From 33cac94476fe1a1341edc2fa3d5a6a02e4d26bf8 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Tue, 29 Nov 2022 20:10:41 +0100
Subject: main: add float depth buffer

---
 main/draw.cpp      | 36 +++++++++++++++++++++++++-----------
 main/main-impl.hpp |  7 +++++++
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/main/draw.cpp b/main/draw.cpp
index 0b797449..3c3ba97b 100644
--- a/main/draw.cpp
+++ b/main/draw.cpp
@@ -6,6 +6,7 @@
 #include <Corrade/Containers/ArrayView.h>
 #include <Magnum/GL/DefaultFramebuffer.h>
 #include <Magnum/GL/Renderer.h>
+#include <Magnum/GL/RenderbufferFormat.h>
 #include <Magnum/Math/Color.h>
 #include <algorithm>
 #include <thread>
@@ -14,6 +15,21 @@ namespace floormat {
 
 void main_impl::recalc_viewport(Vector2i size) noexcept
 {
+    if (_screen.fb.id())
+    {
+        _screen.fb.detach(GL::Framebuffer::ColorAttachment{0});
+        _screen.fb.detach(GL::Framebuffer::BufferAttachment::Depth);
+    }
+
+    _screen.fb = GL::Framebuffer{{{}, size}};
+    _screen.color = GL::Renderbuffer{};
+    _screen.color.setStorage(GL::RenderbufferFormat::RGBA8, size);
+    _screen.depth = GL::Renderbuffer{};
+    _screen.depth.setStorage(GL::RenderbufferFormat::DepthComponent32F, size);
+
+    _screen.fb.attachRenderbuffer(GL::Framebuffer::ColorAttachment{0}, _screen.color);
+    _screen.fb.attachRenderbuffer(GL::Framebuffer::BufferAttachment::Depth, _screen.depth);
+
     update_window_state();
     _shader.set_scale(Vector2{size});
     GL::defaultFramebuffer.setViewport({{}, size });
@@ -26,9 +42,12 @@ void main_impl::recalc_viewport(Vector2i size) noexcept
     GL::Renderer::disable(R::Feature::DepthTest);
     GL::Renderer::enable(R::Feature::Blending);
     GL::Renderer::enable(R::Feature::ScissorTest);
+    GL::Renderer::enable(R::Feature::DepthClamp);
     GL::Renderer::setDepthFunction(R::DepthFunction::Greater);
     GL::Renderer::setScissor({{}, size});
 
+    _screen.fb.bind();
+
     // -- user--
     app.on_viewport_event(size);
 }
@@ -79,8 +98,8 @@ void main_impl::draw_world() noexcept
         }
 
     GL::Renderer::enable(GL::Renderer::Feature::DepthTest);
-    constexpr float clear_depth = 0;
-    GL::defaultFramebuffer.clearDepthStencil(clear_depth, 0);
+    constexpr float clear_depth = -1 << 24;
+    _screen.fb.clearDepth(clear_depth);
     for (std::int16_t y = miny; y <= maxy; y++)
         for (std::int16_t x = minx; x <= maxx; x++)
         {
@@ -90,7 +109,6 @@ void main_impl::draw_world() noexcept
             if (check_chunk_visible(_shader.camera_offset(), sz))
                 _wall_mesh.draw(_shader, c);
         }
-    GL::Renderer::disable(GL::Renderer::Feature::DepthTest);
 }
 
 void main_impl::draw_anim() noexcept
@@ -99,8 +117,6 @@ void main_impl::draw_anim() noexcept
     const auto [minx, maxx, miny, maxy] = get_draw_bounds();
     _clickable_scenery.clear();
 
-    GL::Renderer::enable(GL::Renderer::Feature::DepthTest);
-
     for (std::int16_t y = miny; y <= maxy; y++)
         for (std::int16_t x = minx; x <= maxx; x++)
         {
@@ -129,8 +145,6 @@ void main_impl::draw_anim() noexcept
                     }
                 }
         }
-
-    GL::Renderer::disable(GL::Renderer::Feature::DepthTest);
 }
 
 bool main_impl::check_chunk_visible(const Vector2d& offset, const Vector2i& size) noexcept
@@ -184,16 +198,16 @@ void main_impl::drawEvent()
     _shader.set_tint({1, 1, 1, 1});
 
     {
+        _shader.set_tint({1, 1, 1, 1});
         const auto clear_color = 0x222222ff_rgbaf;
-
-        GL::defaultFramebuffer.clearColor(clear_color);
-
+        _screen.fb.clearColor(0, clear_color);
         draw_world();
-        _shader.set_tint({1, 1, 1, 1});
         draw_anim();
+        GL::Renderer::disable(GL::Renderer::Feature::DepthTest);
     }
 
     app.draw();
+    GL::Framebuffer::blit(_screen.fb, GL::defaultFramebuffer, {{}, windowSize()}, GL::FramebufferBlit::Color);
     GL::Renderer::flush();
 
     do_update();
diff --git a/main/main-impl.hpp b/main/main-impl.hpp
index cc17f9bc..85c61951 100644
--- a/main/main-impl.hpp
+++ b/main/main-impl.hpp
@@ -12,6 +12,8 @@
 #include <Magnum/Timeline.h>
 #include <Magnum/Math/Range.h>
 #include <Magnum/GL/DebugOutput.h>
+#include <Magnum/GL/Framebuffer.h>
+#include <Magnum/GL/Renderbuffer.h>
 #include <Magnum/Platform/Sdl2Application.h>
 
 namespace floormat {
@@ -76,6 +78,11 @@ private:
     tile_shader _shader;
     std::vector<clickable<anim_atlas, scenery>> _clickable_scenery;
     struct world _world{};
+
+    struct {
+        GL::Framebuffer fb{NoCreate};
+        GL::Renderbuffer color{NoCreate}, depth{NoCreate};
+    } _screen;
     Magnum::Timeline timeline;
     floor_mesh _floor_mesh;
     wall_mesh _wall_mesh;
-- 
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