Add axes & sphere drawing for gfx::painter

libs/gfx/include/psemek/gfx/painter.hpp

@@ -53,9 +53,14 @@ namespace psemek::gfx
 		void circle(geom::point<float, 2> const & center, float radius, color const & c);
 		void line(geom::point<float, 2> const & p0, geom::point<float, 2> const & p1, float width, color const & c, bool smooth = true);
 
+		// 2D text
 		geom::vector<float, 2> text_size(std::string_view str, font f = font::font_9x12, float scale = 1.f);
 		void text(geom::point<float, 2> const & p, std::string_view str, text_options const & opts);
 
+		// 3D
+		void axes(geom::point<float, 3> const & p, float length, float width);
+		void sphere(geom::point<float, 3> const & p, float radius, color const & c, int quality = 6);
+
 		// Should be called on each frame
 		void render(geom::matrix<float, 4, 4> const & transform);
 

libs/gfx/source/painter.cpp

@@ -292,6 +292,131 @@ namespace psemek::gfx
 		}
 	}
 
+	void painter::axes(geom::point<float, 3> const & p, float length, float width)
+	{
+		geom::vector<float, 3> const d[3]
+		{
+			{ 1.f, 0.f, 0.f },
+			{ 0.f, 1.f, 0.f },
+			{ 0.f, 0.f, 1.f },
+		};
+
+		color const c[3]
+		{
+			{ 255, 0, 0, 255 },
+			{ 0, 255, 0, 255 },
+			{ 0, 0, 255, 255 },
+		};
+
+		for (int i = 0; i < 3; ++i)
+		{
+			int j = (i + 1) % 3;
+			int k = (i + 2) % 3;
+
+			std::uint32_t const base = impl().vertices.size();
+
+			impl().vertices.push_back({p + d[i] * length, c[i]});
+			impl().vertices.push_back({p + d[j] * width, c[i]});
+			impl().vertices.push_back({p + d[k] * width, c[i]});
+			impl().vertices.push_back({p - d[j] * width, c[i]});
+			impl().vertices.push_back({p - d[k] * width, c[i]});
+
+			impl().indices.push_back(base + 0);
+			impl().indices.push_back(base + 1);
+			impl().indices.push_back(base + 2);
+			impl().indices.push_back(base + 0);
+			impl().indices.push_back(base + 2);
+			impl().indices.push_back(base + 3);
+			impl().indices.push_back(base + 0);
+			impl().indices.push_back(base + 3);
+			impl().indices.push_back(base + 4);
+			impl().indices.push_back(base + 0);
+			impl().indices.push_back(base + 4);
+			impl().indices.push_back(base + 1);
+		}
+
+		std::uint32_t const base = impl().vertices.size();
+
+		color const white {255, 255, 255, 255};
+
+		impl().vertices.push_back({p - d[0] * width, white});
+		impl().vertices.push_back({p - d[1] * width, white});
+		impl().vertices.push_back({p - d[2] * width, white});
+
+		impl().indices.push_back(base + 0);
+		impl().indices.push_back(base + 2);
+		impl().indices.push_back(base + 1);
+	}
+
+	void painter::sphere(geom::point<float, 3> const & p, float radius, color const & c, int quality)
+	{
+		std::uint32_t const base = impl().vertices.size();
+
+		impl().vertices.push_back({p - geom::vector{0.f, 0.f, radius}, c});
+		impl().vertices.push_back({p + geom::vector{0.f, 0.f, radius}, c});
+
+		auto const ray = [](float ax, float ay)
+		{
+			return geom::vector{std::cos(ax) * std::cos(ay), std::sin(ax) * std::cos(ay), std::sin(ay)};
+		};
+
+		for (int y = - quality + 1; y < quality; ++y)
+		{
+			for (int x = 0; x < quality * 4; ++x)
+			{
+				float ax = (x * geom::pi) / quality / 2.f;
+				float ay = (y * geom::pi) / quality / 2.f;
+
+				impl().vertices.push_back({p + radius * ray(ax, ay), c});
+			}
+		}
+
+		auto const index = [quality, base](int x, int y)
+		{
+			if (y == -quality)
+				return base;
+			if (y == quality)
+				return base + 1;
+
+			return static_cast<std::uint32_t>(2 + (y + quality - 1) * 4 * quality + x);
+		};
+
+		for (int x = 0; x < quality * 4; ++x)
+		{
+			int xx = (x + 1) % (quality * 4);
+
+			impl().indices.push_back(index(x, - quality + 1));
+			impl().indices.push_back(index(x, - quality));
+			impl().indices.push_back(index(xx, - quality + 1));
+		}
+
+		for (int y = - quality + 1; y + 1 < quality; ++y)
+		{
+			for (int x = 0; x < quality * 4; ++x)
+			{
+				int yy = y + 1;
+				int xx = (x + 1) % (quality * 4);
+
+				impl().indices.push_back(index(x, y));
+				impl().indices.push_back(index(xx, y));
+				impl().indices.push_back(index(xx, yy));
+
+				impl().indices.push_back(index(x, y));
+				impl().indices.push_back(index(xx, yy));
+				impl().indices.push_back(index(x, yy));
+			}
+		}
+
+		for (int x = 0; x < quality * 4; ++x)
+		{
+			int xx = (x + 1) % (quality * 4);
+
+			impl().indices.push_back(index(x, quality - 1));
+			impl().indices.push_back(index(xx, quality - 1));
+			impl().indices.push_back(index(x, quality));
+		}
+	}
+
 	void painter::render(geom::matrix<float, 4, 4> const & transform)
 	{
 		impl().mesh.load(impl().vertices, impl().indices, gl::STREAM_DRAW);

todo.md

@@ -3,3 +3,4 @@
 * Design ui system
 * Add platform deployment tools
 * Add color utilities
+* gfx::painter should support normals & minimal lighting (maybe split into separate 2D & 3D painters?)