Shaders
These examples show how to write your own GPU code. A Shader is a shade(uv, info) function. Ollin wraps it, compiles it, and runs it through the effect graph as a source, a filter, or a two-input combine, with the whole shader library spliced in, or as the paint a shape is filled or stroked with. A Visual chain builds the same per-pixel program from chained Swift calls, so you do not need to write Metal. See Shaders, the shader library reference, and Visuals.
| Example | What it shows |
|---|---|
| HelloShader | the smallest user shader, written both ways: an inline Shader("...") plasma beside the same shader loaded from a .metal file with Shader(resource:in:). The file version hot-reloads on save under OllinLive, with no swiftc pass |
| ShaderFilter | a shader as a one-input filter: it draws a scene into a layer, then re-samples the layer with a wave and posterizes it (sample(info, uv)) |
| ShaderBlend | a shader as a two-input combine: an animated diagonal wipe with a rippling seam (sample + sampleAux) |
| ShaderPaint | a shader as paint: fill(shader) and stroke(shader) run shade at every pixel a shape covers, uv across the shape's own box, info.distance from its edge, info.along a stroke, and info.position on the canvas; a disk ringed from its edge, a turning star striped in its own frame, a ribbon whose pulse travels it, and tiles sharing one grain |
| VisualSynth | the Visual chain API: a source, warps, color moves, and modulations compile into one GPU pass, and every number can animate without a recompile |
| VisualCatalog | the Visual chain catalog on one switchable contact sheet: sources, warps, color adjustments, two-chain combines, and per-pixel modulations, chosen by a family parameter, with every tile labeled with the calls it chains |
| DomainWarp | runtime shader parameters: Shader(_, params:) takes floats that MSL reads back as param(info, n), which animates a hand-written domain-warp marble with no recompile |
| ComplexPlane | the shader library's complex module beside the CPU Complex value: a shader colors every pixel by the phase and size of the ratio of two moving points (complexPlane, cdiv, domainColor), and draw() works out the circles that ratio is made of and lays them over the layer, where they land on the shader's rulings |
| ImaginaryLog | the imaginary part of a logarithm as a picture: clog of the ratio of two turning points through a cosine palette that never completes a cycle, so the branch cut between the points shows as a soft seam, and draw() can mark that segment with Complex |
| Meromorphic | a ratio of two cubic polynomials built from six roots that draw() moves as Complex values, multiplied out with cmul and painted by the phase of its clog through a palette whose frequency is a parameter: tame at one, bands piling up around the poles when wild |
| BlackHole | light bent round a black hole by the orbit equation for light, traced backward from every pixel: the shadow, the far side of the disk standing over the hole and under it, stars smeared into arcs, and one star behind the hole seen as a ring. The disk shines as a black body at the temperature its radius gives it, shifted blue-white where it turns toward the camera and red where it turns away. The physics lives in physics.metal, which the picture's blackhole.metal includes and the tests read on its own |