Make the UI renderer more efficient

3 files changed, 24 insertions, 19 deletions

diff --git a/c2.cpp b/c2.cpp
index 3c862a6..58f3831 100644
--- a/c2.cpp
+++ b/c2.cpp
@@ -17,7 +17,7 @@ extern "C" {
 
 #define video_arena_size (1024 * 1024 * 16)
 #define asset_arena_size (1024 * 1024 * 4)
-#define ui_arena_size    (1024 * 1024 * 64)
+#define ui_arena_size    (1024 * 1024)
 #define scene_arena_size (1024)
 #define per_frame_memory_size (1024 * 1024)
 
@@ -879,13 +879,13 @@ struct C2 : public App {
 		ctx.debug_pop();
 
 		ctx.debug_push("ui");
-		ui->render(&frame_arena);
 		{
 			int s = ui->ren.bound.w * ui->ren.bound.h * 4;
 			void* pixels = dev->map_buffer(ui_buffer, 0, s);
-			memcpy(pixels, ui->ren.pixels, s);
+			bool dirty = ui->render(&frame_arena, pixels);
 			dev->unmap_buffer(ui_buffer);
-			ctx.copy(ui_texture, ui_buffer);
+			if (dirty)
+				ctx.copy(ui_texture, ui_buffer);
 
 			pb.begin_rp();
 			pb.rp_target(dev->get_backbuffer(), Clear_Mode::restore);
diff --git a/ui.cpp b/ui.cpp
index 387b5ac..e20a18c 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -310,8 +310,7 @@ void UI::Renderer::clear(const Rect& r) {
 	}
 }
 
-const App* g_app;
-void UI::Renderer::flush(int x, int y) {
+void UI::Renderer::flush_cell(int x, int y) {
 	Cmd* cmd = (Cmd*)cmd_buf;
 	Cmd* last = (Cmd*)(cmd_buf + cmd_buf_ptr);
 	Rect cell = Rect(
@@ -344,36 +343,43 @@ void UI::Renderer::flush(int x, int y) {
 	}
 }
 
-void UI::Renderer::flush() {
+bool UI::Renderer::flush(void* target) {
 	uint64_t* next = grid == grid_a? grid_b: grid_a;
 	uint64_t* h = grid;
 	uint64_t* p = next;
+	bool dirty = false;
+	pixels = (Colour*)target;
 	int i, j;
 	for (j = 0; j < grid_size; j++) {
 		for (i = 0; i < grid_size; i++) {
 			if (*p != *h) {
-				flush(i, j);
+				dirty = true;
+				flush_cell(i, j);
 			}
 			h++;
 			p++;
 		}
 	}
 	grid = next;
+	return dirty;
 }
 
 void UI::Renderer::resize(int w, int h) {
-	heap_free(arena, pixels);
-	pixels = (Colour*)heap_alloc(arena, w * h * sizeof *pixels);
-	assert(pixels != 0);
+	int i, e = grid_size * grid_size;
+	uint64_t* next = grid == grid_a? grid_b: grid_a;
 	bound = Rect(0, 0, w, h);
+	for (i = 0; i < e; i++)
+		next[i] = 0;
 }
 
 void UI::Renderer::init(Heap* heap, int w, int h) {
 	arena = heap;
-	pixels = (Colour*)heap_alloc(heap, w * h * sizeof *pixels);
-	assert(pixels != 0);
+	int i, e = grid_size * grid_size;
+	bound = Rect(0, 0, w, h);
 	bound = Rect(0, 0, w, h);
 	grid = grid_a;
+	for (i = 0; i < e; i++)
+		grid[i] = 0;
 }
 
 UI* UI::create(
@@ -479,13 +485,12 @@ void UI::update(Arena* s) {
 		layout(area.w, area.h);
 }
 
-void UI::render(Arena* s) {
+bool UI::render(Arena* s, void* pixels) {
 	if (area.w != ren.bound.w || area.h != ren.bound.h)
 		ren.resize(area.w, area.h);
 	ren.reset(ren.bound);
 	root->render();
-	g_app = app;
-	ren.flush();
+	return ren.flush(pixels);
 }
 
 void UI::draw_container(const Rect& bound, Colour c) {
diff --git a/ui.hpp b/ui.hpp
index 37726cb..1ac3602 100644
--- a/ui.hpp
+++ b/ui.hpp
@@ -65,8 +65,8 @@ struct UI {
 		void reset(const Rect& cl);
 		void set_clip(const Rect& r);
 		void clear(const Rect& r);
-		void flush(int x, int y);
-		void flush();
+		void flush_cell(int x, int y);
+		bool flush(void* target);
 		void resize(int w, int h);
 		void init(Heap* heap, int w, int h);
 	} ren;
@@ -95,7 +95,7 @@ struct UI {
 	void layout(int w, int h);
 	void text_input(const char* buf);
 	void update(Arena* s);
-	void render(Arena* s);
+	bool render(Arena* s, void* pixels);
 
 	void draw_container(const Rect& r, Colour c);
 	void draw_containeri(const Rect& r, Colour c);