there are overlays to be rendered.
The overlay mode is rendered before the object mode.

1 files changed, 185 insertions, 0 deletions

diff --git a/source/blender/draw/modes/overlay_mode.c b/source/blender/draw/modes/overlay_mode.c
new file mode 100644
index 00000000000..d7e87cf238f
--- /dev/null
+++ b/source/blender/draw/modes/overlay_mode.c
@@ -0,0 +1,185 @@
+/*
+ * Copyright 2016, Blender Foundation.
+ *
+ * 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): Blender Institute
+ *
+ */
+
+/** \file overlay_mode.c
+ *  \ingroup draw_engine
+ */
+
+#include "DRW_render.h"
+
+#include "GPU_shader.h"
+#include "DNA_view3d_types.h"
+
+/* Structures */
+typedef struct OVERLAY_StorageList {
+	struct OVERLAY_PrivateData *g_data;
+} OVERLAY_StorageList;
+
+typedef struct OVERLAY_PassList {
+	struct DRWPass *depth_pass;
+	struct DRWPass *face_orientation_pass;
+} OVERLAY_PassList;
+
+typedef struct OVERLAY_Data {
+	void *engine_type;
+	DRWViewportEmptyList *fbl;
+	DRWViewportEmptyList *txl;
+	OVERLAY_PassList *psl;
+	OVERLAY_StorageList *stl;
+} OVERLAY_Data;
+
+typedef struct OVERLAY_PrivateData {
+	DRWShadingGroup *depth_shgrp;
+	DRWShadingGroup *face_orientation_shgrp;
+	int overlays;
+} OVERLAY_PrivateData; /* Transient data */
+
+typedef struct OVERLAY_MaterialData {
+	/* Solid color */
+	float color[3];
+
+	/* Linked shgroup for drawing */
+	DRWShadingGroup *shgrp;
+} OVERLAY_MaterialData;
+
+/* *********** STATIC *********** */
+static struct {
+	struct GPUShader *depth_sh;
+
+	/* Solid flat mode */
+	struct GPUShader *face_orientation_sh;
+
+} e_data = {NULL};
+
+/* Shaders */
+extern char datatoc_overlay_face_orientation_frag_glsl[];
+extern char datatoc_overlay_face_orientation_vert_glsl[];
+
+
+/* Functions */
+static void overlay_engine_init(void *UNUSED(vedata))
+{
+	if (!e_data.depth_sh) {
+		/* Depth pass */
+		e_data.depth_sh = DRW_shader_create_3D_depth_only();
+
+		/* Solid flat */
+		e_data.face_orientation_sh = DRW_shader_create(datatoc_overlay_face_orientation_vert_glsl, NULL, datatoc_overlay_face_orientation_frag_glsl, "\n");
+	}
+}
+
+static void overlay_cache_init(void *vedata)
+{
+
+	OVERLAY_Data * data = (OVERLAY_Data *)vedata;
+	OVERLAY_PassList *psl = data->psl;
+	OVERLAY_StorageList *stl = data->stl;
+
+	const DRWContextState *DCS = DRW_context_state_get();
+
+	if (!stl->g_data) {
+		/* Alloc transient pointers */
+		stl->g_data = MEM_mallocN(sizeof(*stl->g_data), __func__);
+	}
+
+	View3D *v3d = DCS->v3d;
+	if (v3d) {
+		stl->g_data->overlays = v3d->overlays;
+	}
+	else {
+		stl->g_data->overlays = 0;
+	}
+
+
+	/* Depth Pass */
+	{
+		int state = DRW_STATE_WRITE_DEPTH | DRW_STATE_DEPTH_LESS;
+		psl->depth_pass = DRW_pass_create("Depth Pass", state);
+		stl->g_data->depth_shgrp = DRW_shgroup_create(e_data.depth_sh, psl->depth_pass);
+	}
+
+	/* Face Orientation Pass */
+	if (stl->g_data->overlays & V3D_OVERLAY_FACE_ORIENTATION)
+	{
+		int state = DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_EQUAL;
+		psl->face_orientation_pass = DRW_pass_create("Face Orientation", state);
+		stl->g_data->face_orientation_shgrp = DRW_shgroup_create(e_data.face_orientation_sh, psl->face_orientation_pass);
+	}
+}
+
+static void overlay_cache_populate(void *vedata, Object *ob)
+{
+	OVERLAY_Data * data = (OVERLAY_Data *)vedata;
+	OVERLAY_StorageList *stl = data->stl;
+	OVERLAY_PrivateData *pd = stl->g_data;
+
+	if (!DRW_object_is_renderable(ob))
+		return;
+
+	struct Gwn_Batch *geom = DRW_cache_object_surface_get(ob);
+	if (geom) {
+		/* Depth */
+		DRW_shgroup_call_add(pd->depth_shgrp, geom, ob->obmat);
+
+		/* Face Orientation */
+		if (stl->g_data->overlays & V3D_OVERLAY_FACE_ORIENTATION) {
+			DRW_shgroup_call_add(pd->face_orientation_shgrp, geom, ob->obmat);
+		}
+	}
+
+}
+
+static void overlay_cache_finish(void *UNUSED(vedata))
+{
+}
+
+static void overlay_draw_scene(void *vedata)
+{
+	OVERLAY_Data * data = (OVERLAY_Data *)vedata;
+	OVERLAY_PassList *psl = data->psl;
+
+	DRW_draw_pass(psl->depth_pass);
+	DRW_draw_pass(psl->face_orientation_pass);
+}
+
+static void overlay_engine_free(void)
+{
+	DRW_SHADER_FREE_SAFE(e_data.face_orientation_sh);
+}
+
+static const DrawEngineDataSize overlay_data_size = DRW_VIEWPORT_DATA_SIZE(OVERLAY_Data);
+
+DrawEngineType draw_engine_overlay_type = {
+	NULL, NULL,
+	N_("OverlayEngine"),
+	&overlay_data_size,
+	&overlay_engine_init,
+	&overlay_engine_free,
+	&overlay_cache_init,
+	&overlay_cache_populate,
+	&overlay_cache_finish,
+	NULL,
+	&overlay_draw_scene,
+	NULL,
+	NULL,
+	NULL,
+};
+