OpenGL ES 代码在 Android 中工作，但 glAttachShader 不在 iOS 中工作

Question

我有一些在 Android 上运行良好的 OpenGL ES C 代码。代码质量很差（随机错误代码，使用全局变量等），因为我只是想在重构和清理之前起床运行。但是，它适用于 Android 并正确显示红色三角形。

但相同的代码不适用于 iOS。我在调用 glAttachShader 时得到 GL_INVALID_VALUE （我在下面评论了相关行），即使之前的每个调用都成功了。

代码如下：

#include "gl_render.h"
#include "gl_wrapper.h"
#include <math.h>

GLuint globalProgramObject;
int surfaceWidth;
int surfaceHeight;

GLuint LoadShader ( GLenum type, const char *shaderSrc )
{
   GLuint shader;
   GLint compiled;
   GLenum error;

   shader = glCreateShader ( type );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -50;
   }

   glShaderSource ( shader, 1, &shaderSrc, NULL );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -51;
   }

   glCompileShader ( shader );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -52;
   }

   glGetShaderiv ( shader, GL_COMPILE_STATUS, &compiled );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -53;
   }

   if ( !compiled )
   {
      GLint infoLen = 0;

      glGetShaderiv ( shader, GL_INFO_LOG_LENGTH, &infoLen );

      error = glGetError();
      if (error != GL_NO_ERROR) {
         return -54;
      }

      if ( infoLen > 1 )
      {
         char *infoLog = malloc ( sizeof ( char ) * infoLen );

         glGetShaderInfoLog ( shader, infoLen, NULL, infoLog );

         error = glGetError();
         if (error != GL_NO_ERROR) {
            return -55;
         }

         free ( infoLog );
      }

      glDeleteShader ( shader );

      error = glGetError();
      if (error != GL_NO_ERROR) {
         return -56;
      }

      return -2;
   }

   return shader;

}

int on_surface_created(int width, int height) {
   surfaceWidth = width;
   surfaceHeight = height;

   char vShaderStr[] =
      "#version 300 es                          \n"
      "layout(location = 0) in vec4 vPosition;  \n"
      "void main()                              \n"
      "{                                        \n"
      "   gl_Position = vPosition;              \n"
      "}                                        \n";

   char fShaderStr[] =
      "#version 300 es                              \n"
      "precision mediump float;                     \n"
      "out vec4 fragColor;                          \n"
      "void main()                                  \n"
      "{                                            \n"
      "   fragColor = vec4 ( 1.0, 0.0, 0.0, 1.0 );  \n"
      "}                                            \n";

   GLuint vertexShader;
   GLuint fragmentShader;
   GLuint programObject;
   GLint linked;
   GLenum error;

   vertexShader = LoadShader ( GL_VERTEX_SHADER, vShaderStr );

   if (vertexShader <= 0) {
      return -155;
   }

   fragmentShader = LoadShader ( GL_FRAGMENT_SHADER, fShaderStr );

   if (fragmentShader <= 0) {
      return -156;
   }

   programObject = glCreateProgram ( );

   if (programObject == 0) {
      return -157;
   }

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -57;
   }

   // this is failing with GL_INVALID_VALUE
   glAttachShader ( programObject, vertexShader );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -58;
   }

   glAttachShader ( programObject, fragmentShader );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -59;
   }

   glLinkProgram ( programObject );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -60;
   }

   glGetProgramiv ( programObject, GL_LINK_STATUS, &linked );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -61;
   }

   if ( !linked )
   {
      GLint infoLen = 0;

      glGetProgramiv ( programObject, GL_INFO_LOG_LENGTH, &infoLen );

      error = glGetError();
      if (error != GL_NO_ERROR) {
         return -62;
      }

      if ( infoLen > 1 )
      {
         char *infoLog = malloc ( sizeof ( char ) * infoLen );

         glGetProgramInfoLog ( programObject, infoLen, NULL, infoLog );

         error = glGetError();
         if (error != GL_NO_ERROR) {
            return -63;
         }

         free ( infoLog );
      }

      glDeleteProgram ( programObject );

      error = glGetError();
      if (error != GL_NO_ERROR) {
         return -64;
      }

      return -2;
   }

   glClearColor ( 1.0f, 1.0f, 1.0f, 0.0f );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -65;
   }

   globalProgramObject = programObject;

   return 0;
}

int on_draw_frame() {
   GLenum error;

   GLfloat vVertices[] = {  0.0f,  0.5f, 0.0f,
                            -0.5f, -0.5f, 0.0f,
                            0.5f, -0.5f, 0.0f
                         };

   glViewport ( 0, 0, surfaceWidth, surfaceHeight );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -66;
   }

   glClear ( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -67;
   }

   glUseProgram ( globalProgramObject );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -68;
   }

   glVertexAttribPointer ( 0, 3, GL_FLOAT, GL_FALSE, 0, vVertices );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -69;
   }

   glEnableVertexAttribArray ( 0 );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -70;
   }

   glDrawArrays ( GL_TRIANGLES, 0, 3 );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -71;
   }

   glDisableVertexAttribArray ( 0 );

   error = glGetError();
   if (error != GL_NO_ERROR) {
      return -72;
   }

   return 0;
}

对于额外的上下文，这里是 Objective C 我用来托管 OpenGL worker 的代码：

#import "OpenGLRender.h"
#import <OpenGLES/EAGL.h>
#import <OpenGLES/ES2/gl.h>
#import <OpenGLES/ES2/glext.h>

@interface OpenGLRender()
@property (strong, nonatomic) EAGLContext *context;
@property (strong, nonatomic) id<OpenGLRenderWorker> worker;
@property (copy, nonatomic) void(^onNewFrame)(void);

@property (nonatomic) GLuint frameBuffer;
@property (nonatomic) GLuint depthBuffer;
@property (nonatomic) CVPixelBufferRef target;
@property (nonatomic) CVOpenGLESTextureCacheRef textureCache;
@property (nonatomic) CVOpenGLESTextureRef texture;
@property (nonatomic) CGSize renderSize;
@property (nonatomic) BOOL running;
@end

@implementation OpenGLRender

- (instancetype)initWithSize:(CGSize)renderSize
                      worker:(id<OpenGLRenderWorker>)worker
                  onNewFrame:(void(^)(void))onNewFrame {
    self = [super init];
    if (self){
        self.renderSize = renderSize;
        self.running = YES;
        self.onNewFrame = onNewFrame;
        self.worker = worker;

        NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(run) object:nil];
        thread.name = @"OpenGLRender";
        [thread start];
    }
    return self;
}

- (void)run {
    [self initGL];
    int result = [_worker onCreateWithWidth: self.renderSize.width andHeight: self.renderSize.height];

    if (result != 0) {
        NSLog(@"Failed to call onCreateWithWidth %f AndHeight %f: %d", self.renderSize.width, self.renderSize.height, result);
    }

    while (_running) {
        CFTimeInterval loopStart = CACurrentMediaTime();
        result = [_worker onDraw];

        if (result != 0) {
            NSLog(@"Failed to call onDraw: %d", result);
        } else {
            glFlush();
            dispatch_async(dispatch_get_main_queue(), self.onNewFrame);
        }

        CFTimeInterval waitDelta = 0.016 - (CACurrentMediaTime() - loopStart);
        if (waitDelta > 0) {
            [NSThread sleepForTimeInterval:waitDelta];
        }
    }
    [self deinitGL];
}

#pragma mark - Public

- (void)dispose {
    _running = NO;
}

#pragma mark - FlutterTexture

- (CVPixelBufferRef _Nullable)copyPixelBuffer {
    CVBufferRetain(_target);
    return _target;
}

#pragma mark - Private

- (void)initGL {
    _context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];

    [EAGLContext setCurrentContext:_context];
    [self createCVBufferWithSize:_renderSize withRenderTarget:&_target withTextureOut:&_texture];

    glBindTexture(CVOpenGLESTextureGetTarget(_texture), CVOpenGLESTextureGetName(_texture));

    glTexImage2D(GL_TEXTURE_2D,
                 0, GL_RGBA,
                 _renderSize.width, _renderSize.height,
                 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, NULL);

    glGenRenderbuffers(1, &_depthBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, _depthBuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, _renderSize.width, _renderSize.height);

    glGenFramebuffers(1, &_frameBuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, _frameBuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, CVOpenGLESTextureGetName(_texture), 0);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _depthBuffer);

    if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
        NSLog(@"failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));
    } else {
        NSLog(@"Successfully initialized GL");
    }
}

- (void)createCVBufferWithSize:(CGSize)size
              withRenderTarget:(CVPixelBufferRef *)target
                withTextureOut:(CVOpenGLESTextureRef *)texture {

    CVReturn err = CVOpenGLESTextureCacheCreate(kCFAllocatorDefault, NULL, _context, NULL, &_textureCache);

    if (err) return;

    CFDictionaryRef empty;
    CFMutableDictionaryRef attrs;
    empty = CFDictionaryCreate(kCFAllocatorDefault,
                               NULL,
                               NULL,
                               0,
                               &kCFTypeDictionaryKeyCallBacks,
                               &kCFTypeDictionaryValueCallBacks);

    attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 1,
                                      &kCFTypeDictionaryKeyCallBacks,
                                      &kCFTypeDictionaryValueCallBacks);

    CFDictionarySetValue(attrs, kCVPixelBufferIOSurfacePropertiesKey, empty);
    CVPixelBufferCreate(kCFAllocatorDefault, size.width, size.height,
                        kCVPixelFormatType_32BGRA, attrs, target);

    CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
                                                 _textureCache,
                                                 *target,
                                                 NULL, // texture attributes
                                                 GL_TEXTURE_2D,
                                                 GL_RGBA, // opengl format
                                                 size.width,
                                                 size.height,
                                                 GL_BGRA, // native iOS format
                                                 GL_UNSIGNED_BYTE,
                                                 0,
                                                 texture);

    CFRelease(empty);
    CFRelease(attrs);
}

- (void)deinitGL {
    glDeleteFramebuffers(1, &_frameBuffer);
    glDeleteFramebuffers(1, &_depthBuffer);
    CFRelease(_target);
    CFRelease(_textureCache);
    CFRelease(_texture);
}

@end

谁能告诉我为什么这在 iOS 上不起作用，尽管它在 Android 上运行良好？

Answer 1

您已经创建了 GLES2 上下文 (kEAGLRenderingAPIOpenGLES2)，但您使用的是 GLES3 着色器 (#version 300 es)。

我有点惊讶这个错误没有被 glCompileShader 捕获，但我猜 iOS 驱动程序正在推迟实际编译，直到 glAttachShader 被调用。

OpenGL ES 代码在 Android 中工作，但 glAttachShader 不在 iOS 中工作

OpenGL ES code working in Android but not glAttachShader not working on iOS

c

opengl-es

objective-c

ios