[Bf-blender-cvs] [461b3c817e9] blender2.8: Camera Reconstruction: Camera Path

[Dalai Felinto]

Commit: 461b3c817e981f9a6dbc354a2c142d1d1d344976
Author: Dalai Felinto
Date:   Wed Aug 15 12:22:29 2018 -0300
Branches: blender2.8
https://developer.blender.org/rB461b3c817e981f9a6dbc354a2c142d1d1d344976

Camera Reconstruction: Camera Path

The only difference from 2.7x is that we were using glLineWidth(2.0) before,
which is not supported reliably in the latest OpenGL.

Big thanks to Clément Foucault for helping with this, on the design as well as
debugging the implementation.

For the records, I'm creating and destroying batches for the path geometry at
every draw. The pipeline is as follows:

 1. Create GPUBatch with all the points
 2. Create new shgroup with simple shader
 3. Add call with the gpubatch
 4. Save it in a linked list in stl->g_data
 5. Free it after all drawing is done

===================================================================

M	source/blender/draw/modes/object_mode.c

===================================================================

diff --git a/source/blender/draw/modes/object_mode.c b/source/blender/draw/modes/object_mode.c
index 290f5d308df..cc4142529ec 100644
--- a/source/blender/draw/modes/object_mode.c
+++ b/source/blender/draw/modes/object_mode.c
@@ -61,9 +61,10 @@
 
 #include "ED_view3d.h"
 
+#include "GPU_batch.h"
+#include "GPU_draw.h"
 #include "GPU_shader.h"
 #include "GPU_texture.h"
-#include "GPU_draw.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -223,6 +224,7 @@ typedef struct OBJECT_PrivateData {
 	DRWShadingGroup *camera_clip_points;
 	DRWShadingGroup *camera_mist;
 	DRWShadingGroup *camera_mist_points;
+	ListBase camera_path;
 
 	/* Outlines */
 	DRWShadingGroup *outlines_active;
@@ -1188,6 +1190,8 @@ static void OBJECT_cache_init(void *vedata)
 		stl->g_data->camera_clip_points = shgroup_distance_lines_instance(psl->non_meshes, geom);
 		stl->g_data->camera_mist_points = shgroup_distance_lines_instance(psl->non_meshes, geom);
 
+		BLI_listbase_clear(&stl->g_data->camera_path);
+
 		/* Texture Space */
 		geom = DRW_cache_empty_cube_get();
 		stl->g_data->texspace = shgroup_instance(psl->non_meshes, geom);
@@ -1523,7 +1527,41 @@ static void DRW_shgroup_lamp(OBJECT_StorageList *stl, Object *ob, ViewLayer *vie
 	DRW_shgroup_call_dynamic_add(stl->g_data->lamp_groundpoint, ob->obmat[3]);
 }
 
-static void DRW_shgroup_camera(OBJECT_StorageList *stl, Object *ob, ViewLayer *view_layer)
+static GPUBatch *batch_camera_path_get(
+        ListBase *camera_paths, const MovieTrackingReconstruction *reconstruction)
+{
+	GPUBatch *geom;
+	static GPUVertFormat format = { 0 };
+	static struct { uint pos; } attr_id;
+	if (format.attr_len == 0) {
+		attr_id.pos = GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+	}
+	GPUVertBuf *vbo = GPU_vertbuf_create_with_format(&format);
+	GPU_vertbuf_data_alloc(vbo, reconstruction->camnr);
+
+	MovieReconstructedCamera *camera = reconstruction->cameras;
+	for (int a = 0; a < reconstruction->camnr; a++, camera++) {
+		GPU_vertbuf_attr_set(vbo, attr_id.pos, a, camera->mat[3]);
+	}
+
+	geom = GPU_batch_create_ex(GPU_PRIM_LINE_STRIP, vbo, NULL, GPU_BATCH_OWNS_VBO);
+
+	/* Store the batch to do cleanup after drawing. */
+	BLI_addtail(camera_paths, BLI_genericNodeN(geom));
+	return geom;
+}
+
+static void batch_camera_path_free(ListBase *camera_paths)
+{
+	LinkData *link;
+	while ((link = BLI_pophead(camera_paths))) {
+		GPUBatch *camera_path = link->data;
+		GPU_batch_discard(camera_path);
+		MEM_freeN(link);
+	}
+}
+
+static void DRW_shgroup_camera(OBJECT_StorageList *stl, OBJECT_PassList *psl, Object *ob, ViewLayer *view_layer)
 {
 	const DRWContextState *draw_ctx = DRW_context_state_get();
 	View3D *v3d = draw_ctx->v3d;
@@ -1623,6 +1661,7 @@ static void DRW_shgroup_camera(OBJECT_StorageList *stl, Object *ob, ViewLayer *v
 	/* Motion Tracking. */
 	MovieClip *clip = BKE_object_movieclip_get(scene, ob, false);
 	if ((v3d->flag2 & V3D_SHOW_RECONSTRUCTION) && (clip != NULL)){
+		BLI_assert(BLI_listbase_is_empty(&stl->g_data->camera_path));
 		const bool is_select = DRW_state_is_select();
 		const bool is_solid_bundle = (v3d->bundle_drawtype == OB_EMPTY_SPHERE) &&
 		                             ((v3d->shading.type != OB_SOLID) ||
@@ -1740,6 +1779,22 @@ static void DRW_shgroup_camera(OBJECT_StorageList *stl, Object *ob, ViewLayer *v
 					                   is_selected ? text_color_selected : text_color_unselected);
 				}
 			}
+
+			if ((v3d->flag2 & V3D_SHOW_CAMERAPATH) && (tracking_object->flag & TRACKING_OBJECT_CAMERA) && !is_select) {
+				MovieTrackingReconstruction *reconstruction;
+				reconstruction = BKE_tracking_object_get_reconstruction(tracking, tracking_object);
+
+				if (reconstruction->camnr) {
+					static float camera_path_color[4];
+					UI_GetThemeColor4fv(TH_CAMERA_PATH, camera_path_color);
+
+					GPUBatch *geom = batch_camera_path_get(&stl->g_data->camera_path, reconstruction);
+					GPUShader *shader = GPU_shader_get_builtin_shader(GPU_SHADER_3D_UNIFORM_COLOR);
+					DRWShadingGroup *shading_group = DRW_shgroup_create(shader, psl->non_meshes);
+					DRW_shgroup_uniform_vec4(shading_group, "color", camera_path_color, 1);
+					DRW_shgroup_call_add(shading_group, geom, camera_mat);
+				}
+			}
 		}
 	}
 }
@@ -2601,7 +2656,7 @@ static void OBJECT_cache_populate(void *vedata, Object *ob)
 			if (hide_object_extra) {
 				break;
 			}
-			 DRW_shgroup_camera(stl, ob, view_layer);
+			 DRW_shgroup_camera(stl, psl, ob, view_layer);
 			break;
 		case OB_EMPTY:
 			if (hide_object_extra) {
@@ -2793,6 +2848,7 @@ static void OBJECT_draw_scene(void *vedata)
 	}
 
 	volumes_free_smoke_textures();
+	batch_camera_path_free(&stl->g_data->camera_path);
 }
 
 static const DrawEngineDataSize OBJECT_data_size = DRW_VIEWPORT_DATA_SIZE(OBJECT_Data);