allow configuring msaa samples at runtime

3 files changed, 70 insertions, 37 deletions

diff --git a/editor/app.cpp b/editor/app.cpp
index 986f6102..b031d6f3 100644
--- a/editor/app.cpp
+++ b/editor/app.cpp
@@ -52,16 +52,36 @@ static bool parse_bool(StringView name, const Corrade::Utility::Arguments& args,
     return def;
 }
 
+static int atoi_(const char* str)
+{
+    bool negative = false;
+
+    switch (*str)
+    {
+    case '+': ++str; break;
+    case '-': ++str; negative = true; break;
+    }
+
+    int result = 0;
+    for (; *str >= '0' && *str <= '9'; ++str)
+    {
+        int digit = *str - '0';
+        result *= 10;
+        result -= digit; // calculate in negatives to support INT_MIN, LONG_MIN,..
+    }
+
+    return negative ? result : -result;
+}
+
 int app::run_from_argv(const int argc, const char* const* const argv)
 {
     fm_settings opts;
     Corrade::Utility::Arguments args{};
     args.addOption("vsync", "1")
         .addOption("gpu-debug", "1")
-        .addOption("msaa", "1")
+        .addOption("msaa", "")
         .parse(argc, argv);
     opts.vsync = parse_bool("vsync", args, opts.vsync);
-    opts.msaa  = parse_bool("msaa", args, opts.msaa);
     if (auto str = args.value<StringView>("gpu-debug"); str == "no-error" || str == "none")
         opts.gpu_debug = fm_gpu_debug::no_error;
     else if (str == "robust" || str == "full")
@@ -71,12 +91,21 @@ int app::run_from_argv(const int argc, const char* const* const argv)
                          ? fm_gpu_debug::on
                          : fm_gpu_debug::off;
 
+    if (auto str = args.value<StringView>("msaa"); !str.isEmpty())
+    {
+        if (int n = atoi_(str.data()); (unsigned)n > 32 || (n & (n - 1)) != 0)
+            fm_warn("invalid '--msaa' argument '%s': must be a power of two between 0 and 128", str.data());
+        else
+            opts.msaa_samples = (std::uint8_t)n;
+    }
+
     int ret;
     Pointer<floormat_main> ptr;
     {
         app application{std::move(opts)};
         ret = application.exec();
         ptr = std::move(application.M);
+        (void)ptr;
     }
     loader_::destroy();
     return ret;
diff --git a/floormat/settings.hpp b/floormat/settings.hpp
index 39b5b137..01ded6c4 100644
--- a/floormat/settings.hpp
+++ b/floormat/settings.hpp
@@ -20,16 +20,15 @@ struct fm_settings
     Magnum::Math::Vector2<int> resolution{1024, 768};
     Corrade::Containers::String title{"Test"};
     Corrade::Containers::String disabled_extensions; // TODO
-    std::uint8_t msaa_samples = 16;
     bool vsync = true;
     fm_gpu_debug gpu_debug = fm_gpu_debug::on;
     fm_log_level log_level = fm_log_level::normal;
-    std::uint8_t resizable          : 1 = true,
-                 fullscreen         : 1 = false,
-                 fullscreen_desktop : 1 = false,
-                 borderless         : 1 = false,
-                 maximized          : 1 = false,
-                 msaa               : 1 = false;
+    unsigned resizable          : 1 = true,
+             fullscreen         : 1 = false,
+             fullscreen_desktop : 1 = false,
+             borderless         : 1 = false,
+             maximized          : 1 = false;
+    std::uint8_t msaa_samples = 16;
 };
 
 } // namespace floormat
diff --git a/main/draw.cpp b/main/draw.cpp
index 45113958..98f5da85 100644
--- a/main/draw.cpp
+++ b/main/draw.cpp
@@ -7,8 +7,6 @@
 #include <algorithm>
 #include <thread>
 
-//#define FM_SKIP_MSAA
-
 namespace floormat {
 
 void main_impl::recalc_viewport(Vector2i size) noexcept
@@ -25,16 +23,19 @@ void main_impl::recalc_viewport(Vector2i size) noexcept
     else
         _msaa_framebuffer = GL::Framebuffer{{{}, size}};
 
-    // --- color ---
-    _msaa_color = Magnum::GL::Renderbuffer{};
     const int samples = std::min(_msaa_color.maxSamples(), (int)s.msaa_samples);
-    _msaa_color.setStorageMultisample(samples, GL::RenderbufferFormat::RGBA8, size);
-    _msaa_framebuffer.attachRenderbuffer(GL::Framebuffer::ColorAttachment{0}, _msaa_color);
-
-    // --- depth ---
-    _msaa_depth = Magnum::GL::Renderbuffer{};
-    _msaa_depth.setStorageMultisample(samples, GL::RenderbufferFormat::DepthStencil, size);
-    _msaa_framebuffer.attachRenderbuffer(GL::Framebuffer::BufferAttachment::DepthStencil, _msaa_depth);
+    if (samples != s.msaa_samples)
+        fm_warn_once("using only %d MSAA samples (instead of %hhu)", samples, s.msaa_samples);
+    if (s.msaa_samples > 0) {
+        // color
+        _msaa_color = Magnum::GL::Renderbuffer{};
+        _msaa_color.setStorageMultisample(samples, GL::RenderbufferFormat::RGBA8, size);
+        _msaa_framebuffer.attachRenderbuffer(GL::Framebuffer::ColorAttachment{0}, _msaa_color);
+        // depth
+        _msaa_depth = Magnum::GL::Renderbuffer{};
+        _msaa_depth.setStorageMultisample(samples, GL::RenderbufferFormat::DepthStencil, size);
+        _msaa_framebuffer.attachRenderbuffer(GL::Framebuffer::BufferAttachment::DepthStencil, _msaa_depth);
+    }
 
     // -- state ---
     using R = GL::Renderer;
@@ -98,11 +99,10 @@ void main_impl::draw_world() noexcept
 
     GL::Renderer::enable(GL::Renderer::Feature::DepthTest);
     constexpr float clear_depth = 0;
-#ifdef FM_SKIP_MSAA
-    GL::defaultFramebuffer.clearDepthStencil(clear_depth, 0);
-#else
-    _msaa_framebuffer.clearDepthStencil(clear_depth, 0);
-#endif
+    if (s.msaa_samples == 0)
+        GL::defaultFramebuffer.clearDepthStencil(clear_depth, 0);
+    else
+        _msaa_framebuffer.clearDepthStencil(clear_depth, 0);
     for (std::int16_t y = miny; y <= maxy; y++)
         for (std::int16_t x = minx; x <= maxx; x++)
         {
@@ -165,20 +165,25 @@ void main_impl::drawEvent()
 
     {
         const auto clear_color = 0x222222ff_rgbaf;
-#ifdef FM_SKIP_MSAA
-        GL::defaultFramebuffer.clearColor(clear_color);
-#else
-        _msaa_framebuffer.clearColor(0, clear_color);
-        _msaa_framebuffer.bind();
-#endif
+
+        if (s.msaa_samples == 0)
+            GL::defaultFramebuffer.clearColor(clear_color);
+        else
+        {
+            _msaa_framebuffer.clearColor(0, clear_color);
+            _msaa_framebuffer.bind();
+        }
+
         draw_world();
         app.draw_msaa();
-#ifndef FM_SKIP_MSAA
-        GL::defaultFramebuffer.bind();
-        using Blit = GL::FramebufferBlit;
-        constexpr auto blit_mask = Blit::Color /* | Blit::Depth | Blit::Stencil */;
-        GL::Framebuffer::blit(_msaa_framebuffer, GL::defaultFramebuffer, {{}, windowSize()}, blit_mask);
-#endif
+
+        if (s.msaa_samples > 0)
+        {
+            GL::defaultFramebuffer.bind();
+            using Blit = GL::FramebufferBlit;
+            constexpr auto blit_mask = Blit::Color /* | Blit::Depth | Blit::Stencil */;
+            GL::Framebuffer::blit(_msaa_framebuffer, GL::defaultFramebuffer, {{}, windowSize()}, blit_mask);
+        }
     }
 
     app.draw();