// very experimental :)
Currently this class represents the CoreImage CIKernel you can apply to a SCImage. The Kernel language is a subset of the OpenGL Shading Language. more information about the Kernel Language can be found here : http://developer.apple.com/documentation/GraphicsImaging/Reference/CIKernelLangRef/Introduction/chapter_1_section_1.html
here is the translation table between Kernel language Objects and SuperCollider objects
| Kernel Language Object | SuperCollider Object |
| sampler | SCImage |
| __color | Color |
| float | Number |
| vec2, vec3, vec4 | Array |
| __table | SCImage (basically the __table modifier just use Images as a data providers - LUT) |
creates a new SCImageKernel
| shader |
optional. the shader code string. nil by default |
| values |
optional. the values that match the kernel proc function defined in the shader string. nil by default |
| bounds |
optional. not used for now. nil by default |
get or set the shader string.
get or set the values array. When setting the object indexes in the values Array must match the argument declaration order as defined in the main kernel vec4 routine. See examples for more info.
very basic verification to tell if all arguments of the shader are set.
compile the SCImageKernel object (and cache it).
/**** Kernels ****/// very experimental// COLOR INVERSION SHADER EXAMPLE(a = SCImage.new(SCDoc.helpSourceDir +/+ "images/vduck2.jpg"); // get the imagek = SCImageKernel.new;k.shader_("vec4 invertPixel(vec4 pix) { return vec4(1.0 - pix.r, 1.0 - pix.g, 1.0 - pix.b, pix.a);}kernel vec4 _invertColor(sampler source){ vec4 pixel; pixel = sample(source, samplerCoord(source)); unpremultiply(pixel); return unpremultiply(invertPixel(pixel));}");// the argument order should be kept in the array// here we need only the "sampler" argument which should be as the translation table informs you a SCImage// the signature of the Kernel function is normally 'kernel vec4'// you can of course add other functions in the shaderk.values_([a]);k.isValid.postln; // is it oka.applyKernel(k);w = a.plot(freeOnClose:true);)(// ANOTHER APPLE KERNEL EXAMPLE - See CoreImage programming guide for original examplea = SCImage.new(SCDoc.helpSourceDir +/+ "images/vduck2.jpg"); // get the imagek = SCImageKernel.new;k.shader_("vec2 testVec(float x, float y){ return vec2(x, y);}kernel vec4 testKernelFromApple( sampler src, __color color, float distance, float slope ){ vec4 t; float d; d = destCoord().y * slope + distance; t = unpremultiply(sample(src, samplerCoord(src))); t = (t - d*color) / (1.0-d); return premultiply(t);}");// as stated in the Apple Example// distance - min: 0.0 max: 1.0// slope - min: -0.01 max: 0.01k.values_( [ a, // arg 0: the SCImage Color.white, // arg 1: color 0.5, // arg 2: distance -0.002 // arg 3: slope ]);a.applyKernel(k);w = a.plot(freeOnClose:true);)(// OK a Better Colorful Kernela = SCImage.new(600@600); // get the imagek = SCImageKernel.new;k.shader_(// shader/kernel from toneburst.com// Generates spherical and planar displacement maps for VBO-based 3D heightfield.// http://machinesdontcare.wordpress.com"const float PI = 3.14159265359;const float TWOPI = 6.28318530718;kernel vec4 _heightMap(sampler image, vec3 scale){ vec2 xyNorm = samplerCoord(image) / samplerSize(image); float u = xyNorm.x * PI; float v = xyNorm.y * TWOPI; vec3 spherical; spherical.r = cos(v) * sin(u); spherical.g = sin(v) * sin(u); spherical.b = cos(u); spherical.r = (spherical.r * 0.5 + 0.5) * scale.x; spherical.g = (spherical.g * 0.5 + 0.5) * scale.y; spherical.b = (spherical.b * 0.5 + 0.5) * scale.z; return vec4(spherical,1.0);}");k.values_([a, [1.0, 1.0, 1.0]]);// k.isValid; // is it oka.applyKernel(k);//.flatten; // ensure a bitmap rep so the kernel is not applied at each rendering call - uncomment that and rescale the plot window to see the difference.w = a.plot(freeOnClose:true);)