Android Open Source - FxCameraApp Gl Perlin Noise Shader

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Back to project page FxCameraApp.
License

The source code is released under:
MIT License
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Java Source Code

package com.af.experiments.FxCameraApp.shaders;
import com.af.experiments.FxCameraApp.renderer.GLES20FramebufferObject;
//w  w w . j a  va  2s .  c  o  m
import static android.opengl.GLES20.*;

public class GlPerlinNoiseShader extends GlShader {

  private static final String FRAGMENT_SHADER =
      "precision highp float;" +  // ?????????????????

      "varying highp vec2 vTextureCoord;" +
      "uniform float scale;" +
      "uniform vec4 colorStart;" +
      "uniform vec4 colorFinish;" +

      // Description : Array and textureless GLSL 2D/3D/4D simplex noise functions.
      // Author : Ian McEwan, Ashima Arts.
      // Maintainer : ijm
      // Lastmod : 20110822 (ijm)
      // License : Copyright (C) 2011 Ashima Arts. All rights reserved.
      // Distributed under the MIT License. See LICENSE file.
      // https://github.com/ashima/webgl-noise

      "vec4 mod289(vec4 x) {" +
        "return x - floor(x * (1.0 / 289.0)) * 289.0;" +
      "}" +

      "vec4 permute(vec4 x) {" +
        "return mod289(((x * 34.0) + 1.0) * x);" +
      "}" +

      "vec4 taylorInvSqrt(vec4 r) {" +
        "return 1.79284291400159 - 0.85373472095314 * r;" +
      "}" +

      "vec2 fade(vec2 t) {" +
        "return t*t*t*(t*(t*6.0-15.0)+10.0);" +
      "}" +

      // Classic Perlin noise
      "float cnoise(vec2 P) {" +
        "vec4 Pi = floor(P.xyxy) + vec4(0.0, 0.0, 1.0, 1.0);" +
        "vec4 Pf = fract(P.xyxy) - vec4(0.0, 0.0, 1.0, 1.0);" +
        "Pi = mod289(Pi);" +  // To avoid truncation effects in permutation

        "vec4 ix = Pi.xzxz;" +
        "vec4 iy = Pi.yyww;" +
        "vec4 fx = Pf.xzxz;" +
        "vec4 fy = Pf.yyww;" +

        "vec4 i = permute(permute(ix) + iy);" +

        "vec4 gx = fract(i * (1.0 / 41.0)) * 2.0 - 1.0 ;" +
        "vec4 gy = abs(gx) - 0.5;" +
        "vec4 tx = floor(gx + 0.5);" +
        "gx = gx - tx;" +

        "vec2 g00 = vec2(gx.x,gy.x);" +
        "vec2 g10 = vec2(gx.y,gy.y);" +
        "vec2 g01 = vec2(gx.z,gy.z);" +
        "vec2 g11 = vec2(gx.w,gy.w);" +

        "vec4 norm = taylorInvSqrt(vec4(dot(g00, g00), dot(g01, g01), dot(g10, g10), dot(g11, g11)));" +
        "g00 *= norm.x;" +
        "g01 *= norm.y;" +
        "g10 *= norm.z;" +
        "g11 *= norm.w;" +

        "float n00 = dot(g00, vec2(fx.x, fy.x));" +
        "float n10 = dot(g10, vec2(fx.y, fy.y));" +
        "float n01 = dot(g01, vec2(fx.z, fy.z));" +
        "float n11 = dot(g11, vec2(fx.w, fy.w));" +

        "vec2 fade_xy = fade(Pf.xy);" +
        "vec2 n_x = mix(vec2(n00, n01), vec2(n10, n11), fade_xy.x);" +
        "float n_xy = mix(n_x.x, n_x.y, fade_xy.y);" +
        "return 2.3 * n_xy;" +
      "}" +

      "void main() {" +
        "float n1 = (cnoise(vTextureCoord * scale) + 1.0) / 2.0;" +

        "vec4 colorDiff = colorFinish - colorStart;" +
        "vec4 color = colorStart + colorDiff * n1;" +

        "gl_FragColor = color;" +
      "}";

  private float mScale = 8.0f;
  private float[] mColorStart = new float[]{ 0.0f, 0.0f, 0.0f, 1.0f };
  private float[] mColorFinish = new float[]{ 1.0f, 1.0f, 1.0f, 1.0f };

  public GlPerlinNoiseShader() {
    super(DEFAULT_VERTEX_SHADER, FRAGMENT_SHADER);
  }


  @Override
  public void draw(final int texName, final GLES20FramebufferObject fbo) {
    useProgram();

    glBindBuffer(GL_ARRAY_BUFFER, getVertexBufferName());
    glEnableVertexAttribArray(getHandle(DEFAULT_ATTRIB_POSITION));
    glVertexAttribPointer(getHandle(DEFAULT_ATTRIB_POSITION), VERTICES_DATA_POS_SIZE, GL_FLOAT, false, VERTICES_DATA_STRIDE_BYTES, VERTICES_DATA_POS_OFFSET);
    glEnableVertexAttribArray(getHandle(DEFAULT_ATTRIB_TEXTURE_COORDINATE));
    glVertexAttribPointer(getHandle(DEFAULT_ATTRIB_TEXTURE_COORDINATE), VERTICES_DATA_UV_SIZE, GL_FLOAT, false, VERTICES_DATA_STRIDE_BYTES, VERTICES_DATA_UV_OFFSET);

    glUniform1f(getHandle("scale"), mScale);
    glUniform4fv(getHandle("colorStart"), 0, mColorStart, 0);
    glUniform4fv(getHandle("colorFinish"), 0, mColorFinish, 0);

    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    glDisableVertexAttribArray(getHandle(DEFAULT_ATTRIB_POSITION));
    glDisableVertexAttribArray(getHandle(DEFAULT_ATTRIB_TEXTURE_COORDINATE));
    glBindBuffer(GL_ARRAY_BUFFER, 0);
  }

}
Java Source Code List
