Multi-View and Stereo 3D

Official Documentation:
http://www.blender.org/manual/render/workflows/multiview.html

Implemented Features
====================
Builtin Stereo Camera
* Convergence Mode
* Interocular Distance
* Convergence Distance
* Pivot Mode

Viewport
* Cameras
* Plane
* Volume

Compositor
* View Switch Node
* Image Node Multi-View OpenEXR support

Sequencer
* Image/Movie Strips 'Use Multiview'

UV/Image Editor
* Option to see Multi-View images in Stereo-3D or its individual images
* Save/Open Multi-View (OpenEXR, Stereo3D, individual views) images

I/O
* Save/Open Multi-View (OpenEXR, Stereo3D, individual views) images

Scene Render Views
* Ability to have an arbitrary number of views in the scene

Missing Bits
============
First rule of Multi-View bug report: If something is not working as it should *when Views is off* this is a severe bug, do mention this in the report.

Second rule is, if something works *when Views is off* but doesn't (or crashes) when *Views is on*, this is a important bug. Do mention this in the report.

Everything else is likely small todos, and may wait until we are sure none of the above is happening.

Apart from that there are those known issues:
* Compositor Image Node poorly working for Multi-View OpenEXR
(this was working prefectly before the 'Use Multi-View' functionality)
* Selecting camera from Multi-View when looking from camera is problematic
* Animation Playback (ctrl+F11) doesn't support stereo formats
* Wrong filepath when trying to play back animated scene
* Viewport Rendering doesn't support Multi-View
* Overscan Rendering
* Fullscreen display modes need to warn the user
* Object copy should be aware of views suffix

Acknowledgments
===============
* Francesco Siddi for the help with the original feature specs and design
* Brecht Van Lommel for the original review of the code and design early on
* Blender Foundation for the Development Fund to support the project wrap up

Final patch reviewers:
* Antony Riakiotakis (psy-fi)
* Campbell Barton (ideasman42)
* Julian Eisel (Severin)
* Sergey Sharybin (nazgul)
* Thomas Dinged (dingto)

Code contributors of the original branch in github:
* Alexey Akishin
* Gabriel Caraballo

3 files changed, 402 insertions, 31 deletions

diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index f14c19dc07e..f0b78649307 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -1741,6 +1741,238 @@ static void draw_viewport_reconstruction(Scene *scene, Base *base, View3D *v3d,
 		GPU_select_load_id(base->selcol);
 }
 
+static void drawcamera_volume(float near_plane[4][3], float far_plane[4][3], const GLenum mode)
+{
+	glBegin(mode);
+	glVertex3fv(near_plane[0]);
+	glVertex3fv(far_plane[0]);
+	glVertex3fv(far_plane[1]);
+	glVertex3fv(near_plane[1]);
+	glEnd();
+
+	glBegin(mode);
+	glVertex3fv(near_plane[1]);
+	glVertex3fv(far_plane[1]);
+	glVertex3fv(far_plane[2]);
+	glVertex3fv(near_plane[2]);
+	glEnd();
+
+	glBegin(mode);
+	glVertex3fv(near_plane[2]);
+	glVertex3fv(near_plane[1]);
+	glVertex3fv(far_plane[1]);
+	glVertex3fv(far_plane[2]);
+	glEnd();
+
+	glBegin(mode);
+	glVertex3fv(far_plane[0]);
+	glVertex3fv(near_plane[0]);
+	glVertex3fv(near_plane[3]);
+	glVertex3fv(far_plane[3]);
+	glEnd();
+}
+
+/* camera frame */
+static void drawcamera_frame(float vec[4][3], const GLenum mode)
+{
+	glBegin(mode);
+	glVertex3fv(vec[0]);
+	glVertex3fv(vec[1]);
+	glVertex3fv(vec[2]);
+	glVertex3fv(vec[3]);
+	glEnd();
+}
+
+/* center point to camera frame */
+static void drawcamera_framelines(float vec[4][3], float origin[3])
+{
+	glBegin(GL_LINE_STRIP);
+	glVertex3fv(vec[1]);
+	glVertex3fv(origin);
+	glVertex3fv(vec[0]);
+	glVertex3fv(vec[3]);
+	glVertex3fv(origin);
+	glVertex3fv(vec[2]);
+	glEnd();
+}
+
+static bool drawcamera_is_stereo3d(Scene *scene, View3D *v3d, Object *ob)
+{
+	return (ob == v3d->camera) &&
+	        (scene->r.scemode & R_MULTIVIEW) != 0 &&
+	        (v3d->stereo3d_flag);
+}
+
+static void drawcamera_stereo3d(
+        Scene *scene, View3D *v3d, RegionView3D *rv3d, Object *ob, const Camera *cam,
+        float vec[4][3], float drawsize, const float scale[3])
+{
+	int i, j;
+	float obmat[4][4];
+	float vec_lr[2][4][3];
+	const float fac = (cam->stereo.pivot == CAM_S3D_PIVOT_CENTER) ? 2.0f : 1.0f;
+	float origin[2][3] = {{0}};
+	float tvec[3];
+	const Camera *cam_lr[2];
+	const char *names[2] = {STEREO_LEFT_NAME, STEREO_RIGHT_NAME};
+
+	const bool is_stereo3d_cameras = (v3d->stereo3d_flag & V3D_S3D_DISPCAMERAS) && (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D);
+	const bool is_stereo3d_plane = (v3d->stereo3d_flag & V3D_S3D_DISPPLANE) && (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D);
+	const bool is_stereo3d_volume = (v3d->stereo3d_flag & V3D_S3D_DISPVOLUME);
+
+	zero_v3(tvec);
+
+	glPushMatrix();
+
+	for (i = 0; i < 2; i++) {
+		ob = BKE_camera_multiview_render(scene, ob, names[i]);
+		cam_lr[i] = ob->data;
+
+		glLoadMatrixf(rv3d->viewmat);
+		BKE_camera_multiview_model_matrix(&scene->r, ob, names[i], obmat);
+		glMultMatrixf(obmat);
+
+		copy_m3_m3(vec_lr[i], vec);
+		copy_v3_v3(vec_lr[i][3], vec[3]);
+
+		if (cam->stereo.convergence_mode == CAM_S3D_OFFAXIS) {
+			const float shift_x =
+			        ((BKE_camera_multiview_shift_x(&scene->r, ob, names[i]) - cam->shiftx) *
+			         (drawsize * scale[0] * fac));
+
+			for (j = 0; j < 4; j++) {
+				vec_lr[i][j][0] += shift_x;
+			}
+		}
+
+		if (is_stereo3d_cameras) {
+			/* camera frame */
+			drawcamera_frame(vec_lr[i], GL_LINE_LOOP);
+
+			/* center point to camera frame */
+			drawcamera_framelines(vec_lr[i], tvec);
+		}
+
+		/* connecting line */
+		mul_m4_v3(obmat, origin[i]);
+
+		/* convergence plane */
+		if (is_stereo3d_plane || is_stereo3d_volume) {
+			for (j = 0; j < 4; j++) {
+				mul_m4_v3(obmat, vec_lr[i][j]);
+			}
+		}
+	}
+
+
+	/* the remaining drawing takes place in the view space */
+	glLoadMatrixf(rv3d->viewmat);
+
+	if (is_stereo3d_cameras) {
+		/* draw connecting lines */
+		glPushAttrib(GL_ENABLE_BIT);
+
+		glLineStipple(2, 0xAAAA);
+		glEnable(GL_LINE_STIPPLE);
+
+		glBegin(GL_LINES);
+		glVertex3fv(origin[0]);
+		glVertex3fv(origin[1]);
+		glEnd();
+		glPopAttrib();
+	}
+
+	/* draw convergence plane*/
+	if (is_stereo3d_plane) {
+		float axis_center[3], screen_center[3];
+		float world_plane[4][3];
+		float local_plane[4][3];
+		float offset;
+
+		mid_v3_v3v3(axis_center, origin[0], origin[1]);
+
+		for (i = 0; i < 4; i++) {
+			mid_v3_v3v3(world_plane[i], vec_lr[0][i], vec_lr[1][i]);
+			sub_v3_v3v3(local_plane[i], world_plane[i], axis_center);
+		}
+
+		mid_v3_v3v3(screen_center, world_plane[0], world_plane[2]);
+		offset = cam->stereo.convergence_distance / len_v3v3(screen_center, axis_center);
+
+		for (i = 0; i < 4; i++) {
+			mul_v3_fl(local_plane[i], offset);
+			add_v3_v3(local_plane[i], axis_center);
+		}
+
+		glColor3f(0.0f, 0.0f, 0.0f);
+
+		/* camera frame */
+		drawcamera_frame(local_plane, GL_LINE_LOOP);
+
+		if (v3d->stereo3d_convergence_alpha > 0.0f) {
+			glEnable(GL_BLEND);
+			glDepthMask(0);  /* disable write in zbuffer, needed for nice transp */
+
+			glColor4f(0.0f, 0.0f, 0.0f, v3d->stereo3d_convergence_alpha);
+
+			drawcamera_frame(local_plane, GL_QUADS);
+
+			glDisable(GL_BLEND);
+			glDepthMask(1);  /* restore write in zbuffer */
+		}
+	}
+
+	/* draw convergence plane*/
+	if (is_stereo3d_volume) {
+		float screen_center[3];
+		float near_plane[4][3], far_plane[4][3];
+		float offset;
+		int j;
+
+		for (i = 0; i < 2; i++) {
+			mid_v3_v3v3(screen_center, vec_lr[i][0], vec_lr[i][2]);
+
+			offset = len_v3v3(screen_center, origin[i]);
+
+			for (j = 0; j < 4; j++) {
+				sub_v3_v3v3(near_plane[j], vec_lr[i][j], origin[i]);
+				mul_v3_fl(near_plane[j], cam_lr[i]->clipsta / offset);
+				add_v3_v3(near_plane[j], origin[i]);
+
+				sub_v3_v3v3(far_plane[j], vec_lr[i][j], origin[i]);
+				mul_v3_fl(far_plane[j], cam_lr[i]->clipend / offset);
+				add_v3_v3(far_plane[j], origin[i]);
+			}
+
+			/* camera frame */
+			glColor3f(0.0f, 0.0f, 0.0f);
+
+			drawcamera_frame(near_plane, GL_LINE_LOOP);
+			drawcamera_frame(far_plane, GL_LINE_LOOP);
+			drawcamera_volume(near_plane, far_plane, GL_LINE_LOOP);
+
+			if (v3d->stereo3d_volume_alpha > 0.0f) {
+				glEnable(GL_BLEND);
+				glDepthMask(0);  /* disable write in zbuffer, needed for nice transp */
+
+				if (i == 0)
+					glColor4f(0.0f, 1.0f, 1.0f, v3d->stereo3d_volume_alpha);
+				else
+					glColor4f(1.0f, 0.0f, 0.0f, v3d->stereo3d_volume_alpha);
+
+				drawcamera_frame(near_plane, GL_QUADS);
+				drawcamera_frame(far_plane, GL_QUADS);
+				drawcamera_volume(near_plane, far_plane, GL_QUADS);
+
+				glDisable(GL_BLEND);
+				glDepthMask(1);  /* restore write in zbuffer */
+			}
+		}
+	}
+
+	glPopMatrix();
+}
+
 /* flag similar to draw_object() */
 static void drawcamera(Scene *scene, View3D *v3d, RegionView3D *rv3d, Base *base,
                        const short dflag, const unsigned char ob_wire_col[4])
@@ -1755,6 +1987,12 @@ static void drawcamera(Scene *scene, View3D *v3d, RegionView3D *rv3d, Base *base
 	const bool is_view = (rv3d->persp == RV3D_CAMOB && ob == v3d->camera);
 	MovieClip *clip = BKE_object_movieclip_get(scene, base->object, false);
 
+	const bool is_stereo3d = drawcamera_is_stereo3d(scene, v3d, ob);
+	const bool is_stereo3d_cameras = (ob == scene->camera) &&
+	                                 (scene->r.scemode & R_MULTIVIEW) &&
+	                                 (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D) &&
+	                                 (v3d->stereo3d_flag & V3D_S3D_DISPCAMERAS);
+
 	/* draw data for movie clip set as active for scene */
 	if (clip) {
 		draw_viewport_reconstruction(scene, base, v3d, clip, dflag, ob_wire_col, false);
@@ -1791,12 +2029,8 @@ static void drawcamera(Scene *scene, View3D *v3d, RegionView3D *rv3d, Base *base
 	glDisable(GL_CULL_FACE);
 
 	/* camera frame */
-	glBegin(GL_LINE_LOOP);
-	glVertex3fv(vec[0]);
-	glVertex3fv(vec[1]);
-	glVertex3fv(vec[2]);
-	glVertex3fv(vec[3]);
-	glEnd();
+	if (!is_stereo3d_cameras)
+		drawcamera_frame(vec, GL_LINE_LOOP);
 
 	if (is_view)
 		return;
@@ -1804,20 +2038,12 @@ static void drawcamera(Scene *scene, View3D *v3d, RegionView3D *rv3d, Base *base
 	zero_v3(tvec);
 
 	/* center point to camera frame */
-	glBegin(GL_LINE_STRIP);
-	glVertex3fv(vec[1]);
-	glVertex3fv(tvec);
-	glVertex3fv(vec[0]);
-	glVertex3fv(vec[3]);
-	glVertex3fv(tvec);
-	glVertex3fv(vec[2]);
-	glEnd();
-
+	if (!is_stereo3d_cameras)
+		drawcamera_framelines(vec, tvec);
 
 	/* arrow on top */
 	tvec[2] = vec[1][2]; /* copy the depth */
 
-
 	/* draw an outline arrow for inactive cameras and filled
 	 * for active cameras. We actually draw both outline+filled
 	 * for active cameras so the wire can be seen side-on */
@@ -1867,6 +2093,11 @@ static void drawcamera(Scene *scene, View3D *v3d, RegionView3D *rv3d, Base *base
 			glPopMatrix();
 		}
 	}
+
+	/* stereo cameras drawing */
+	if (is_stereo3d) {
+		drawcamera_stereo3d(scene, v3d, rv3d, ob, cam, vec, drawsize, scale);
+	}
 }
 
 /* flag similar to draw_object() */
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index ddb3e2f20c5..f8345e91afd 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -344,7 +344,13 @@ static SpaceLink *view3d_new(const bContext *C)
 	
 	v3d->bundle_size = 0.2f;
 	v3d->bundle_drawtype = OB_PLAINAXES;
-	
+
+	/* stereo */
+	v3d->stereo3d_camera = STEREO_3D_ID;
+	v3d->stereo3d_flag |= V3D_S3D_DISPPLANE;
+	v3d->stereo3d_convergence_alpha = 0.15f;
+	v3d->stereo3d_volume_alpha = 0.05f;
+
 	/* header */
 	ar = MEM_callocN(sizeof(ARegion), "header for view3d");
 	
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index e480593b1e5..95a1ab87348 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -50,6 +50,7 @@
 #include "BLI_math.h"
 #include "BLI_utildefines.h"
 #include "BLI_endian_switch.h"
+#include "BLI_threads.h"
 
 #include "BKE_anim.h"
 #include "BKE_camera.h"
@@ -100,6 +101,11 @@
 
 #include "view3d_intern.h"  /* own include */
 
+/* prototypes */
+static void view3d_stereo3d_setup(Scene *scene, View3D *v3d, ARegion *ar);
+static void view3d_stereo3d_setup_offscreen(Scene *scene, View3D *v3d, ARegion *ar,
+                                            float winmat[4][4], const char *viewname);
+
 /* handy utility for drawing shapes in the viewport for arbitrary code.
  * could add lines and points too */
 // #define DEBUG_DRAW
@@ -1603,6 +1609,24 @@ exit:
 
 /* ************************************************************* */
 
+static void view3d_stereo_bgpic_setup(Scene *scene, View3D *v3d, Image *ima, ImageUser *iuser)
+{
+	if ((ima->flag & IMA_IS_STEREO)) {
+		iuser->flag |= IMA_SHOW_STEREO;
+
+		if ((scene->r.scemode & R_MULTIVIEW) == 0)
+			iuser->multiview_eye = STEREO_LEFT_ID;
+
+		/* show only left or right camera */
+		else if (v3d->stereo3d_camera != STEREO_3D_ID)
+			iuser->multiview_eye = v3d->stereo3d_camera;
+
+		BKE_image_multiview_index(ima, iuser);
+	}
+	else
+		iuser->flag &= ~IMA_SHOW_STEREO;
+}
+
 static void view3d_draw_bgpic(Scene *scene, ARegion *ar, View3D *v3d,
                               const bool do_foreground, const bool do_camera_frame)
 {
@@ -1646,6 +1670,7 @@ static void view3d_draw_bgpic(Scene *scene, ARegion *ar, View3D *v3d,
 					ibuf = NULL; /* frame is out of range, dont show */
 				}
 				else {
+					view3d_stereo_bgpic_setup(scene, v3d, ima, &bgpic->iuser);
 					ibuf = BKE_image_acquire_ibuf(ima, &bgpic->iuser, &lock);
 					releaseibuf = ibuf;
 				}
@@ -2551,7 +2576,7 @@ static void gpu_update_lamps_shadows_world(Scene *scene, View3D *v3d)
 		ED_view3d_draw_offscreen(
 		            scene, v3d, &ar, winsize, winsize, viewmat, winmat,
 		            false, false, true,
-		            NULL, NULL, NULL);
+		            NULL, NULL, NULL, NULL);
 		GPU_lamp_shadow_buffer_unbind(shadow->lamp);
 		
 		v3d->drawtype = drawtype;
@@ -3097,7 +3122,8 @@ void ED_view3d_draw_offscreen(
         float viewmat[4][4], float winmat[4][4],
         bool do_bgpic, bool do_sky, bool is_persp,
         GPUOffScreen *ofs,
-        GPUFX *fx, GPUFXSettings *fx_settings)
+        GPUFX *fx, GPUFXSettings *fx_settings,
+        const char *viewname)
 {
 	struct bThemeState theme_state;
 	int bwinx, bwiny;
@@ -3132,7 +3158,10 @@ void ED_view3d_draw_offscreen(
 	}
 
 	/* setup view matrices before fx or unbinding the offscreen buffers will cause issues */
-	view3d_main_area_setup_view(scene, v3d, ar, viewmat, winmat);
+	if ((viewname != NULL && viewname[0] != '\0') && (viewmat == NULL))
+		view3d_stereo3d_setup_offscreen(scene, v3d, ar, winmat, viewname);
+	else
+		view3d_main_area_setup_view(scene, v3d, ar, viewmat, winmat);
 
 	/* framebuffer fx needed, we need to draw offscreen first */
 	if (v3d->fx_settings.fx_flag && fx) {
@@ -3196,7 +3225,7 @@ void ED_view3d_draw_offscreen(
 
 /* utility func for ED_view3d_draw_offscreen */
 ImBuf *ED_view3d_draw_offscreen_imbuf(Scene *scene, View3D *v3d, ARegion *ar, int sizex, int sizey, unsigned int flag,
-                                      bool draw_background, int alpha_mode, char err_out[256])
+                                      bool draw_background, int alpha_mode, const char *viewname, char err_out[256])
 {
 	RegionView3D *rv3d = ar->regiondata;
 	ImBuf *ibuf;
@@ -3221,28 +3250,29 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Scene *scene, View3D *v3d, ARegion *ar, in
 	if (rv3d->persp == RV3D_CAMOB && v3d->camera) {
 		CameraParams params;
 		GPUFXSettings fx_settings = {NULL};
-		Object *camera = v3d->camera;
+		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);
 
 		BKE_camera_params_init(&params);
 		/* fallback for non camera objects */
 		params.clipsta = v3d->near;
 		params.clipend = v3d->far;
-		BKE_camera_params_from_object(&params, v3d->camera);
+		BKE_camera_params_from_object(&params, camera);
+		BKE_camera_multiview_params(&scene->r, &params, camera, viewname);
 		BKE_camera_params_compute_viewplane(&params, sizex, sizey, scene->r.xasp, scene->r.yasp);
 		BKE_camera_params_compute_matrix(&params);
 
 		BKE_camera_to_gpu_dof(camera, &fx_settings);
 
 		ED_view3d_draw_offscreen(
-		        scene, v3d, ar, sizex, sizey, NULL, params.winmat,
+            scene, v3d, ar, sizex, sizey, NULL, params.winmat,
 		        draw_background, draw_sky, !params.is_ortho,
-		        ofs, NULL, &fx_settings);
+		        ofs, NULL, &fx_settings, viewname);
 	}
 	else {
 		ED_view3d_draw_offscreen(
 		        scene, v3d, ar, sizex, sizey, NULL, NULL,
 		        draw_background, draw_sky, true,
-		        ofs, NULL, NULL);
+		        ofs, NULL, NULL, viewname);
 	}
 
 	/* read in pixels & stamp */
@@ -3267,7 +3297,8 @@ ImBuf *ED_view3d_draw_offscreen_imbuf(Scene *scene, View3D *v3d, ARegion *ar, in
 
 /* creates own 3d views, used by the sequencer */
 ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Scene *scene, Object *camera, int width, int height, unsigned int flag, int drawtype,
-                                             bool use_solid_tex, bool use_gpencil, bool draw_background, int alpha_mode, char err_out[256])
+                                             bool use_solid_tex, bool use_gpencil, bool draw_background, int alpha_mode,
+                                             const char *viewname, char err_out[256])
 {
 	View3D v3d = {NULL};
 	ARegion ar = {NULL};
@@ -3297,9 +3328,11 @@ ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Scene *scene, Object *camera, int w
 
 	{
 		CameraParams params;
+		Object *camera = BKE_camera_multiview_render(scene, v3d.camera, viewname);
 
 		BKE_camera_params_init(&params);
-		BKE_camera_params_from_object(&params, v3d.camera);
+		BKE_camera_params_from_object(&params, camera);
+		BKE_camera_multiview_params(&scene->r, &params, camera, viewname);
 		BKE_camera_params_compute_viewplane(&params, width, height, scene->r.xasp, scene->r.yasp);
 		BKE_camera_params_compute_matrix(&params);
 
@@ -3313,7 +3346,7 @@ ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Scene *scene, Object *camera, int w
 	invert_m4_m4(rv3d.persinv, rv3d.viewinv);
 
 	return ED_view3d_draw_offscreen_imbuf(scene, &v3d, &ar, width, height, flag,
-	                                      draw_background, alpha_mode, err_out);
+	                                      draw_background, alpha_mode, viewname, err_out);
 
 	// seq_view3d_cb(scene, cfra, render_size, seqrectx, seqrecty);
 }
@@ -3518,6 +3551,104 @@ static void view3d_main_area_draw_engine_info(View3D *v3d, RegionView3D *rv3d, A
 	ED_region_info_draw(ar, rv3d->render_engine->text, 1, fill_color);
 }
 
+static bool view3d_stereo3d_active(const bContext *C, Scene *scene, View3D *v3d, RegionView3D *rv3d)
+{
+	wmWindow *win = CTX_wm_window(C);
+
+	if ((scene->r.scemode & R_MULTIVIEW) == 0)
+		return false;
+
+	if (WM_stereo3d_enabled(win, true) == false)
+		return false;
+
+	if ((v3d->camera == NULL) || rv3d->persp != RV3D_CAMOB)
+		return false;
+
+	if (scene->r.views_format & SCE_VIEWS_FORMAT_MULTIVIEW) {
+		if (v3d->stereo3d_camera == STEREO_MONO_ID)
+			return false;
+
+		return BKE_scene_multiview_is_stereo3d(&scene->r);
+	}
+
+	return true;
+}
+
+/* setup the view and win matrices for the multiview cameras
+ *
+ * unlike view3d_stereo3d_setup_offscreen, when view3d_stereo3d_setup is called
+ * we have no winmatrix (i.e., projection matrix) defined at that time.
+ * Since the camera and the camera shift are needed for the winmat calculation
+ * we do a small hack to replace it temporarily so we don't need to change the
+ * view3d)main_area_setup_view() code to account for that.
+ */
+static void view3d_stereo3d_setup(Scene *scene, View3D *v3d, ARegion *ar)
+{
+	bool is_left;
+	const char *names[2] = {STEREO_LEFT_NAME, STEREO_RIGHT_NAME};
+	const char *viewname;
+
+	/* show only left or right camera */
+	if (v3d->stereo3d_camera != STEREO_3D_ID)
+		v3d->multiview_eye = v3d->stereo3d_camera;
+
+	is_left = v3d->multiview_eye == STEREO_LEFT_ID;
+	viewname = names[is_left ? STEREO_LEFT_ID : STEREO_RIGHT_ID];
+
+	/* update the viewport matrices with the new camera */
+	if (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D) {
+		Camera *data;
+		float viewmat[4][4];
+		float shiftx;
+
+		data = (Camera *)v3d->camera->data;
+		shiftx = data->shiftx;
+
+		BLI_lock_thread(LOCK_VIEW3D);
+		data->shiftx = BKE_camera_multiview_shift_x(&scene->r, v3d->camera, viewname);
+
+		BKE_camera_multiview_view_matrix(&scene->r, v3d->camera, is_left, viewmat);
+		view3d_main_area_setup_view(scene, v3d, ar, viewmat, NULL);
+
+		data->shiftx = shiftx;
+		BLI_unlock_thread(LOCK_VIEW3D);
+	}
+	else { /* SCE_VIEWS_FORMAT_MULTIVIEW */
+		float viewmat[4][4];
+		Object *view_ob = v3d->camera;
+		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);
+
+		BLI_lock_thread(LOCK_VIEW3D);
+		v3d->camera = camera;
+
+		BKE_camera_multiview_view_matrix(&scene->r, camera, false, viewmat);
+		view3d_main_area_setup_view(scene, v3d, ar, viewmat, NULL);
+
+		v3d->camera = view_ob;
+		BLI_unlock_thread(LOCK_VIEW3D);
+	}
+}
+
+static void view3d_stereo3d_setup_offscreen(Scene *scene, View3D *v3d, ARegion *ar,
+                                            float winmat[4][4], const char *viewname)
+{
+	/* update the viewport matrices with the new camera */
+	if (scene->r.views_format == SCE_VIEWS_FORMAT_STEREO_3D) {
+		float viewmat[4][4];
+		const bool is_left = STREQ(viewname, STEREO_LEFT_NAME);
+
+		BKE_camera_multiview_view_matrix(&scene->r, v3d->camera, is_left, viewmat);
+		view3d_main_area_setup_view(scene, v3d, ar, viewmat, winmat);
+	}
+	else { /* SCE_VIEWS_FORMAT_MULTIVIEW */
+		float viewmat[4][4];
+		Object *camera = BKE_camera_multiview_render(scene, v3d->camera, viewname);
+
+		BKE_camera_multiview_view_matrix(&scene->r, camera, false, viewmat);
+		view3d_main_area_setup_view(scene, v3d, ar, viewmat, winmat);
+	}
+}
+
 #ifdef WITH_GAMEENGINE
 static void update_lods(Scene *scene, float camera_pos[3])
 {
@@ -3551,8 +3682,11 @@ static void view3d_main_area_draw_objects(const bContext *C, Scene *scene, View3
 		GPU_default_lights();
 	}
 
-	/* setup view matrices */
-	view3d_main_area_setup_view(scene, v3d, ar, NULL, NULL);
+	/* setup the view matrix */
+	if (view3d_stereo3d_active(C, scene, v3d, rv3d))
+		view3d_stereo3d_setup(scene, v3d, ar);
+	else
+		view3d_main_area_setup_view(scene, v3d, ar, NULL, NULL);
 
 	rv3d->rflag &= ~RV3D_IS_GAME_ENGINE;
 #ifdef WITH_GAMEENGINE