[cogl/fosdem-2012: 1/5] kms: Use GBM surfaces

[Neil Roberts <nroberts src gnome org>]

commit bfc97f0d92f531a6f02903a000a9fa492dccab5d
Author: Neil Roberts <neil linux intel com>
Date:   Mon Dec 19 15:37:26 2011 +0000

    kms: Use GBM surfaces
    
    Instead of creating FBOs on the GL side, the KMS EGL platform uses the
    latest changes to Mesa to create an EGL surface using a GBM surface as
    the native surface type. This removes some of the special vtable hooks
    that the KMS platform needed because it is now much more similar to
    the other platforms.

 cogl/winsys/cogl-winsys-egl-kms.c     |  233 ++++++++++-----------------------
 cogl/winsys/cogl-winsys-egl-private.h |    5 -
 cogl/winsys/cogl-winsys-egl.c         |    5 -
 3 files changed, 72 insertions(+), 171 deletions(-)
---
diff --git a/cogl/winsys/cogl-winsys-egl-kms.c b/cogl/winsys/cogl-winsys-egl-kms.c
index ec1d02b..f92b2a1 100644
--- a/cogl/winsys/cogl-winsys-egl-kms.c
+++ b/cogl/winsys/cogl-winsys-egl-kms.c
@@ -49,6 +49,8 @@
 
 static const CoglWinsysEGLVtable _cogl_winsys_egl_vtable;
 
+static const CoglWinsysVtable *parent_vtable;
+
 typedef struct _CoglRendererKMS
 {
   int fd;
@@ -66,11 +68,11 @@ typedef struct _CoglDisplayKMS
 
 typedef struct _CoglOnscreenKMS
 {
-  uint32_t fb_id[2];
-  struct gbm_bo *bo[2];
-  unsigned int fb, color_rb[2], depth_rb;
-  EGLImageKHR image[2];
-  int current_frame;
+  struct gbm_surface *surface;
+  uint32_t current_fb_id;
+  uint32_t next_fb_id;
+  struct gbm_bo *current_bo;
+  struct gbm_bo *next_bo;
 } CoglOnscreenKMS;
 
 static const char device_name[] = "/dev/dri/card0";
@@ -254,27 +256,13 @@ _cogl_winsys_egl_display_destroy (CoglDisplay *display)
 }
 
 static gboolean
-_cogl_winsys_egl_try_create_context (CoglDisplay *display,
-                                     EGLint *attribs,
-                                     GError **error)
+_cogl_winsys_egl_context_created (CoglDisplay *display,
+                                  GError **error)
 {
   CoglRenderer *renderer = display->renderer;
   CoglRendererEGL *egl_renderer = renderer->winsys;
   CoglDisplayEGL *egl_display = display->winsys;
 
-  egl_display->egl_context = eglCreateContext (egl_renderer->edpy,
-                                               NULL,
-                                               EGL_NO_CONTEXT,
-                                               attribs);
-
-  if (egl_display->egl_context == NULL)
-    {
-      g_set_error (error, COGL_WINSYS_ERROR,
-                   COGL_WINSYS_ERROR_CREATE_CONTEXT,
-                   "Couldn't create EGL context");
-      return FALSE;
-    }
-
   if (!eglMakeCurrent (egl_renderer->edpy,
                        EGL_NO_SURFACE,
                        EGL_NO_SURFACE,
@@ -323,33 +311,39 @@ _cogl_winsys_onscreen_swap_buffers (CoglOnscreen *onscreen)
   CoglRendererKMS *kms_renderer = egl_renderer->platform;
   CoglOnscreenEGL *egl_onscreen = onscreen->winsys;
   CoglOnscreenKMS *kms_onscreen = egl_onscreen->platform;
-
-  if (drmModeSetCrtc (kms_renderer->fd,
-                      kms_display->encoder->crtc_id,
-                      kms_onscreen->fb_id[kms_onscreen->current_frame],
-                      0, 0,
-                      &kms_display->connector->connector_id,
-                      1,
-                      &kms_display->mode) != 0)
+  struct gbm_bo *next_bo;
+  EGLint handle, pitch;
+  uint32_t next_fb_id;
+
+  /* First chain-up. This will call eglSwapBuffers */
+  parent_vtable->onscreen_swap_buffers (onscreen);
+
+  /* Now we need to set the CRTC to whatever is the front buffer */
+  next_bo = gbm_surface_get_bo (kms_onscreen->surface);
+
+  pitch = gbm_bo_get_pitch (next_bo);
+  handle = gbm_bo_get_handle (next_bo).u32;
+
+  if (drmModeAddFB (kms_renderer->fd,
+                    kms_display->width,
+                    kms_display->height,
+                    24, /* depth */
+                    32, /* bpp */
+                    pitch,
+                    handle,
+                    &next_fb_id) == 0)
     {
-      g_error (G_STRLOC ": Setting CRTC failed");
+      if (drmModeSetCrtc (kms_renderer->fd,
+                          kms_display->encoder->crtc_id,
+                          next_fb_id,
+                          0, 0, /* x, y */
+                          &kms_display->connector->connector_id,
+                          1, /* count */
+                          &kms_display->mode) != 0)
+        g_error (G_STRLOC ": Setting CRTC failed");
     }
 
-  /* Update frame that we're drawing to be the new one */
-  kms_onscreen->current_frame ^= 1;
-
-  context->glBindFramebuffer (GL_FRAMEBUFFER_EXT, kms_onscreen->fb);
-  context->glFramebufferRenderbuffer (GL_FRAMEBUFFER_EXT,
-                                      GL_COLOR_ATTACHMENT0_EXT,
-                                      GL_RENDERBUFFER_EXT,
-                                      kms_onscreen->
-                                      color_rb[kms_onscreen->current_frame]);
-
-  if (context->glCheckFramebufferStatus (GL_FRAMEBUFFER_EXT) !=
-      GL_FRAMEBUFFER_COMPLETE)
-    {
-      g_error (G_STRLOC ": FBO not complete");
-    }
+  gbm_surface_release_bo (kms_onscreen->surface, next_bo);
 }
 
 static gboolean
@@ -366,7 +360,6 @@ _cogl_winsys_onscreen_init (CoglOnscreen *onscreen,
   CoglRendererKMS *kms_renderer = egl_renderer->platform;
   CoglOnscreenEGL *egl_onscreen;
   CoglOnscreenKMS *kms_onscreen;
-  int i;
 
   _COGL_RETURN_VAL_IF_FAIL (egl_display->egl_context, FALSE);
 
@@ -376,81 +369,31 @@ _cogl_winsys_onscreen_init (CoglOnscreen *onscreen,
   kms_onscreen = g_slice_new0 (CoglOnscreenKMS);
   egl_onscreen->platform = kms_onscreen;
 
-  context->glGenRenderbuffers (2, kms_onscreen->color_rb);
-
-  for (i = 0; i < 2; i++)
-    {
-      uint32_t handle, stride;
-
-      kms_onscreen->bo[i] =
-        gbm_bo_create (kms_renderer->gbm,
-                       kms_display->mode.hdisplay, kms_display->mode.vdisplay,
-                       GBM_BO_FORMAT_XRGB8888,
-                       GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING);
-      if (!kms_onscreen->bo[i])
-        {
-          g_set_error (error, COGL_WINSYS_ERROR,
-                       COGL_WINSYS_ERROR_CREATE_CONTEXT,
-                       "Failed to allocate buffer");
-          return FALSE;
-        }
-
-      kms_onscreen->image[i] =
-        _cogl_egl_create_image (context,
-                                EGL_NATIVE_PIXMAP_KHR,
-                                kms_onscreen->bo[i],
-                                NULL);
-
-      if (kms_onscreen->image[i] == EGL_NO_IMAGE_KHR)
-        {
-          g_set_error (error, COGL_WINSYS_ERROR,
-                       COGL_WINSYS_ERROR_CREATE_CONTEXT,
-                       "Failed to create EGL image");
-          return FALSE;
-        }
-
-      context->glBindRenderbuffer (GL_RENDERBUFFER_EXT,
-                                   kms_onscreen->color_rb[i]);
-      context->glEGLImageTargetRenderbufferStorage (GL_RENDERBUFFER,
-                                                    kms_onscreen->image[i]);
-      context->glBindRenderbuffer (GL_RENDERBUFFER_EXT, 0);
-
-      handle = gbm_bo_get_handle (kms_onscreen->bo[i]).u32;
-      stride = gbm_bo_get_pitch (kms_onscreen->bo[i]);
-
-      if (drmModeAddFB (kms_renderer->fd,
+  kms_onscreen->surface =
+    gbm_surface_create (kms_renderer->gbm,
                         kms_display->mode.hdisplay,
                         kms_display->mode.vdisplay,
-                        24, 32,
-                        stride,
-                        handle,
-                        &kms_onscreen->fb_id[i]) != 0)
-        {
-          g_set_error (error, COGL_WINSYS_ERROR,
-                       COGL_WINSYS_ERROR_CREATE_CONTEXT,
-                       "Failed to create framebuffer from buffer");
-          return FALSE;
-        }
+                        GBM_BO_FORMAT_XRGB8888);
+  if (!kms_onscreen->surface)
+    {
+      g_set_error (error, COGL_WINSYS_ERROR,
+                   COGL_WINSYS_ERROR_CREATE_ONSCREEN,
+                   "Failed to allocate surface");
+      return FALSE;
     }
 
-  context->glGenFramebuffers (1, &kms_onscreen->fb);
-  context->glBindFramebuffer (GL_FRAMEBUFFER_EXT, kms_onscreen->fb);
-
-  context->glGenRenderbuffers (1, &kms_onscreen->depth_rb);
-  context->glBindRenderbuffer (GL_RENDERBUFFER_EXT, kms_onscreen->depth_rb);
-  context->glRenderbufferStorage (GL_RENDERBUFFER_EXT,
-                                  GL_DEPTH_COMPONENT16,
-                                  kms_display->mode.hdisplay,
-                                  kms_display->mode.vdisplay);
-  context->glBindRenderbuffer (GL_RENDERBUFFER_EXT, 0);
-
-  context->glFramebufferRenderbuffer (GL_FRAMEBUFFER_EXT,
-                                      GL_DEPTH_ATTACHMENT_EXT,
-                                      GL_RENDERBUFFER_EXT,
-                                      kms_onscreen->depth_rb);
-
-  kms_onscreen->current_frame = 0;
-  _cogl_winsys_onscreen_swap_buffers (onscreen);
+  egl_onscreen->egl_surface =
+    eglCreateWindowSurface (egl_renderer->edpy,
+                            egl_display->egl_config,
+                            (NativeWindowType) kms_onscreen->surface,
+                            NULL);
+  if (egl_onscreen->egl_surface == EGL_NO_SURFACE)
+    {
+      g_set_error (error, COGL_WINSYS_ERROR,
+                   COGL_WINSYS_ERROR_CREATE_ONSCREEN,
+                   "Failed to allocate surface");
+      return FALSE;
+    }
 
   _cogl_framebuffer_winsys_update_size (framebuffer,
                                         kms_display->width,
@@ -466,10 +409,8 @@ _cogl_winsys_onscreen_deinit (CoglOnscreen *onscreen)
   CoglContext *context = framebuffer->context;
   CoglRenderer *renderer = context->display->renderer;
   CoglRendererEGL *egl_renderer = renderer->winsys;
-  CoglRendererKMS *kms_renderer = egl_renderer->platform;
   CoglOnscreenEGL *egl_onscreen = onscreen->winsys;
   CoglOnscreenKMS *kms_onscreen;
-  int i;
 
   /* If we never successfully allocated then there's nothing to do */
   if (egl_onscreen == NULL)
@@ -477,23 +418,16 @@ _cogl_winsys_onscreen_deinit (CoglOnscreen *onscreen)
 
   kms_onscreen = egl_onscreen->platform;
 
-  context->glBindFramebuffer (GL_FRAMEBUFFER_EXT, kms_onscreen->fb);
-  context->glFramebufferRenderbuffer (GL_FRAMEBUFFER_EXT,
-                                      GL_COLOR_ATTACHMENT0_EXT,
-                                      GL_RENDERBUFFER_EXT,
-                                      0);
-  context->glDeleteRenderbuffers(2, kms_onscreen->color_rb);
-  context->glFramebufferRenderbuffer (GL_FRAMEBUFFER_EXT,
-                                      GL_DEPTH_ATTACHMENT_EXT,
-                                      GL_RENDERBUFFER_EXT,
-                                      0);
-  context->glDeleteRenderbuffers(1, &kms_onscreen->depth_rb);
-
-  for (i = 0; i < 2; i++)
+  if (egl_onscreen->egl_surface != EGL_NO_SURFACE)
     {
-      drmModeRmFB (kms_renderer->fd, kms_onscreen->fb_id[i]);
-      _cogl_egl_destroy_image (context, kms_onscreen->image[i]);
-      gbm_bo_destroy (kms_onscreen->bo[i]);
+      eglDestroySurface (egl_renderer->edpy, egl_onscreen->egl_surface);
+      egl_onscreen->egl_surface = EGL_NO_SURFACE;
+    }
+
+  if (kms_onscreen->surface)
+    {
+      gbm_surface_destroy (kms_onscreen->surface);
+      kms_onscreen->surface = NULL;
     }
 
   g_slice_free (CoglOnscreenKMS, kms_onscreen);
@@ -501,32 +435,12 @@ _cogl_winsys_onscreen_deinit (CoglOnscreen *onscreen)
   onscreen->winsys = NULL;
 }
 
-static void
-_cogl_winsys_onscreen_bind (CoglOnscreen *onscreen)
-{
-  CoglContext *context = COGL_FRAMEBUFFER (onscreen)->context;
-  CoglDisplayEGL *egl_display = context->display->winsys;
-  CoglRenderer *renderer = context->display->renderer;
-  CoglRendererEGL *egl_renderer = renderer->winsys;
-
-  eglMakeCurrent (egl_renderer->edpy,
-                  EGL_NO_SURFACE,
-                  EGL_NO_SURFACE,
-                  egl_display->egl_context);
-}
-
-static void
-_cogl_winsys_onscreen_update_swap_throttled (CoglOnscreen *onscreen)
-{
-  _cogl_winsys_onscreen_bind (onscreen);
-}
-
 static const CoglWinsysEGLVtable
 _cogl_winsys_egl_vtable =
   {
     .display_setup = _cogl_winsys_egl_display_setup,
     .display_destroy = _cogl_winsys_egl_display_destroy,
-    .try_create_context = _cogl_winsys_egl_try_create_context,
+    .context_created = _cogl_winsys_egl_context_created,
     .cleanup_context = _cogl_winsys_egl_cleanup_context
   };
 
@@ -541,7 +455,8 @@ _cogl_winsys_egl_kms_get_vtable (void)
       /* The EGL_KMS winsys is a subclass of the EGL winsys so we
          start by copying its vtable */
 
-      vtable = *_cogl_winsys_egl_get_vtable ();
+      parent_vtable = _cogl_winsys_egl_get_vtable ();
+      vtable = *parent_vtable;
 
       vtable.id = COGL_WINSYS_ID_EGL_KMS;
       vtable.name = "EGL_KMS";
@@ -551,15 +466,11 @@ _cogl_winsys_egl_kms_get_vtable (void)
 
       vtable.onscreen_init = _cogl_winsys_onscreen_init;
       vtable.onscreen_deinit = _cogl_winsys_onscreen_deinit;
-      vtable.onscreen_bind = _cogl_winsys_onscreen_bind;
 
       /* The KMS winsys doesn't support swap region */
       vtable.onscreen_swap_region = NULL;
       vtable.onscreen_swap_buffers = _cogl_winsys_onscreen_swap_buffers;
 
-      vtable.onscreen_update_swap_throttled =
-        _cogl_winsys_onscreen_update_swap_throttled;
-
       vtable_inited = TRUE;
     }
 
diff --git a/cogl/winsys/cogl-winsys-egl-private.h b/cogl/winsys/cogl-winsys-egl-private.h
index 6658278..9f501ee 100644
--- a/cogl/winsys/cogl-winsys-egl-private.h
+++ b/cogl/winsys/cogl-winsys-egl-private.h
@@ -39,11 +39,6 @@ typedef struct _CoglWinsysEGLVtable
   (* display_destroy) (CoglDisplay *display);
 
   gboolean
-  (* try_create_context) (CoglDisplay *display,
-                          EGLint *attribs,
-                          GError **error);
-
-  gboolean
   (* context_created) (CoglDisplay *display,
                        GError **error);
 
diff --git a/cogl/winsys/cogl-winsys-egl.c b/cogl/winsys/cogl-winsys-egl.c
index e5618da..3f81c2b 100644
--- a/cogl/winsys/cogl-winsys-egl.c
+++ b/cogl/winsys/cogl-winsys-egl.c
@@ -249,11 +249,6 @@ try_create_context (CoglDisplay *display,
   else
     attribs[0] = EGL_NONE;
 
-  /* Divert to the platform implementation if one is defined */
-  if (egl_renderer->platform_vtable->try_create_context)
-    return egl_renderer->platform_vtable->
-      try_create_context (display, attribs, error);
-
   egl_attributes_from_framebuffer_config (display,
                                           &display->onscreen_template->config,
                                           with_stencil_buffer,