OpenGL纹理初始化/渲染问题

Question

我试图使用创建纹理的模型类渲染非2的纹理，并存储它的ID和大小（感谢ADC和另一个stackoverflow成员），以及创建VBO的其他代码并渲染它（代码为VBO和渲染用于测试目的，在我的模型中适当划分。）

当我使用此代码，但删除纹理特定的代码时，它工作正常。然而，当添加纹理特定代码时，它只渲染我认为是右下角像素，从尝试多个复杂图像并使用DigitalColor Meter检查图像和输出。

我不认为在使用此设置时必须明确指定纹理坐标，如果有，我会怎么做？

主OpenGL代码

    // Create vertex buffer
    GLuint memoryPointer = 0;
    GLuint colourMemoryPointer = 0;

    GLfloat *vertices;
    size_t vertex_size = 0;

    int check = AllocateVertexBuffer(2, 4, &vertices, &vertex_size);
    CDMeshVertexesCreateRectangle(200, 200, vertices);


    // Create colour buffer
    GLfloat *colors;
    size_t color_size;

    int check2 = AllocateVertexBuffer(4, 4, &colors, &color_size);
    CDMeshColorsCreateGrey(1.0, 4, colors);


    // Create texture buffer
    CDTexture *texture = [CDTexture loadPngTexture:@"Rawr"];

    // Allocate the buffer
    glGenBuffers(1, &memoryPointer);
    // Bind the buffer object (tell OpenGL what to use)
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);

    // Allocate space for the VBO
    glBufferData(GL_ARRAY_BUFFER, vertex_size, vertices, GL_STATIC_DRAW);


    // Allocate the buffer
    glGenBuffers(1, &colourMemoryPointer);
    // Bind the buffer object (tell OpenGL what to use)
    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);

    // Allocate space for the VBO
    glBufferData(GL_ARRAY_BUFFER, color_size, colors, GL_STATIC_DRAW);

    glEnableClientState(GL_VERTEX_ARRAY); // Activate vertex coordinates array
    glEnableClientState(GL_COLOR_ARRAY);

    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glVertexPointer(2, GL_FLOAT, 0, 0);   

    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glColorPointer(4, GL_FLOAT, 0, 0);

    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, texture.ID);
    glTexCoordPointer(2, GL_FLOAT, 0, 0);

    //[texture render];

    //render
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    glDisableClientState(GL_VERTEX_ARRAY); // Deactivate vertex coordinates array
    glDisableClientState(GL_COLOR_ARRAY);

    free(vertices);
    free(colors);

CDTexture loadPngTexture：方法

CFURLRef textureURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(),
                                              (CFStringRef)fileName,
                                              CFSTR("png"),
                                              NULL);

NSAssert(textureURL, @"Texture name invalid");

// Get the image source using a file path
CGImageSourceRef myImageSourceRef = CGImageSourceCreateWithURL(textureURL, NULL);
NSAssert(myImageSourceRef, @"Invalid Image Path.");
NSAssert((CGImageSourceGetCount(myImageSourceRef) > 0), @"No Image in Image Source.");

// Get the image reference using the source reference, -_-
CGImageRef myImageRef = CGImageSourceCreateImageAtIndex (myImageSourceRef, 0, NULL);
NSAssert(myImageSourceRef, @"Image not created.");

// Start gathering data from the image, before releasing it
GLuint myTextureName;
size_t width = CGImageGetWidth(myImageRef);
size_t height = CGImageGetHeight(myImageRef);
CGRect rect = {{0, 0}, {width, height}};
void * myData = calloc(width * 4, height);
CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
CGContextRef myBitmapContext = CGBitmapContextCreate (myData,
                                                      width, height, 8,
                                                      width*4, space,
                                                      kCGBitmapByteOrder32Host |
                                                      kCGImageAlphaPremultipliedFirst);

CGColorSpaceRelease(space);
// Flip so that it isn't upside-down
CGContextTranslateCTM(myBitmapContext, 0, height);
CGContextScaleCTM(myBitmapContext, 1.0f, -1.0f);
CGContextSetBlendMode(myBitmapContext, kCGBlendModeCopy);
CGContextDrawImage(myBitmapContext, rect, myImageRef);
CGContextRelease(myBitmapContext);

glEnable(GL_TEXTURE_RECTANGLE_ARB);

// Generate texture buffer
glGenTextures(1, &myTextureName);

// Bind buffer for use
glBindTexture(GL_TEXTURE_RECTANGLE_ARB, myTextureName);

// Set storage methods
glPixelStorei(GL_UNPACK_ROW_LENGTH, width);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

// Set the parameter required for non power of two textures
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB,
                GL_TEXTURE_MIN_FILTER, GL_LINEAR);

// Load the texture data into the buffer
glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA8, width, height,
             0, GL_BGRA_EXT, GL_UNSIGNED_INT_8_8_8_8_REV, myData);

// Free the data used, as it's now in the buffer
free(myData);

// Return information on texture object
CDTexture *texture = [[CDTexture alloc] init];

texture.ID = myTextureName;
texture.size = NSMakeSize(width, height);

return texture;

更新
我已经尝试使用纹理指针来定义区域，这会导致同样的问题。即使没有绑定和使用指针，它绘制的颜色/纹理也会这样做。我还尝试在使用和渲染之前和之后启用和禁用GL_TEXTURE_COORD_ARRAY，并导致同样的问题。

除非我做错了什么，否则这个问题似乎与纹理指针无关。

GLfloat texCoords[8] = {
0.0, 0.0,
0.0, 1.0,
1.0, 1.0,
1.0, 0.0
};

...

glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
glColorPointer(4, GL_FLOAT, 0, 0);

glBindTexture(GL_TEXTURE_RECTANGLE_ARB, texture.ID);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);

//[texture render];

//render
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

更新2
我尝试从OpenGL获取错误代码以尝试解决问题，但没有打印错误代码。

更新3
我尝试使用不同的方法来获取原始图像数据，并且会发生相同的结果（虽然有些变色，因为我不能使用正确的颜色设置）。 OpenGL对数据的解释必须有缺陷。我已经尝试过glPixelStorei（）但到目前为止没有任何改变。由于OpenGL没有报告任何错误，它必须与数据的程序解释，所以我设置的数据如何存储的参数，或导致只显示1个像素的顶点问题，尽管因此精度，最有可能是参数。

原始图像数据的新流程（感谢另一个stackoverflow用户）。张贴供参考。

 NSBitmapImageRep *theImage;
int bitsPPixel, bytesPRow;
NSSize size;
unsigned char *theImageData;

NSData* imgData = [NSData dataWithContentsOfFile:fileName options:NSUncachedRead error:nil];  // use FileURL

theImage = [NSBitmapImageRep imageRepWithData:imgData]; 


if( theImage != nil )
{
    bitsPPixel = [theImage bitsPerPixel];
    bytesPRow = [theImage bytesPerRow];
    size.width = [theImage pixelsWide];
    size.height = [theImage pixelsHigh];
}

enter code here

更新4
更改为GL_TEXTURE_2D以提高效率。左下角的像素仍然只是被渲染。以下是代码的完整顺序：

// Create vertex buffer
    GLuint memoryPointer = 0;
    GLuint colourMemoryPointer = 0;

    GLfloat *vertices;
    size_t vertex_size = 0;

    AllocateVertexBuffer(2, 4, &vertices, &vertex_size);
    CDMeshVertexesCreateRectangle(200, 200, vertices);


    // Create colour buffer
    GLfloat *colors;
    size_t color_size;

    AllocateVertexBuffer(4, 4, &colors, &color_size);
    CDMeshColorsCreateGrey(1.0, 4, colors);

    // Create Texture UV Coordinates
    GLfloat *texture;
    size_t texture_size;
    AllocateVertexBuffer(4, 2, &texture, &texture_size);
    CDMeshVertexesCreateRectangle(1, 1, texture);

    // Create texture buffer
    NSString *fileName = @"Rawr3";

    CFURLRef textureURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(),
                                                  (CFStringRef)fileName,
                                                  CFSTR("png"),
                                                  NULL);

    NSAssert(textureURL, @"Texture name invalid");

    // Get the image source using a file path
    CGImageSourceRef myImageSourceRef = CGImageSourceCreateWithURL(textureURL, NULL);
    NSAssert(myImageSourceRef, @"Invalid Image Path.");
    NSAssert((CGImageSourceGetCount(myImageSourceRef) > 0), @"No Image in Image Source.");

    // Get the image reference using the source reference, -_-
    CGImageRef myImageRef = CGImageSourceCreateImageAtIndex (myImageSourceRef, 0, NULL);
    NSAssert(myImageSourceRef, @"Image not created.");

    // Start gathering data from the image, before releasing it
    GLuint myTextureName;
    size_t width = CGImageGetWidth(myImageRef);
    size_t height = CGImageGetHeight(myImageRef);
    CGRect rect = {{0, 0}, {width, height}};    //Doesnt need fiddling
    void * myData = calloc(width * 4, height); //Fiddled
    CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
    CGContextRef myBitmapContext = CGBitmapContextCreate (myData,
                                                          width, height, 8,
                                                          width*4, space,
                                                          kCGBitmapByteOrder32Host |
                                                          kCGImageAlphaPremultipliedFirst);

    CGColorSpaceRelease(space);
    // Flip so that it isn't upside-down
    CGContextTranslateCTM(myBitmapContext, 0, height);
    CGContextScaleCTM(myBitmapContext, 1.0f, -1.0f);
    CGContextSetBlendMode(myBitmapContext, kCGBlendModeCopy);
    CGContextDrawImage(myBitmapContext, rect, myImageRef);
    CGContextRelease(myBitmapContext);

    // Generate texture buffer
    glGenTextures(1, &myTextureName);

    // Bind buffer for use
    glBindTexture(GL_TEXTURE_2D, myTextureName);

    // Set storage methods
    glTexParameteri(GL_TEXTURE_2D,
                    GL_TEXTURE_STORAGE_HINT_APPLE,
                    GL_STORAGE_CACHED_APPLE);

    glPixelStorei(GL_UNPACK_CLIENT_STORAGE_APPLE, GL_TRUE);

    // Set clamping and rendering preferences
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, 
                    GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, 
                    GL_NEAREST);

    // Load the texture data into the buffer
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
                 0, GL_BGRA_EXT, GL_UNSIGNED_INT_8_8_8_8_REV, myData);

    glGetError();

    // Free the data used, as it's now in the buffer
    free(myData);

    // Return information on texture object
    CDTexture *textureObj = [[CDTexture alloc] init];

    textureObj.ID = myTextureName;
    textureObj.size = NSMakeSize(width, height);

    // Allocate the buffer
    glGenBuffers(1, &memoryPointer);
    // Bind the buffer object (tell OpenGL what to use)
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);

    // Allocate space for the VBO
    glBufferData(GL_ARRAY_BUFFER, vertex_size, vertices, GL_STATIC_DRAW);


    // Allocate the buffer
    glGenBuffers(1, &colourMemoryPointer);
    // Bind the buffer object (tell OpenGL what to use)
    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);

    // Allocate space for the VBO
    glBufferData(GL_ARRAY_BUFFER, color_size, colors, GL_STATIC_DRAW);

    glEnableClientState(GL_VERTEX_ARRAY); // Activate vertex coordinates array
    glEnableClientState(GL_COLOR_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glEnable(GL_TEXTURE_2D);

    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glVertexPointer(2, GL_FLOAT, 0, 0);   

    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glColorPointer(4, GL_FLOAT, 0, 0);

    glBindTexture(GL_TEXTURE_2D, textureObj.ID);
    glTexCoordPointer(2, GL_FLOAT, 0, texture);

    GetGLError();

    //render
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    glDisableClientState(GL_VERTEX_ARRAY); // Deactivate vertex coordinates array
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisable(GL_TEXTURE_2D);

    glDeleteBuffers(1, &memoryPointer);
    glDeleteBuffers(1, &colourMemoryPointer);
    GLuint texID = textureObj.ID;
    glDeleteBuffers(1, &texID);

    free(vertices);
    free(colors);
    free(texture);


}

更新5 从glTexImage2D（）开始，它将渲染纹理的左下角像素，即使我没有绑定纹理并为其添加坐标，这看起来很奇怪，考虑到它应该使用glTexCoordPointer（）绘制。

更新6 可能是最后一次更新，使用纹理初始化代码和另一种更多的“手动”绘图技术，它运行良好。我删除了Apple特定的元素。从此代码中删除颜色VBO和指针时，仍然会出于某种奇怪的原因呈现白框。问题出在VBO上，但我不明白为什么。 GL_TEXTURE_RECTANGLE_ARB现在只用于我的彩色纹理，当这个问题解决后会被更改。

// Create vertex buffer
    GLuint memoryPointer = 0;
    GLuint colourMemoryPointer = 0;

    GLfloat *vertices;
    size_t vertex_size = 0;

    AllocateVertexBuffer(2, 4, &vertices, &vertex_size);
    CDMeshVertexesCreateRectangle(200, 200, vertices);

    GetGLError();

    // Create colour buffer
    GLfloat *colors;
    size_t color_size;

    AllocateVertexBuffer(4, 4, &colors, &color_size);
    CDMeshColorsCreateGrey(0.4, 4, colors);

    // Allocate the buffer
    glGenBuffers(1, &memoryPointer);
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glBufferData(GL_ARRAY_BUFFER, vertex_size, vertices, GL_STATIC_DRAW);

    // Allocate the buffer
    glGenBuffers(1, &colourMemoryPointer);
    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glBufferData(GL_ARRAY_BUFFER, color_size, colors, GL_STATIC_DRAW);

    // Enable client states for drawing the various arrays
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    // Bind each buffer and use the VBO's to draw (apart from the texture buffer)
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glVertexPointer(2, GL_FLOAT, 0, 0);   

    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glColorPointer(4, GL_FLOAT, 0, 0);

    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, myTextureName); //
    glTexCoordPointer(2, GL_FLOAT, 0, texture);

    //render
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    // Disale client states as were done with them.
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisable(GL_TEXTURE_RECTANGLE_ARB);

    GetGLError();

    // Delete buffers to avoid problems
    glDeleteBuffers(1, &memoryPointer);
    glDeleteBuffers(1, &colourMemoryPointer);
    glDeleteBuffers(1, &myTextureName);

    free(vertices);
    free(colors);
    free(texture);

Answer 1

当然你必须提供纹理坐标。作为顶点属性向量的一部分，或者通过生成它们（在着色器中）。但是你必须以某种方式提供纹理坐标，你无法解决这个问题。

Answer 2

我通过为纹理创建顶点缓冲对象（VBO）来解决问题（最终），而不是尝试直接向glTextureCoordPointer（）提供顶点数据。我想这里的教训是，如果您打算使用VBO，请将它们用于一切！作为参考，这是完整的代码：

纹理创建

// Create texture buffer, start with the name of the image.
    NSString *fileName = @"Rawr";

    CFURLRef textureURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(),
                                                  (CFStringRef)fileName,
                                                  CFSTR("png"),
                                                  NULL);

    NSAssert(textureURL, @"Texture name invalid");

    // Get the image source using a file path
    CGImageSourceRef myImageSourceRef = CGImageSourceCreateWithURL(textureURL, NULL);
    NSAssert(myImageSourceRef, @"Invalid Image Path.");
    NSAssert((CGImageSourceGetCount(myImageSourceRef) > 0), @"No Image in Image Source.");

    // Get the image reference using the source reference, -_-
    CGImageRef myImageRef = CGImageSourceCreateImageAtIndex (myImageSourceRef, 0, NULL);
    NSAssert(myImageSourceRef, @"Image not created.");

    // Start gathering data from the image, before releasing it
    GLuint myTextureName;
    size_t width = CGImageGetWidth(myImageRef);
    size_t height = CGImageGetHeight(myImageRef);
    CGRect rect = {{0, 0}, {width, height}};    //Doesnt need fiddling
    void * myData = calloc(width * 4, height); //Fiddled
    CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
    CGContextRef myBitmapContext = CGBitmapContextCreate (myData,
                                                          width, height, 8,
                                                          width*4, space,
                                                          kCGBitmapByteOrder32Host |
                                                          kCGImageAlphaPremultipliedFirst);

    CGColorSpaceRelease(space);
    // Flip so that it isn't upside-down
    CGContextTranslateCTM(myBitmapContext, 0, height);
    CGContextScaleCTM(myBitmapContext, 1.0f, -1.0f);
    CGContextSetBlendMode(myBitmapContext, kCGBlendModeCopy);
    CGContextDrawImage(myBitmapContext, rect, myImageRef);
    CGContextRelease(myBitmapContext);

    GetGLError();

    // The extension GL_TEXTURE_RECTANGLE_ARB can be used for non-power of two textures, but it is slower than GL_TEXTURE_2D and not
    // supported by all graphics cards.
    glEnable(GL_TEXTURE_RECTANGLE_ARB);
    glGenTextures(1, &myTextureName);
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, myTextureName);
    glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER,GL_NEAREST);
    glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER,GL_NEAREST);
    glTexParameterf(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_BGRA, GL_UNSIGNED_BYTE, myData);
    //glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT ,GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_RECTANGLE_ARB,myTextureName, 0);
    free(myData);

VBO创作

// Create vertex buffer
    GLuint memoryPointer = 0;
    GLuint colourMemoryPointer = 0;
    GLuint texPointer = 0;

    GLfloat *vertices;
    size_t vertex_size = 0;

    AllocateVertexBuffer(2, 4, &vertices, &vertex_size);
    CDMeshVertexesCreateRectangle(200, 200, vertices);

    GetGLError();

    // Create colour buffer
    GLfloat *colors;
    size_t color_size;

    AllocateVertexBuffer(4, 4, &colors, &color_size);
    CDMeshColorsCreateGrey(0.0, 4, colors);

    // Create Texture UV Coordinates
    GLfloat *texture;
    size_t texture_size;
    AllocateVertexBuffer(2, 4, &texture, &texture_size);
    CDMeshVertexesCreateRectangle(200, 200, texture);

    // Allocate the vertex VBO
    glGenBuffers(1, &memoryPointer);
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glBufferData(GL_ARRAY_BUFFER, vertex_size, vertices, GL_STATIC_DRAW);

    // Allocate the colour VBO
    glGenBuffers(1, &colourMemoryPointer);
    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glBufferData(GL_ARRAY_BUFFER, color_size, colors, GL_STATIC_DRAW);

    // Allocate the texture VBO
    glGenBuffers(1, &texPointer);
    glBindBuffer(GL_ARRAY_BUFFER, texPointer);
    glBufferData(GL_ARRAY_BUFFER, texture_size, texture, GL_STATIC_DRAW);

渲染和删除VBO和数据

// Enable client states for drawing the various arrays
    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_COLOR_ARRAY);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    // Bind each buffer and use the VBO's to draw
    glBindBuffer(GL_ARRAY_BUFFER, memoryPointer);
    glVertexPointer(2, GL_FLOAT, 0, 0);   

    glBindBuffer(GL_ARRAY_BUFFER, colourMemoryPointer);
    glColorPointer(4, GL_FLOAT, 0, 0);

    glBindBuffer(GL_ARRAY_BUFFER, texPointer);
    glTexCoordPointer(2, GL_FLOAT, 0, 0);
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, myTextureName);

    // RENDER!
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

    // Disale client states as were done with them.
    glDisableClientState(GL_VERTEX_ARRAY);
    glDisableClientState(GL_COLOR_ARRAY);
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glDisable(GL_TEXTURE_RECTANGLE_ARB);

    GetGLError();

    // Delete buffers when they arent being used.
    glDeleteBuffers(1, &memoryPointer);
    glDeleteBuffers(1, &colourMemoryPointer);
    glDeleteBuffers(1, &myTextureName);
    glGenTextures(GL_TEXTURE_RECTANGLE_ARB, 0);

    // Free vertexes when done using them
    free(vertices);
    free(colors);
    free(texture);