GPUImage API文档之GLProgram类

　　GLProgram是GPUImage中代表openGL ES 中的program，具有glprogram功能。

　　属性

　　@property(readwrite, nonatomic) BOOL initialized

　　　作用：该属性用于指示program的初始化工作是否成功，成功返回YES,反之返回NO　

 　　　@property(readwrite, copy, nonatomic) NSString *vertexShaderLog

　　　　作用：该属性用于设置或获取顶点着色器的日志。

　　　　@property(readwrite, copy, nonatomic) NSString *fragmentShaderLog

　　　　作用：该属性用于设置或获取片段着色器的日志。

　　　　@property(readwrite, copy, nonatomic) NSString *programLog

　　　　作用：该属性用于设置或获取program的日志。

　　方法

　　　　- (id)initWithVertexShaderString:(NSString *)vShaderString fragmentShaderString:(NSString *)fShaderString

　　　　说明：使用一个顶点着色字符串和一个片段着色字符串创建一个GLProgram对象

　　　　参数：顶点着色字符串，片段着色字符串

　　　　返回：GLProgram对象

　　　　相似方法：- (id)initWithVertexShaderString:(NSString *)vShaderString fragmentShaderFilename:(NSString *)fShaderFilename;
　　　　　　　　　- (id)initWithVertexShaderFilename:(NSString *)vShaderFilename fragmentShaderFilename:(NSString *)fShaderFilename（从文件中读取内容）

　　　　实现

- (id)initWithVertexShaderString:(NSString *)vShaderString 
            fragmentShaderString:(NSString *)fShaderString;
{
    if ((self = [super init])) 
    {
        _initialized = NO;
        
        attributes = [[NSMutableArray alloc] init];
        uniforms = [[NSMutableArray alloc] init];
        program = glCreateProgram();
        
        if (![self compileShader:&vertShader 
                            type:GL_VERTEX_SHADER 
                          string:vShaderString])
        {
            NSLog(@"Failed to compile vertex shader");
        }
        
        // Create and compile fragment shader
        if (![self compileShader:&fragShader 
                            type:GL_FRAGMENT_SHADER 
                          string:fShaderString])
        {
            NSLog(@"Failed to compile fragment shader");
        }
        
        glAttachShader(program, vertShader);
        glAttachShader(program, fragShader);
    }
    
    return self;
}

　　　　详解：1.使用glCreateProgram()函数创建一个program

　　　　　　　2.编译着色器

　　　　　　　3.附加着色器。glAttachShader(program, fragShader)

　　　　- (void)addAttribute:(NSString *)attributeName

　　　　说明：该方法用于向一个program对象中添加属性

　　　　参数：需要添加的属性名称

　　　　返回：void

　　　　实现：

- (void)addAttribute:(NSString *)attributeName
{
    if (![attributes containsObject:attributeName])
    {
        [attributes addObject:attributeName];
        glBindAttribLocation(program, 
                             (GLuint)[attributes indexOfObject:attributeName],
                             [attributeName UTF8String]);
    }
}

　　　　详解：void glBindAttribLocation( GLuint program, GLuint index,const GLchar *name)函数用来将属性绑定到具体位置。program是使用的program对象，index是位置索引，*name是需要绑定的属性名

　　　　- (GLuint)attributeIndex:(NSString *)attributeName

　　　　说明：返回具体属性名的索引

　　　　参数：指定的属性名

　　　　返回：指定属性名的索引

　　　　- (GLuint)uniformIndex:(NSString *)uniformName

　　　　说明:返回Uniform的索引

　　　　参数：指定的Uniform名

　　　　返回：指定Uniform的索引

　　　　- (BOOL)link

　　　　说明：判断program是否link成功

　　　 返回：YES说明link成功，反之失败

　　　 实现：

　　　　

- (BOOL)link
{
    GLint status;
    
    glLinkProgram(program);
    
    glGetProgramiv(program, GL_LINK_STATUS, &status);
    if (status == GL_FALSE)
        return NO;
    
    if (vertShader)
    {
        glDeleteShader(vertShader);
        vertShader = 0;
    }
    if (fragShader)
    {
        glDeleteShader(fragShader);
        fragShader = 0;
    }
    
    self.initialized = YES;


    return YES;
}

　　　 详解：glLinkProgram(program)函数link一个创建好的program对象，glGetProgramiv(program, GL_LINK_STATUS, &status)用来查询link结果。

　　　　- (void)use

　　　　说明：使用program

　　　　
　　　　- (void)validate

　　　　说明：program对象是否有效

　　　　- (BOOL)compileShader:(GLuint *)shader type:(GLenum)type string:(NSString *)shaderString

　　　　说明：编译着色器

　　　　参数：shader是着色器   type为着色器类型（顶点和片段）  shaderString为着色器内容字符串。

　　　　实现

　　　　

- (BOOL)compileShader:(GLuint *)shader 
                 type:(GLenum)type 
               string:(NSString *)shaderString
{
//    CFAbsoluteTime startTime = CFAbsoluteTimeGetCurrent();

    GLint status;
    const GLchar *source;
    
    source = 
      (GLchar *)[shaderString UTF8String];
    if (!source)
    {
        NSLog(@"Failed to load vertex shader");
        return NO;
    }
    
    *shader = glCreateShader(type);
    glShaderSource(*shader, 1, &source, NULL);
    glCompileShader(*shader);
    
    glGetShaderiv(*shader, GL_COMPILE_STATUS, &status);

    if (status != GL_TRUE)
    {
        GLint logLength;
        glGetShaderiv(*shader, GL_INFO_LOG_LENGTH, &logLength);
        if (logLength > 0)
        {
            GLchar *log = (GLchar *)malloc(logLength);
            glGetShaderInfoLog(*shader, logLength, &logLength, log);
            if (shader == &vertShader)
            {
                self.vertexShaderLog = [NSString stringWithFormat:@"%s", log];
            }
            else
            {
                self.fragmentShaderLog = [NSString stringWithFormat:@"%s", log];
            }

            free(log);
        }
    }    
    
//    CFAbsoluteTime linkTime = (CFAbsoluteTimeGetCurrent() - startTime);
//    NSLog(@"Compiled in %f ms", linkTime * 1000.0);

    return status == GL_TRUE;
}

#import <Foundation/Foundation.h>

#if TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
#import <OpenGLES/ES2/gl.h>
#import <OpenGLES/ES2/glext.h>
#else
#import <OpenGL/OpenGL.h>
#import <OpenGL/gl.h>
#endif

@interface GLProgram : NSObject 
{
    NSMutableArray  *attributes;
    NSMutableArray  *uniforms;
    GLuint          program,
    vertShader, 
    fragShader;    
}

@property(readwrite, nonatomic) BOOL initialized;
@property(readwrite, copy, nonatomic) NSString *vertexShaderLog;
@property(readwrite, copy, nonatomic) NSString *fragmentShaderLog;
@property(readwrite, copy, nonatomic) NSString *programLog;

- (id)initWithVertexShaderString:(NSString *)vShaderString 
            fragmentShaderString:(NSString *)fShaderString;
- (id)initWithVertexShaderString:(NSString *)vShaderString 
          fragmentShaderFilename:(NSString *)fShaderFilename;
- (id)initWithVertexShaderFilename:(NSString *)vShaderFilename 
            fragmentShaderFilename:(NSString *)fShaderFilename;
- (void)addAttribute:(NSString *)attributeName;
- (GLuint)attributeIndex:(NSString *)attributeName;
- (GLuint)uniformIndex:(NSString *)uniformName;
- (BOOL)link;
- (void)use;
- (void)validate;
@end

#import "GLProgram.h"
// START:typedefs
#pragma mark Function Pointer Definitions
typedef void (*GLInfoFunction)(GLuint program, GLenum pname, GLint* params);
typedef void (*GLLogFunction) (GLuint program, GLsizei bufsize, GLsizei* length, GLchar* infolog);
// END:typedefs
#pragma mark -
#pragma mark Private Extension Method Declaration
// START:extension
@interface GLProgram()

- (BOOL)compileShader:(GLuint *)shader 
                 type:(GLenum)type 
               string:(NSString *)shaderString;
@end
// END:extension
#pragma mark -

@implementation GLProgram
// START:init

@synthesize initialized = _initialized;

- (id)initWithVertexShaderString:(NSString *)vShaderString 
            fragmentShaderString:(NSString *)fShaderString;
{
    if ((self = [super init])) 
    {
        _initialized = NO;
        
        attributes = [[NSMutableArray alloc] init];
        uniforms = [[NSMutableArray alloc] init];
        program = glCreateProgram();
        
        if (![self compileShader:&vertShader 
                            type:GL_VERTEX_SHADER 
                          string:vShaderString])
        {
            NSLog(@"Failed to compile vertex shader");
        }
        
        // Create and compile fragment shader
        if (![self compileShader:&fragShader 
                            type:GL_FRAGMENT_SHADER 
                          string:fShaderString])
        {
            NSLog(@"Failed to compile fragment shader");
        }
        
        glAttachShader(program, vertShader);
        glAttachShader(program, fragShader);
    }
    
    return self;
}

- (id)initWithVertexShaderString:(NSString *)vShaderString 
          fragmentShaderFilename:(NSString *)fShaderFilename;
{
    NSString *fragShaderPathname = [[NSBundle mainBundle] pathForResource:fShaderFilename ofType:@"fsh"];
    NSString *fragmentShaderString = [NSString stringWithContentsOfFile:fragShaderPathname encoding:NSUTF8StringEncoding error:nil];
    
    if ((self = [self initWithVertexShaderString:vShaderString fragmentShaderString:fragmentShaderString])) 
    {
    }
    
    return self;
}

- (id)initWithVertexShaderFilename:(NSString *)vShaderFilename 
            fragmentShaderFilename:(NSString *)fShaderFilename;
{
    NSString *vertShaderPathname = [[NSBundle mainBundle] pathForResource:vShaderFilename ofType:@"vsh"];
    NSString *vertexShaderString = [NSString stringWithContentsOfFile:vertShaderPathname encoding:NSUTF8StringEncoding error:nil];

    NSString *fragShaderPathname = [[NSBundle mainBundle] pathForResource:fShaderFilename ofType:@"fsh"];
    NSString *fragmentShaderString = [NSString stringWithContentsOfFile:fragShaderPathname encoding:NSUTF8StringEncoding error:nil];
    
    if ((self = [self initWithVertexShaderString:vertexShaderString fragmentShaderString:fragmentShaderString])) 
    {
    }
    
    return self;
}
// END:init
// START:compile
- (BOOL)compileShader:(GLuint *)shader 
                 type:(GLenum)type 
               string:(NSString *)shaderString
{
//    CFAbsoluteTime startTime = CFAbsoluteTimeGetCurrent();

    GLint status;
    const GLchar *source;
    
    source = 
      (GLchar *)[shaderString UTF8String];
    if (!source)
    {
        NSLog(@"Failed to load vertex shader");
        return NO;
    }
    
    *shader = glCreateShader(type);
    glShaderSource(*shader, 1, &source, NULL);
    glCompileShader(*shader);
    
    glGetShaderiv(*shader, GL_COMPILE_STATUS, &status);

    if (status != GL_TRUE)
    {
        GLint logLength;
        glGetShaderiv(*shader, GL_INFO_LOG_LENGTH, &logLength);
        if (logLength > 0)
        {
            GLchar *log = (GLchar *)malloc(logLength);
            glGetShaderInfoLog(*shader, logLength, &logLength, log);
            if (shader == &vertShader)
            {
                self.vertexShaderLog = [NSString stringWithFormat:@"%s", log];
            }
            else
            {
                self.fragmentShaderLog = [NSString stringWithFormat:@"%s", log];
            }

            free(log);
        }
    }    
    
//    CFAbsoluteTime linkTime = (CFAbsoluteTimeGetCurrent() - startTime);
//    NSLog(@"Compiled in %f ms", linkTime * 1000.0);

    return status == GL_TRUE;
}
// END:compile
#pragma mark -
// START:addattribute
- (void)addAttribute:(NSString *)attributeName
{
    if (![attributes containsObject:attributeName])
    {
        [attributes addObject:attributeName];
        glBindAttribLocation(program, 
                             (GLuint)[attributes indexOfObject:attributeName],
                             [attributeName UTF8String]);
    }
}
// END:addattribute
// START:indexmethods
- (GLuint)attributeIndex:(NSString *)attributeName
{
    return (GLuint)[attributes indexOfObject:attributeName];
}
- (GLuint)uniformIndex:(NSString *)uniformName
{
    return glGetUniformLocation(program, [uniformName UTF8String]);
}
// END:indexmethods
#pragma mark -
// START:link
- (BOOL)link
{
//    CFAbsoluteTime startTime = CFAbsoluteTimeGetCurrent();

    GLint status;
    
    glLinkProgram(program);
    
    glGetProgramiv(program, GL_LINK_STATUS, &status);
    if (status == GL_FALSE)
        return NO;
    
    if (vertShader)
    {
        glDeleteShader(vertShader);
        vertShader = 0;
    }
    if (fragShader)
    {
        glDeleteShader(fragShader);
        fragShader = 0;
    }
    
    self.initialized = YES;

//    CFAbsoluteTime linkTime = (CFAbsoluteTimeGetCurrent() - startTime);
//    NSLog(@"Linked in %f ms", linkTime * 1000.0);

    return YES;
}
// END:link
// START:use
- (void)use
{
    glUseProgram(program);
}
// END:use
#pragma mark -

- (void)validate;
{
    GLint logLength;
    
    glValidateProgram(program);
    glGetProgramiv(program, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0)
    {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetProgramInfoLog(program, logLength, &logLength, log);
        self.programLog = [NSString stringWithFormat:@"%s", log];
        free(log);
    }    
}

#pragma mark -
// START:dealloc
- (void)dealloc
{
    if (vertShader)
        glDeleteShader(vertShader);
        
    if (fragShader)
        glDeleteShader(fragShader);
    
    if (program)
        glDeleteProgram(program);
       
}
// END:dealloc
@end