android白圈闪现动画,Android基于Shader的图像处理(9)-仿抖音闪白特效

有了之前的缩放特效，闪白就很容易了，闪白的原理就是在原像素rgb分量上加个[0,1]之间的参数。

fragment shader如下:

precision mediump float;

uniform sampler2D u_TextureUnit;

varying vec2 v_TextureCoordinates;

uniform float texelWidthOffset;

uniform float texelHeightOffset;

uniform float uflashParam;

void main()

{

vec4 fragColor = texture2D(u_TextureUnit, v_TextureCoordinates);

gl_FragColor = vec4(fragColor.r + uflashParam,fragColor.g + uflashParam,fragColor.b + uflashParam,fragColor.a);

}

uflashParam就是加的参数，由每帧的index决定，具体代码为:

private void prepareDraw(){

float progress;

if (curFrame <= MiddleFrame) {

progress = curFrame * 1.0f / MiddleFrame;

} else {

progress = 2f - curFrame * 1.0f / MiddleFrame;

}

glUniform1f(flashWhiteProgram.getFlashAttributeLocation(), progress);

curFrame++;

if(curFrame > MaxFrame){

curFrame = 0;

}

}

最后效果如下：

flash_white.gif