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| -rw-r--r-- | docs/architecture.md | 2 | ||||
| -rw-r--r-- | docs/physics.md | 10 |
2 files changed, 4 insertions, 8 deletions
diff --git a/docs/architecture.md b/docs/architecture.md index 4eb4153..5762dfd 100644 --- a/docs/architecture.md +++ b/docs/architecture.md @@ -169,7 +169,7 @@ The editor and the simulation are the same world, not two separate scenes. The constant `SCENE_UNITS_PER_RS = 3.0` connects them: three editor grid units equal one Schwarzschild radius. `SceneRenderer` draws the black-hole marker's horizon at that radius, and `BlackHoleRenderer` takes every placed `SceneObject`, multiplies -its position and radius by $\text{SagA\_rs}/3$ to reach physical metres, and uploads +its position and radius by $r_s/3$ (the code's `SagA_rs / 3`) to reach physical metres, and uploads them into the shader's `Objects` uniform (up to 16 spheres). So a sphere placed on the Scene tab shows up in the same spot on the Simulation diff --git a/docs/physics.md b/docs/physics.md index 4877f64..d484cb0 100644 --- a/docs/physics.md +++ b/docs/physics.md @@ -73,7 +73,7 @@ R_ISCO = 3.0 * SagA_rs // ISCO (6M) The scene editor uses a friendlier grid. The constant `SCENE_UNITS_PER_RS = 3.0` (in [`src/scene/scene_types.h`](../src/scene/scene_types.h)) sets three grid units to one Schwarzschild radius. When the renderer hands a placed object to the shader -it scales the position by $\text{SagA\_rs}/3$ to get metres, so the editor and the +it scales the position by $r_s/3$ (the code's `SagA_rs / 3`) to get metres, so the editor and the simulation always agree on where things sit. ## The Schwarzschild metric @@ -188,14 +188,10 @@ far from the hole and lose the trajectory near it, so the step scales with dista from the photon sphere: $$ -\Delta\lambda = \operatorname{clamp}\!\left(0.02\,\max(r - r_\text{photon},\,0),\; \Delta_\text{min},\; \Delta_\text{max}\right), -\qquad -\begin{aligned} -\Delta_\text{min} &= 10^6\\ -\Delta_\text{max} &= 2\times10^{10} -\end{aligned} +\Delta\lambda = \mathrm{clamp}\!\left(0.02\,\max(r - r_\text{photon},\,0),\; \Delta_\text{min},\; \Delta_\text{max}\right), $$ +with $\Delta_\text{min} = 10^6$ and $\Delta_\text{max} = 2\times10^{10}$ metres. Far out, the ray is in near-flat space and crosses it in a handful of long strides. Near the photon sphere, where the path bends hardest and mistakes show the most, the step shrinks to follow the curve. A second clamp forces the step |