Kotlin Shading Language

Core Language Features

Types & Operators

• ✅ Basic types (Float2/3/4, Int2/3/4, UInt2/3/4, Mat2/3/4)
• ✅ Vector/matrix arithmetic operators
• ✅ Swizzling (xyz, rgb, xyzw, rgba etc.)
• ✅ Type casting (toFloat, toInt, toUInt etc.)
• ✅ Bitwise operators (and, or, xor, shl, shr, inv)
• ✅ Unary minus, unary not
• ✅ Constants (const val PI = 3.14159f)
• ✅ Arrays - fixed-size (Array<Light>(4))
• ✅ Arrays - unsized (in storage buffers)
• ✅ Array indexing (lights[i])

Control Flow

• ✅ if / else if / else
• ✅ for loop
• ✅ while loop
• ✅ switch / when
• ✅ break / continue
• ✅ return

Functions

• ✅ Helper functions (utility @Shader classes / includes)
• ✅ User-defined functions
• ✅ kotlin.math builtins (sin, cos, sqrt etc.)
• ✅ KSL math builtins (dot, cross, normalize, mix, clamp etc.)
• ✅ pow() vector broadcasting for GLSL
• 🔲 transpose()
• 🔲 determinant()
• 🔲 Derivative functions - dFdx, dFdy, fwidth (fragment only)
• 🔲 Atomic operations - atomicAdd, atomicMin, atomicMax etc.

Resources

• ✅ Uniform buffers (@UniformBuffer)
• ✅ Storage buffers (@StorageBuffer, read/write + read-only)
• ✅ Samplers (Sampler, SamplerShadow)
• ✅ Textures (Texture2D, Texture3D, TextureCube, Texture2DArray etc.)
• ✅ Sampler methods (sample, sampleLod, sampleBias, sampleGrad, sampleShadow)
• 🔲 Push constants (@PushConstant)
• 🔲 Shared/threadgroup memory (@Shared) for compute
• 🔲 Storage textures — read/write textures in compute

Builtin Variables

• ✅ Vertex - position, vertexIndex, instanceIndex
• ✅ Fragment - fragCoord, frontFacing
• ✅ Compute - globalInvocationId, localInvocationId, workgroupId, localInvocationIndex

---

Translation

GLSL

• ✅ Version header (#version 460)
• ✅ in/out flat globals with in_/out_ prefix
• ✅ gl_Position, gl_FragCoord etc.
• ✅ Uniform buffer (std140)
• ✅ Storage buffer (std430)
• ✅ Sampler + texture separate objects
• ✅ texture(sampler2D(tex, samp), uv) call site
• ✅ Reserved keyword validation

WGSL

• ✅ Struct-based I/O
• ✅ @group/@binding layout
• ✅ var / var
• ✅ sampler / texture_2d etc.
• ✅ Entry point builtin parameters (@builtin annotation)
• 🔲 Storage texture (texture_storage_2d)

MSL

• ✅ Struct-based I/O with [[attribute(n)]]
• ✅ [[buffer(n)]] layout
• ✅ Sampler/texture as function parameters [[sampler(n)]] [[texture(n)]]
• ✅ Entry point builtin parameters ([[thread_position_in_grid]] etc.)
• 🔲 Inject resources as parameters into main() function
• 🔲 Storage texture

---

Testing

• 🔲 Snapshot testing, erasing whitespacing and formatting
• 🔲 SPIR-V validation as test assertion
• 🔲 WGSL validation (naga or tint)
• 🔲 MSL validation (xcrun metal on macOS)
• 🔲 Array tests
• 🔲 Bitwise operator tests
• 🔲 Type casting tests
• 🔲 Compute shader tests
• 🔲 Include/utility shader tests
• 🔲 Edge case tests for all new features

---

IntelliJ Plugin

• ✅ Live type validation (@Shader class property types)
• ✅ Reserved keyword inspection per language
• ✅ K2 Analysis API (KaSession)
• ✅ Hot reload via ProjectService + VFS file watcher
• ✅ Gradle continuous build triggered on .kt save
• ✅ Build success/failure notifications
• ✅ Read and apply configs from build.gradle.kts from correct KSL project
• 🔲 File creation/deletion watcher fix (cleanup is not working)
• 🔲 In-process compiler (replace ProcessBuilder - faster hot reload)
• 🔲 Show shader errors inline in editor (not just notification)
• 🔲 Publish KSL plugin and compiler to Maven and IDE

---

Kanvas Integration

• 🔲 @NativeData binary encoding aligned with std140/std430
• 🔲 UniformBuffer<T> base class with correct size/layout
• 🔲 StorageBuffer<T> base class
• 🔲 Shader pipeline binding matching KSL group/binding indices
• 🔲 Hot reload in Kanvas engine viewport
• 🔲 Shader error reporting in Kanvas editor UI

---

Tooling

• 🔲 Shader playground (web API or desktop app)
• 🔲 Source maps - map shader errors back to Kotlin line numbers
• 🔲 KSL version in generated shader file header comment

---

Known Bugs

• 🐛 No cleanup by KSL watcher of stale generated shaders
• 🐛 MSL samplers/textures not injected as entry point parameters
• 🐛 WGSL samplers/textures not injected as entry point parameters