4 files changed, 51 insertions, 24 deletions

diff --git a/video/out/opengl/context.c b/video/out/opengl/context.c
index cdaf6320cd..8f44119210 100644
--- a/video/out/opengl/context.c
+++ b/video/out/opengl/context.c
@@ -251,16 +251,21 @@ struct mp_image *ra_gl_ctx_screenshot(struct ra_swapchain *sw)
 {
     struct priv *p = sw->priv;
 
+    struct mp_image *screen = mp_image_alloc(IMGFMT_RGB24, p->wrapped_fb->params.w,
+                                             p->wrapped_fb->params.h);
+    if (!screen)
+        return NULL;
+
+    int dir = p->params.flipped ? 1 : -1;
+
     assert(p->wrapped_fb);
-    struct mp_image *screen = gl_read_fbo_contents(p->gl, p->main_fb,
-                                                   p->wrapped_fb->params.w,
-                                                   p->wrapped_fb->params.h);
-
-    // OpenGL FB is also read in flipped order, so we need to flip when the
-    // rendering is *not* flipped, which in our case is whenever
-    // p->params.flipped is true. I hope that made sense
-    if (screen && p->params.flipped)
-        mp_image_vflip(screen);
+    if (!gl_read_fbo_contents(p->gl, p->main_fb, dir, GL_RGB, GL_UNSIGNED_BYTE,
+                              p->wrapped_fb->params.w, p->wrapped_fb->params.h,
+                              screen->planes[0], screen->stride[0]))
+    {
+        talloc_free(screen);
+        return NULL;
+    }
 
     return screen;
 }
diff --git a/video/out/opengl/ra_gl.c b/video/out/opengl/ra_gl.c
index 356ed81d03..7112464e87 100644
--- a/video/out/opengl/ra_gl.c
+++ b/video/out/opengl/ra_gl.c
@@ -277,6 +277,13 @@ static struct ra_tex *gl_tex_create_blank(struct ra *ra,
         tex_gl->target = GL_TEXTURE_EXTERNAL_OES;
     }
 
+    if (params->downloadable && !(params->dimensions == 2 &&
+                                  params->format->renderable))
+    {
+        gl_tex_destroy(ra, tex);
+        return NULL;
+    }
+
     return tex;
 }
 
@@ -329,8 +336,11 @@ static struct ra_tex *gl_tex_create(struct ra *ra,
 
     gl_check_error(gl, ra->log, "after creating texture");
 
-    // Even blitting needs an FBO in OpenGL for strange reasons
-    if (tex->params.render_dst || tex->params.blit_src || tex->params.blit_dst) {
+    // Even blitting needs an FBO in OpenGL for strange reasons.
+    // Download is handled by reading from an FBO.
+    if (tex->params.render_dst || tex->params.blit_src ||
+        tex->params.blit_dst || tex->params.downloadable)
+    {
         if (!tex->params.format->renderable) {
             MP_ERR(ra, "Trying to create renderable texture with unsupported "
                    "format.\n");
@@ -512,6 +522,18 @@ static bool gl_tex_upload(struct ra *ra,
     return true;
 }
 
+static bool gl_tex_download(struct ra *ra, struct ra_tex_download_params *params)
+{
+    GL *gl = ra_gl_get(ra);
+    struct ra_tex *tex = params->tex;
+    struct ra_tex_gl *tex_gl = tex->priv;
+    if (!tex_gl->fbo)
+        return false;
+    return gl_read_fbo_contents(gl, tex_gl->fbo, 1, tex_gl->format, tex_gl->type,
+                                tex->params.w, tex->params.h, params->dst,
+                                params->stride);
+}
+
 static void gl_buf_destroy(struct ra *ra, struct ra_buf *buf)
 {
     if (!buf)
@@ -1134,6 +1156,7 @@ static struct ra_fns ra_fns_gl = {
     .tex_create             = gl_tex_create,
     .tex_destroy            = gl_tex_destroy,
     .tex_upload             = gl_tex_upload,
+    .tex_download           = gl_tex_download,
     .buf_create             = gl_buf_create,
     .buf_destroy            = gl_buf_destroy,
     .buf_update             = gl_buf_update,
diff --git a/video/out/opengl/utils.c b/video/out/opengl/utils.c
index 34f4736705..a551ce4299 100644
--- a/video/out/opengl/utils.c
+++ b/video/out/opengl/utils.c
@@ -105,25 +105,23 @@ void gl_upload_tex(GL *gl, GLenum target, GLenum format, GLenum type,
     gl->PixelStorei(GL_UNPACK_ALIGNMENT, 4);
 }
 
-mp_image_t *gl_read_fbo_contents(GL *gl, int fbo, int w, int h)
+bool gl_read_fbo_contents(GL *gl, int fbo, int dir, GLenum format, GLenum type,
+                          int w, int h, uint8_t *dst, int dst_stride)
 {
-    if (gl->es)
-        return NULL; // ES can't read from front buffer
-    mp_image_t *image = mp_image_alloc(IMGFMT_RGB24, w, h);
-    if (!image)
-        return NULL;
+    assert(dir == 1 || dir == -1);
+    if (fbo == 0 && gl->es)
+        return false; // ES can't read from front buffer
     gl->BindFramebuffer(GL_FRAMEBUFFER, fbo);
     GLenum obj = fbo ? GL_COLOR_ATTACHMENT0 : GL_FRONT;
     gl->PixelStorei(GL_PACK_ALIGNMENT, 1);
     gl->ReadBuffer(obj);
-    //flip image while reading (and also avoid stride-related trouble)
-    for (int y = 0; y < h; y++) {
-        gl->ReadPixels(0, h - y - 1, w, 1, GL_RGB, GL_UNSIGNED_BYTE,
-                       image->planes[0] + y * image->stride[0]);
-    }
+    // reading by line allows flipping, and avoids stride-related trouble
+    int y1 = dir > 0 ? 0 : h;
+    for (int y = 0; y < h; y++)
+        gl->ReadPixels(0, y, w, 1, format, type, dst + (y1 + dir * y) * dst_stride);
     gl->PixelStorei(GL_PACK_ALIGNMENT, 4);
     gl->BindFramebuffer(GL_FRAMEBUFFER, 0);
-    return image;
+    return true;
 }
 
 static void gl_vao_enable_attribs(struct gl_vao *vao)
diff --git a/video/out/opengl/utils.h b/video/out/opengl/utils.h
index 53127e479e..9bcadae91c 100644
--- a/video/out/opengl/utils.h
+++ b/video/out/opengl/utils.h
@@ -32,7 +32,8 @@ void gl_upload_tex(GL *gl, GLenum target, GLenum format, GLenum type,
                    const void *dataptr, int stride,
                    int x, int y, int w, int h);
 
-mp_image_t *gl_read_fbo_contents(GL *gl, int fbo, int w, int h);
+bool gl_read_fbo_contents(GL *gl, int fbo, int dir, GLenum format, GLenum type,
+                          int w, int h, uint8_t *dst, int dst_stride);
 
 struct gl_vao {
     GL *gl;