This function returns an alpha value at specified time.

Syntax

• float GetAlphaAtTime(float time)

Parameters

• time: - a value between 0.0 and 1.0 corresponding to a particle's lifetime. 0.0 being birth and 1.0 being death.

Returns

This function returns a float containing the alpha value between 0.0 and 1.0, 0 being transparent and 1 being opaque.

Example

#include "Leadwerks.h"

using namespace Leadwerks;

int main(int argc, const char *argv[])
{
    float time = 0.5;

    Leadwerks::Window* window = Leadwerks::Window::Create();
    Context* context = Context::Create(window);
    World* world = World::Create();
    Camera* camera = Camera::Create();
    camera->SetRotation(35, 0, 0);
    camera->Move(0, 0, -3);
    Light* light = DirectionalLight::Create();
    light->SetRotation(35, 35, 0);

    //Create an emitter
    Emitter* emitter = Emitter::Create(100);

    emitter->ClearAlphaControlPoints();//Remove default control points

    emitter->AddAlphaControlPoint(0, 0); //at spawn the particle will have an alpha of 0 (fully transparent)
    emitter->AddAlphaControlPoint(.5, 1); //halfway through the particle's lifetime alpha will be 1 (ie not transparent)
    emitter->AddAlphaControlPoint(1, 0); //at death the particle will be fully transparent

    while (true)
    {
        if (window->Closed() || window->KeyDown(Key::Escape)) return false;

        Leadwerks::Leadwerks::Time::Update();
        world->Update();
        world->Render();

        if (window->KeyDown(Key::Up) && time < 1.0)
        {
            time += .01;
        }
        else if (window->KeyDown(Key::Down) && time > 0.0)
        {
            time -= .01;
        }
        time = Math::Clamp(time, 0, 1);

        context->SetBlendMode(Blend::Alpha);
        context->DrawText("At  " + String(time * 100) + " percent of the particles life alpha will be :" + String(emitter->GetAlphaAtTime(time)), 2, 2);
        context->SetBlendMode(Blend::Solid);

        context->Sync();
    }
}