diff options
| author | Alec Thomas <alec@swapoff.org> | 2017-01-07 23:06:00 +1100 |
|---|---|---|
| committer | Alec Thomas <alec@swapoff.org> | 2017-01-07 23:06:00 +1100 |
| commit | 36e33cd6f39df3bd830c0832ec605d11cbee4c91 (patch) | |
| tree | e93e6e8a06ea0a00c50ee246b62f0c6a036318e8 | |
| parent | 3c6eff56897d44afd8424900a005112cc32b8a86 (diff) | |
Updates to example.
- Fade in bodies.
- Spin particles per their rotation (this fell by the wayside when
translated to a vertex array).
| -rw-r--r-- | examples/example.cc | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/examples/example.cc b/examples/example.cc index 5e2bc88..a1ec1c1 100644 --- a/examples/example.cc +++ b/examples/example.cc @@ -41,15 +41,17 @@ float r(int a, float b = 0) { struct Body { Body(const sf::Vector2f &position, const sf::Vector2f &direction, float rotationd = 0.0) - : position(position), direction(direction), rotationd(rotationd) {} + : position(position), direction(direction), rotationd(rotationd), alpha(0.0) {} sf::Vector2f position; sf::Vector2f direction; - float rotation = 0.0, rotationd; + float rotation = 0.0, rotationd, alpha; }; + using Renderable = std::shared_ptr<sf::Shape>; + struct Particle { explicit Particle(sf::Color colour, float radius, float duration) : colour(colour), radius(radius), alpha(colour.a), d(colour.a / duration) {} @@ -96,7 +98,7 @@ public: // Shape to apply to entity. Renderable shape(new sf::CircleShape(collideable->radius)); - shape->setFillColor(sf::Color(r(128, 127), r(128, 127), r(128, 127))); + shape->setFillColor(sf::Color(r(128, 127), r(128, 127), r(128, 127), 0)); shape->setOrigin(collideable->radius, collideable->radius); entity.assign<Renderable>(shape); } @@ -111,9 +113,11 @@ private: // Updates a body's position and rotation. struct BodySystem : public ex::System<BodySystem> { void update(ex::EntityManager &es, ex::EventManager &events, ex::TimeDelta dt) override { - es.each<Body>([dt](ex::Entity entity, Body &body) { - body.position += body.direction * static_cast<float>(dt); - body.rotation += body.rotationd * dt; + const float fdt = static_cast<float>(dt); + es.each<Body>([fdt](ex::Entity entity, Body &body) { + body.position += body.direction * fdt; + body.rotation += body.rotationd * fdt; + body.alpha = std::min(1.0f, body.alpha + fdt); }); }; }; @@ -219,6 +223,7 @@ private: }; +// Fade out and then remove particles. class ParticleSystem : public ex::System<ParticleSystem> { public: void update(ex::EntityManager &es, ex::EventManager &events, ex::TimeDelta dt) override { @@ -234,6 +239,7 @@ public: }; +// Renders all explosion particles efficiently as a quad vertex array. class ParticleRenderSystem : public ex::System<ParticleRenderSystem> { public: explicit ParticleRenderSystem(sf::RenderTarget &target) : target(target) {} @@ -242,10 +248,13 @@ public: sf::VertexArray vertices(sf::Quads); es.each<Particle, Body>([&vertices](ex::Entity entity, Particle &particle, Body &body) { const float r = particle.radius; - vertices.append(sf::Vertex(body.position + sf::Vector2f(-r, -r), particle.colour)); - vertices.append(sf::Vertex(body.position + sf::Vector2f(r, -r), particle.colour)); - vertices.append(sf::Vertex(body.position + sf::Vector2f(r, r), particle.colour)); - vertices.append(sf::Vertex(body.position + sf::Vector2f(-r, r), particle.colour)); + // Spin the particles. + sf::Transform transform; + transform.rotate(body.rotation); + vertices.append(sf::Vertex(body.position + transform.transformPoint(sf::Vector2f(-r, -r)), particle.colour)); + vertices.append(sf::Vertex(body.position + transform.transformPoint(sf::Vector2f(r, -r)), particle.colour)); + vertices.append(sf::Vertex(body.position + transform.transformPoint(sf::Vector2f(r, r)), particle.colour)); + vertices.append(sf::Vertex(body.position + transform.transformPoint(sf::Vector2f(-r, r)), particle.colour)); }); target.draw(vertices); } @@ -319,6 +328,9 @@ public: void update(ex::EntityManager &es, ex::EventManager &events, ex::TimeDelta dt) override { es.each<Body, Renderable>([this](ex::Entity entity, Body &body, Renderable &renderable) { + sf::Color fillColor = renderable->getFillColor(); + fillColor.a = sf::Uint8(body.alpha * 255); + renderable->setFillColor(fillColor); renderable->setPosition(body.position); renderable->setRotation(body.rotation); target.draw(*renderable.get()); |