你需要渲染一个图像(尺寸需要是2的幂次)以opengl。
,您可以将图像放置在您的3D世界中,以便它看起来像是背景(我这样做是因为我的相机角度是固定的),或者您可以在绘制图像之前推动一些矩阵以利用glOrthof,并关闭矩阵后。
下面是一些代码,以帮助您的图像绘制到OpenGL
glPushMatrix();
glGenTextures(1, &texture[0]);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
UIImage *image = [UIImage imageNamed:@"map1.jpg"];
if (image == nil)
NSLog(@"Do real error checking here");
GLuint width = CGImageGetWidth(image.CGImage);
GLuint height = CGImageGetHeight(image.CGImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
void *imageData = malloc(height * width * 4);
CGContextRef context = CGBitmapContextCreate(imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGContextTranslateCTM (context, 0, height);
CGContextScaleCTM (context, 1.0, -1.0);
CGColorSpaceRelease(colorSpace);
CGContextClearRect(context, CGRectMake(0, 0, width, height));
CGContextTranslateCTM(context, 0, height - height);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), image.CGImage);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
CGContextRelease(context);
free(imageData);
[image release];
static const GLfloat texCoords[] = {
0.0, 1.0,
1.0, 1.0,
0.0, 0.0,
1.0, 0.0
};
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
static const GLfloat vertices[] = {
-1.0, 1.0, -0.0,
1.0, 1.0, -0.0,
-1.0, -1.0, -0.0,
1.0, -1.0, -0.0
};
static const GLfloat normals[] = {
0.0, 0.0, 1.0,
0.0, 0.0, 1.0,
0.0, 0.0, 1.0,
0.0, 0.0, 1.0
};
glBindTexture(GL_TEXTURE_2D, texture[0]);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glNormalPointer(GL_FLOAT, 0, normals);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glPopMatrix();
注意,纹理尺寸不需要两个iOS设备上支持OpenGL ES 2.0的支持非是权力,或1 -power-of-two扩展:http://stackoverflow.com/questions/4760174/rendering-to-non-power-of-two-texture-on-iphone/4761453#4761453 – 2011-01-27 22:49:39