[vlc-commits] vout: opengl: set the view frustum in function of the window size for 360 video

[Adrien Maglo]

vlc | branch: master | Adrien Maglo <magsoft at videolan.org> | Mon Nov 21 18:24:54 2016 +0100| [2f4ae29134d9165e214c85227392c674e004ff02] | committer: Thomas Guillem

vout: opengl: set the view frustum in function of the window size for 360 video

Previously, the frustum aspect ratio was set in function of the flat video
resolution, which is not related at all to the view frustum shape.

Signed-off-by: Thomas Guillem <thomas at gllm.fr>

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=2f4ae29134d9165e214c85227392c674e004ff02
---

 modules/video_output/opengl.c | 52 +++++++++++++++++++++++++++++++++----------
 modules/video_output/opengl.h |  3 +++
 2 files changed, 43 insertions(+), 12 deletions(-)

diff --git a/modules/video_output/opengl.c b/modules/video_output/opengl.c
index aefa63f..bb54674 100644
--- a/modules/video_output/opengl.c
+++ b/modules/video_output/opengl.c
@@ -212,6 +212,8 @@ struct vout_display_opengl_t {
     float f_fov;
     float f_zoom;
     float f_zoom_min;
+    float f_zoom_unscaled;
+    float f_sar;
 };
 
 static inline int GetAlignedSize(unsigned size)
@@ -788,6 +790,26 @@ void vout_display_opengl_Delete(vout_display_opengl_t *vgl)
     free(vgl);
 }
 
+static void UpdateZoom(vout_display_opengl_t *vgl)
+{
+    const float f_zoom_max = 0.5f * SPHERE_RADIUS;
+    vgl->f_zoom = vgl->f_zoom_unscaled
+                * (vgl->f_zoom_unscaled >= 0 ? f_zoom_max : vgl->f_zoom_min);
+}
+
+static void CalculateZoomMin(vout_display_opengl_t *vgl)
+{
+    /* Do trigonometry to calculate the minimal zoom value
+     * that will allow us to zoom out without seeing the outside of the
+     * sphere (black borders). */
+    float sar = vgl->f_sar;
+    float fovx = 2 * atanf(tanf(vgl->f_fov / 2) * sar);
+    float tan_fovx_2 = tanf(fovx / 2);
+    float tan_fovy_2 = tanf(vgl->f_fov / 2 );
+    vgl->f_zoom_min = SPHERE_RADIUS / sinf(atanf(sqrtf(
+                      tan_fovx_2 * tan_fovx_2 + tan_fovy_2 * tan_fovy_2)));
+}
+
 int vout_display_opengl_SetViewpoint(vout_display_opengl_t *vgl,
                                      const vlc_viewpoint_t *p_vp)
 {
@@ -803,24 +825,30 @@ int vout_display_opengl_SetViewpoint(vout_display_opengl_t *vgl,
 
     if (fabsf(f_fov - vgl->f_fov) >= 0.001f)
     {
-        /* The fov changed, do trigonometry to calculate the minimal zoom value
-         * that will allow us to zoom out without seeing the outside of the
-         * sphere (black borders). */
-        float sar = (float) vgl->fmt.i_visible_width / vgl->fmt.i_visible_height;
-        float fovx = 2 * atanf(tanf(f_fov / 2) * sar);
-        float tan_fovx_2 = tanf(fovx / 2);
-        float tan_fovy_2 = tanf(f_fov / 2 );
-        vgl->f_zoom_min = SPHERE_RADIUS / sinf(atanf(sqrtf(
-                          tan_fovx_2 * tan_fovx_2 + tan_fovy_2 * tan_fovy_2)));
+        vgl->f_fov = f_fov;
+        CalculateZoomMin(vgl);
     }
 
-    vgl->f_fov  = f_fov;
-    vgl->f_zoom = p_vp->zoom * (p_vp->zoom >= 0 ? 0.5 * SPHERE_RADIUS : vgl->f_zoom_min);
+    vgl->f_zoom_unscaled = p_vp->zoom;
+    UpdateZoom(vgl);
 
     return VLC_SUCCESS;
 #undef RAD
 }
 
+
+void vout_display_opengl_SetWindowAspectRatio(vout_display_opengl_t *vgl,
+                                              float f_sar)
+{
+    /* Each time the window size changes, we must recompute the minimum zoom
+     * since the aspect ration changes.
+     * We must also set the new current zoom value. */
+    vgl->f_sar = f_sar;
+    CalculateZoomMin(vgl);
+    UpdateZoom(vgl);
+}
+
+
 picture_pool_t *vout_display_opengl_GetPool(vout_display_opengl_t *vgl, unsigned requested_count)
 {
     if (vgl->pool)
@@ -1601,7 +1629,7 @@ static void DrawWithShaders(vout_display_opengl_t *vgl,
     if (vgl->fmt.projection_mode == PROJECTION_MODE_EQUIRECTANGULAR
         || vgl->fmt.projection_mode == PROJECTION_MODE_CUBEMAP_LAYOUT_STANDARD)
     {
-        float sar = (float) vgl->fmt.i_visible_width / vgl->fmt.i_visible_height;
+        float sar = (float) vgl->f_sar;
         getProjectionMatrix(sar, vgl->f_fov, projectionMatrix);
         getYRotMatrix(vgl->f_teta, yRotMatrix);
         getXRotMatrix(vgl->f_phi, xRotMatrix);
diff --git a/modules/video_output/opengl.h b/modules/video_output/opengl.h
index 9aff95b..7d6f55c 100644
--- a/modules/video_output/opengl.h
+++ b/modules/video_output/opengl.h
@@ -99,6 +99,9 @@ picture_pool_t *vout_display_opengl_GetPool(vout_display_opengl_t *vgl, unsigned
 
 int vout_display_opengl_SetViewpoint(vout_display_opengl_t *vgl, const vlc_viewpoint_t*);
 
+void vout_display_opengl_SetWindowAspectRatio(vout_display_opengl_t *vgl,
+                                              float f_sar);
+
 int vout_display_opengl_Prepare(vout_display_opengl_t *vgl,
                                 picture_t *picture, subpicture_t *subpicture);
 int vout_display_opengl_Display(vout_display_opengl_t *vgl,