我想这是一个两部分问题,这就是为什么我找不到更合适的职位。
我正在使用DevIL加载图像,然后将其转换为熟悉的格式。以下是我遇到麻烦的代码部分:
//Copy to OpenGL texture
if(!ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE))
{
throw runtime_error(std::string("Unable to convert image") +filename +std::string(" to display friendly format"));
}
glGenTextures(1, &Main::texture);
glBindTexture(GL_TEXTURE_2D, Main::texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Use nice (linear) scaling
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); // Use nice (linear) scaling
glTexImage2D(GL_TEXTURE_2D, 0, ilGetInteger(IL_IMAGE_BPP), width, height, 0, ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, ilGetData());
现在,对于glGenTextures()
方法,我得到了
error C2664: 'glGenTextures' : cannot convert parameter 2 from 'GLuint Main::* ' to 'GLuint *'
和glBindTexure()
error C2597: illegal reference to non-static member 'Main::texture'
我尝试过多种不同方式声明texture
,
static Gluint Main::texture;
static Gluint texture;
Gluint texture;
Gluint Main::texture;
在我的.cpp文件和我的.h文件中,但都不起作用。如果我尝试在.h文件中将其声明为static Gluint Main::texture
,则每个DevIL函数都会出现LNK2019: unresolved external symbol__imp_
错误(如果您希望我发布它们,请告诉我。)
我很漂亮它是代码中的东西,而不是我的依赖项或我的.lib或.dll文件不在正确的位置。那么我做错了什么?
编辑:这是我目前的代码
头文件
class Main
{
private:
static GLuint texture;
public:
static void Init(int argc, char ** argv);
static void DisplayScene();
static void Idle();
static void Resize(int w, int h);
};
void main(int argc, char ** argv)
{
Main::Init(argc, argv);
}
.cpp文件
#include <IL\il.h>
#include <IL\ilu.h>
#include <IL\ilut.h>
GLuint Main::texture = 0;
double xRes, yRes;
void Main::Init(int argc, char ** argv) //Initialisation method
{
////Window Management
glutInit( &argc, argv); //Initialises GLUT and processes any command line arguements.
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); //Specifies whether to use an RGBA or colour-index colour model. Can also specify whether to use a single or a double buffered window.
glutInitWindowSize(1024, 768);
glutCreateWindow("Adventure"); //Creates a window with an OpenGL context. It returns a unique identifier for the new window. Until glutMainLoop() is called, the window is not yet displayed.
/// Set up OpenGL for 2d rendering
gluOrtho2D(0.0, xRes, yRes, 0.0); //1.0 0.0
/// Enable textures
glEnable(GL_TEXTURE_2D);
/// Enable blending
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
ilInit(); //Initialise DevIL.
glOrtho(0.0, 1.0, 0.0, 1.0, -1.0, 1.0); //Specifies the coordinate system OpenGL assumes as it draws the final image and how the image is mapped to the screen.
///The Display Callback
glutDisplayFunc(Main::DisplayScene); //Defines all the routines needed to draw the scene.
glutIdleFunc(Main::Idle);
///Running The Program
glutMainLoop(); //All windows that have been created are now shown, and rendering to those windows is now effective.
}
void Main::Idle()
{
glutPostRedisplay();
}
void Main::DisplayScene()
{
///Declarations
int x = 0;
int y = 0;
//float alpha;
const char* filename = "back.bmp";
ILboolean ilLoadImage(const char *filename);
//GLuint texture;
///Generate DevIL image and make it current context
ILuint image;
ilGenImages(1, &image);
ilBindImage(image);
///Load the image
if (!ilLoadImage(filename))
{
throw runtime_error(std::string("Unable to load image") +filename);
}
int width = ilGetInteger(IL_IMAGE_WIDTH);
int height = ilGetInteger(IL_IMAGE_HEIGHT);
///Copy to OpenGL texture
if(!ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE))
{
throw runtime_error(std::string("Unable to convert image") +filename +std::string(" to display friendly format"));
}
glGenTextures(1, &Main::texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Use nice (linear) scaling
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); // Use nice (linear) scaling
glTexImage2D(GL_TEXTURE_2D, 0, ilGetInteger(IL_IMAGE_BPP), width, height, 0, ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, ilGetData());
/// Free DevIL image since we have it in a texture now
ilDeleteImages(1, &image);
}
答案 0 :(得分:3)
出现错误是因为您没有Main
类型的实例(对象),但当然您需要Main
才能使用其中的任何内容。
现在你有几种方法可以解决这个问题 - 看起来你已经尝试了一些。您可以通过在类范围内使用static
或在命名空间范围内使用“普通”全局来使纹理变量成为全局变量。
对于第一种情况,您在.h文件中声明您的班级中的static GLuint texture;
>> 定义它在.cpp文件中为GLuint Main::texture = 0;
。您尝试此操作时似乎没有定义变量。
对于第二种情况,您在班级外的.h中将其声明为extern GLuint texture;
,并在任何函数之外将其定义为GLuint texture
。
两种解决方案的风格都不是很好,所以如果你只是在你的Main类中添加一个GLuint texture
,然后创建一个Main实例并使用它的成员变量 - 最好是从Main中的一个函数,所以你可以使用this
。
理想情况下,你会像Texture
类这样的东西:
class Texture
{
Texture() {glGenTextures(1, &id);}
~Texture() {glDeleteTextures(1, &id);}
void Bind() {glBindTexture(GL_TEXTURE_2D, id);}
private:
GLuint id;
};
void someFunction()
{
Texture myTexture;
myTexture.Bind();
// do stuff with the texture - like glTexParameteri, glTexImage
}
将更多功能转移到Texture类中的奖励积分,但这需要更多地处理OpenGLs愚蠢的绑定机制。
答案 1 :(得分:0)
错误C2664:'glGenTextures':无法将参数2从'GLuint Main :: *'转换为'GLuint *'
&Main::texture
是我们所说的成员字段指针,而不是指针。你需要指向一个实际的纹理实例,所以
Main* mymain; /* = new Main(...); somewehere in the code */
glGenTextures(1, &mymain->texture);
万一你真的想要使用成员指针,这是一个例子(codepad link):
#include <stdio.h>
struct A
{
int p,q,r;
int getp() { return p; }
};
int main()
{
int x;
A a[] = {
{ 1,2,3 },
{ 4,5,6 },
{ 7,8,9 }
};
// ---- pointer to member functions
int A::* member;
member = &A::p;
printf("member p: %i\n", a[2].*member);
member = &A::q;
printf("member q: %i\n", a[2].*member);
member = &A::r;
printf("member r: %i\n", a[2].*member);
// ---- pointer to member functions
int (A::*getter)();
getter = &A::getp;
x = (a[1].*getter)();
printf("getter: %i\n", x);
x = (a[2].*getter)();
printf("getter: %i\n", x);
return 0;
}