vo_opengl: simplify screenshot code

Instead of reading back the image from textures, keep a reference to the
original image, and return that.

The main reason this was done this way was that originally, images
weren't refcounted, and would be deallocated or overwritten as soon as
the VO's draw call returned. But now there isn't really a good reason
for this anymore. One possibly _could_ argue that it was better because
other code could reuse the image sooner (e.g. for the cache), but on the
other hand, the VO runs already on a different thread, and filtering and
decoding each run on other threads too, so this argument probably
wouldn't hold up.

3 files changed, 13 insertions, 76 deletions

diff --git a/video/out/gl_common.c b/video/out/gl_common.c
index 9384bc9e18..8bb570684a 100644
--- a/video/out/gl_common.c
+++ b/video/out/gl_common.c
@@ -211,7 +211,6 @@ static const struct gl_functions gl_functions[] = {
                     MPGL_CAP_1ST_CLASS_ARRAYS,
         .functions = (const struct gl_function[]) {
             DEF_FN(DrawBuffer),
-            DEF_FN(GetTexImage),
             DEF_FN(GetTexLevelParameteriv),
             DEF_FN(MapBuffer),
             DEF_FN(ReadBuffer),
@@ -705,29 +704,6 @@ void glClearTex(GL *gl, GLenum target, GLenum format, GLenum type,
     }
 }
 
-/**
- * \brief download a texture, handling things like stride and slices
- * \param target texture target, usually GL_TEXTURE_2D
- * \param format OpenGL format of data
- * \param type OpenGL type of data
- * \param dataptr destination memory for download
- * \param stride data stride (must be positive)
- * \ingroup gltexture
- */
-void glDownloadTex(GL *gl, GLenum target, GLenum format, GLenum type,
-                   void *dataptr, int stride)
-{
-    if (!gl->GetTexImage)
-        abort();
-    assert(gl->mpgl_caps & MPGL_CAP_ROW_LENGTH);
-    // this is not always correct, but should work for MPlayer
-    gl->PixelStorei(GL_PACK_ALIGNMENT, get_alignment(stride));
-    gl->PixelStorei(GL_PACK_ROW_LENGTH, stride / glFmt2bpp(format, type));
-    gl->GetTexImage(target, 0, format, type, dataptr);
-    gl->PixelStorei(GL_PACK_ROW_LENGTH, 0);
-    gl->PixelStorei(GL_PACK_ALIGNMENT, 4);
-}
-
 mp_image_t *glGetWindowScreenshot(GL *gl)
 {
     if (gl->es)
diff --git a/video/out/gl_common.h b/video/out/gl_common.h
index 7c9fbc0045..24c6091ade 100644
--- a/video/out/gl_common.h
+++ b/video/out/gl_common.h
@@ -59,8 +59,6 @@ void glUploadTex(GL *gl, GLenum target, GLenum format, GLenum type,
                  int x, int y, int w, int h, int slice);
 void glClearTex(GL *gl, GLenum target, GLenum format, GLenum type,
                 int x, int y, int w, int h, uint8_t val, void **scratch);
-void glDownloadTex(GL *gl, GLenum target, GLenum format, GLenum type,
-                   void *dataptr, int stride);
 void glCheckError(GL *gl, struct mp_log *log, const char *info);
 mp_image_t *glGetWindowScreenshot(GL *gl);
 
@@ -200,7 +198,6 @@ struct GL {
     void (GLAPIENTRY *TexSubImage2D)(GLenum, GLint, GLint, GLint,
                                      GLsizei, GLsizei, GLenum, GLenum,
                                      const GLvoid *);
-    void (GLAPIENTRY *GetTexImage)(GLenum, GLint, GLenum, GLenum, GLvoid *);
     void (GLAPIENTRY *TexParameteri)(GLenum, GLenum, GLint);
     void (GLAPIENTRY *GetIntegerv)(GLenum, GLint *);
     void (GLAPIENTRY *GetBooleanv)(GLenum, GLboolean *);
diff --git a/video/out/gl_video.c b/video/out/gl_video.c
index 1f32844c07..568e6feaa4 100644
--- a/video/out/gl_video.c
+++ b/video/out/gl_video.c
@@ -98,7 +98,7 @@ struct texplane {
 struct video_image {
     struct texplane planes[4];
     bool image_flipped;
-    struct mp_image *hwimage;   // if hw decoding is active
+    struct mp_image *mpi;       // original input image
 };
 
 struct scaler {
@@ -172,7 +172,6 @@ struct gl_video {
     int plane_count;
 
     struct video_image image;
-    bool have_image;
 
     struct fbotex indirect_fbo;         // RGB target
     struct fbotex scale_sep_fbo;        // first pass when doing 2 pass scaling
@@ -1532,9 +1531,10 @@ static void set_image_textures(struct gl_video *p, struct video_image *vimg,
     if (!imgtex)
         imgtex = dummy;
 
+    assert(vimg->mpi);
+
     if (p->hwdec_active) {
-        assert(vimg->hwimage);
-        p->hwdec->driver->map_image(p->hwdec, vimg->hwimage, imgtex);
+        p->hwdec->driver->map_image(p->hwdec, vimg->mpi, imgtex);
     } else {
         for (int n = 0; n < p->plane_count; n++)
             imgtex[n] = vimg->planes[n].gl_texture;
@@ -1667,7 +1667,7 @@ static void uninit_video(struct gl_video *p)
         plane->buffer_ptr = NULL;
         plane->buffer_size = 0;
     }
-    mp_image_unrefp(&vimg->hwimage);
+    mp_image_unrefp(&vimg->mpi);
 
     fbotex_uninit(p, &p->indirect_fbo);
     fbotex_uninit(p, &p->scale_sep_fbo);
@@ -1774,7 +1774,7 @@ void gl_video_render_frame(struct gl_video *p, int fbo)
         gl->Clear(GL_COLOR_BUFFER_BIT);
     }
 
-    if (!p->have_image) {
+    if (!vimg->mpi) {
         gl->Clear(GL_COLOR_BUFFER_BIT);
         goto draw_osd;
     }
@@ -1967,12 +1967,11 @@ void gl_video_upload_image(struct gl_video *p, struct mp_image *mpi)
 
     p->osd_pts = mpi->pts;
 
-    if (p->hwdec_active) {
-        talloc_free(vimg->hwimage);
-        vimg->hwimage = mpi;
-        p->have_image = true;
+    talloc_free(vimg->mpi);
+    vimg->mpi = mpi;
+
+    if (p->hwdec_active)
         return;
-    }
 
     assert(mpi->num_planes == p->plane_count);
 
@@ -2006,46 +2005,12 @@ void gl_video_upload_image(struct gl_video *p, struct mp_image *mpi)
     gl->ActiveTexture(GL_TEXTURE0);
     if (pbo)
         gl->BindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
-
-    p->have_image = true;
-    talloc_free(mpi);
 }
 
 struct mp_image *gl_video_download_image(struct gl_video *p)
 {
-    GL *gl = p->gl;
-
     struct video_image *vimg = &p->image;
-
-    if (!p->have_image)
-        return NULL;
-
-    if (p->hwdec_active)
-        return mp_image_new_ref(vimg->hwimage);
-
-    if (!gl->GetTexImage)
-        return NULL;
-
-    set_image_textures(p, vimg, NULL);
-
-    assert(p->texture_w >= p->image_params.w);
-    assert(p->texture_h >= p->image_params.h);
-
-    mp_image_t *image = mp_image_alloc(p->image_format, p->texture_w,
-                                                        p->texture_h);
-    if (image) {
-        for (int n = 0; n < p->plane_count; n++) {
-            struct texplane *plane = &vimg->planes[n];
-            gl->ActiveTexture(GL_TEXTURE0 + n);
-            glDownloadTex(gl, p->gl_target, plane->gl_format, plane->gl_type,
-                          image->planes[n], image->stride[n]);
-        }
-        mp_image_set_attributes(image, &p->image_params);
-    }
-
-    unset_image_textures(p);
-
-    return image;
+    return vimg->mpi ? mp_image_new_ref(vimg->mpi) : NULL;
 }
 
 static void draw_osd_cb(void *ctx, struct sub_bitmaps *imgs)
@@ -2529,8 +2494,7 @@ bool gl_video_check_format(struct gl_video *p, int mp_format)
 
 void gl_video_config(struct gl_video *p, struct mp_image_params *params)
 {
-    p->have_image = false;
-    mp_image_unrefp(&p->image.hwimage);
+    mp_image_unrefp(&p->image.mpi);
 
     if (!mp_image_params_equal(&p->image_params, params)) {
         uninit_video(p);
@@ -2667,5 +2631,5 @@ void gl_video_resize_redraw(struct gl_video *p, int w, int h)
 void gl_video_set_hwdec(struct gl_video *p, struct gl_hwdec *hwdec)
 {
     p->hwdec = hwdec;
-    mp_image_unrefp(&p->image.hwimage);
+    mp_image_unrefp(&p->image.mpi);
 }