Send display/framebuffer to JS

Updates mihaip/infinite-mac#219

Author: mihaip

devices/video/display_js.cpp

@@ -1,35 +1,60 @@
 #include <devices/video/display.h>
 #include <loguru.hpp>
+#include <emscripten.h>
 
-class Display::Impl {
+class Display::Impl
+{
 public:
+    std::unique_ptr<uint8_t[]> browser_framebuffer;
+    int browser_framebuffer_size;
+    int browser_framebuffer_pitch;
 };
 
-Display::Display(): impl(std::make_unique<Impl>()) {
-    LOG_F(INFO, "Display::Display()");
+Display::Display(): impl(std::make_unique<Impl>())
+{
+    // No-op in JS
 }
 
 Display::~Display() {
-    LOG_F(INFO, "Display::!Display()");
+    // No-op in JS
 }
 
-bool Display::configure(int width, int height) {
-    LOG_F(INFO, "Display::configure(%d, %d)", width, height);
+bool Display::configure(int width, int height)
+{
+    impl->browser_framebuffer_pitch = width * 4;
+    impl->browser_framebuffer_size = height * impl->browser_framebuffer_pitch;
+    impl->browser_framebuffer = std::make_unique<uint8_t[]>(impl->browser_framebuffer_size);
+    EM_ASM_({ workerApi.didOpenVideo($0, $1); }, width, height);
     return true;
 }
 
-void Display::handle_events(const WindowEvent& wnd_event) {
-    LOG_F(INFO, "Display::handle_events()");
+void Display::handle_events(const WindowEvent& wnd_event)
+{
+    // No-op in JS
 }
 
-void Display::blank() {
-    LOG_F(INFO, "Display::blank()");
+void Display::blank()
+{
+    // Replace contents with opaque black.
+    uint8_t *browser_framebuffer = impl->browser_framebuffer.get();
+    int browser_framebuffer_size = impl->browser_framebuffer_size;
+    for (int i = 0; i < browser_framebuffer_size; i += 4) {
+        browser_framebuffer[i] = 0x00;
+        browser_framebuffer[i + 1] = 0x00;
+        browser_framebuffer[i + 2] = 0x00;
+        browser_framebuffer[i + 3] = 0xff;
+    }
+    EM_ASM_({ workerApi.blit($0, $1); }, browser_framebuffer, browser_framebuffer_size);
 }
 
-void Display::update(std::function<void(uint8_t *dst_buf, int dst_pitch)> convert_fb_cb, bool draw_hw_cursor, int cursor_x, int cursor_y) {
-    LOG_F(INFO, "Display::update()");
+void Display::update(std::function<void(uint8_t *dst_buf, int dst_pitch)> convert_fb_cb, bool draw_hw_cursor, int cursor_x, int cursor_y)
+{
+    convert_fb_cb(impl->browser_framebuffer.get(), impl->browser_framebuffer_pitch);
+    // TODO: has contents and avoid sending framebuffer if unchanged
+    EM_ASM_({ workerApi.blit($0, $1); }, impl->browser_framebuffer.get(), impl->browser_framebuffer_size);
 }
 
-void Display::setup_hw_cursor(std::function<void(uint8_t *dst_buf, int dst_pitch)> draw_hw_cursor, int cursor_width, int cursor_height) {
+void Display::setup_hw_cursor(std::function<void(uint8_t *dst_buf, int dst_pitch)> draw_hw_cursor, int cursor_width, int cursor_height)
+{
     LOG_F(INFO, "Display::setup_hw_cursor()");
 }