[vlc-devel] [PATCH 03/16] opengl: handle the viewpoint changes when rendering

[Thomas Guillem]

From: Steve Lhomme <robux4 at videolabs.io>

vout_display_opengl_SetViewpoint is used to convert from the data within a
vlc_viewpoint_t so that it can be, equivalently interpreted by opengl.

The function will be called from the video-output modules that are using our
opengl implementation as their backend.

Signed-off-by: Thomas Guillem <thomas at gllm.fr>
---
 modules/video_output/opengl.c | 44 ++++++++++++++++++++++++++++++++++---------
 modules/video_output/opengl.h |  3 +++
 2 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/modules/video_output/opengl.c b/modules/video_output/opengl.c
index 26aaec9..d4f5662 100644
--- a/modules/video_output/opengl.c
+++ b/modules/video_output/opengl.c
@@ -37,6 +37,7 @@
 #include <vlc_subpicture.h>
 #include <vlc_opengl.h>
 #include <vlc_memory.h>
+#include <vlc_vout.h>
 
 #include "opengl.h"
 
@@ -205,6 +206,7 @@ struct vout_display_opengl_t {
     /* View point */
     float f_teta;
     float f_phi;
+    float f_roll;
     float f_zoom;
 };
 
@@ -422,6 +424,15 @@ static void BuildXYZFragmentShader(vout_display_opengl_t *vgl,
 
 #endif
 
+static int
+SetViewpoint(vout_display_opengl_t *vgl, float f_teta, float f_phi, float f_roll)
+{
+    vgl->f_teta = f_teta - (float) M_PI / 2;
+    vgl->f_phi  = f_phi;
+    vgl->f_roll = f_roll;
+    return VLC_SUCCESS;
+}
+
 vout_display_opengl_t *vout_display_opengl_New(video_format_t *fmt,
                                                const vlc_fourcc_t **subpicture_chromas,
                                                vlc_gl_t *gl)
@@ -692,9 +703,9 @@ vout_display_opengl_t *vout_display_opengl_New(video_format_t *fmt,
     if (vgl->fmt.projection_mode == PROJECTION_MODE_EQUIRECTANGULAR
         || vgl->fmt.projection_mode == PROJECTION_MODE_CUBEMAP_LAYOUT_STANDARD)
     {
-        vgl->f_teta = vgl->fmt.f_pose_roll_degrees / 180. * (float) M_PI;
-        vgl->f_phi  = vgl->fmt.f_pose_yaw_degrees  / 180. * (float) M_PI;
-        vgl->f_teta -= (float) M_PI/2;
+        SetViewpoint(vgl, vgl->fmt.f_pose_yaw_degrees   / 180.f * (float) M_PI,
+                     vgl->fmt.f_pose_pitch_degrees / 180.f * (float) M_PI,
+                     vgl->fmt.f_pose_roll_degrees  / 180.f * (float) M_PI);
     }
 
     /* */
@@ -777,6 +788,13 @@ void vout_display_opengl_Delete(vout_display_opengl_t *vgl)
     free(vgl);
 }
 
+int vout_display_opengl_SetViewpoint(vout_display_opengl_t *vgl, const vlc_viewpoint_t *p_viewpoint)
+{
+    return SetViewpoint(vgl, p_viewpoint->yaw / (float) VLC_VIEWPOINT_RADIAN_UNIT,
+                        p_viewpoint->pitch / (float) VLC_VIEWPOINT_RADIAN_UNIT,
+                        p_viewpoint->roll / (float) VLC_VIEWPOINT_RADIAN_UNIT);
+}
+
 picture_pool_t *vout_display_opengl_GetPool(vout_display_opengl_t *vgl, unsigned requested_count)
 {
     if (vgl->pool)
@@ -1077,17 +1095,25 @@ static void getZoomMatrix(float zoom, GLfloat matrix[static 16]) {
 
 static void getProjectionMatrix(float sar, GLfloat matrix[static 16]) {
 
-    float f = 3;
-    float n = 0.1;
+    float zFar  = 1000;
+    float zNear = 0.01;
 
     float fovy = (float) M_PI / 3;
     float d = 1 / tan(fovy / 2);
 
+    if (fovy > (float) M_PI -0.001)
+        fovy = (float) M_PI -0.001;
+
+    if (fovy < 0.001)
+        fovy = 0.001;
+
+    float f = 1 / tan(fovy / 2);
+
     const GLfloat m[] = {
-        d / sar, 0.0, 0.0,                   0.0,
-        0.0,     d,   0.0,                   0.0,
-        0.0,     0.0, (n + f) / (n - f),     -1.0,
-        0.0,     0.0, (2 * n * f) / (n - f), 0.0};
+        f / sar, 0.0,                   0.0,                0.0,
+        0.0,     f,                     0.0,                0.0,
+        0.0,     0.0,     (zNear + zFar) / (zNear - zFar), -1.0,
+        0.0,     0.0, (2 * zNear * zFar) / (zNear - zFar),  0.0};
 
      memcpy(matrix, m, sizeof(m));
 }
diff --git a/modules/video_output/opengl.h b/modules/video_output/opengl.h
index 4ae9400..4d382b5 100644
--- a/modules/video_output/opengl.h
+++ b/modules/video_output/opengl.h
@@ -31,6 +31,7 @@
 
 #include <vlc_common.h>
 #include <vlc_picture_pool.h>
+#include <vlc_vout_display.h>
 #include <vlc_opengl.h>
 
 /* Change USE_OPENGL_ES value to set the OpenGL ES version (1, 2) you want to use
@@ -96,6 +97,8 @@ void vout_display_opengl_Delete(vout_display_opengl_t *vgl);
 
 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*);
+
 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,
-- 
2.9.3