OpenGL （一）OpenGL ES 绘制基础
OpenGL （二）GLSurface 视频录制
OpenGL （三）滤镜filter 应用
OpenGL （四）贴纸和磨皮理论
用到了人脸识别定位。SeetaFace2
具体内容搜索关键字，到github搜搜，找到Android编译，不再用链接，这里的书写环境用到链接容易锁文章
编译好之后，进行配置android C++ 环境
具体api的时候参考他的example
大眼萌算法
其实就是根据photoshop上面功能的算法公式
Local Scale warps 局部缩放
前提：定位到眼睛的位置
local_scale_wraps.png
解释： rmax为圆形选区的半径，r为控制点移动位移，即目的矢量，as是(-1,1)之间的缩放参数，a<0表示缩小，a>0表示放大，给出点X时，可以求出它变换前的坐标U（精确的浮点坐标），然后用变化前图像在U点附近的像素进行插值，求出U的像素值。如此对圆形选区内的每一个像素进行求值，便可得出变换后的图像。
变换后的公式.png
理解图像
眼睛缩放黑眼白.png
实现
写着色器
bigeye_frag.frag
precision mediump float;//数据精度
varying vec2 aCoord;
uniform sampler2D vTexture;// samplerExternalOES 图片，采样器
uniform vec2 left_eye;
uniform vec2 right_eye;
//r: 要画的点与眼睛的距离
//max 最大半径
//0.4 放大系数 -1 -- 1 大于0 就是放大
float fs(float r,float rmax){
// return (1.0-pow(r/rmax-1.0,2.0)* 0.5)*r;
return (1.0-pow(r/rmax-1.0,2.0)* 0.5);
}
vec2 newCoord(vec2 coord,vec2 eye,float rmax){
vec2 p = cood;
//得到要画的点coord，与眼睛的距离
float r = distance(coord,eye);
if(r < rmax){
// 在这个范围,新的点与眼睛的距离
float fsr = fs(r,rmax);
// （缩放后的点- 眼睛的点）/（原点-眼睛的点）= fsr /r
//缩放的点=fsr/r * (原点-眼睛的点) + 眼睛的点
// p = fsr/r*(coord-eye) + eye;
// 优化 抵消掉，这需要除，上面公式需要乘
p = fsr/(coord-eye) + eye;
}
return p;
}
void main(){
// gl_FragColor = texture2D(vTexture,aCoord);//从图片中找到像素点，赋值
float rmax = distance(left_eye,right_eye)/2.0;
vec2 p = newCoord(aCoord,left_eye,rmax);
p = newCoord(aCoord,right_eye,rmax);
gl_FragColor = texture2D(vTexture,p);//从图片中找到像素点，赋值
}
opecv 相关+CameraX采集人脸数据
参考之前的文章
OpenCV 系列人脸定位&人脸定位模型训练
将识别的人脸图像通过SeetaFace2 定位到眼睛的位置，
然后计算，利用着色器在指定区域着色。
大眼滤镜
public class BigEyeFilter extends AbstractFrameFilter {
private FloatBuffer left;
private FloatBuffer right;
int left_eye;
int right_eye;
Face face;
public BigEyeFilter(Context context) {
super(context, R.raw.base_vert, R.raw.bigeye_frag);
left = ByteBuffer.allocateDirect(8).order(ByteOrder.nativeOrder()).asFloatBuffer();
right = ByteBuffer.allocateDirect(8).order(ByteOrder.nativeOrder()).asFloatBuffer();
}
@Override
public void initGL(Context context, int vertexShaderId, int fragmentShaderId) {
super.initGL(context, vertexShaderId, fragmentShaderId);
left_eye = GLES20.glGetUniformLocation(program, "left_eye");
right_eye = GLES20.glGetUniformLocation(program, "right_eye");
}
@Override
public int onDraw(int texture, FilterChain filterChain) {
FilterContext filterContext = filterChain.filterContext;
face = filterContext.face;
return super.onDraw(texture, filterChain);
}
@Override
public void beforeDraw() {
super.beforeDraw();
if (face == null) {
// Log.e("zcw_opengl","未识别到人脸");
return;
}
Log.e("zcw_opengl","是一个-------人脸");
float x = face.left_x / face.imgWidth;
float y = 1.0f - face.left_y / face.imgHeight;
left.clear();
left.put(x).put(y).position(0);
GLES20.glUniform2fv(left_eye, 1, left);
x = face.right_x / face.imgWidth;
y = 1.0f - face.right_y / face.imgHeight;
right.clear();
right.put(x).put(y).position(0);
GLES20.glUniform2fv(right_eye, 1, right);
}
}
责任连模式，使用滤镜开发更简单
public class FilterContext {
public Face face; // 人脸
public float[] cameraMtx; //摄像头转换矩阵
public int width;
public int height;
public void setSize(int width, int height) {
this.width = width;
this.height = height;
}
public void setTransformMatrix(float[] mtx) {
this.cameraMtx = mtx;
}
public void setFace(Face face) {
this.face = face;
}
}
--------
public class FilterChain {
public FilterContext filterContext;
private List filters;
private int index;
public FilterChain(List filters, int index, FilterContext filterContext) {
this.filters = filters;
this.index = index;
this.filterContext = filterContext;
}
public int proceed(int textureId) {
if (index >= filters.size()) {
return textureId;
}
FilterChain nextFilterChain = new FilterChain(filters, index + 1, filterContext);
AbstractFilter abstractFilter = filters.get(index);
return abstractFilter.onDraw(textureId, nextFilterChain);
}
public void setSize(int width, int height) {
filterContext.setSize(width, height);
}
public void setTransformMatrix(float[] mtx) {
filterContext.setTransformMatrix(mtx);
}
public void setFace(Face face) {
filterContext.setFace(face);
}
public void release() {
for (AbstractFilter filter : filters) {
filter.release();
}
}
}
------
/**
* FBO
*/
public abstract class AbstractFrameFilter extends AbstractFilter {
int[] frameBuffer;
int[] frameTextures;
public AbstractFrameFilter(Context context, int vertexShaderId, int fragmentShaderId) {
super(context, vertexShaderId, fragmentShaderId);
}
public void createFrame(int width, int height) {
releaseFrame();
//創建FBO
/**
* 1、创建FBO + FBO中的纹理
*/
frameBuffer = new int[1];
frameTextures = new int[1];
GLES20.glGenFramebuffers(1, frameBuffer, 0);
OpenGLUtils.glGenTextures(frameTextures);
/**
* 2、fbo与纹理关联
*/
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, frameTextures[0]);
GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGBA, width, height, 0, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE,
null);
//纹理关联 fbo
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffer[0]); //綁定FBO
GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D,
frameTextures[0],
0);
/**
* 3、解除绑定
*/
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
}
@Override
public int onDraw(int texture, FilterChain filterChain) {
FilterContext filterContext = filterChain.filterContext;
createFrame(filterContext.width, filterContext.height);
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffer[0]); //綁定fbo
super.onDraw(texture, filterChain);
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0); //
return filterChain.proceed(frameTextures[0]);
}
@Override
public void release() {
super.release();
releaseFrame();
}
private void releaseFrame() {
if (frameTextures != null) {
GLES20.glDeleteTextures(1, frameTextures, 0);
frameTextures = null;
}
if (frameBuffer != null) {
GLES20.glDeleteFramebuffers(1, frameBuffer, 0);
}
}
}
核心 onDraw
public int onDraw(int texture, FilterChain filterChain) {
FilterContext filterContext = filterChain.filterContext;
createFrame(filterContext.width, filterContext.height);
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffer[0]); //綁定fbo
super.onDraw(texture, filterChain);
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0); //
return filterChain.proceed(frameTextures[0]);
}
我们有很多过滤器，可以看成不同处理流程，都继承超类AbstractFrameFilter 并且实现onDraw 调用super.onDraw
CameraFilter,BigEyeFilter,ScreenFilter,RecordFilter
参考项目