extend to support rendering to RenderTarget/OpenGL texture on Linux

linux/filament_pb_texture.cc

@@ -0,0 +1,67 @@
+#include <flutter_linux/flutter_linux.h>
+#include <flutter_linux/fl_texture_registrar.h>
+#include <flutter_linux/fl_texture.h>
+#include <flutter_linux/fl_pixel_buffer_texture.h>
+#include <flutter_linux/fl_texture_gl.h>
+#include <gtk/gtk.h>
+#include <sys/utsname.h>
+
+#include <epoxy/gl.h>
+#include "include/polyvox_filament/filament_pb_texture.h"
+
+#include <iostream>
+#include <vector>
+
+
+G_DEFINE_TYPE(FilamentPBTexture,
+              filament_pb_texture,
+              fl_pixel_buffer_texture_get_type())
+
+
+static gboolean video_texture_copy_pixels (FlPixelBufferTexture* texture,
+                               const uint8_t** out_buffer,
+                               uint32_t* width,
+                               uint32_t* height,
+                               GError** error) {
+
+    auto buffer = new std::vector<uint8_t>(400*200*4);
+    for (int i = 0; i < 400*200*4; i++)
+    {
+      if(i%4 == 1 || i % 4 == 3) {
+        buffer->at(i) = (uint8_t)255;
+      } else {
+        buffer->at(i) = (uint8_t)0;
+      }
+    }
+  *width = 400;
+  *height = 200;
+  *out_buffer = buffer->data();
+  std::cout << "COPY" << std::endl;
+  return TRUE;
+}
+
+void filament_pb_texture_dispose(GObject* object) {
+    G_OBJECT_CLASS(filament_pb_texture_parent_class)->dispose(object);
+}
+
+void filament_pb_texture_class_init(FilamentPBTextureClass* klass) {
+  G_OBJECT_CLASS(klass)->dispose = filament_pb_texture_dispose;
+  FL_PIXEL_BUFFER_TEXTURE_CLASS(klass)->copy_pixels = video_texture_copy_pixels;
+}
+
+void filament_pb_texture_init(FilamentPBTexture* self) { }
+
+FLUTTER_PLUGIN_EXPORT FlTexture* create_filament_pb_texture(uint32_t width, uint32_t height, FlTextureRegistrar* registrar) {
+
+    auto pbTexture = FILAMENT_PB_TEXTURE(g_object_new(filament_pb_texture_get_type(), nullptr));
+
+    g_autoptr(FlTexture) texture = FL_TEXTURE(pbTexture);
+   
+    if(fl_texture_registrar_register_texture(registrar, texture) == TRUE) { 
+       if(fl_texture_registrar_mark_texture_frame_available(registrar,
+                                                       texture) != TRUE) {
+         std::cout << "FAILED" << std::endl;
+       } 
+    }
+    return texture;
+}