[OpenGL ES _ 入门_01](http://www.jianshu.com/p/f66906b27819)
[OpenGL ES _ 入门_02](http://www.jianshu.com/p/dc49c946438e)
[OpenGL ES _ 入门_03](http://www.jianshu.com/p/00b5be729e4b)
[OpenGL ES _ 入门_04](http://www.jianshu.com/p/516b0b8be9d8)
[OpenGL ES _ 入门_05](http://www.jianshu.com/p/08c51c298d47)
[OpenGL ES _ 入门练习_01](http://www.jianshu.com/p/eebaf64e3e0a)
[OpenGL ES _ 入门练习_02](http://www.jianshu.com/p/6155d60dab20)
[OpenGL ES _ 入门练习_03](http://www.jianshu.com/p/36d9dac03345)
[OpenGL ES _ 入门练习_04](http://www.jianshu.com/p/1ca30e9387dd)
[OpenGL ES _ 入门练习_05](http://www.jianshu.com/p/ac9375962f34)
[OpenGL ES _ 入门练习_06](http://www.jianshu.com/p/c63dc219f7a0)
[OpenGL ES _ 着色器 _ 介绍](http://www.jianshu.com/p/309d489bc344)
[OpenGL ES _ 着色器 _ 程序](http://www.jianshu.com/p/ed0c617bcd67)
[OpenGL ES _ 着色器 _ 语法](http://www.jianshu.com/p/c5b89b294995)
[OpenGL ES_着色器_纹理图像](http://www.jianshu.com/p/8c0ad4e3e40f)
[OpenGL ES_着色器_预处理](http://www.jianshu.com/p/5e9837b0b219)
[OpenGL ES_着色器_顶点着色器详解](http://www.jianshu.com/p/9d7dca6b70c7)
[OpenGL ES_着色器_片断着色器详解](http://www.jianshu.com/p/55461927c419 )
[OpenGL ES_着色器_实战01](http://www.jianshu.com/p/18d6b37363c8)
[OpenGL ES_着色器_实战02](http://www.jianshu.com/p/45d959c8f1db)
[OpenGL ES_着色器_实战03](http://www.jianshu.com/p/0f740901da59)
演示:
学习目标:
创建一个移动的球体
技术:
OpenGL ES 1
实现思路:
第一步: 创建GLKViewController 控制器(在里面实现方法)
第二步: 创建EAGContext 跟踪所有状态,命令和资源
第三步: 生成球体的顶点坐标和颜色数据
第三步: 清除命令
第四步: 创建投影坐标系
第五步: 创建对象坐标
第六步: 导入顶点数据
第七步: 导入颜色数据
第八步: 绘制
代码部分
/**
* 创建EAGContext 跟踪所有状态,命令和资源
*/
- (void)createEagContext{
self.eagContext = [[EAGLContext alloc]initWithAPI:kEAGLRenderingAPIOpenGLES1];
[EAGLContext setCurrentContext:self.eagContext];
}
/**
* 配置view
*/
- (void)configure{
GLKView *view = (GLKView*)self.view;
view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
view.context = self.eagContext;
}
/**
* 清除
*/
-(void)clear{
glEnable(GL_DEPTH_TEST);
glClearColor(1, 1, 1, 0.1);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
}
/**
* 创建投影坐标
*/
- (void)initProjectionMatrix{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
}
/**
* 创建物体坐标
*/
-(void)initModelViewMatrix{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
static GLfloat transY = 0.0;
static GLfloat z=-2;
static CGFloat scale = 1;
static BOOL isBig = true;
if (isBig){
scale += 0.01;
}else{
scale -= 0.01;
}
if (scale>=1.5){
isBig = false;
}
if (scale<=0.5){
isBig = true;
}
//1
static GLfloat spinX=0;
static GLfloat spinY=0;
glTranslatef(0.0, (GLfloat)(sinf(transY)/2.0), z);
glRotatef(spinY, 0.0, 1.0, 0.0);
glRotatef(spinX, 1.0, 0.0, 0.0);
glScalef(scale, scale, scale);
transY += 0.075f;
spinY+=.25;
spinX+=.25;
}
/**
* 导出顶点坐标
* glVertexPointer 第一个参数:每个顶点数据的个数,第二个参数,顶点数据的数据类型,第三个偏移量，第四个顶点数组地址
*/
- (void)loadVertexData{
glVertexPointer(3, GL_FLOAT, 0, _vertexArray);
glEnableClientState(GL_VERTEX_ARRAY);
}
/**
* 导入颜色数据
*/
- (void)loadColorBuffer{
glColorPointer(4, GL_UNSIGNED_BYTE, 0, _colorsArray);
glEnableClientState(GL_COLOR_ARRAY);
}
/**
* 导入索引数据
*/
-(void)draw{
// 开启剔除面功能
glEnable(GL_CULL_FACE); //3
glCullFace(GL_BACK); // 剔除背面
glDrawArrays(GL_TRIANGLE_STRIP, 0, (m_Slices +1)*2*(m_Stacks-1)+2);
// free(_vertexArray);
// free(_colorsArray);
}
/**
* 生成球体的顶点坐标和颜色数据
*/
-(void)calculate{
unsigned int colorIncrment=0; //1
unsigned int blue=0;
unsigned int red=255;
unsigned int green = 0;
static int big = 1;
static float scale = 0;
if (big){
scale += 0.01;
}else{
scale -= 0.01;
}
if (scale >= 0.5){
big = 0;
}
if (scale <= 0){
big = 1;
}
m_Scale = 0.5 + scale;
m_Slices = 100;
m_Squash = 1;
m_Stacks = 100;
colorIncrment = 255/m_Stacks; //2
//vertices
GLfloat *vPtr = _vertexArray =
(GLfloat*)malloc(sizeof(GLfloat) * 3 * ((m_Slices*2+2) * (m_Stacks))); //3
//color data
GLubyte *cPtr = _colorsArray =
(GLubyte*)malloc(sizeof(GLubyte) * 4 * ((m_Slices *2+2) * (m_Stacks))); //4
unsigned int phiIdx, thetaIdx;
//latitude
for(phiIdx=0; phiIdx < m_Stacks; phiIdx++) //5
{
float phi0 = M_PI * ((float)(phiIdx+0) * (1.0f/(float)( m_Stacks)) - 0.5f);
float phi1 = M_PI * ((float)(phiIdx+1) * (1.0f/(float)( m_Stacks)) - 0.5f);
float cosPhi0 = cos(phi0); //8
float sinPhi0 = sin(phi0);
float cosPhi1 = cos(phi1);
float sinPhi1 = sin(phi1);
float cosTheta, sinTheta;
for(thetaIdx=0; thetaIdx < m_Slices; thetaIdx++)
{
float theta = 2.0f*M_PI * ((float)thetaIdx) * (1.0f/(float)( m_Slices -1));
cosTheta = cos(theta);
sinTheta = sin(theta);
vPtr [0] = m_Scale*cosPhi0 * cosTheta;
vPtr [1] = m_Scale*sinPhi0*m_Squash;
vPtr [2] = m_Scale*cosPhi0 * sinTheta;
vPtr [3] = m_Scale*cosPhi1 * cosTheta;
vPtr [4] = m_Scale*sinPhi1*m_Squash;
vPtr [5] = m_Scale* cosPhi1 * sinTheta;
cPtr [0] = red;
cPtr [1] = green;
cPtr [2] = blue;
cPtr [4] = red;
cPtr [5] = green;
cPtr [6] = blue;
cPtr [3] = cPtr[7] = 255;
cPtr += 2*4;
vPtr += 2*3;
}
blue+=colorIncrment;
red-=colorIncrment;
green += colorIncrment;
}
}
/**
* 设置窗口及投影坐标的位置
*/
-(void)setClipping
{
float aspectRatio;
const float zNear = .1;
const float zFar = 1000;
const float fieldOfView = 60.0;
GLfloat size;
CGRect frame = [[UIScreen mainScreen] bounds];
aspectRatio=(float)frame.size.width/(float)frame.size.height;
[self initProjectionMatrix];
size = zNear * tanf(GLKMathDegreesToRadians (fieldOfView) / 2.0);
// 设置视图窗口的大小 和 坐标系统
glFrustumf(-size, size, -size /aspectRatio, size /aspectRatio, zNear, zFar);
glViewport(0, 0, frame.size.width, frame.size.height);
}
在GLVViewController 中的代码实现过程:
- (void)viewDidLoad {
[super viewDidLoad];
UIImageView *imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"bg.jpg"]];
imageView.frame = self.view.bounds;
[self.view addSubview:imageView];
imageView.alpha = 0.5;
[self createEagContext];
[self configure];
[self calculate];
[self setClipping];
}
-(void)glkView:(GLKView *)view drawInRect:(CGRect)rect{
[self clear];
[self initModelViewMatrix];
[self loadVertexData];
[self loadColorBuffer];
[self draw];
}
代码下载地址:https://github.com/XJALYN/OpenGL_005
