Android平台3D引擎研究2

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最老程序员 2022-12-15 11:19:35 博主文章分类：Android 3D引擎 ©著作权

文章标签 android 平台 float 引擎编程 文章分类 Spark 大数据

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在上一篇文章中，我们看到可以通过很少的代码，就可以在屏幕上显示出一个立方体，相当于min3d中的Hello World程序。但是，对于OpenGL ES编程来说，我们通常需要处理的数据是三角片，可惜使用min3d这样的引擎把这些细节给隐藏了。在这里我们自己手动生成一个放在原点上的立方体，给出顶点、三角片、法向量，然后由min3d引擎来显示，这样可以更深入理解OpenGL ES的工作原理。具体实现如下代码所示：

public MgnavObject(boolean useUvs, boolean useNormals, boolean useVertexColors) {
super(4*6, 2*6, useUvs, useNormals,useVertexColors);
float width = 1.0f / 2;
float height = 1.0f / 2;
float deepth = 1.0f / 2;
float textureU = 0.0f;
float textureV = 0.0f;
float normalX = 0.0f;
float normalY = 0.0f;
float normalZ = 0.0f;
short colorR = 0;
short colorG = 0;
short colorB = 0;
short colorA = 0;
// 显示正对的立方体：
// 面编号：从前面开始，面编号为1（前）、2（右）、3（后）、4（左）、5（上）、6（下）
// 顶点编号：前面从左上角点开始，顺时针1、2、3、4；后面与前面编号规则相同即4对5，2对6，3对7，4对8
// 如顶点1在前面时编号为：f1p1，对与上面时f5p1，参与左面时f4p1
// 1. front
normalX = 0f;
normalY = 0f;
normalZ = 1.0f;
// 1.1. 加入前面右上部三角片
short f1p1Idx = vertices().addVertex(-width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f1p3Idx = vertices().addVertex(width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f1p2Idx = vertices().addVertex(width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f1p1Idx, f1p3Idx, f1p2Idx);
// 1.2. 加入前面的左下部三角片
short f1p4Idx = vertices().addVertex(-width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f1p1Idx, f1p4Idx, f1p3Idx);
// 2. 加右面
normalX = 1.0f;
normalY = 0.0f;
normalZ = 0.0f;
// 2.1. 加三角片2,3,7
short f2p2Idx = vertices().addVertex(width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f2p3Idx = vertices().addVertex(width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f2p7Idx = vertices().addVertex(width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f2p2Idx, f2p3Idx, f2p7Idx);
// 2.2. 加三角片2,7,5
short f2p5Idx = vertices().addVertex(width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f2p2Idx, f2p7Idx, f2p5Idx);
// 3. 加后面
normalX = 0.0f;
normalY = 0.0f;
normalZ = -1.0f;
// 3.1. 加三角片6,7,8
short f3p6Idx = vertices().addVertex(width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f3p7Idx = vertices().addVertex(width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f3p8Idx = vertices().addVertex(-width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f3p6Idx, f3p7Idx, f3p8Idx);
// 3.2. 加三角片6,8,5
short f3p5Idx = vertices().addVertex(-width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f3p6Idx, f3p8Idx, f3p5Idx);
// 4. 加左面4
normalX = -1.0f;
normalY = 0.0f;
normalZ = 0.0f;
// 4.1. 加三角片1,5,8
short f4p1Idx = vertices().addVertex(-width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f4p5Idx = vertices().addVertex(-width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f4p8Idx = vertices().addVertex(-width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f4p1Idx, f4p5Idx, f4p8Idx);
// 4.2. 加三角片1,8,4
short f4p4Idx = vertices().addVertex(-width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f4p1Idx, f4p8Idx, f4p4Idx);
// 5. 上面
normalX = 0.0f;
normalY = 1.0f;
normalZ = 0.0f;
// 5.1. 添加三角片2,6,5
short f5p2Idx = vertices().addVertex(width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f5p6Idx = vertices().addVertex(width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f5p5Idx = vertices().addVertex(-width, height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f5p2Idx, f5p6Idx, f5p5Idx);
// 5.2. 添加三角片2,5,1
short f5p1Idx = vertices().addVertex(-width, height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f5p2Idx, f5p5Idx, f5p1Idx);
// 6. 下面
normalX = 0.0f;
normalY = -1.0f;
normalZ = 0.0f;
// 6.1. 添加三角片3,4,8
short f6p3Idx = vertices().addVertex(width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f6p4Idx = vertices().addVertex(-width, -height, deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
short f6p8Idx = vertices().addVertex(-width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f6p3Idx, f6p4Idx, f6p8Idx);
// 6.2. 添加三角片3,8,7
short f6p7Idx = vertices().addVertex(width, -height, -deepth,
textureU, textureV,
normalX, normalY, normalZ,
colorR, colorG, colorB, colorA);
faces().add(f6p3Idx, f6p8Idx, f6p7Idx);
}