Android多媒体之GLES2战记第六集--九层之台

九层之台，起于累土;千里之行，始于足下

第九副本：擎天之柱：

拿出草稿纸，自己画一画，抛开书本(发现那本书的画法思路不怎么样，不优雅)
咱们来自己算，自己画,该副本的代码在shape/part,琐碎的小点就省去了
一路走到这里，套路基本上都一样，本文研究的只是图形画法,基本用法不会的就前补吧

1.第一关卡：GL_TRIANGLES画圆

图片立体圆裁剪.png

1.1：顶点的计算

顶点的计算.png

    /*** 初始化顶点坐标数据的方法** @param r          半径* @param splitCount 切分的份数*/public void initVertex(float r, int splitCount) {float dθ = 360.0f / splitCount;//顶角的度数vertexCount = 3 * splitCount;//顶点个数，共有n个三角形，每个三角形都有三个顶点float[] vertices = new float[vertexCount * 3];//坐标数据for (int v = 0, t = 0; v < vertexCount; v += 3, t += 3) {int n = v / 3;vertices[3 * v] = 0;//顶点坐标:p0vertices[3 * v + 1] = 0;vertices[3 * v + 2] = 0;vertices[3 * v + 3] = r * cos(n * dθ);//顶点坐标:p1vertices[3 * v + 4] = r * sin(n * dθ);vertices[3 * v + 5] = 0;vertices[3 * v + 6] = r * cos((n + 1) * dθ);//顶点坐标:p2vertices[3 * v + 7] = r * sin((n + 1) * dθ);vertices[3 * v + 8] = 0;}}

1.2：贴图坐标的计算

贴图坐标计算.png

for (int v = 0, t = 0; v < vertexCount; v += 3, t += 3) {int n = v / 3;//顶点坐标计算同上, 略 ....textures[2 * t] = 0.5f;//贴图：p0textures[2 * t + 1] = 0.5f;textures[2 * t + 2] = 0.5f + 0.5f * r * cos(n * dθ);//贴图：p1textures[2 * t + 3] = 0.5f - 0.5f * r * sin(n * dθ);textures[2 * t + 4] = 0.5f + 0.5f * r * cos((n + 1) * dθ);//贴图：p2textures[2 * t + 5] = 0.5f - 0.5f * r * sin((n + 1) * dθ);
}

2.第二关卡：圆柱侧面

旋转圆柱.gif

圆柱的点位计算.png

 /*** 圆柱侧面* @param r          半径* @param h          高度* @param splitCount 切分的份数*/public void initVertex(float r, float h, int splitCount) {float dθ = 360.0f / splitCount;vertexCount = splitCount * 4 * 3;//顶点个数，共有3*splitCount*4个三角形，每个三角形都有三个顶点//坐标数据初始化float[] vertices = new float[vertexCount * 3];float[] textures = new float[vertexCount * 2];//顶点纹理S、T坐标值数组for (int v = 0, t = 0; v < vertexCount; v += 6, t += 6) {int n = v / 6;float x = r * cos(n * dθ);float xNext = r * cos(n * dθ + dθ);float z = -r * sin(n * dθ);float zNext = -r * sin(n * dθ + dθ);vertices[3 * v + 0] = x;//底部p0vertices[3 * v + 1] = 0;vertices[3 * v + 2] = z;vertices[3 * v + 3] = xNext;//顶部p2vertices[3 * v + 4] = h;vertices[3 * v + 5] = zNext;vertices[3 * v + 6] = x;//顶部p1vertices[3 * v + 7] = h;//yvertices[3 * v + 8] = z;//zvertices[3 * v + 9] = x;//底部p0vertices[3 * v + 10] = 0;vertices[3 * v + 11] = z;vertices[3 * v + 12] = xNext;//底部p3vertices[3 * v + 13] = 0;//yvertices[3 * v + 14] = zNext;//zvertices[3 * v + 15] = xNext;//顶部p2vertices[3 * v + 16] = h;//yvertices[3 * v + 17] = zNext;//zfloat s = n * dθ / 360.f;float sNext = (n + 1) * dθ / 360.f;textures[2 * t + 0] = s;//贴图：p0textures[2 * t + 1] = 1;textures[2 * t + 2] = sNext;//贴图：p2textures[2 * t + 3] = 0;textures[2 * t + 4] = s;//贴图：p1textures[2 * t + 5] = 0;textures[2 * t + 6] = s;//贴图：p0textures[2 * t + 7] = 1;textures[2 * t + 8] = sNext;//贴图：p3textures[2 * t + 9] = 1;textures[2 * t + 10] = sNext;//贴图：p2textures[2 * t + 11] = 0;}//法向量数据初始化float[] normals = new float[vertices.length];for (int i = 0; i < vertices.length; i++) {if (i % 3 == 1) {normals[i] = 0;} else {normals[i] = vertices[i];}}vertexBuffer = GLUtil.getFloatBuffer(vertices);mNormalBuffer = GLUtil.getFloatBuffer(normals);mTexCoorBuffer = GLUtil.getFloatBuffer(textures);}

圆柱面.png

侧面旋转90°

旋转90°.png

3.第三关卡：圆柱的拼接

圆柱体.gif

3.1:移动和旋转的辅助方法MatrixStack

将MatrixStack在保存状态下重置，再进行变换操作，最后restore，感觉用着蛮不错的

/*** 设置沿xyz轴移动 注意:本方法和restore联合使用** @param x 移动的 x 分量* @param y 移动的 y 分量* @param z 移动的 z 分量*/
public static void reTranslate(float[] target, float x, float y, float z) {save();reset();Matrix.translateM(MatrixStack.getOpMatrix(), 0, target, 0,x, y, z);
}
/*** 设置沿(x,y,z)点旋转 注意:本方法和restore联合使用** @param deg 角度* @param x   旋转点的 x 分量* @param y   旋转点的 y 分量* @param z   旋转点的 z 分量*/
public static void reRotate(float[] target, float deg, float x, float y, float z) {save();reset();Matrix.rotateM(MatrixStack.getOpMatrix(), 0, target, 0,deg, x, y, z);
}

3.2:三块拼型：Cylinder.java

这个比较简单，圆和侧面都有了，拼起来就行了

/*** 作者：张风捷特烈<br/>* 时间：2019/1/16/016:19:22<br/>* 邮箱：1981462002@qq.com<br/>* 说明：圆柱类*/
public class Cylinder extends RendererAble {private final Circle mBottomCircle;//底圆private final Circle mTopCircle;//顶圆private final CylinderSide mCylinderSide;private float mH;/*** @param context     上下文* @param h           高* @param r           底面半径* @param splitCount  切割数* @param textureIdX3 贴图id 上、下、周围贴图*/public Cylinder(Context context, float r, float h, int splitCount, int[] textureIdX3) {super(context);if (textureIdX3.length != 3) {throw new IllegalArgumentException("the length of textureIdX3 must be 3");}mH = h;mBottomCircle = new Circle(context, r, splitCount, textureIdX3[0]);mTopCircle = new Circle(context, r, splitCount, textureIdX3[1]);mCylinderSide = new CylinderSide(mContext, r, h, splitCount, textureIdX3[2]);}@Overridepublic void draw(float[] mvpMatrix) {MatrixStack.reTranslate(mvpMatrix, 0, 0, mH);mTopCircle.draw(MatrixStack.getOpMatrix());MatrixStack.restore();MatrixStack.reRotate(mvpMatrix, 90, 1, 0, 0);mCylinderSide.draw(MatrixStack.getOpMatrix());MatrixStack.restore();mBottomCircle.draw(mvpMatrix);}
}

第十副本：钻天之锥：

其他立体图形的思路基本一致，就是寻找三角形坐标、贴图坐标、法向量坐标
其中法向量坐标是和光照相关的，这里暂时不讨论，后面光照会详细讨论
写了这么多感觉重复的代码很多，抽取了一个父类EvnRender来做一些通用的事
它的孩子只需在意：三角形坐标、贴图坐标、法向量坐标三个数组即可

圆锥侧面.gif

1.第一关卡：GL_TRIANGLE_FAN绘制 三角形，拼合圆形

好处：顶点少 以前是：3*splitCount ,现在是splitCount+2

图片立体圆裁剪.png

image

/*** 初始化顶点坐标数据的方法** @param r          半径* @param splitCount 切分的份数*/
public void initVertex(float r, int splitCount) {float dθ = 360.0f / splitCount;//顶角的度数int vertexCount = splitCount + 2;//顶点个数，共有n个三角形，每个三角形都有三个顶点float[] vertices = new float[vertexCount * 3];//坐标数据float[] textures = new float[vertexCount * 2];//顶点纹理S、T坐标值数组vertices[0] = 0;vertices[1] = 0;vertices[2] = 0;textures[0] = 0.5f;textures[1] = 0.5f;for (int n = 1; n < vertexCount; n++) {//顶点坐标vertices[n * 3 + 0] = r * cos((n - 1) * dθ);//xvertices[n * 3 + 1] = r * sin((n - 1) * dθ);//yvertices[n * 3 + 2] = 0;//z//纹理坐标textures[2 * n] = 0.5f + 0.5f * cos((n - 1) * dθ);textures[2 * n + 1] = 0.5f - 0.5f * sin((n - 1) * dθ);}
}

2.第二关卡：圆锥侧面方式一：GL_TRIANGLES

image

/*** 初始化顶点* @param r          半径* @param h          高度* @param splitCount 切分的份数*/
public void initVertexData(float r, float h, int splitCount) {float dθ = 360.0f / splitCount;int vCount = splitCount * 3;//顶点个数，共有3*splitCount*4个三角形，每个三角形都有三个顶点//坐标数据初始化float[] vertices = new float[vCount * 3];float[] textures = new float[vCount * 2];//顶点纹理S、T坐标值数组float[] normals = new float[vertices.length];//法向量数组for (int v = 0, t = 0; v < vCount; v += 3, t += 3) {int n = v / 3;float x = r * cos(n * dθ);float xNext = r * cos(n * dθ + dθ);float z = r * sin(n * dθ);float zNext = r * sin(n * dθ + dθ);//顶点坐标vertices[3 * v + 0] = 0;//p0vertices[3 * v + 1] = h;vertices[3 * v + 2] = 0;vertices[3 * v + 3] = x;//p1vertices[3 * v + 4] = 0;vertices[3 * v + 5] = z;vertices[3 * v + 6] = xNext;//p2vertices[3 * v + 7] = 0;vertices[3 * v + 8] = zNext;//纹理坐标float s = n * dθ / 360.f;float sNext = (n + 1) * dθ / 360.f;textures[2 * t + 0] = 0.5f;//p0textures[2 * t + 1] = 0f;textures[2 * t + 2] = s;//p1textures[2 * t + 3] = 1f;textures[2 * t + 4] = sNext;//p2textures[2 * t + 5] = 1f;}
}

3.第三关卡：圆锥侧面方式二：GL_TRIANGLE_FAN

省顶点，而且写起来简单

/*** 初始化顶点** @param r          半径* @param h          高度* @param splitCount 切分的份数*/
public void initVertexData(float r, float h, int splitCount) {float dθ = 360.0f / splitCount;int vCount = splitCount + 2;//顶点个数，共有3*splitCount*4个三角形，每个三角形都有三个顶点//坐标数据初始化float[] vertices = new float[vCount * 3];float[] textures = new float[vCount * 2];//顶点纹理S、T坐标值数组float[] normals = new float[vertices.length];//法向量数组//顶点坐标vertices[0] = 0;//p0vertices[1] = h;vertices[2] = 0;textures[0] = 0.5f;//p0textures[1] = 0f;for (int n = 1; n < vCount; n++) {float x = r * cos(n * dθ);float z = r * sin(n * dθ);//顶点坐标vertices[3 * n + 0] = x;//p1vertices[3 * n + 1] = 0;vertices[3 * n + 2] = z;//纹理坐标float s = n * dθ / 360.f;textures[2 * n + 0] = s;//p1textures[2 * n + 1] = 1f;}
}

4.第三关卡：拼接圆锥

圆锥拼合.png

/*** 作者：张风捷特烈<br/>* 时间：2019/1/16/016:19:22<br/>* 邮箱：1981462002@qq.com<br/>* 说明：圆锥类*/
public class Cone extends RenderAble {private  CircleFanEvn mBottomCircleTris;//底圆private  ConeSideFanEvn mConeSide;//侧面private float mH;/*** @param context     上下文* @param h           高* @param r           底面半径* @param splitCount  切割数* @param textureIdX2 贴图id 下、周围贴图*/public Cone(Context context, float r, float h, int splitCount, int[] textureIdX2) {super(context);if (textureIdX2.length != 2) {throw new IllegalArgumentException("the length of textureIdX3 must be 2");}mH = h;mBottomCircleTris = new CircleFanEvn(context, textureIdX2[0], r, splitCount);mConeSide = new ConeSideFanEvn(context, textureIdX2[1], r, h,splitCount);}@Overridepublic void draw(float[] mvpMatrix) {MatrixStack.reRotate(mvpMatrix, 90, 1, 0, 0);mConeSide.draw(MatrixStack.getOpMatrix());MatrixStack.restore();mBottomCircleTris.draw(mvpMatrix);}
}

圆锥拼合.gif

第十一副本： 立方之魔

封装立方，拼合魔方

魔方.gif

1.第一关卡：面封装

image

/*** 作者：张风捷特烈<br/>* 时间：2019/1/17/017:11:28<br/>* 邮箱：1981462002@qq.com<br/>* 说明：与Y轴组成的面*/
public class RectangleEvn extends EvnRender {public RectangleEvn(Context context, int tId, float x, float y, float z) {super(context, tId, GLES20.GL_TRIANGLE_STRIP);initVertex(x, y, z);}private void initVertex(float x, float y, float z) {int vertexCount = 4;//顶点个数，共有n个三角形，每个三角形都有三个顶点float[] vertices = new float[vertexCount * 3];//坐标数据float[] textures = new float[vertexCount * 2];//顶点纹理S、T坐标值数组float[] normals = new float[vertices.length];//顶点坐标vertices[0] = 0;//p0vertices[1] = 0;vertices[2] = 0;vertices[3] = 0;//p1vertices[4] = y;vertices[5] = 0;vertices[6] = x;//p3vertices[7] = 0;vertices[8] = z;vertices[9] = x;//p2vertices[10] = y;vertices[11] = z;//贴图坐标textures[0] = 0;//p0textures[1] = 1;textures[2] = 0;//p1textures[3] = 0;textures[4] = 1;//p3textures[5] = 1;textures[6] = 1;//p2textures[7] = 0;init(vertices, textures, normals);}
}

2.第二关卡：封装立方

立方贴图.gif

/*** 作者：张风捷特烈<br/>* 时间：2019/1/9 0009:20:09<br/>* 邮箱：1981462002@qq.com<br/>* 说明：贴图立方*/
public class Cube3d extends RenderAble {private final RectangleEvn mRectA;private final RectangleEvn mRectB;private final RectangleEvn mRectD;private final RectangleEvn mRectC;private final RectangleEvn mRectE;private final RectangleEvn mRectF;private float rate;private float mX;private float mY;private float mZ;public Cube3d(Context context, float x, float y, float z, int[] textureIdX6) {super(context);if (textureIdX6.length != 6) {throw new IllegalArgumentException("the length of textureIdX3 must be 6");}mX = x;mY = y;mZ = z;mRectA = new RectangleEvn(mContext, textureIdX6[0], 0, y, z);mRectB = new RectangleEvn(mContext, textureIdX6[1], 0, y, z);mRectC = new RectangleEvn(mContext, textureIdX6[2], 0, y, z);mRectD = new RectangleEvn(mContext, textureIdX6[3], 0, y, z);mRectE = new RectangleEvn(mContext, textureIdX6[4], 0, y, z);mRectF = new RectangleEvn(mContext, textureIdX6[5], 0, y, z);}@Overridepublic void draw(float[] mvpMatrix) {mRectA.draw(mvpMatrix);MatrixStack.reTranslate(mvpMatrix, 0, 0, mZ);MatrixStack.rotate(90, 0, 1, 0);mRectB.draw(MatrixStack.getOpMatrix());MatrixStack.restore();MatrixStack.reTranslate(mvpMatrix, mX, 0, 0);MatrixStack.rotate(90, 0, -1, 0);mRectD.draw(MatrixStack.getOpMatrix());MatrixStack.restore();MatrixStack.reTranslate(mvpMatrix, 0, 0, 0);MatrixStack.rotate(-90, 0, 0, 1);MatrixStack.translate(0, 0, mZ);MatrixStack.rotate(180, 0, 1, 0);mRectF.draw(MatrixStack.getOpMatrix());MatrixStack.restore();MatrixStack.reTranslate(mvpMatrix, 0, mY, 0);MatrixStack.rotate(-90, 0, 0, 1);mRectE.draw(MatrixStack.getOpMatrix());MatrixStack.restore();MatrixStack.reTranslate(mvpMatrix, mX, 0, mZ);MatrixStack.rotate(-180, 0, 1, 0);mRectC.draw(MatrixStack.getOpMatrix());MatrixStack.restore();}public void setRate(float rate) {this.rate = rate;}
}

3.第三关卡：拼合魔方

魔方.gif

---->[WorldShape#draw]----------
//立方的偏移数组mTrans = new float[]{0, 0, 0,0, 0, 0.5f,0, 0, -0.5f,0, 0.5f, 0,0, 0.5f, 0.5f,0, 0.5f, -0.5f,0.5f, 0.5f, 0,0.5f, 0.5f, 0.5f,0.5f, 0.5f, -0.5f,0.5f, 0f, 0,0.5f, 0f, 0.5f,0.5f, 0f, -0.5f,0.5f, -0.5f, 0,0.5f, -0.5f, 0.5f,0.5f, -0.5f, -0.5f,0f, -0.5f, 0,0f, -0.5f, 0.5f,0f, -0.5f, -0.5f,-0.5f, -0.5f, 0,-0.5f, -0.5f, 0.5f,-0.5f, -0.5f, -0.5f,-0.5f, 0f, 0,-0.5f, 0f, 0.5f,-0.5f, 0f, -0.5f,-0.5f, 0.5f, 0,-0.5f, 0.5f, 0.5f,-0.5f, 0.5f, -0.5f,};---->[WorldShape#draw]----------for (int i = 0; i < mTrans.length / 3; i++) {MatrixStack.reTranslate(mvpMatrix, mTrans[3 * i], mTrans[3 * i + 1], mTrans[3 * i + 2]);mCube3d.draw(MatrixStack.getOpMatrix());MatrixStack.restore();
}

第十二副本： GLES2战记下季预告

到此，我们已经可以对OpenGL的世界有了简单的认识，如果你和我一路走来
相信你的运算能力和代码控制力以及学习能力都会有一定的提高，之后的路还要自己去走
第一季到此结束：九层之台，起于累土;千里之行，始于足下,切莫眼高手低
下一季(如果有的话)我们再见，临走，丢几个图...自己实现去。

接下来继续原来的多媒体路线。

圆环面.gif

螺线管.gif

球.gif

后记：捷文规范

1.本文成长记录及勘误表

2.更多关于我

3.声明

1----本文由张风捷特烈原创,转载请注明
2----欢迎广大编程爱好者共同交流
3----个人能力有限，如有不正之处欢迎大家批评指证，必定虚心改正
4----看到这里，我在此感谢你的喜欢与支持

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