/**
* @author meatbags / xavierburrow.com, github/meatbags
*
* RGB Halftone shader for three.js.
* NOTE:
* Shape (1 = Dot, 2 = Ellipse, 3 = Line, 4 = Square)
* Blending Mode (1 = Linear, 2 = Multiply, 3 = Add, 4 = Lighter, 5 = Darker)
*/
var HalftoneShader = {
uniforms: {
"tDiffuse": { value: null },
"shape": { value: 1 },
"radius": { value: 4 },
"rotateR": { value: Math.PI / 12 * 1 },
"rotateG": { value: Math.PI / 12 * 2 },
"rotateB": { value: Math.PI / 12 * 3 },
"scatter": { value: 0 },
"width": { value: 1 },
"height": { value: 1 },
"blending": { value: 1 },
"blendingMode": { value: 1 },
"greyscale": { value: false },
"disable": { value: false }
},
vertexShader: [
"varying vec2 vUV;",
"void main() {",
" vUV = uv;",
" gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);",
"}"
].join( "\n" ),
fragmentShader: [
"#define SQRT2_MINUS_ONE 0.41421356",
"#define SQRT2_HALF_MINUS_ONE 0.20710678",
"#define PI2 6.28318531",
"#define SHAPE_DOT 1",
"#define SHAPE_ELLIPSE 2",
"#define SHAPE_LINE 3",
"#define SHAPE_SQUARE 4",
"#define BLENDING_LINEAR 1",
"#define BLENDING_MULTIPLY 2",
"#define BLENDING_ADD 3",
"#define BLENDING_LIGHTER 4",
"#define BLENDING_DARKER 5",
"uniform sampler2D tDiffuse;",
"uniform float radius;",
"uniform float rotateR;",
"uniform float rotateG;",
"uniform float rotateB;",
"uniform float scatter;",
"uniform float width;",
"uniform float height;",
"uniform int shape;",
"uniform bool disable;",
"uniform float blending;",
"uniform int blendingMode;",
"varying vec2 vUV;",
"uniform bool greyscale;",
"const int samples = 8;",
"float blend( float a, float b, float t ) {",
// linear blend
" return a * ( 1.0 - t ) + b * t;",
"}",
"float hypot( float x, float y ) {",
// vector magnitude
" return sqrt( x * x + y * y );",
"}",
"float rand( vec2 seed ){",
// get pseudo-random number
"return fract( sin( dot( seed.xy, vec2( 12.9898, 78.233 ) ) ) * 43758.5453 );",
"}",
"float distanceToDotRadius( float channel, vec2 coord, vec2 normal, vec2 p, float angle, float rad_max ) {",
// apply shape-specific transforms
" float dist = hypot( coord.x - p.x, coord.y - p.y );",
" float rad = channel;",
" if ( shape == SHAPE_DOT ) {",
" rad = pow( abs( rad ), 1.125 ) * rad_max;",
" } else if ( shape == SHAPE_ELLIPSE ) {",
" rad = pow( abs( rad ), 1.125 ) * rad_max;",
" if ( dist != 0.0 ) {",
" float dot_p = abs( ( p.x - coord.x ) / dist * normal.x + ( p.y - coord.y ) / dist * normal.y );",
" dist = ( dist * ( 1.0 - SQRT2_HALF_MINUS_ONE ) ) + dot_p * dist * SQRT2_MINUS_ONE;",
" }",
" } else if ( shape == SHAPE_LINE ) {",
" rad = pow( abs( rad ), 1.5) * rad_max;",
" float dot_p = ( p.x - coord.x ) * normal.x + ( p.y - coord.y ) * normal.y;",
" dist = hypot( normal.x * dot_p, normal.y * dot_p );",
" } else if ( shape == SHAPE_SQUARE ) {",
" float theta = atan( p.y - coord.y, p.x - coord.x ) - angle;",
" float sin_t = abs( sin( theta ) );",
" float cos_t = abs( cos( theta ) );",
" rad = pow( abs( rad ), 1.4 );",
" rad = rad_max * ( rad + ( ( sin_t > cos_t ) ? rad - sin_t * rad : rad - cos_t * rad ) );",
" }",
" return rad - dist;",
"}",
"struct Cell {",
// grid sample positions
" vec2 normal;",
" vec2 p1;",
" vec2 p2;",
" vec2 p3;",
" vec2 p4;",
" float samp2;",
" float samp1;",
" float samp3;",
" float samp4;",
"};",
"vec4 getSample( vec2 point ) {",
// multi-sampled point
" vec4 tex = texture2D( tDiffuse, vec2( point.x / width, point.y / height ) );",
" float base = rand( vec2( floor( point.x ), floor( point.y ) ) ) * PI2;",
" float step = PI2 / float( samples );",
" float dist = radius * 0.66;",
" for ( int i = 0; i < samples; ++i ) {",
" float r = base + step * float( i );",
" vec2 coord = point + vec2( cos( r ) * dist, sin( r ) * dist );",
" tex += texture2D( tDiffuse, vec2( coord.x / width, coord.y / height ) );",
" }",
" tex /= float( samples ) + 1.0;",
" return tex;",
"}",
"float getDotColour( Cell c, vec2 p, int channel, float angle, float aa ) {",
// get colour for given point
" float dist_c_1, dist_c_2, dist_c_3, dist_c_4, res;",
" if ( channel == 0 ) {",
" c.samp1 = getSample( c.p1 ).r;",
" c.samp2 = getSample( c.p2 ).r;",
" c.samp3 = getSample( c.p3 ).r;",
" c.samp4 = getSample( c.p4 ).r;",
" } else if (channel == 1) {",
" c.samp1 = getSample( c.p1 ).g;",
" c.samp2 = getSample( c.p2 ).g;",
" c.samp3 = getSample( c.p3 ).g;",
" c.samp4 = getSample( c.p4 ).g;",
" } else {",
" c.samp1 = getSample( c.p1 ).b;",
" c.samp3 = getSample( c.p3 ).b;",
" c.samp2 = getSample( c.p2 ).b;",
" c.samp4 = getSample( c.p4 ).b;",
" }",
" dist_c_1 = distanceToDotRadius( c.samp1, c.p1, c.normal, p, angle, radius );",
" dist_c_2 = distanceToDotRadius( c.samp2, c.p2, c.normal, p, angle, radius );",
" dist_c_3 = distanceToDotRadius( c.samp3, c.p3, c.normal, p, angle, radius );",
" dist_c_4 = distanceToDotRadius( c.samp4, c.p4, c.normal, p, angle, radius );",
" res = ( dist_c_1 > 0.0 ) ? clamp( dist_c_1 / aa, 0.0, 1.0 ) : 0.0;",
" res += ( dist_c_2 > 0.0 ) ? clamp( dist_c_2 / aa, 0.0, 1.0 ) : 0.0;",
" res += ( dist_c_3 > 0.0 ) ? clamp( dist_c_3 / aa, 0.0, 1.0 ) : 0.0;",
" res += ( dist_c_4 > 0.0 ) ? clamp( dist_c_4 / aa, 0.0, 1.0 ) : 0.0;",
" res = clamp( res, 0.0, 1.0 );",
" return res;",
"}",
"Cell getReferenceCell( vec2 p, vec2 origin, float grid_angle, float step ) {",
// get containing cell
" Cell c;",
// calc grid
" vec2 n = vec2( cos( grid_angle ), sin( grid_angle ) );",
" float threshold = step * 0.5;",
" float dot_normal = n.x * ( p.x - origin.x ) + n.y * ( p.y - origin.y );",
" float dot_line = -n.y * ( p.x - origin.x ) + n.x * ( p.y - origin.y );",
" vec2 offset = vec2( n.x * dot_normal, n.y * dot_normal );",
" float offset_normal = mod( hypot( offset.x, offset.y ), step );",
" float normal_dir = ( dot_normal < 0.0 ) ? 1.0 : -1.0;",
" float normal_scale = ( ( offset_normal < threshold ) ? -offset_normal : step - offset_normal ) * normal_dir;",
" float offset_line = mod( hypot( ( p.x - offset.x ) - origin.x, ( p.y - offset.y ) - origin.y ), step );",
" float line_dir = ( dot_line < 0.0 ) ? 1.0 : -1.0;",
" float line_scale = ( ( offset_line < threshold ) ? -offset_line : step - offset_line ) * line_dir;",
// get closest corner
" c.normal = n;",
" c.p1.x = p.x - n.x * normal_scale + n.y * line_scale;",
" c.p1.y = p.y - n.y * normal_scale - n.x * line_scale;",
// scatter
" if ( scatter != 0.0 ) {",
" float off_mag = scatter * threshold * 0.5;",
" float off_angle = rand( vec2( floor( c.p1.x ), floor( c.p1.y ) ) ) * PI2;",
" c.p1.x += cos( off_angle ) * off_mag;",
" c.p1.y += sin( off_angle ) * off_mag;",
" }",
// find corners
" float normal_step = normal_dir * ( ( offset_normal < threshold ) ? step : -step );",
" float line_step = line_dir * ( ( offset_line < threshold ) ? step : -step );",
" c.p2.x = c.p1.x - n.x * normal_step;",
" c.p2.y = c.p1.y - n.y * normal_step;",
" c.p3.x = c.p1.x + n.y * line_step;",
" c.p3.y = c.p1.y - n.x * line_step;",
" c.p4.x = c.p1.x - n.x * normal_step + n.y * line_step;",
" c.p4.y = c.p1.y - n.y * normal_step - n.x * line_step;",
" return c;",
"}",
"float blendColour( float a, float b, float t ) {",
// blend colours
" if ( blendingMode == BLENDING_LINEAR ) {",
" return blend( a, b, 1.0 - t );",
" } else if ( blendingMode == BLENDING_ADD ) {",
" return blend( a, min( 1.0, a + b ), t );",
" } else if ( blendingMode == BLENDING_MULTIPLY ) {",
" return blend( a, max( 0.0, a * b ), t );",
" } else if ( blendingMode == BLENDING_LIGHTER ) {",
" return blend( a, max( a, b ), t );",
" } else if ( blendingMode == BLENDING_DARKER ) {",
" return blend( a, min( a, b ), t );",
" } else {",
" return blend( a, b, 1.0 - t );",
" }",
"}",
"void main() {",
" if ( ! disable ) {",
// setup
" vec2 p = vec2( vUV.x * width, vUV.y * height );",
" vec2 origin = vec2( 0, 0 );",
" float aa = ( radius < 2.5 ) ? radius * 0.5 : 1.25;",
// get channel samples
" Cell cell_r = getReferenceCell( p, origin, rotateR, radius );",
" Cell cell_g = getReferenceCell( p, origin, rotateG, radius );",
" Cell cell_b = getReferenceCell( p, origin, rotateB, radius );",
" float r = getDotColour( cell_r, p, 0, rotateR, aa );",
" float g = getDotColour( cell_g, p, 1, rotateG, aa );",
" float b = getDotColour( cell_b, p, 2, rotateB, aa );",
// blend with original
" vec4 colour = texture2D( tDiffuse, vUV );",
" r = blendColour( r, colour.r, blending );",
" g = blendColour( g, colour.g, blending );",
" b = blendColour( b, colour.b, blending );",
" if ( greyscale ) {",
" r = g = b = (r + b + g) / 3.0;",
" }",
" gl_FragColor = vec4( r, g, b, 1.0 );",
" } else {",
" gl_FragColor = texture2D( tDiffuse, vUV );",
" }",
"}"
].join( "\n" )
};
export { HalftoneShader };
