打开GL游戏(方块)

Question

我是第一次打开Xcode的gl游戏端。我一直在玩立方体，并设法旋转它们等，但有几件事，我有在我的脑海里，我想实现，但由于我缺乏知识，我只是不能。例如，我想改变立方体说四面体或添加不同的颜色的立方体的每一面，或者甚至可能添加第三个立方体作为默认代码只提供给我们只有2个立方体。

视图controller.h

#import <UIKit/UIKit.h>
#import <GLKit/GLKit.h>
@interface ViewController : GLKViewController
@end

视图controller.m

#import "ViewController.h"
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
// Uniform index.
enum
{
    UNIFORM_MODELVIEWPROJECTION_MATRIX,
    UNIFORM_NORMAL_MATRIX,
    NUM_UNIFORMS
};
GLint uniforms[NUM_UNIFORMS];
// Attribute index.
enum
{
    ATTRIB_VERTEX,
    ATTRIB_NORMAL,
    NUM_ATTRIBUTES
};
GLfloat gCubeVertexData[216] = 
{
    // Data layout for each line below is:
    // positionX, positionY, positionZ,     normalX, normalY, normalZ,
    0.5f, -0.5f, -0.5f,        1.0f, 0.0f, 0.0f,
    0.5f, 0.5f, -0.5f,         1.0f, 0.0f, 0.0f,
    0.5f, -0.5f, 0.5f,         1.0f, 0.0f, 0.0f,
    0.5f, -0.5f, 0.5f,         1.0f, 0.0f, 0.0f,
    0.5f, 0.5f, -0.5f,          1.0f, 0.0f, 0.0f,
    0.5f, 0.5f, 0.5f,         1.0f, 0.0f, 0.0f,
    0.5f, 0.5f, -0.5f,         0.0f, 1.0f, 0.0f,
    -0.5f, 0.5f, -0.5f,        0.0f, 1.0f, 0.0f,
    0.5f, 0.5f, 0.5f,          0.0f, 1.0f, 0.0f,
    0.5f, 0.5f, 0.5f,          0.0f, 1.0f, 0.0f,
    -0.5f, 0.5f, -0.5f,        0.0f, 1.0f, 0.0f,
    -0.5f, 0.5f, 0.5f,         0.0f, 1.0f, 0.0f,
    -0.5f, 0.5f, -0.5f,        -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, -0.5f,       -1.0f, 0.0f, 0.0f,
    -0.5f, 0.5f, 0.5f,         -1.0f, 0.0f, 0.0f,
    -0.5f, 0.5f, 0.5f,         -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, -0.5f,       -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, 0.5f,        -1.0f, 0.0f, 0.0f,
    -0.5f, -0.5f, -0.5f,       0.0f, -1.0f, 0.0f,
    0.5f, -0.5f, -0.5f,        0.0f, -1.0f, 0.0f,
    -0.5f, -0.5f, 0.5f,        0.0f, -1.0f, 0.0f,
    -0.5f, -0.5f, 0.5f,        0.0f, -1.0f, 0.0f,
    0.5f, -0.5f, -0.5f,        0.0f, -1.0f, 0.0f,
    0.5f, -0.5f, 0.5f,         0.0f, -1.0f, 0.0f,
    0.5f, 0.5f, 0.5f,          0.0f, 0.0f, 1.0f,
    -0.5f, 0.5f, 0.5f,         0.0f, 0.0f, 1.0f,
    0.5f, -0.5f, 0.5f,         0.0f, 0.0f, 1.0f,
    0.5f, -0.5f, 0.5f,         0.0f, 0.0f, 1.0f,
    -0.5f, 0.5f, 0.5f,         0.0f, 0.0f, 1.0f,
    -0.5f, -0.5f, 0.5f,        0.0f, 0.0f, 1.0f,
    0.5f, -0.5f, -0.5f,        0.0f, 0.0f, -1.0f,
    -0.5f, -0.5f, -0.5f,       0.0f, 0.0f, -1.0f,
    0.5f, 0.5f, -0.5f,         0.0f, 0.0f, -1.0f,
    0.5f, 0.5f, -0.5f,         0.0f, 0.0f, -1.0f,
    -0.5f, -0.5f, -0.5f,       0.0f, 0.0f, -1.0f,
    -0.5f, 0.5f, -0.5f,        0.0f, 0.0f, -1.0f
};
@interface ViewController () {
    GLuint _program;
    GLKMatrix4 _modelViewProjectionMatrix;
    GLKMatrix3 _normalMatrix;
    float _rotation;
    GLuint _vertexArray;
    GLuint _vertexBuffer;
}
@property (strong, nonatomic) EAGLContext *context;
@property (strong, nonatomic) GLKBaseEffect *effect;
- (void)setupGL;
- (void)tearDownGL;
- (BOOL)loadShaders;
- (BOOL)compileShader:(GLuint *)shader type:(GLenum)type file:(NSString *)file;
- (BOOL)linkProgram:(GLuint)prog;
- (BOOL)validateProgram:(GLuint)prog;
@end
@implementation ViewController
- (void)viewDidLoad
{
    [super viewDidLoad];
    self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
    if (!self.context) {
        NSLog(@"Failed to create ES context");
    }
    GLKView *view = (GLKView *)self.view;
    view.context = self.context;
    view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
    [self setupGL];
}
- (void)dealloc
{    
    [self tearDownGL];
    if ([EAGLContext currentContext] == self.context) {
        [EAGLContext setCurrentContext:nil];
    }
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    if ([self isViewLoaded] && ([[self view] window] == nil)) {
        self.view = nil;
        [self tearDownGL];
        if ([EAGLContext currentContext] == self.context) {
            [EAGLContext setCurrentContext:nil];
        }
        self.context = nil;
    }
    // Dispose of any resources that can be recreated.
}
- (void)setupGL
{
    [EAGLContext setCurrentContext:self.context];
    [self loadShaders];
    self.effect = [[GLKBaseEffect alloc] init];
    self.effect.light0.enabled = GL_TRUE;
    self.effect.light0.diffuseColor = GLKVector4Make(1.0f, 0.4f, 0.4f, 1.0f);
    glEnable(GL_DEPTH_TEST);
    glGenVertexArraysOES(1, &_vertexArray);
    glBindVertexArrayOES(_vertexArray);
    glGenBuffers(1, &_vertexBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(gCubeVertexData), gCubeVertexData, GL_STATIC_DRAW);
    glEnableVertexAttribArray(GLKVertexAttribPosition);
    glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(0));
    glEnableVertexAttribArray(GLKVertexAttribNormal);
    glVertexAttribPointer(GLKVertexAttribNormal, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(12));
    glBindVertexArrayOES(0);
}
- (void)tearDownGL
{
    [EAGLContext setCurrentContext:self.context];
    glDeleteBuffers(1, &_vertexBuffer);
    glDeleteVertexArraysOES(1, &_vertexArray);
    self.effect = nil;
    if (_program) {
        glDeleteProgram(_program);
        _program = 0;
    }
}
#pragma mark - GLKView and GLKViewController delegate methods
- (void)update
{
    float aspect = fabsf(self.view.bounds.size.width / self.view.bounds.size.height);
    GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 0.1f, 100.0f);
    self.effect.transform.projectionMatrix = projectionMatrix;
    GLKMatrix4 baseModelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -4.0f);
    baseModelViewMatrix = GLKMatrix4Rotate(baseModelViewMatrix, _rotation, 0.0f, 1.0f, 0.0f);
    // Compute the model view matrix for the object rendered with GLKit
    GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -1.5f);
    modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f);
    modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix);
    self.effect.transform.modelviewMatrix = modelViewMatrix;
    // Compute the model view matrix for the object rendered with ES2
    modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 1.5f);
    modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f);
    modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix);
    _normalMatrix = GLKMatrix3InvertAndTranspose(GLKMatrix4GetMatrix3(modelViewMatrix), NULL);
    _modelViewProjectionMatrix = GLKMatrix4Multiply(projectionMatrix, modelViewMatrix);
    _rotation += self.timeSinceLastUpdate * 0.5f;
}
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
    glClearColor(0.65f, 0.65f, 0.65f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glBindVertexArrayOES(_vertexArray);
    // Render the object with GLKit
    [self.effect prepareToDraw];
    glDrawArrays(GL_TRIANGLES, 0, 36);
    // Render the object again with ES2
    glUseProgram(_program);
    glUniformMatrix4fv(uniforms[UNIFORM_MODELVIEWPROJECTION_MATRIX], 1, 0,   _modelViewProjectionMatrix.m);
    glUniformMatrix3fv(uniforms[UNIFORM_NORMAL_MATRIX], 1, 0, _normalMatrix.m);
    glDrawArrays(GL_TRIANGLES, 0, 36);
}
#pragma mark -  OpenGL ES 2 shader compilation
- (BOOL)loadShaders
{
    GLuint vertShader, fragShader;
    NSString *vertShaderPathname, *fragShaderPathname;
    // Create shader program.
    _program = glCreateProgram();
    // Create and compile vertex shader.
    vertShaderPathname = [[NSBundle mainBundle] pathForResource:@"Shader" ofType:@"vsh"];
    if (![self compileShader:&vertShader type:GL_VERTEX_SHADER file:vertShaderPathname]) {
        NSLog(@"Failed to compile vertex shader");
        return NO;
    }
    // Create and compile fragment shader.
    fragShaderPathname = [[NSBundle mainBundle] pathForResource:@"Shader" ofType:@"fsh"];
    if (![self compileShader:&fragShader type:GL_FRAGMENT_SHADER file:fragShaderPathname]) {
        NSLog(@"Failed to compile fragment shader");
        return NO;
    }
    // Attach vertex shader to program.
    glAttachShader(_program, vertShader);
    // Attach fragment shader to program.
    glAttachShader(_program, fragShader);
    // Bind attribute locations.
    // This needs to be done prior to linking.
    glBindAttribLocation(_program, GLKVertexAttribPosition, "position");
    glBindAttribLocation(_program, GLKVertexAttribNormal, "normal");
    // Link program.
    if (![self linkProgram:_program]) {
        NSLog(@"Failed to link program: %d", _program);
        if (vertShader) {
            glDeleteShader(vertShader);
            vertShader = 0;
        }
        if (fragShader) {
            glDeleteShader(fragShader);
            fragShader = 0;
        }
        if (_program) {
            glDeleteProgram(_program);
            _program = 0;
        }
        return NO;
    }
    // Get uniform locations.
    uniforms[UNIFORM_MODELVIEWPROJECTION_MATRIX] = glGetUniformLocation(_program, "modelViewProjectionMatrix");
    uniforms[UNIFORM_NORMAL_MATRIX] = glGetUniformLocation(_program, "normalMatrix");
    // Release vertex and fragment shaders.
    if (vertShader) {
        glDetachShader(_program, vertShader);
        glDeleteShader(vertShader);
    }
    if (fragShader) {
        glDetachShader(_program, fragShader);
        glDeleteShader(fragShader);
    }
    return YES;
}
- (BOOL)compileShader:(GLuint *)shader type:(GLenum)type file:(NSString *)file
{
    GLint status;
    const GLchar *source;
    source = (GLchar *)[[NSString stringWithContentsOfFile:file encoding:NSUTF8StringEncoding error:nil] UTF8String];
    if (!source) {
        NSLog(@"Failed to load vertex shader");
        return NO;
    }
    *shader = glCreateShader(type);
    glShaderSource(*shader, 1, &source, NULL);
    glCompileShader(*shader);
#if defined(DEBUG)
    GLint logLength;
    glGetShaderiv(*shader, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0) {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetShaderInfoLog(*shader, logLength, &logLength, log);
        NSLog(@"Shader compile log:n%s", log);
        free(log);
    }
#endif
    glGetShaderiv(*shader, GL_COMPILE_STATUS, &status);
    if (status == 0) {
        glDeleteShader(*shader);
        return NO;
    }
    return YES;
}
- (BOOL)linkProgram:(GLuint)prog
{
    GLint status;
    glLinkProgram(prog);
#if defined(DEBUG)
    GLint logLength;
    glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0) {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetProgramInfoLog(prog, logLength, &logLength, log);
        NSLog(@"Program link log:n%s", log);
        free(log);
    }
#endif
    glGetProgramiv(prog, GL_LINK_STATUS, &status);
    if (status == 0) {
        return NO;
    }
    return YES;
}
- (BOOL)validateProgram:(GLuint)prog
{
    GLint logLength, status;
    glValidateProgram(prog);
    glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0) {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetProgramInfoLog(prog, logLength, &logLength, log);
        NSLog(@"Program validate log:n%s", log);
        free(log);
    }
    glGetProgramiv(prog, GL_VALIDATE_STATUS, &status);
    if (status == 0) {
        return NO;
    }
    return YES;
}
@end

Answer 1

列出您的请求:

脸颜色:

根据你报告的代码，它不支持顶点颜色属性。事实上，你创建的顶点数组覆盖顶点位置和法线，但不覆盖颜色(positionX, positionY, positionZ, normalX, normalY, normalZ)

最后，为了支持颜色，你应该这样做:

positionX, positionY, positionZ, normalX, normalY, normalZ，红色，绿色，蓝色

这将设置颜色所需的数据信息。

关于"渲染"颜色，你的片段着色器需要被修改，颜色作为附加属性传递。

你没有包括着色器的源代码，会很高兴看到它更好地理解。

关于传递额外的属性，你可以这样做:

glEnableVertexAttribArray(属性ID);glVertexAttribPointer(属性的ID, 3, GL_FLOAT, GL_FALSE, 24, BUFFER_OFFSET(36));

关于四面体

:

计算不同顶点的坐标是相当简单的。

最后你有4个三角形，计算12个顶点(共有5个)是一个很好的练习，在纸上需要5分钟。我建议你试一试看看。这是一个很好的做法:)