[retro-gtk] Add RetroFramebuffer

[Adrien Plazas <aplazas src gnome org>]

commit 513ccbfac3b19557f075b486f964b5dec35ad13f
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Sun Jan 19 06:04:14 2020 +0500

    Add RetroFramebuffer
    
    This will be used to provide fast video output via shared memory.

 shared/meson.build                 |   1 +
 shared/retro-framebuffer-private.h |  47 ++++++
 shared/retro-framebuffer.c         | 300 +++++++++++++++++++++++++++++++++++++
 3 files changed, 348 insertions(+)
---
diff --git a/shared/meson.build b/shared/meson.build
index 60d6f7f..f62a2f7 100644
--- a/shared/meson.build
+++ b/shared/meson.build
@@ -2,6 +2,7 @@ shared_sources = files([
   'retro-controller-codes.c',
   'retro-controller-state.c',
   'retro-controller-type.c',
+  'retro-framebuffer.c',
   'retro-input.c',
   'retro-memfd.c',
   'retro-memory-type.c',
diff --git a/shared/retro-framebuffer-private.h b/shared/retro-framebuffer-private.h
new file mode 100644
index 0000000..a3aaed9
--- /dev/null
+++ b/shared/retro-framebuffer-private.h
@@ -0,0 +1,47 @@
+// This file is part of retro-gtk. License: GPL-3.0+.
+
+#pragma once
+
+#if !defined(__RETRO_GTK_INSIDE__) && !defined(RETRO_GTK_COMPILATION)
+# error "Only <retro-gtk.h> can be included directly."
+#endif
+
+#include <glib-object.h>
+#include "retro-pixel-format-private.h"
+
+G_BEGIN_DECLS
+
+#define RETRO_TYPE_FRAMEBUFFER (retro_framebuffer_get_type())
+
+G_DECLARE_FINAL_TYPE (RetroFramebuffer, retro_framebuffer, RETRO, FRAMEBUFFER, GObject)
+
+RetroFramebuffer *retro_framebuffer_new (gint fd);
+
+gint retro_framebuffer_get_fd (RetroFramebuffer *self);
+
+void retro_framebuffer_lock (RetroFramebuffer *self);
+void retro_framebuffer_unlock (RetroFramebuffer *self);
+
+#ifdef RETRO_RUNNER_COMPILATION
+
+void retro_framebuffer_set_data (RetroFramebuffer *self,
+                                 RetroPixelFormat  format,
+                                 gsize             rowstride,
+                                 guint             width,
+                                 guint             height,
+                                 float             aspect_ratio,
+                                 gpointer          data);
+
+#else
+
+gboolean retro_framebuffer_get_is_dirty (RetroFramebuffer *self);
+RetroPixelFormat retro_framebuffer_get_format (RetroFramebuffer *self);
+gsize retro_framebuffer_get_rowstride (RetroFramebuffer *self);
+guint retro_framebuffer_get_width (RetroFramebuffer *self);
+guint retro_framebuffer_get_height (RetroFramebuffer *self);
+gdouble retro_framebuffer_get_aspect_ratio (RetroFramebuffer *self);
+gpointer retro_framebuffer_get_pixels (RetroFramebuffer *self);
+
+#endif
+
+G_END_DECLS
diff --git a/shared/retro-framebuffer.c b/shared/retro-framebuffer.c
new file mode 100644
index 0000000..094f238
--- /dev/null
+++ b/shared/retro-framebuffer.c
@@ -0,0 +1,300 @@
+// This file is part of retro-gtk. License: GPL-3.0+.
+
+#include "retro-framebuffer-private.h"
+
+#include <semaphore.h>
+#include <errno.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+typedef struct {
+  sem_t semaphore;
+  gboolean is_dirty;
+  RetroPixelFormat format;
+  gsize rowstride;
+  guint width;
+  guint height;
+  gfloat aspect_ratio;
+} RetroFramebufferMetadata;
+
+struct _RetroFramebuffer
+{
+  GObject parent_instance;
+
+  gint fd;
+  gsize size;
+  gpointer shared_data;
+  RetroFramebufferMetadata *metadata;
+  gpointer framebuffer;
+};
+
+G_DEFINE_TYPE (RetroFramebuffer, retro_framebuffer, G_TYPE_OBJECT)
+
+enum {
+  PROP_0,
+  PROP_FD,
+  N_PROPS,
+};
+
+static GParamSpec *properties [N_PROPS];
+
+static void
+resize (RetroFramebuffer *self,
+        gsize             size)
+{
+  size += sizeof (RetroFramebufferMetadata);
+
+  if (G_LIKELY (size == self->size))
+    return;
+
+  if (self->shared_data) {
+    munmap (self->shared_data, self->size);
+    self->shared_data = NULL;
+  }
+
+  self->size = size;
+
+  if (ftruncate (self->fd, size) != 0)
+    g_critical ("Couldn't truncate framebuffer: %s", g_strerror (errno));
+
+  self->shared_data = mmap (NULL, size,
+                            PROT_READ | PROT_WRITE, MAP_SHARED, self->fd, 0);
+
+  self->metadata = (RetroFramebufferMetadata *) self->shared_data;
+  self->framebuffer = (self->shared_data + sizeof (RetroFramebufferMetadata));
+}
+
+static void
+retro_framebuffer_constructed (GObject *object)
+{
+  RetroFramebuffer *self = RETRO_FRAMEBUFFER (object);
+
+  G_OBJECT_CLASS (retro_framebuffer_parent_class)->constructed (object);
+
+  resize (self, 0);
+
+#ifdef RETRO_RUNNER_COMPILATION
+  if (sem_init (&self->metadata->semaphore, 1, 1) != 0)
+    g_critical ("Couldn't init semaphore: %s", g_strerror (errno));
+#endif
+}
+
+static void
+retro_framebuffer_finalize (GObject *object)
+{
+  RetroFramebuffer *self = (RetroFramebuffer *)object;
+
+#ifdef RETRO_RUNNER_COMPILATION
+  if (sem_destroy (&self->metadata->semaphore) != 0)
+    g_critical ("Couldn't destroy semaphore: %s", g_strerror (errno));
+#endif
+
+  if (self->shared_data) {
+    munmap (self->shared_data, self->size);
+    self->shared_data = NULL;
+  }
+
+  close (self->fd);
+
+  G_OBJECT_CLASS (retro_framebuffer_parent_class)->finalize (object);
+}
+
+static void
+retro_framebuffer_get_property (GObject    *object,
+                                guint       prop_id,
+                                GValue     *value,
+                                GParamSpec *pspec)
+{
+  RetroFramebuffer *self = RETRO_FRAMEBUFFER (object);
+
+  switch (prop_id) {
+  case PROP_FD:
+    g_value_set_int (value, self->fd);
+
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+
+    break;
+  }
+}
+
+static void
+retro_framebuffer_set_property (GObject      *object,
+                                guint         prop_id,
+                                const GValue *value,
+                                GParamSpec   *pspec)
+{
+  RetroFramebuffer *self = RETRO_FRAMEBUFFER (object);
+
+  switch (prop_id) {
+  case PROP_FD:
+    self->fd = g_value_get_int (value);
+
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+
+    break;
+  }
+}
+
+static void
+retro_framebuffer_class_init (RetroFramebufferClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = retro_framebuffer_constructed;
+  object_class->finalize = retro_framebuffer_finalize;
+  object_class->get_property = retro_framebuffer_get_property;
+  object_class->set_property = retro_framebuffer_set_property;
+
+  properties[PROP_FD] =
+    g_param_spec_int ("fd",
+                      "File descriptor",
+                      "The file descriptor backing shared memory.",
+                      -1,
+                      G_MAXINT,
+                      -1,
+                      G_PARAM_READWRITE |
+                      G_PARAM_CONSTRUCT_ONLY |
+                      G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (G_OBJECT_CLASS (klass), N_PROPS, properties);
+}
+
+static void
+retro_framebuffer_init (RetroFramebuffer *self)
+{
+}
+
+RetroFramebuffer *
+retro_framebuffer_new (gint fd)
+{
+  g_return_val_if_fail (fd >= 0, NULL);
+
+  return g_object_new (RETRO_TYPE_FRAMEBUFFER, "fd", fd, NULL);
+}
+
+gint
+retro_framebuffer_get_fd (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0);
+
+  return self->fd;
+}
+
+void
+retro_framebuffer_lock (RetroFramebuffer *self)
+{
+  g_return_if_fail (RETRO_IS_FRAMEBUFFER (self));
+
+  if (sem_wait (&self->metadata->semaphore) != 0)
+    g_critical ("Couldn't lock: %s", g_strerror (errno));
+}
+
+void
+retro_framebuffer_unlock (RetroFramebuffer *self)
+{
+  g_return_if_fail (RETRO_IS_FRAMEBUFFER (self));
+
+  if (sem_post (&self->metadata->semaphore) != 0)
+    g_critical ("Couldn't unlock: %s", g_strerror (errno));
+}
+
+#ifdef RETRO_RUNNER_COMPILATION
+
+void
+retro_framebuffer_set_data (RetroFramebuffer *self,
+                            RetroPixelFormat  format,
+                            gsize             rowstride,
+                            guint             width,
+                            guint             height,
+                            float             aspect_ratio,
+                            gpointer          data)
+{
+  gsize size;
+
+  g_return_if_fail (RETRO_IS_FRAMEBUFFER (self));
+
+  size = height * rowstride;
+
+  resize (self, size);
+
+  self->metadata->is_dirty = TRUE;
+  self->metadata->format = format;
+  self->metadata->rowstride = rowstride;
+  self->metadata->width = width;
+  self->metadata->height = height;
+  self->metadata->aspect_ratio = aspect_ratio;
+
+  if (size && data)
+    memcpy (self->framebuffer, data, size);
+}
+
+#else
+
+gboolean
+retro_framebuffer_get_is_dirty (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), FALSE);
+
+  return self->metadata->is_dirty;
+}
+
+RetroPixelFormat
+retro_framebuffer_get_format (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0);
+
+  return self->metadata->format;
+}
+
+gsize
+retro_framebuffer_get_rowstride (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0);
+
+  return self->metadata->rowstride;
+}
+
+guint
+retro_framebuffer_get_width (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0);
+
+  return self->metadata->width;
+}
+
+guint
+retro_framebuffer_get_height (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0);
+
+  return self->metadata->height;
+}
+
+gdouble
+retro_framebuffer_get_aspect_ratio (RetroFramebuffer *self)
+{
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), 0.0);
+
+  return self->metadata->aspect_ratio;
+}
+
+gpointer
+retro_framebuffer_get_pixels (RetroFramebuffer *self)
+{
+  gsize size;
+
+  g_return_val_if_fail (RETRO_IS_FRAMEBUFFER (self), NULL);
+
+  size = self->metadata->height * self->metadata->rowstride;
+  resize (self, size);
+
+  self->metadata->is_dirty = FALSE;
+
+  return self->framebuffer;
+}
+
+#endif