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我正在尝试使用NSOpenGL山狮在 OpenGL 中绘制一个非常简单的带有红色背景的蓝色正方形。代码很简单，应该可以工作，我假设这是我设置上下文的问题。

这是我的 GLView 界面：

#import <Cocoa/Cocoa.h>
#import <OpenGL/gl.h>
#import <GLKit/GLKit.h>

typedef struct {
    char *Name;
    GLint Location;
} Uniform;

@interface MyOpenGLView : NSOpenGLView {
    Uniform *_uniformArray;
    int _uniformArraySize;
    GLKMatrix4 _projectionMatrix;
    GLKMatrix4 _modelViewMatrix;
    IBOutlet NSWindow *window;
    int height, width;
}

-(void)drawRect:(NSRect)bounds;

@end

实施：

GLfloat square[] = {
    -0.5, -0.5,
    0.5, -0.5,
    -0.5, 0.5,
    0.5, 0.5
};

- (id)initWithFrame:(NSRect)frame {
    self = [super initWithFrame:frame];
    if (self) {

    }
    return self;
}

-(void)awakeFromNib {
    NSString *vertexShaderSource = [NSString stringWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"VertexShader" ofType:@"vsh"] encoding:NSUTF8StringEncoding error:nil];

    const char *vertexShaderSourceCString = [vertexShaderSource cStringUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"%s",vertexShaderSourceCString);

    NSString *fragmentShaderSource = [NSString stringWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"FragmentShader" ofType:@"fsh"] encoding:NSUTF8StringEncoding error:nil];
    const char *fragmentShaderSourceCString = [fragmentShaderSource cStringUsingEncoding:NSUTF8StringEncoding];

    NSLog(@"%s",fragmentShaderSourceCString);

    NSOpenGLContext *glContext = [self openGLContext];
    [glContext makeCurrentContext];

    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSourceCString, NULL);
    glCompileShader(fragmentShader);

    GLint compileSuccess;
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &compileSuccess);
    if (compileSuccess == GL_FALSE) {
        GLint logLength;
        glGetShaderiv(fragmentShader, GL_INFO_LOG_LENGTH, &logLength);
        if(logLength > 0) {
            GLchar *log = (GLchar *)malloc(logLength);
            glGetShaderInfoLog(fragmentShader, logLength, &logLength, log);
            NSLog(@"Shader compile log:\n%s", log);
            free(log);
        }
        exit(1);
    }

    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSourceCString, NULL);
    glCompileShader(vertexShader);

    GLuint program = glCreateProgram();
    glAttachShader(program, fragmentShader);
    glAttachShader(program, vertexShader);
    glLinkProgram(program);

    glUseProgram(program);

    const char *aPositionCString = [@"a_position" cStringUsingEncoding:NSUTF8StringEncoding];
    GLuint aPosition = glGetAttribLocation(program, aPositionCString);

    glVertexAttribPointer(aPosition, 2, GL_FLOAT, GL_FALSE, 0, square);
    glEnable(aPosition);

    GLint maxUniformLength;
    GLint numberOfUniforms;
    char *uniformName;

    glGetProgramiv(program, GL_ACTIVE_UNIFORMS, &numberOfUniforms);
    glGetProgramiv(program, GL_ACTIVE_UNIFORM_MAX_LENGTH, &maxUniformLength);

    _uniformArray = malloc(numberOfUniforms * sizeof(Uniform));
    _uniformArraySize = numberOfUniforms;

    for (int i =0; i <numberOfUniforms; i++) {
        GLint size;
        GLenum type;
        GLint location;

        uniformName = malloc(sizeof(char*)*maxUniformLength);
        glGetActiveUniform(program, i, maxUniformLength, NULL, &size, &type, uniformName);
        _uniformArray[i].Name = uniformName;
        location = glGetUniformLocation(program, uniformName);
        _uniformArray[i].Location = location;
    }

    _modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 0.0f);
    _projectionMatrix = GLKMatrix4MakeOrtho(-1, 1, -1.5, 1.5, -1, 1);
}

- (void)drawRect:(NSRect)bounds {
    glClearColor(1.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);

    glViewport(0, 0, 480, 360);

    for (int i = 0; i <_uniformArraySize; i++) {
        if (strcmp(_uniformArray[i].Name, "ModelViewProjectionMatrix")==0) {
            // Multiply the transformation matrices together
            GLKMatrix4 modelViewProjectionMatrix = GLKMatrix4Multiply(_projectionMatrix,        _modelViewMatrix);
            glUniformMatrix4fv(_uniformArray[i].Location, 1, GL_FALSE,           modelViewProjectionMatrix.m);
        }
    }
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    glFlush();
}

我非常简单的片段着色器：

void main() {
    gl_FragColor = vec4(0.0, 0.0, 1.0, 1.0);
}

简单的顶点着色器：

attribute vec4 a_position;

uniform mat4 ModelViewProjectionMatrix;

void main() {
    gl_Position = a_position * ModelViewProjectionMatrix;
}

我没有编译错误，只是一个红色的屏幕，没有蓝色的方块。有人可以帮我找出问题所在。不过，我确实收到了警告，指出 Gl.h 和 gl3.h 都包括在内。我想使用 OpenGL 2

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1 回答 1

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您的视图矩阵（又名您的查看矩阵）在哪里？对于我的 NSOpenGLView，我至少有三个矩阵，模型视图（由旋转和平移矩阵的乘法结果组成），投影矩阵（考虑了您的平截头体比例、纵横比、近平面和远平面）和视图矩阵（考虑了“世界”中观察者的眼睛位置、焦点和向上向量的方向）。我会说把代码放在 awakeFromNib 中，教会了我一些东西......

于 2013-09-09T00:14:48.733 回答