From ebdd90c5201833476fb29888ad81088963116052 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Wed, 25 May 2022 22:53:20 +0300
Subject: [PATCH] Add ui::painter::draw_triangle with per-vertex colors

---
 libs/ui/include/psemek/ui/painter.hpp      | 8 +++++++-
 libs/ui/include/psemek/ui/painter_impl.hpp | 2 +-
 libs/ui/source/painter_impl.cpp            | 8 ++++----
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/libs/ui/include/psemek/ui/painter.hpp b/libs/ui/include/psemek/ui/painter.hpp
index 3faf2257..2870944d 100644
--- a/libs/ui/include/psemek/ui/painter.hpp
+++ b/libs/ui/include/psemek/ui/painter.hpp
@@ -33,7 +33,13 @@ namespace psemek::ui
 	struct painter
 	{
 		virtual void draw_rect(geom::box<float, 2> const & rect, gfx::color_rgba const & color) = 0;
-		virtual void draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & color) = 0;
+
+		virtual void draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & color)
+		{
+			draw_triangle(tri, color, color, color);
+		}
+
+		virtual void draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & c0, gfx::color_rgba const & c1, gfx::color_rgba const & c2) = 0;
 
 		using color_mode = detail::color_mode;
 		using image_options = detail::image_options;
diff --git a/libs/ui/include/psemek/ui/painter_impl.hpp b/libs/ui/include/psemek/ui/painter_impl.hpp
index ed97c207..cc6af6df 100644
--- a/libs/ui/include/psemek/ui/painter_impl.hpp
+++ b/libs/ui/include/psemek/ui/painter_impl.hpp
@@ -16,7 +16,7 @@ namespace psemek::ui
 		~painter_impl();
 
 		void draw_rect(geom::box<float, 2> const & rect, gfx::color_rgba const & color) override;
-		void draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & color) override;
+		void draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & c0, gfx::color_rgba const & c1, gfx::color_rgba const & c2) override;
 
 		void draw_image(geom::box<float, 2> const & rect, gfx::texture_view_2d const & tex, image_options const & opts) override;
 
diff --git a/libs/ui/source/painter_impl.cpp b/libs/ui/source/painter_impl.cpp
index 39d8b932..15f7925f 100644
--- a/libs/ui/source/painter_impl.cpp
+++ b/libs/ui/source/painter_impl.cpp
@@ -245,16 +245,16 @@ void main()
 		impl().draw_bbox |= rect;
 	}
 
-	void painter_impl::draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & color)
+	void painter_impl::draw_triangle(geom::triangle<geom::point<float, 2>> const & tri, gfx::color_rgba const & c0, gfx::color_rgba const & c1, gfx::color_rgba const & c2)
 	{
 		auto & batch = impl().batch<colored_batch>({});
 
 		std::uint32_t const depth = impl().depth++;
 		std::uint32_t const base = batch.vertices.size();
 
-		batch.vertices.push_back({tri[0], depth, color});
-		batch.vertices.push_back({tri[1], depth, color});
-		batch.vertices.push_back({tri[2], depth, color});
+		batch.vertices.push_back({tri[0], depth, c0});
+		batch.vertices.push_back({tri[1], depth, c1});
+		batch.vertices.push_back({tri[2], depth, c2});
 
 		batch.indices.insert(batch.indices.end(), {base + 0, base + 1, base + 2});