软糖的基本效果图如下：
软糖的长方体类，其代码如下：
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import android.opengl.GLES20;
//代表软糖的长方体
public class Cuboid
{
int mProgram;//自定义渲染管线着色器程序id
int muMVPMatrixHandle;//总变换矩阵引用id
int maPositionHandle; //顶点位置属性引用id
int maTexCoorHandle; //顶点纹理坐标属性引用id
int uAngleSpanHandle;//扭曲总角度跨度引用id
int uYStartHandle;//Y坐标起始引用id
int uYSpanHandle;//Y坐标跨度引用id
String mVertexShader;//顶点着色器
String mFragmentShader;//片元着色器
FloatBuffer mVertexBuffer;//顶点坐标数据缓冲
FloatBuffer mTexCoorBuffer;//顶点纹理坐标数据缓冲
int vCount=0;
final float Y_MAX=1.5f;
final float Y_MIN=-1.5f;
final int FD=6;
final float hw=0.575f;
float angleSpan=0;
float angleStep=2f;
public Cuboid(MySurfaceView mv)
{
//初始化顶点坐标与着色数据
initVertexData();
//初始化shader
intShader(mv);
}
//初始化顶点坐标与着色数据的方法
public void initVertexData()
{
//顶点坐标数据的初始化================begin============================
vCount=FD*4*6;
float vertices[]=new float[vCount*3];
float texCoor[]=new float[vCount*2];
float yStart=Y_MIN;
float ySpan=(Y_MAX-Y_MIN)/FD;
int count=0;
int tCount=0;
for(int i=0;i<FD;i++)
{
float x1=-hw;
float y1=yStart;
float z1=hw;
float x2=hw;
float y2=yStart;
float z2=hw;
float x3=hw;
float y3=yStart;
float z3=-hw;
float x4=-hw;
float y4=yStart;
float z4=-hw;
float x5=-hw;
float y5=yStart+ySpan;
float z5=hw;
float x6=hw;
float y6=yStart+ySpan;
float z6=hw;
float x7=hw;
float y7=yStart+ySpan;
float z7=-hw;
float x8=-hw;
float y8=yStart+ySpan;
float z8=-hw;
//512
vertices[count++]=x5;
vertices[count++]=y5;
vertices[count++]=z5;
vertices[count++]=x1;
vertices[count++]=y1;
vertices[count++]=z1;
vertices[count++]=x2;
vertices[count++]=y2;
vertices[count++]=z2;
//526
vertices[count++]=x5;
vertices[count++]=y5;
vertices[count++]=z5;
vertices[count++]=x2;
vertices[count++]=y2;
vertices[count++]=z2;
vertices[count++]=x6;
vertices[count++]=y6;
vertices[count++]=z6;
//
vertices[count++]=x6;
vertices[count++]=y6;
vertices[count++]=z6;
vertices[count++]=x2;
vertices[count++]=y2;
vertices[count++]=z2;
vertices[count++]=x3;
vertices[count++]=y3;
vertices[count++]=z3;
vertices[count++]=x6;
vertices[count++]=y6;
vertices[count++]=z6;
vertices[count++]=x3;
vertices[count++]=y3;
vertices[count++]=z3;
vertices[count++]=x7;
vertices[count++]=y7;
vertices[count++]=z7;
vertices[count++]=x7;
vertices[count++]=y7;
vertices[count++]=z7;
vertices[count++]=x3;
vertices[count++]=y3;
vertices[count++]=z3;
vertices[count++]=x4;
vertices[count++]=y4;
vertices[count++]=z4;
vertices[count++]=x7;
vertices[count++]=y7;
vertices[count++]=z7;
vertices[count++]=x4;
vertices[count++]=y4;
vertices[count++]=z4;
vertices[count++]=x8;
vertices[count++]=y8;
vertices[count++]=z8;
vertices[count++]=x8;
vertices[count++]=y8;
vertices[count++]=z8;
vertices[count++]=x4;
vertices[count++]=y4;
vertices[count++]=z4;
vertices[count++]=x1;
vertices[count++]=y1;
vertices[count++]=z1;
vertices[count++]=x8;
vertices[count++]=y8;
vertices[count++]=z8;
vertices[count++]=x1;
vertices[count++]=y1;
vertices[count++]=z1;
vertices[count++]=x5;
vertices[count++]=y5;
vertices[count++]=z5;
yStart=yStart+ySpan;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
texCoor[tCount++]=0;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=1;
texCoor[tCount++]=0;
}
//创建顶点坐标数据缓冲
//vertices.length*4是因为一个整数四个字节
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
vbb.order(ByteOrder.nativeOrder());//设置字节顺序
mVertexBuffer = vbb.asFloatBuffer();//转换为Float型缓冲
mVertexBuffer.put(vertices);//向缓冲区中放入顶点坐标数据
mVertexBuffer.position(0);//设置缓冲区起始位置
//特别提示：由于不同平台字节顺序不同数据单元不是字节的一定要经过ByteBuffer
//转换，关键是要通过ByteOrder设置nativeOrder()，否则有可能会出问题
//顶点坐标数据的初始化================end============================
//顶点纹理坐标数据的初始化================begin============================
//创建顶点纹理坐标数据缓冲
ByteBuffer cbb = ByteBuffer.allocateDirect(texCoor.length*4);
cbb.order(ByteOrder.nativeOrder());//设置字节顺序
mTexCoorBuffer = cbb.asFloatBuffer();//转换为Float型缓冲
mTexCoorBuffer.put(texCoor);//向缓冲区中放入顶点着色数据
mTexCoorBuffer.position(0);//设置缓冲区起始位置
//特别提示：由于不同平台字节顺序不同数据单元不是字节的一定要经过ByteBuffer
//转换，关键是要通过ByteOrder设置nativeOrder()，否则有可能会出问题
//顶点纹理坐标数据的初始化================end============================
}
//初始化shader
public void intShader(MySurfaceView mv)
{
//加载顶点着色器的脚本内容
mVertexShader=ShaderUtil.loadFromAssetsFile("vertex_tex.sh", mv.getResources());
//加载片元着色器的脚本内容
mFragmentShader=ShaderUtil.loadFromAssetsFile("frag_tex.sh", mv.getResources());
//基于顶点着色器与片元着色器创建程序
mProgram = createProgram(mVertexShader, mFragmentShader);
//获取程序中顶点位置属性引用id
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
//获取程序中顶点纹理坐标属性引用id
maTexCoorHandle= GLES20.glGetAttribLocation(mProgram, "aTexCoor");
//获取程序中总变换矩阵引用id
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
//获取程序中总扭曲角度跨度
uAngleSpanHandle = GLES20.glGetUniformLocation(mProgram, "angleSpan");
//获取程序中Y坐标起始引用id
uYStartHandle = GLES20.glGetUniformLocation(mProgram, "yStart");
//获取程序中Y坐标跨度引用id
uYSpanHandle = GLES20.glGetUniformLocation(mProgram, "ySpan");
}
public void drawSelf(int texId)
{
//制定使用某套shader程序
GLES20.glUseProgram(mProgram);
//将最终变换矩阵传入shader程序
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, MatrixState.getFinalMatrix(), 0);
//将顶点位置数据传入渲染管线
GLES20.glVertexAttribPointer
(
maPositionHandle,
3,
GLES20.GL_FLOAT,
false,
3*4,
mVertexBuffer
);
//将顶点纹理坐标数据传入渲染管线
GLES20.glVertexAttribPointer
(
maTexCoorHandle,
2,
GLES20.GL_FLOAT,
false,
2*4,
mTexCoorBuffer
);
//启用顶点位置、纹理坐标数据
GLES20.glEnableVertexAttribArray(maPositionHandle);
GLES20.glEnableVertexAttribArray(maTexCoorHandle);
//绑定纹理
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, texId);
angleSpan=(float) (angleSpan+Math.toRadians(angleStep));
if(Math.toDegrees(angleSpan)>90)
{
angleStep=-2f;
}
else if(Math.toDegrees(angleSpan)<-90)
{
angleStep=2f;
}
GLES20.glUniform1f(uAngleSpanHandle , angleSpan);
GLES20.glUniform1f(uYStartHandle , Y_MIN);
GLES20.glUniform1f(uYSpanHandle , Y_MAX-Y_MIN);
try {
Thread.sleep(20);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//绘制纹理矩形
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vCount);
}
}
实现软糖扭动的顶点着色器：
uniform mat4 uMVPMatrix; //总变换矩阵
attribute vec3 aPosition; //顶点位置
attribute vec2 aTexCoor; //顶点纹理坐标
varying vec2 vTextureCoord; //用于传递给片元着色器的变量
uniform float angleSpan;//扭曲总角度跨度
uniform float yStart;//Y坐标起始点
uniform float ySpan;//Y坐标跨度
void main()
{
//计算当前顶点角度跨度
float tempAS= angleSpan*(aPosition.y-yStart)/ySpan;
vec3 tPosition=aPosition;
//若不是最下面一排顶点计算XZ位置
if(aPosition.y>yStart)
{
tPosition.x=(cos(tempAS)*aPosition.x-sin(tempAS)*aPosition.z);
tPosition.z=(sin(tempAS)*aPosition.x+cos(tempAS)*aPosition.z);
}
gl_Position = uMVPMatrix * vec4(tPosition,1); //根据总变换矩阵计算此次绘制此顶点位置
vTextureCoord = aTexCoor;//将接收的纹理坐标传递给片元着色器
}