examples

commit 483fbed7782d799ef4a4b04619e61b8949b4674d
parent a9a3d1db2af2ca9a43e1884bfda67dfc32afc665
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Thu, 27 Jun 2024 00:09:21 +0100

sdl-gl: Add more shapes

Diffstat:
M
src/sdl-gl.cpp
 | 
109
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------

1 file changed, 87 insertions(+), 22 deletions(-)
diff --git a/src/sdl-gl.cpp b/src/sdl-gl.cpp
@@ -191,21 +191,24 @@ point pan = {0, 0};
 
 point mouse_pos;
 
+struct shp
+{
+	std::vector<point> vertices;
+	std::vector<unsigned char> wireframe;
+	GLuint mode;
+};
+
+std::vector<shp> shapes;
+
 struct object
 {
 	circle pos;
 	rgb col;
 	float spin;
 	float rotation;
+	shp& shape;
 };
-std::vector<std::shared_ptr<object>> objs = {
-	std::make_shared<object>(circle{{-1.5f, -1}, 1.f}, rgb{.7,.2,.2}, .2),
-	std::make_shared<object>(circle{{0, 1}, .5f}, rgb{.2,.7,.2}, 0),
-	std::make_shared<object>(circle{{1.5f, -1}, 1.f}, rgb{.2,.2,.7}, -.2),
-};
-
-std::vector<point> shape;
-std::span<point> shape_wireframe;
+std::vector<std::shared_ptr<object>> objs = {};
 
 constexpr auto deref = std::views::transform([](auto const& p) -> auto& { return *p; });
 
@@ -223,8 +226,8 @@ void presentScene(void)
 
 		if (not wireframe)
 		{
-			glBegin(GL_TRIANGLE_FAN);
-			for (auto p : shape)
+			glBegin(o.shape.mode);
+			for (auto p : o.shape.vertices)
 			{
 				p *= o.pos.radius;
 				auto pp = (p * r + pan + o.pos.pos) * scale;
@@ -234,8 +237,9 @@ void presentScene(void)
 		else
 		{
 			glBegin(GL_LINE_LOOP);
-			for (auto p : shape_wireframe)
+			for (auto idx : o.shape.wireframe)
 			{
+				auto p = o.shape.vertices[idx];
 				p *= o.pos.radius;
 				auto pp = (p * r + pan + o.pos.pos) * scale;
 				glVertex2f(pp.x / aspect_ratio, pp.y);
@@ -282,8 +286,6 @@ void panel::draw() const
 	glEnd();
 }
 
-
-
 void key(SDL_KeyboardEvent& e)
 {
 	static std::uniform_real_distribution<float> size_dis{.5f, 1.5f};
@@ -304,7 +306,10 @@ void key(SDL_KeyboardEvent& e)
 
 	case SDLK_a:
 		if (e.state)
-			objs.push_back(std::make_shared<object>(circle{mouse_pos, size_dis(gen)}, rgb::random(), norm_dis(gen), 0));
+		{
+			static int i = 0;
+			objs.push_back(std::make_shared<object>(circle{mouse_pos, size_dis(gen)}, rgb::random(), norm_dis(gen), 0, shapes[i++ % shapes.size()]));
+		}
 		break;
 
 	case SDLK_d:
@@ -314,15 +319,26 @@ void key(SDL_KeyboardEvent& e)
 
 	case SDLK_r:
 		if (e.state)
-		{
 			for (auto& obj : objs | deref)
 				if (obj.pos.colliding(mouse_pos))
 				{
 					std::swap(obj.col.r, obj.col.g);
 					std::swap(obj.col.g, obj.col.b);
 				}
+		break;
 
-		}
+	case SDLK_EQUALS:
+		if (e.state)
+			for (auto& obj : objs | deref)
+				if (obj.pos.colliding(mouse_pos))
+					obj.pos.radius *= 1.2;
+		break;
+
+	case SDLK_MINUS:
+		if (e.state)
+			for (auto& obj : objs | deref)
+				if (obj.pos.colliding(mouse_pos))
+					obj.pos.radius /= 1.2;
 		break;
 
 	case SDLK_s:
@@ -457,12 +473,60 @@ void doInput()
 
 void init_shape()
 {
-	constexpr int n = 10;
-	shape.emplace_back(0,0);
-	for (int i = 0; i <= n; ++i)
-		shape.push_back(point{0, (.65f + i % 2) / -1.65f} * rotor::angle((float)i / n));
-	shape_wireframe = shape;
-	shape_wireframe = shape_wireframe.subspan(1, shape.size() - 2);
+	{
+		constexpr int n = 10;
+		shapes.emplace_back();
+		auto& shape = shapes.back();
+		shape.mode = GL_TRIANGLE_FAN;
+		shape.vertices.emplace_back(0,0);
+		for (int i = 0; i <= n; ++i)
+			shape.vertices.push_back(point{0, (.65f + i % 2) / -1.65f} * rotor::angle((float)i / n));
+		for (int i = 0; i < n; ++i)
+			shape.wireframe.push_back(i+1);
+	}
+	{
+		constexpr int n = 3;
+		shapes.emplace_back();
+		auto& shape = shapes.back();
+		shape.mode = GL_TRIANGLES;
+		for (int i = 0; i < n; ++i)
+			shape.vertices.push_back(point{0, 1} * rotor::angle((float)i / n));
+		for (int i = 0; i < n; ++i)
+			shape.wireframe.push_back(i);
+	}
+	{
+		constexpr int n = 4;
+		shapes.emplace_back();
+		auto& shape = shapes.back();
+		shape.mode = GL_TRIANGLE_FAN;
+		for (int i = 0; i < n; ++i)
+			shape.vertices.push_back(point{0, 1} * rotor::angle((float)i / n));
+		for (int i = 0; i < n; ++i)
+			shape.wireframe.push_back(i);
+	}
+	{
+		constexpr int n = 20;
+		shapes.emplace_back();
+		auto& shape = shapes.back();
+		shape.mode = GL_TRIANGLE_STRIP;
+		for (int i = 0; i <= n; ++i)
+		{
+			float turns = i * .5f / n;
+			float radians = turns * 2 * std::numbers::pi;
+			shape.vertices.push_back(point{0, 1 - i % 2 * .5f * sin(radians)} * rotor::angle(turns));
+		}
+		for (int i = 0; i <= n / 2; ++i)
+			shape.wireframe.push_back(i * 2);
+		for (int i = n / 2; i > 0; --i)
+			shape.wireframe.push_back(i * 2 - 1);
+	}
+}
+
+void init_scene()
+{
+	objs.push_back(std::make_shared<object>(circle{{-1.5f, -1}, 1.f}, rgb{.7,.2,.2}, .2, 0, shapes[0]));
+	objs.push_back(std::make_shared<object>(circle{{0, 1}, .5f}, rgb{.2,.7,.2}, 0, 0, shapes[0]));
+	objs.push_back(std::make_shared<object>(circle{{1.5f, -1}, 1.f}, rgb{.2,.2,.7}, -.2, 0, shapes[0]));
 }
 
 struct psf2
@@ -571,6 +635,7 @@ void draw_UI()
 int main()
 {
 	init_shape();
+	init_scene();
 	mouse_task();
 	initSDL();
 	atexit(SDL_Quit);