Re: [Qemu-devel] [PATCH 6/9] sdl2/opengl: add opengl context and scanout support

[Max Reitz]

On 09.09.2015 13:20, Gerd Hoffmann wrote:
> This allows virtio-gpu to render in 3d mode.
> 
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  include/ui/sdl2.h |  22 ++++++++-
>  ui/sdl2-gl.c      | 133 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  ui/sdl2.c         |   7 +++
>  3 files changed, 161 insertions(+), 1 deletion(-)
> 
> diff --git a/include/ui/sdl2.h b/include/ui/sdl2.h
> index 2fdad8f..b397631 100644
> --- a/include/ui/sdl2.h
> +++ b/include/ui/sdl2.h
> @@ -15,12 +15,18 @@ struct sdl2_console {
>      SDL_Renderer *real_renderer;
>      int idx;
>      int last_vm_running; /* per console for caption reasons */
> -    int x, y;
> +    int x, y, w, h;
>      int hidden;
>      int opengl;
>      int updates;
>      SDL_GLContext winctx;
> +#ifdef CONFIG_OPENGL
>      ConsoleGLState *gls;
> +    GLuint tex_id;
> +    GLuint fbo_id;
> +    bool y0_top;
> +    bool scanout_mode;
> +#endif
>  };
>  
>  void sdl2_window_create(struct sdl2_console *scon);
> @@ -48,4 +54,18 @@ void sdl2_gl_switch(DisplayChangeListener *dcl,
>  void sdl2_gl_refresh(DisplayChangeListener *dcl);
>  void sdl2_gl_redraw(struct sdl2_console *scon);
>  
> +qemu_gl_context sdl2_gl_create_context(DisplayChangeListener *dcl,
> +                                       struct qemu_gl_params *params);
> +void sdl2_gl_destroy_context(DisplayChangeListener *dcl, qemu_gl_context 
> ctx);
> +int sdl2_gl_make_context_current(DisplayChangeListener *dcl,
> +                                 qemu_gl_context ctx);
> +qemu_gl_context sdl2_gl_get_current_context(DisplayChangeListener *dcl);
> +
> +void sdl2_gl_scanout(DisplayChangeListener *dcl,
> +                     uint32_t backing_id, bool backing_y_0_top,
> +                     uint32_t x, uint32_t y,
> +                     uint32_t w, uint32_t h);
> +void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
> +                           uint32_t x, uint32_t y, uint32_t w, uint32_t h);
> +
>  #endif /* SDL2_H */
> diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
> index b604c06..bc73c0e 100644
> --- a/ui/sdl2-gl.c
> +++ b/ui/sdl2-gl.c
> @@ -31,11 +31,36 @@
>  #include "ui/sdl2.h"
>  #include "sysemu/sysemu.h"
>  
> +#include <epoxy/gl.h>
> +
> +static void sdl2_set_scanout_mode(struct sdl2_console *scon, bool scanout)
> +{
> +    if (scon->scanout_mode == scanout) {
> +        return;
> +    }
> +
> +    scon->scanout_mode = scanout;
> +    if (!scon->scanout_mode) {
> +        if (scon->fbo_id) {
> +            glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
> +                                      GL_COLOR_ATTACHMENT0_EXT,
> +                                      GL_TEXTURE_2D, 0, 0);
> +            glDeleteFramebuffers(1, &scon->fbo_id);

I'm not sure, but maybe the framebuffer itself should be unbound here,
too? (i.e., glBindFramebuffer(GL_FRAMEBUFFER, 0))

I know it's deleted but I don't know whether that's enough.

> +            scon->fbo_id = 0;
> +        }
> +        if (scon->surface) {
> +            surface_gl_destroy_texture(scon->gls, scon->surface);
> +            surface_gl_create_texture(scon->gls, scon->surface);
> +        }
> +    }
> +}
> +
>  static void sdl2_gl_render_surface(struct sdl2_console *scon)
>  {
>      int ww, wh;
>  
>      SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
> +    sdl2_set_scanout_mode(scon, false);
>  
>      SDL_GetWindowSize(scon->real_window, &ww, &wh);
>      surface_gl_setup_viewport(scon->gls, scon->surface, ww, wh);
> @@ -110,3 +135,111 @@ void sdl2_gl_redraw(struct sdl2_console *scon)
>          sdl2_gl_render_surface(scon);
>      }
>  }
> +
> +qemu_gl_context sdl2_gl_create_context(DisplayChangeListener *dcl,
> +                                       struct qemu_gl_params *params)
> +{
> +    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
> +    SDL_GLContext ctx;
> +
> +    assert(scon->opengl);
> +
> +    SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
> +
> +    SDL_GL_SetAttribute(SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1);
> +    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,
> +                        SDL_GL_CONTEXT_PROFILE_CORE);
> +    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, params->major_ver);
> +    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, params->minor_ver);
> +
> +    ctx = SDL_GL_CreateContext(scon->real_window);
> +    return (qemu_gl_context)ctx;
> +}
> +
> +void sdl2_gl_destroy_context(DisplayChangeListener *dcl, qemu_gl_context ctx)
> +{
> +    SDL_GLContext sdlctx = (SDL_GLContext)ctx;
> +
> +    SDL_GL_DeleteContext(sdlctx);
> +}
> +
> +int sdl2_gl_make_context_current(DisplayChangeListener *dcl,
> +                                 qemu_gl_context ctx)
> +{
> +    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
> +    SDL_GLContext sdlctx = (SDL_GLContext)ctx;
> +
> +    assert(scon->opengl);
> +
> +    return SDL_GL_MakeCurrent(scon->real_window, sdlctx);
> +}
> +
> +qemu_gl_context sdl2_gl_get_current_context(DisplayChangeListener *dcl)
> +{
> +    SDL_GLContext sdlctx;
> +
> +    sdlctx = SDL_GL_GetCurrentContext();
> +    return (qemu_gl_context)sdlctx;
> +}
> +
> +void sdl2_gl_scanout(DisplayChangeListener *dcl,
> +                     uint32_t backing_id, bool backing_y_0_top,
> +                     uint32_t x, uint32_t y,
> +                     uint32_t w, uint32_t h)
> +{
> +    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
> +
> +    assert(scon->opengl);
> +    scon->x = x;
> +    scon->y = y;
> +    scon->w = w;
> +    scon->h = h;
> +    scon->tex_id = backing_id;
> +    scon->y0_top = backing_y_0_top;
> +
> +    SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
> +
> +    if (scon->tex_id == 0 || scon->w == 0 || scon->h == 0) {
> +        sdl2_set_scanout_mode(scon, false);
> +        return;
> +    }
> +
> +    sdl2_set_scanout_mode(scon, true);
> +    if (!scon->fbo_id) {
> +        glGenFramebuffers(1, &scon->fbo_id);
> +    }
> +
> +    glBindFramebuffer(GL_FRAMEBUFFER_EXT, scon->fbo_id);
> +    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
> +                              GL_TEXTURE_2D, scon->tex_id, 0);
> +}
> +
> +void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
> +                           uint32_t x, uint32_t y, uint32_t w, uint32_t h)
> +{
> +    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
> +    int ww, wh, y1, y2;
> +
> +    assert(scon->opengl);
> +    if (!scon->scanout_mode) {
> +        return;
> +    }
> +    if (!scon->fbo_id) {
> +        return;
> +    }
> +
> +    SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
> +
> +    glBindFramebuffer(GL_READ_FRAMEBUFFER, scon->fbo_id);
> +    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
> +
> +    SDL_GetWindowSize(scon->real_window, &ww, &wh);
> +    glViewport(0, 0, ww, wh);
> +    y1 = scon->y0_top ? 0 : scon->h;
> +    y2 = scon->y0_top ? scon->h : 0;
> +    glBlitFramebuffer(0, y1, scon->w, y2,
> +                      0, 0, ww, wh,
> +                      GL_COLOR_BUFFER_BIT, GL_NEAREST);

Should we bind the FBO back to GL_DRAW_FRAMEBUFFER after the blit operation?

Max

> +
> +    SDL_GL_SwapWindow(scon->real_window);
> +}
> diff --git a/ui/sdl2.c b/ui/sdl2.c
> index 5cb75aa..73a84a8 100644
> --- a/ui/sdl2.c
> +++ b/ui/sdl2.c
> @@ -700,6 +700,13 @@ static const DisplayChangeListenerOps dcl_gl_ops = {
>      .dpy_refresh             = sdl2_gl_refresh,
>      .dpy_mouse_set           = sdl_mouse_warp,
>      .dpy_cursor_define       = sdl_mouse_define,
> +
> +    .dpy_gl_ctx_create       = sdl2_gl_create_context,
> +    .dpy_gl_ctx_destroy      = sdl2_gl_destroy_context,
> +    .dpy_gl_ctx_make_current = sdl2_gl_make_context_current,
> +    .dpy_gl_ctx_get_current  = sdl2_gl_get_current_context,
> +    .dpy_gl_scanout          = sdl2_gl_scanout,
> +    .dpy_gl_update           = sdl2_gl_scanout_flush,
>  };
>  #endif
>  
>

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