From 74e8d3f0278a65fdf86a1185fec8a6016e628e88 Mon Sep 17 00:00:00 2001
From: quou <quou@disroot.org>
Date: Sun, 19 Jan 2025 21:04:51 +1100
Subject: render UI in software

---
 c2.cpp | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 63 insertions(+), 3 deletions(-)

(limited to 'c2.cpp')

diff --git a/c2.cpp b/c2.cpp
index e8e6c82..3c862a6 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 * 16)
+#define ui_arena_size    (1024 * 1024 * 64)
 #define scene_arena_size (1024)
 #define per_frame_memory_size (1024 * 1024)
 
@@ -645,6 +645,8 @@ struct C2 : public App {
 	Buffer_Id vbo, cbuf;
 	Sampler_Id clamped_linear;
 	Texture_Id hdr_target;
+	Texture_Id ui_texture;
+	Buffer_Id ui_buffer;
 	Line_Renderer lr;
 	World* world;
 	UI* ui;
@@ -683,6 +685,7 @@ struct C2 : public App {
 		dev = Device::create(&video_arena, this); 
 		default_texture = make_default_texture(dev);
 		make_hdr_target();
+		make_ui_texture();
 		model_loader.init(dev, &assets);
 		mat_loader.init(&assets, default_texture);
 		register_asset_loader("MODL", &model_loader);
@@ -705,7 +708,7 @@ struct C2 : public App {
 		clamped_linear = create_clamped_linear(dev);
 		world = (World*)arena_alloc(arena, sizeof *world);
 		world->init(arena);
-		ui = UI::create(dev, this, &ui_arena, ui_shader->id);
+		ui = UI::create(this, &ui_arena);
 		init_editor(ui, world);
 		lr.init(dev, &assets);
 		assert(per_frame != 0);
@@ -876,7 +879,39 @@ struct C2 : public App {
 		ctx.debug_pop();
 
 		ctx.debug_push("ui");
-		ui->render(&frame_arena, dev->get_backbuffer());
+		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);
+			dev->unmap_buffer(ui_buffer);
+			ctx.copy(ui_texture, ui_buffer);
+
+			pb.begin_rp();
+			pb.rp_target(dev->get_backbuffer(), Clear_Mode::restore);
+			Render_Pass& ui_pass = pb.build_rp();
+
+			pb.begin();
+			pb.shader(ui_shader->id);
+			pb.vertex_format(ui_shader->vf);
+			pb.blend(
+				Blend_Mode::add,
+				Blend_Factor::src_alpha,
+				Blend_Factor::inv_src_alpha
+			);
+			pb.texture(
+				ui_shader->descriptor_binding("atlas"),
+				ui_texture,
+				clamped_linear
+			);
+			Pipeline& ui_pip = pb.build();
+			quad.render(
+				ctx,
+				ui_pip,
+				ui_pass,
+				ui_shader->binding_index("verts")
+			);
+		}
 		ctx.debug_pop();
 
 		if (mjp(mbtn_left)) {
@@ -920,6 +955,8 @@ struct C2 : public App {
 		assets.destroy();
 		dev->destroy_texture(default_texture);
 		dev->destroy_texture(hdr_target);
+		dev->destroy_texture(ui_texture);
+		dev->destroy_buffer(ui_buffer);
 		dev->destroy_sampler(clamped_linear);
 		dev->destroy_buffer(vbo);
 		dev->destroy_buffer(cbuf);
@@ -930,7 +967,10 @@ struct C2 : public App {
 		ui->layout(w, h);
 		dev->on_resize();
 		dev->destroy_texture(hdr_target);
+		dev->destroy_texture(ui_texture);
+		dev->destroy_buffer(ui_buffer);
 		make_hdr_target();
+		make_ui_texture();
 	}
 
 	void make_hdr_target() {
@@ -947,6 +987,26 @@ struct C2 : public App {
 		);
 	}
 
+	void make_ui_texture() {
+		ui_texture = dev->create_texture(
+			"UI texture",
+			texture_format_rgba8i,
+			Texture_Flags::sampleable | Texture_Flags::copy_dst,
+			w,
+			h,
+			1,
+			1,
+			1,
+			Buffer_Id(0)
+		);
+		ui_buffer = dev->create_buffer(
+			"UI Buffer",
+			w * h * 4,
+			Buffer_Flags::copy_src |
+			Buffer_Flags::cpu_readwrite
+		);
+	}
+
 	void on_text_input(const char* buf) override {
 		ui->text_input(buf);
 	}
-- 
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