WebGPU Kernel Pixel Manipulation e g blur effect Example left side is blurred and the right side is left untouched Kernels What Kernel this is more a signal processing term if you understand the notion of filtering an image as applying a convolution The kernel is a 2D function or small matrix containing the coefficients applying to each neighborhood pixels A Gaussian x y is a very good filter better that all coefficient 1 which is the box filter and it has the nice property than Gaussian x y Gaussian sqrt x y Gaussian x Gaussian y so you can just filter the x values with a 1xN filter store the result then apply a Nx1 filter along the y var script document createElement script script type text javascript script async false script src https cdnjs cloudflare com ajax libs gl matrix 2 6 0 gl matrix min js document head appendChild script const canvas document createElement canvas document body appendChild canvas canvas width canvas height 512 console log canvas width canvas height const context canvas getContext webgpu const gpu navigator gpu console log gpu gpu const adapter await gpu requestAdapter const device await adapter requestDevice const devicePixelRatio 1 1 const presentationSize canvas clientWidth devicePixelRatio canvas clientHeight devicePixelRatio const presentationFormat navigator gpu getPreferredCanvasFormat context getPreferredFormat adapter no longer supported console log presentationFormat context configure device device format presentationFormat size presentationSize var vertWGSL struct VSOut builtin position Position vec4 f32 location 0 uvs vec2 f32 vertex fn main builtin vertex_index VertexIndex u32 VSOut var s 0 9 var pos array vec2 f32 4 vec2 f32 s s vec2 f32 s s vec2 f32 s s vec2 f32 s s s 1 0 var uvs array vec2 f32 4 vec2 f32 s s vec2 f32 s s vec2 f32 s s vec2 f32 s s var vsOut VSOut vsOut Position vec4 f32 pos VertexIndex 0 0 1 0 vsOut uvs uvs VertexIndex 0 5 0 5 0 1 return vsOut var fragWGSL group 0 binding 0 var mySampler sampler group 0 binding 1 var myTexture texture_2d f32 fragment fn main location 0 uvs vec2 f32 location 0 vec4 f32 return textureSample myTexture mySampler uvs return vec4 f32 1 0 1 0 0 0 1 0 var PI 6 28318530718 Pi 2 Blur Kernel var directions 16 0 blur direction Default 16 0 More is better but slower var quality 3 0 blur quality Default 4 0 More is better but slower var radius 1 0 64 0 blur radius size hack only blur right side of the image if uvs x 0 5 radius 0 0 Pixel colour var color textureSample myTexture mySampler uvs Blur calculations for var d 0 0 d PI d d PI directions for var i 1 0 quality i 1 0 i i 1 0 quality let delta uvs vec2 f32 cos d sin d radius i color color textureSample myTexture mySampler delta Output to screen color color quality directions 15 0 return color let textureSampler device createSampler minFilter linear magFilter linear const img document createElement img img src https notebook xbdev net var images test512 png await img decode const basicTexture device createTexture size img width img height 1 format presentationFormat bgra8unorm rgba8unorm usage 0x2 0x4 GPUTextureUsage COPY_DST GPUTextureUsage TEXTURE_BINDING const imageCanvas document createElement canvas imageCanvas width img width imageCanvas height img height const imageCanvasContext imageCanvas getContext 2d imageCanvasContext drawImage img 0 0 imageCanvas width imageCanvas height const imageData imageCanvasContext getImageData 0 0 imageCanvas width imageCanvas height let textureData new Uint8Array img width img height 4 for let x 0 x img width img height 4 x textureData x imageData data x device queue writeTexture texture basicTexture textureData offset 0 bytesPerRow img width 4 rowsPerImage img height img width img height 1 const sceneUniformBindGroupLayout device createBindGroupLayout entries binding 0 visibility GPUShaderStage FRAGMENT sampler type filtering binding 1 visibility GPUShaderStage FRAGMENT texture sampleType float viewDimension 2d const uniformBindGroup device createBindGroup layout sceneUniformBindGroupLayout entries binding 0 resource textureSampler binding 1 resource basicTexture createView const pipeline device createRenderPipeline layout device createPipelineLayout bindGroupLayouts sceneUniformBindGroupLayout vertex module device createShaderModule code vertWGSL entryPoint main fragment module device createShaderModule code fragWGSL entryPoint main targets format presentationFormat primitive topology triangle strip frontFace ccw cullMode back stripIndexFormat uint32 GPURenderPassDescriptor const renderPassDescriptor colorAttachments view undefined asign later in frame loadOp clear clearValue r 0 0 g 0 5 b 0 5 a 1 0 storeOp store function frame renderPassDescriptor colorAttachments 0 view context getCurrentTexture createView const commandEncoder device createCommandEncoder const renderPass commandEncoder beginRenderPass renderPassDescriptor renderPass setPipeline pipeline renderPass setBindGroup 0 uniformBindGroup renderPass draw 4 1 0 0 renderPass end device queue submit commandEncoder finish if you want constant updates animated keep refreshing requestAnimationFrame frame frame console log left side is blurred right side is left untouched
to screen color color quality directions 15 0 return color let textureSampler device createSampler minFilter linear magFilter linear const img document createElement img img src https notebook xbdev net var images test512 png await img decode const basicTexture device createTexture size img width img height 1 format presentationFormat bgra8unorm rgba8unorm usage 0x2 0x4 GPUTextureUsage COPY_DST GPUTextureUsage TEXTURE_BINDING const imageCanvas document createElement canvas imageCanvas width img width imageCanvas height img height const imageCanvasContext imageCanvas getContext 2d imageCanvasContext drawImage img 0 0 imageCanvas width imageCanvas height const imageData imageCanvasContext getImageData 0 0 imageCanvas width imageCanvas height let textureData new Uint8Array img width img height 4 for let x 0 x img width img height 4 x textureData x imageData data x device queue writeTexture texture basicTexture textureData offset 0 bytesPerRow img width 4 rowsPerImage img height img width img height 1 const sceneUniformBindGroupLayout device createBindGroupLayout entries binding 0 visibility GPUShaderStage FRAGMENT sampler type filtering binding 1 visibility GPUShaderStage FRAGMENT texture sampleType float viewDimension 2d const uniformBindGroup device createBindGroup layout sceneUniformBindGroupLayout entries binding 0 resource textureSampler binding 1 resource basicTexture createView const pipeline device createRenderPipeline layout device createPipelineLayout bindGroupLayouts sceneUniformBindGroupLayout vertex module device createShaderModule code vertWGSL entryPoint main fragment module device createShaderModule code fragWGSL entryPoint main targets format presentationFormat primitive topology triangle strip frontFace ccw cullMode back stripIndexFormat uint32 GPURenderPassDescriptor const renderPassDescriptor colorAttachments view undefined asign later in frame loadOp clear clearValue r 0 0 g 0 5 b 0 5 a 1 0 storeOp store function frame renderPassDescriptor colorAttachments 0 view context getCurrentTexture createView const commandEncoder device createCommandEncoder const renderPass commandEncoder beginRenderPass renderPassDescriptor renderPass setPipeline pipeline renderPass setBindGroup 0 uniformBindGroup renderPass draw 4 1 0 0 renderPass end device queue submit commandEncoder finish if you want constant updates animated keep refreshing requestAnimationFrame frame frame console log left side is blurred right side is left untouched