Looks like OpenGL shaders. I found this in BlackWhiteFilter:
private final String mBlackWhiteShader =
51 "precision mediump float;\n" +
52 "uniform sampler2D tex_sampler_0;\n" +
53 "uniform vec2 seed;\n" +
54 "uniform float black;\n" +
55 "uniform float scale;\n" +
56 "uniform float stepsize;\n" +
57 "varying vec2 v_texcoord;\n" +
58 "float rand(vec2 loc) {\n" +
59 // Compute sin(theta), theta = 12.9898 x + 78.233y
60 // because floating point has limited range, make theta =
theta1 + theta2
61 // where theta1 = 12x + 78y and theta2 = 0.9898x + 0.233y)
62 // Note that theta1 and theta2 cover diffent range of theta.
63 " float theta1 = dot(loc, vec2(0.9898, 0.233));\n" +
64 " float theta2 = dot(loc, vec2(12.0, 78.0));\n" +
65 // Use the property sin(theta) =
cos(theta1)*sin(theta2)+sin(theta1)*cos(theta2)
66 // this approach also increases the precisions of sin(theta)
67 " float value = cos(theta1) * sin(theta2) + sin(theta1) *
cos(theta2);\n" +
68 // fract(43758.5453 * x) = fract(43758 * x + 0.5453 * x)
69 // keep value of part1 in range: (2^-14 to 2^14). Since
43758 = 117 * 374
70 // fract(43758 * sin(theta)) = mod(221 * mod(198*sin(theta),
1.0), 1.0)
71 // also to keep as much decimal digits, use the property
72 // mod(mod(198*sin(theta)) = mod(mod(197*sin(theta) +
sin(theta))
73 " float temp = mod(197.0 * value, 1.0) + value;\n" +
74 " float part1 = mod(220.0 * temp, 1.0) + temp;\n" +
75 " float part2 = value * 0.5453;\n" +
76 " float part3 = cos(theta1 + theta2) * 0.43758;\n" +
77 " return fract(part1 + part2 + part3);\n" +
78 "}\n" +
79 "void main() {\n" +
80 " vec4 color = texture2D(tex_sampler_0, v_texcoord);\n" +
81 " float dither = rand(v_texcoord + seed);\n" +
82 " vec3 xform = clamp((color.rgb - black) * scale, 0.0,
1.0);\n" +
83 " vec3 temp = clamp((color.rgb + stepsize - black) * scale,
0.0, 1.0);\n" +
84 " vec3 new_color = clamp(xform + (temp - xform) * (dither -
0.5), 0.0, 1.0);\n" +
85 " gl_FragColor = vec4(new_color, color.a);\n" +
86 "}\n";
On Thursday, December 6, 2012 9:47:36 AM UTC-6, bob wrote:
>
> Does anyone know what most of the EffectFactory effects are like "under
> the hood"?
>
>
> Are they basically GLSL shaders?
>
>
>
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