path: root/src/buffer/vertex
AgeCommit message (Collapse)Author
2019-04-28Experimental visualization of the velocity curlAdrian Kummerlaender
Calculating the curl of our simulated velocity field requires an additional compute shader step. Handling of buffer and shader switching depending on the display mode is implemented rudimentarily for now. Most of this commit is scaffolding, the actual computation is more or less trivial: ``` const float dxvy = (getFluidVelocity(x+1,y).y - getFluidVelocity(x-1,y).y) / (2*convLength); const float dyvx = (getFluidVelocity(x,y+1).x - getFluidVelocity(x,y-1).x) / (2*convLength); setFluidExtra(x, y, dxvy - dyvx); ``` This implements the following discretization of the 2d curl operator: Let $V : \mathbb{N}^2 \to \mathbb{R}^2$ be the simulated velocity field at discrete lattice points spaced by $\Delta x \in \mathbb{R}_{\gt 0}$. We want to approximate the $z$-component of the curl for visualization: $$\omega := \partial_x F_y - \partial_y F_x$$ As we do not possess the actual function $F$ but only its values at a set of discrete points we approximate the two partial derivatives using a second order central difference scheme: $$\overline{\omega}(i,j) := \frac{F_y(i+1,j) - F_y(i-1,j)}{2 \Delta x} - \frac{F_x(i,j+1) - F_x(i,j-1)}{2 \Delta x}$$ Note that the scene shader does some further rescaling of the curl to better fit the color palette. One issue that irks me is the emergence of some artefacts near boundaries as well as isolated "single-cell-vortices". This might be caused by running the simulation too close to divergence but as I am currently mostly interested in building an interactive fluid playground it could be worth it to try running an additional smoothening shader pass to straighten things out.
2019-04-18Bind key to reset lattice buffersAdrian Kummerlaender
i.e. restarting the simulation without clearing the geometry
2019-02-23Store material in fluid buffer and improve visualizationAdrian Kummerlaender
Replaces the density value which is actually not that useful for visualization. Encoding integer values as floats by casting and comparing them using exact floating point comparison is not very safe but works out for now.
2019-02-22Tidy up wall drawing and geometry initializationAdrian Kummerlaender
2019-02-22Improvise interactive wall drawingAdrian Kummerlaender
Internal wall cells need to be disabled to prevent delayed propagation of the reflected populations. This is just quickly thrown together - both the visual drawing and the backend's material handling remain to be improved.
2019-02-20Initialize cells using their equilibrium distributionAdrian Kummerlaender
2018-12-18Hacky mouse-based fluid interactionAdrian Kummerlaender
2018-12-17Try out velocity norm color mappingAdrian Kummerlaender
2018-12-17Fix glDrawArray callAdrian Kummerlaender
2018-12-16Parametrize lattice resolutionAdrian Kummerlaender
2018-12-15Hacky D2Q9 BGK LBM on GPU using GLSL compute shadersAdrian Kummerlaender
Improvised on top of computicles's scaffolding. Works in a world where _works_ is defined as "displays stuff on screen that invokes thoughts of fluid movement".