examples

commit 3f1a9b58f4d9a047f668e47c1f161b5af4f5ae3a
parent ca9406c1b018edf610a767c77a0d22bec8ce2bac
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Sun,  3 Apr 2022 14:17:43 +0100

gl-asteroids: Start rocks offscreen and draw the ship 5 times to avoid popping

Diffstat:
M
src/gl-asteroids.cpp
 | 
59
++++++++++++++++++++++++++++++++++++++++-------------------

1 file changed, 40 insertions(+), 19 deletions(-)
diff --git a/src/gl-asteroids.cpp b/src/gl-asteroids.cpp
@@ -123,8 +123,15 @@ struct physics
 	void move(float dt)
 	{
 		pos += vel * dt;
-		pos.x = wrap(pos.x, -1, 1);
-		pos.y = wrap(pos.y, -1, 1);
+		if (pos.x > 1 && vel.x > 0)
+			pos.x -= 2;
+		else if (pos.x < -1 && vel.x < 0)
+			pos.x += 2;
+
+		if (pos.y > 1 && vel.y > 0)
+			pos.y -= 2;
+		else if (pos.y < -1 && vel.y < 0)
+			pos.y += 2;
 		rot += ang_mom * dt;
 	}
 };
@@ -139,19 +146,26 @@ bool is_colliding(physics const& a, physics const& b)
 
 void draw(visual const& v, physics const& p)
 {
-	static coord const offsets[] = {{0,0}, {2,0}, {0,2}, {-2,0}, {0,-2}};
-	for (auto offset : offsets)
+	glBegin(v.mode);
+
+	for (unsigned i = 0; i < v.v.size(); ++i)
 	{
-		glBegin(v.mode);
+		if (i < v.c.size())
+			glColor(v.c[i]);
+		glCoord(rotate(v.v[i] * p.scale, p.rot) + p.pos);
+	}
 
-		for (unsigned i = 0; i < v.v.size(); ++i)
-		{
-			if (i < v.c.size())
-				glColor(v.c[i]);
-			glCoord(rotate(v.v[i] * p.scale, p.rot) + p.pos + offset);
-		}
+	glEnd();
+}
 
-		glEnd();
+void draw_wrapped(visual const& v, physics p)
+{
+	static coord const offsets[] = {{0,0}, {2,0}, {-2,2}, {-2,-2}, {2,-2}};
+
+	for (auto o : offsets)
+	{
+		p.pos += o;
+		draw(v, p);
 	}
 }
 
@@ -250,19 +264,26 @@ int main(int argc, char* argv[])
 
 			int dir = dis_d(gen);
 
+			auto scale = dis_s(gen);
+			coord p = {dis_p(gen), -1 - scale};
 			coord v(dis_v(gen), dis_v(gen));
+
+			v *= log(t+1);
+
 			if (dir & 1)
 				v.x = -v.x;
 			if (dir & 2)
+			{
+				p.y = -p.y;
 				v.y = -v.y;
-
-			v *= log(t+1);
-
-			coord p = {dis_p(gen), 1};
-			if (dir & 3)
+			}
+			if (dir & 4)
+			{
 				std::swap(p.x, p.y);
+				std::swap(v.x, v.y);
+			}
 
-			rocks.emplace_back(*rock_types[rtype], physics{p, v, 0, dis_a(gen), dis_s(gen)});
+			rocks.emplace_back(*rock_types[rtype], physics{p, v, 0, dis_a(gen), scale});
 		}
 
 		if (is_pressed(GLFW_KEY_SPACE) && bullet_time < t)
@@ -363,7 +384,7 @@ int main(int argc, char* argv[])
 		for (auto& b : bullets)
 			b.draw();
 
-		draw(ship, s);
+		draw_wrapped(ship, s);
 		if (up)
 			draw(flame, s);