[vlc-devel] [PATCH 5/5] opengl: limit the fov and zoom to sane values

[Steve Lhomme]

the zoom translation needs to remain within the sphere
the field of view should be within 20° and 161°

--
applies after the previous OpenGL cleaning patches
---
 modules/video_output/opengl.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/modules/video_output/opengl.c b/modules/video_output/opengl.c
index 7c0ccb6..5be8449 100644
--- a/modules/video_output/opengl.c
+++ b/modules/video_output/opengl.c
@@ -31,6 +31,7 @@
 
 #include <assert.h>
 #include <math.h>
+#include <float.h>
 
 #include <vlc_common.h>
 #include <vlc_picture_pool.h>
@@ -211,7 +212,6 @@ struct vout_display_opengl_t {
     float f_roll;
     float f_fov;
     float f_zoom;
-    float f_zoom_min;
 };
 
 static inline int GetAlignedSize(unsigned size)
@@ -449,8 +449,6 @@ vout_display_opengl_t *vout_display_opengl_New(video_format_t *fmt,
         return NULL;
     }
 
-    vgl->f_fov = -1.f; /* In order to init vgl->f_zoom_min */
-
     const char *extensions = (const char *)glGetString(GL_EXTENSIONS);
 #if !USE_OPENGL_ES
     const unsigned char *ogl_version = glGetString(GL_VERSION);
@@ -792,30 +790,11 @@ int vout_display_opengl_SetViewpoint(vout_display_opengl_t *vgl,
                                      const vlc_viewpoint_t *p_vp)
 {
 #define RAD(d) ((float) ((d) * M_PI / 180.f))
-    float f_fov = RAD(p_vp->fov);
-    if (f_fov > (float) M_PI -0.001f || f_fov < 0.001f)
-        return VLC_EBADVAR;
-    if (p_vp->zoom > 1.f || p_vp->zoom < -1.f)
-        return VLC_EBADVAR;
     vgl->f_teta = RAD(p_vp->yaw) - (float) M_PI_2;
     vgl->f_phi  = RAD(p_vp->pitch);
     vgl->f_roll = RAD(p_vp->roll);
-
-    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;
-    vgl->f_zoom = p_vp->zoom * (p_vp->zoom >= 0 ? 0.5 : vgl->f_zoom_min) * SPHERE_RADIUS;
+    vgl->f_fov  = RAD( VLC_CLIP(p_vp->fov, 20.f, 161.f) );
+    vgl->f_zoom = VLC_CLIP(p_vp->zoom, -1.f+FLT_EPSILON, 0.98f) * SPHERE_RADIUS;
 
     return VLC_SUCCESS;
 #undef RAD
-- 
2.10.1.windows.1