1 /*
2  * GStreamer
3  * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Library General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Library General Public License for more details.
14  *
15  * You should have received a copy of the GNU Library General Public
16  * License along with this library; if not, write to the
17  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18  * Boston, MA 02110-1301, USA.
19  */
20 
21 #ifdef HAVE_CONFIG_H
22 #include "config.h"
23 #endif
24 
25 #include <vector>
26 #include <stdio.h>
27 
28 #include <gst/video/video.h>
29 #include <gst/gl/gl.h>
30 #include <gst/gl/gstglfuncs.h>
31 #include "gstqsgtexture.h"
32 
33 #define GST_CAT_DEFAULT gst_qsg_texture_debug
34 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
35 
GstQSGTexture()36 GstQSGTexture::GstQSGTexture ()
37 {
38   static volatile gsize _debug;
39 
40   initializeOpenGLFunctions();
41 
42   if (g_once_init_enter ((unsigned long *)&_debug)) {
43     GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "qtqsgtexture", 0,
44         "Qt Scenegraph Texture");
45     g_once_init_leave (&_debug, 1);
46   }
47 
48   gst_video_info_init (&this->v_info);
49   this->buffer_ = NULL;
50   this->qt_context_ = NULL;
51   this->sync_buffer_ = gst_buffer_new ();
52   this->dummy_tex_id_ = 0;
53 }
54 
~GstQSGTexture()55 GstQSGTexture::~GstQSGTexture ()
56 {
57   gst_buffer_replace (&this->buffer_, NULL);
58   gst_buffer_replace (&this->sync_buffer_, NULL);
59   if (this->dummy_tex_id_ && QOpenGLContext::currentContext ()) {
60     QOpenGLContext::currentContext ()->functions ()->glDeleteTextures (1,
61         &this->dummy_tex_id_);
62   }
63 }
64 
65 /* only called from the streaming thread with scene graph thread blocked */
66 void
setCaps(GstCaps * caps)67 GstQSGTexture::setCaps (GstCaps * caps)
68 {
69   GST_LOG ("%p setCaps %" GST_PTR_FORMAT, this, caps);
70 
71   gst_video_info_from_caps (&this->v_info, caps);
72 }
73 
74 /* only called from the streaming thread with scene graph thread blocked */
75 gboolean
setBuffer(GstBuffer * buffer)76 GstQSGTexture::setBuffer (GstBuffer * buffer)
77 {
78   GST_LOG ("%p setBuffer %" GST_PTR_FORMAT, this, buffer);
79   /* FIXME: update more state here */
80   if (!gst_buffer_replace (&this->buffer_, buffer))
81     return FALSE;
82 
83   this->qt_context_ = gst_gl_context_get_current ();
84 
85   return TRUE;
86 }
87 
88 /* only called from qt's scene graph render thread */
89 void
bind()90 GstQSGTexture::bind ()
91 {
92   const GstGLFuncs *gl;
93   GstGLContext *context;
94   GstGLSyncMeta *sync_meta;
95   GstMemory *mem;
96   guint tex_id;
97   gboolean use_dummy_tex = TRUE;
98 
99   if (!this->qt_context_)
100     return;
101 
102   gst_gl_context_activate (this->qt_context_, TRUE);
103 
104   if (!this->buffer_)
105     goto out;
106   if (GST_VIDEO_INFO_FORMAT (&this->v_info) == GST_VIDEO_FORMAT_UNKNOWN)
107     goto out;
108 
109   this->mem_ = gst_buffer_peek_memory (this->buffer_, 0);
110   if (!this->mem_)
111     goto out;
112 
113   g_assert (this->qt_context_);
114   gl = this->qt_context_->gl_vtable;
115 
116   /* FIXME: should really lock the memory to prevent write access */
117   if (!gst_video_frame_map (&this->v_frame, &this->v_info, this->buffer_,
118         (GstMapFlags) (GST_MAP_READ | GST_MAP_GL))) {
119     g_assert_not_reached ();
120     goto out;
121   }
122 
123   mem = gst_buffer_peek_memory (this->buffer_, 0);
124   g_assert (gst_is_gl_memory (mem));
125 
126   context = ((GstGLBaseMemory *)mem)->context;
127 
128   sync_meta = gst_buffer_get_gl_sync_meta (this->sync_buffer_);
129   if (!sync_meta)
130     sync_meta = gst_buffer_add_gl_sync_meta (context, this->sync_buffer_);
131 
132   gst_gl_sync_meta_set_sync_point (sync_meta, context);
133 
134   gst_gl_sync_meta_wait (sync_meta, this->qt_context_);
135 
136   tex_id = *(guint *) this->v_frame.data[0];
137   GST_LOG ("%p binding Qt texture %u", this, tex_id);
138 
139   gl->BindTexture (GL_TEXTURE_2D, tex_id);
140 
141   gst_video_frame_unmap (&this->v_frame);
142 
143   /* Texture was successfully bound, so we do not need
144    * to use the dummy texture */
145   use_dummy_tex = FALSE;
146 
147 out:
148   if (G_UNLIKELY (use_dummy_tex)) {
149     QOpenGLContext *qglcontext = QOpenGLContext::currentContext ();
150     QOpenGLFunctions *funcs = qglcontext->functions ();
151 
152     /* Create dummy texture if not already present.
153      * Use the Qt OpenGL functions instead of the GstGL ones,
154      * since we are using the Qt OpenGL context here, and we must
155      * be able to delete the texture in the destructor. */
156     if (this->dummy_tex_id_ == 0) {
157       /* Make this a black 64x64 pixel RGBA texture.
158        * This size and format is supported pretty much everywhere, so these
159        * are a safe pick. (64 pixel sidelength must be supported according
160        * to the GLES2 spec, table 6.18.)
161        * Set min/mag filters to GL_LINEAR to make sure no mipmapping is used. */
162       const int tex_sidelength = 64;
163       std::vector < guint8 > dummy_data (tex_sidelength * tex_sidelength * 4, 0);
164 
165       funcs->glGenTextures (1, &this->dummy_tex_id_);
166       funcs->glBindTexture (GL_TEXTURE_2D, this->dummy_tex_id_);
167       funcs->glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
168       funcs->glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
169       funcs->glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, tex_sidelength,
170           tex_sidelength, 0, GL_RGBA, GL_UNSIGNED_BYTE, &dummy_data[0]);
171     }
172 
173     g_assert (this->dummy_tex_id_ != 0);
174 
175     funcs->glBindTexture (GL_TEXTURE_2D, this->dummy_tex_id_);
176   }
177 
178   gst_gl_context_activate (this->qt_context_, FALSE);
179 }
180 
181 /* can be called from any thread */
182 int
textureId() const183 GstQSGTexture::textureId () const
184 {
185   int tex_id = 0;
186 
187   if (this->buffer_) {
188     GstMemory *mem = gst_buffer_peek_memory (this->buffer_, 0);
189 
190     tex_id = ((GstGLMemory *) mem)->tex_id;
191   }
192 
193   GST_LOG ("%p get texture id %u", this, tex_id);
194 
195   return tex_id;
196 }
197 
198 /* can be called from any thread */
199 QSize
textureSize() const200 GstQSGTexture::textureSize () const
201 {
202   if (GST_VIDEO_INFO_FORMAT (&this->v_info) == GST_VIDEO_FORMAT_UNKNOWN)
203     return QSize (0, 0);
204 
205   GST_TRACE ("%p get texture size %ux%u", this, this->v_info.width,
206       this->v_info.height);
207 
208   return QSize (this->v_info.width, this->v_info.height);
209 }
210 
211 /* can be called from any thread */
212 bool
hasAlphaChannel() const213 GstQSGTexture::hasAlphaChannel () const
214 {
215   /* FIXME: support RGB textures */
216   return true;
217 }
218 
219 /* can be called from any thread */
220 bool
hasMipmaps() const221 GstQSGTexture::hasMipmaps () const
222 {
223   return false;
224 }
225