Android基于Shader的图像处理(12)-仿抖音抖动特效

完整代码查看# AndroidShaderDemo下的ShakeRender

抖动特效和缩放特效很像，除了图像缩放，还在图像颜色分界处混合了颜色。颜色分界处混合颜色和之前说的高斯模糊，边缘检测很像，找到当前纹理周围的纹理，和当前纹理颜色混在一起。这里将左下角，右上角的颜色分量和当前颜色分量组合新的RGB，fragment shader如下：

precision mediump float;
uniform sampler2D u_TextureUnit;
varying vec2 v_TextureCoordinates;

uniform float u_Offset;

void main()
{
    vec4 origin = texture2D(u_TextureUnit, v_TextureCoordinates);
    vec4 green = texture2D(u_TextureUnit, vec2(v_TextureCoordinates.x + u_Offset,v_TextureCoordinates.y + u_Offset));
    vec4 red = texture2D(u_TextureUnit, vec2(v_TextureCoordinates.x - u_Offset,v_TextureCoordinates.y - u_Offset));
    gl_FragColor = vec4(red.x, green.y, origin.z, origin.w);
}

ShakeRender的onDrawFrame方法和灵魂出窍那部分代码差不多，只是这里不用画两次了，只用画一次。代码如下:

@Override
    public void onDrawFrame(GL10 gl) {
        glClear(GL_COLOR_BUFFER_BIT);

        float progress;
        if (curFrame <= MaxFrame) {
            progress = curFrame * 1.0f / MaxFrame;
        } else {
            curFrame = 0;
            progress = 0;
        }

        float scale = 1f + progress * 0.3f;
        float offset = progress * 0.01f;
        curFrame++;

        drawLayer(scale, offset);
    }

最终效果: