implement cubes exporter for web viewer

engine/canvas.cpp

@@ -1254,6 +1254,72 @@ void ui::Canvas::export_anim(std::string data_path)
     glActiveTexture(GL_TEXTURE0);
 }
 
+void ui::Canvas::export_cubes(std::string data_path)
+{
+	std::array<std::string, 6> names {
+		"pz", "px", "nz", "nx",
+		"py", "ny"
+	};
+	const int stride = m_width * 4;
+	auto buffer = std::make_unique<uint8_t[]>(m_width * m_height * 4);
+	auto flipped = std::make_unique<uint8_t[]>(m_width * m_height * 4);
+	for (auto i : m_order)
+	{
+		for (int plane = 0; plane < 6; plane++)
+		{
+			auto& l = m_layers[i];
+			l.m_rtt[plane].bindFramebuffer();
+			glReadPixels(0, 0, m_width, m_height, GL_RGBA, GL_UNSIGNED_BYTE, buffer.get());
+			l.m_rtt[plane].unbindFramebuffer();
+
+			if (plane < 4)
+			{
+				for (int y = 0; y < m_height; y++)
+				{
+					int y_rev = m_height - y - 1;
+					std::copy_n(buffer.get() + y * stride, stride, flipped.get() + y_rev * stride);
+				}
+				std::swap(buffer, flipped);
+			}
+			else
+			{
+				for (int y = 0; y < m_height; y++)
+				{
+					auto src = (glm::u8vec4*)(buffer.get() + y * stride);
+					auto dst = (glm::u8vec4*)(flipped.get() + y * stride);
+					for (int x = 0; x < m_width; x++)
+					{
+						int x_rev = m_width - x - 1;
+						dst[x_rev] = src[x];
+					}
+					//std::copy_backward(src + stride, src, dst + stride);
+				}
+				std::swap(buffer, flipped);
+			}
+
+			static char name[128];
+			sprintf(name, "%s-%02d-%d.png", data_path.c_str(), i, plane);
+			int ret = stbi_write_png(name, m_width, m_height, 4, buffer.get(), 0);
+
+
+#ifdef __IOS__
+			[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
+				NSURL* url = [NSURL fileURLWithPath : [NSString stringWithUTF8String : name]];
+				PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImageAtFileURL : url];
+				changeRequest.creationDate = [NSDate date];
+			} completionHandler: ^ (BOOL success, NSError *error) {
+				if (success) {
+					NSLog(@"successfully saved");
+				}
+				else {
+					NSLog(@"error saving to photos : %@", error);
+				}
+			}];
+#endif
+		}
+	}
+}
+
 void ui::Canvas::project_save(std::string file_path)
 {
     std::thread t(&ui::Canvas::project_save_thread, this, file_path);