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Update 2D_lensing.cpp

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cleaner, full geodesic grid with initrays func
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kavan 2025-05-24 11:16:25 -04:00 • committed by GitHub
parent daab5f29bf
commit e3be2cbd2c
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1 changed files with 25 additions and 15 deletions
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40
2D_lensing.cpp
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@ -77,7 +77,6 @@ struct physics {
return r_s * meterToPx; // convert to pixels
}
};
struct Engine {
GLFWwindow* window;
int WIDTH = 800;
@ -164,7 +163,7 @@ struct Engine {
for (size_t i = 0; i < N; ++i) {
// older points (i=0) get alpha≈0, newer get alpha≈1
float alpha = float(i) / float(N - 1);
glColor4f(1.0f, 1.0f, 1.0f, std::max(alpha, 1.05f));
glColor4f(1.0f, 1.0f, 1.0f, std::max(alpha, 0.05f));
glVertex2f(ray.trail[i].x, ray.trail[i].y);
}
glEnd();
@ -172,19 +171,35 @@ struct Engine {
glDisable(GL_BLEND);
}
void initRays (vector<Ray>& rays) {
for (int i = -10; i < 34; ++i) {
float y = i * 25;
rays.push_back({ vec2(800.0f, y), vec2(-c, 0.0f) });
}
for (int i = -10; i < 42; ++i) {
float x = i * 25;
rays.push_back({ vec2(x, 0.0f), vec2(0.0f, c) });
}
for (int i = -10; i < 34; ++i) {
float y = i * 25;
rays.push_back({ vec2(0.0f, y), vec2(c, 0.0f) });
}
for (int i = -10; i < 42; ++i) {
float x = i * 25;
rays.push_back({ vec2(x, 600.0f), vec2(0.0f, -c) });
}
}
static void mouseButtonCallback(GLFWwindow* window, int button, int action, int mods) {
if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS) {
Engine* engine = static_cast<Engine*>(glfwGetWindowUserPointer(window));
if (engine->raysPtr) {
for (int i = 0; i < 100; ++i) {
float y = 100 + i * 4;
engine->raysPtr->push_back({ vec2(800.0f, y), vec2(-c / 100.0f, 0.0f) });
}
engine->initRays(*engine->raysPtr);
}
}
}
};
void geodesicRHS(const Ray& ray, double rhs[4], double rs) {
double r = ray.r;
double dr = ray.dr;
@ -238,14 +253,9 @@ void rk4Step(Ray& ray, double dλ, double rs) {
int main() {
Engine engine;
physics phys;
std::vector<Ray> rays;
vector<Ray> rays;
// Init rays
for (int i = 0; i < 150; ++i) {
float y = 50 + i * 4;
rays.push_back({ vec2(800.0f, y), vec2(-c / 100.0f, 0.0f) });
}
//rays.push_back({ vec2(800.0f, 300.0f), vec2(-c, 0.0f) });
engine.initRays(rays);
// point engine to rays vector
engine.raysPtr = &rays;
@ -257,11 +267,11 @@ int main() {
glLoadIdentity();
// Update rays
float dt = 0.1f;
float dt = 0.001f;
for (auto& ray : rays) {
// - Check Event Horizon - //
if (length(vec2(ray.x, ray.y) - blackHolePos) < phys.rs_m()) continue;
if (length(vec2(ray.x, ray.y) - blackHolePos) < phys.rs_m()) {ray.trail.empty(); continue;};
ray.step(dt, phys.rs_m()); // evolve physics (r,φ,dr,dφ)