support receiving canvas

7 files changed, 102 insertions, 4 deletions

diff --git a/README.md b/README.md
index c234d19..9ab89ea 100644
--- a/README.md
+++ b/README.md
@@ -2,13 +2,15 @@
 
 A LÖVE library for sharing GPU textures between processes.
 
-This wraps the OpenGL C API of [texture-share-vk](https://github.com/DigitOtter/texture-share-vk) and allows publishing a LÖVE Canvas object.
+This wraps the OpenGL C API of [texture-share-vk](https://github.com/DigitOtter/texture-share-vk) and allows sending and receiving LÖVE Canvas contents.
 
 ## API
 
 - `tvs.new()`: creates a new `Client` object (`texture-share-gl` client).
 - `Client:newSharedCanvas(name, ...)`: creates a new `SharedCanvas` object by delegating to [`love.graphics.newCanvas(...)`](https://love2d.org/wiki/love.graphics.newCanvas) and publishes it.
+- `Client:loadSharedCanvas(name)`: loads a `SharedCanvas` object from another publisher.
 - `Canvas.name`: the name passed in the SharedCanvas constructor
 - `Canvas.canvas`: the love2d `Canvas` object
 - `Canvas:send()`: Sends the current contents of the Canvas to subscribers, call this after drawing to the Canvas.
+- `Canvas:load()`: Loads updated contents from the publisher, call this before drawing the Canvas.
 - `Canvas:any_other_method()`: delegated to the love2d `Canvas` object
diff --git a/example/texture-share-vk.lua b/example/texture-share-vk.lua
deleted file mode 120000
index f828f1e..0000000
--- a/example/texture-share-vk.lua
+++ /dev/null
@@ -1 +0,0 @@
-../texture-share-vk.lua
\ No newline at end of file
diff --git a/examples/recv/main.lua b/examples/recv/main.lua
new file mode 100644
index 0000000..c9ebd30
--- /dev/null
+++ b/examples/recv/main.lua
@@ -0,0 +1,17 @@
+local tvs = require 'texture-share-vk'
+local client, shared
+
+function love.load()
+  client = tvs.new()
+  shared = client:loadSharedCanvas("love2d")
+
+  print(shared:getDimensions()) -- NOTE: delegated to LÖVE Canvas
+end
+
+function love.draw()
+  shared:recv()
+
+  love.graphics.reset()
+  love.graphics.setBlendMode("alpha", "premultiplied")
+  love.graphics.draw(shared.canvas) -- NOTE: different from normal canvas
+end
diff --git a/examples/recv/texture-share-vk.lua b/examples/recv/texture-share-vk.lua
new file mode 120000
index 0000000..78b332b
--- /dev/null
+++ b/examples/recv/texture-share-vk.lua
@@ -0,0 +1 @@
+../../texture-share-vk.lua
\ No newline at end of file
diff --git a/example/main.lua b/examples/send/main.lua
index 4788361..4788361 100644
--- a/example/main.lua
+++ b/examples/send/main.lua
diff --git a/examples/send/texture-share-vk.lua b/examples/send/texture-share-vk.lua
new file mode 120000
index 0000000..78b332b
--- /dev/null
+++ b/examples/send/texture-share-vk.lua
@@ -0,0 +1 @@
+../../texture-share-vk.lua
\ No newline at end of file
diff --git a/texture-share-vk.lua b/texture-share-vk.lua
index b8e2523..f8f9c4c 100644
--- a/texture-share-vk.lua
+++ b/texture-share-vk.lua
@@ -18,6 +18,19 @@ typedef enum ImgFormat {
     Undefined,
 } ImgFormat;
 
+typedef uint8_t ImgName[1024];
+
+typedef struct ShmemDataInternal {
+    ImgName name;
+    uint32_t handle_id;
+    uint32_t width;
+    uint32_t height;
+    enum ImgFormat format;
+    uint64_t allocation_size;
+    uint64_t gpu_device_uuid_0;
+    uint64_t gpu_device_uuid_1;
+} ShmemDataInternal;
+
 // texture_share_gl_client/texture_share_gl_client.h
 typedef enum ImageLookupResult {
     Error = -1,
@@ -59,6 +72,18 @@ enum ImageLookupResult gl_client_init_image(struct GlClient *gl_client,
                                             ImgFormat format,
                                             bool overwrite_existing);
 
+enum ImageLookupResult gl_client_find_image(struct GlClient *gl_client,
+                                            const char *image_name,
+                                            bool force_update);
+
+struct ClientImageDataGuard *gl_client_find_image_data(struct GlClient *gl_client,
+                                                       const char *image_name,
+                                                       bool force_update);
+
+const ShmemDataInternal *gl_client_image_data_guard_read(const struct ClientImageDataGuard *image_data_guard);
+
+void gl_client_image_data_guard_destroy(struct ClientImageDataGuard *image_data_guard);
+
 int gl_client_send_image(struct GlClient *gl_client,
                          const char *image_name,
                          GLuint src_texture_id,
@@ -66,6 +91,14 @@ int gl_client_send_image(struct GlClient *gl_client,
                          bool invert,
                          GLuint prev_fbo,
                          const struct GlImageExtent *extents);
+
+int gl_client_recv_image(struct GlClient *gl_client,
+                         const char *image_name,
+                         GLuint src_texture_id,
+                         GLenum src_texture_target,
+                         bool invert,
+                         GLuint prev_fbo,
+                         const struct GlImageExtent *extents);
 ]]
 
 -- from texture_share_vk/config.h
@@ -83,6 +116,8 @@ local GL_TEXTURE_2D                         = 0x0DE1
 local IMAGE_FORMATS = {
   rgba8 = ffi.C.R8G8B8A8,
   rgb8 = ffi.C.R8G8B8,
+  [ffi.C.R8G8B8A8] = "rgba8",
+  [ffi.C.R8G8B8] = "rgb8",
 }
 
 local tvs = ffi.load("texture_share_gl_client")
@@ -135,7 +170,38 @@ function Client:newSharedCanvas(name, ...)
     name = name,
     canvas = canvas,
     client = self,
-    texture_id = name_ptr[0]
+    texture_id = name_ptr[0],
+  }, Canvas)
+end
+
+function Client:loadSharedCanvas(name)
+  local guard = assert(
+    tvs.gl_client_find_image_data(self.client, name, false),
+    "failed to load image"
+  )
+
+  local data = tvs.gl_client_image_data_guard_read(guard)
+  local format = assert(IMAGE_FORMATS[tonumber(data.format)], "unsupported Texture format")
+  local canvas = love.graphics.newCanvas(data.width, data.height, { format = format })
+  tvs.gl_client_image_data_guard_destroy(guard)
+
+  local last_canvas = love.graphics.getCanvas()
+  love.graphics.setCanvas(canvas)
+
+  local name_ptr = ffi.typeof('GLint[1]')()
+  gl.glGetFramebufferAttachmentParameteriv(
+    GL_FRAMEBUFFER,
+    GL_COLOR_ATTACHMENT0,
+    GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME,
+    name_ptr
+  )
+  love.graphics.setCanvas(last_canvas)
+
+  return setmetatable({
+    name = name,
+    canvas = canvas,
+    client = self,
+    texture_id = name_ptr[0],
   }, Canvas)
 end
 
@@ -144,7 +210,19 @@ function Client:__gc()
 end
 
 function Canvas:send()
-  tvs.gl_client_send_image(
+  return tvs.gl_client_send_image(
+    self.client.client,
+    self.name,
+    self.texture_id,
+    GL_TEXTURE_2D,
+    false,
+    0,
+    nil
+  )
+end
+
+function Canvas:recv()
+  return tvs.gl_client_recv_image(
     self.client.client,
     self.name,
     self.texture_id,