c - glUseProgram 是否有任何原因可能导致我的程序崩溃？ (C Win32)

Question

我正在用 C 语言学习 OpenGL 和 Win32，我刚刚开始想要实现着色器。我这样做更多是作为一种学习体验而不是一个项目，所以我决定不使用典型的扩展管理器库，如 glew 或其他东西。这是我的扩展抓取器头文件:

glExtensions.h:

#include <windows.h>

#define WGL_DRAW_TO_WINDOW_ARB         0x2001
#define WGL_ACCELERATION_ARB           0x2003
#define WGL_SWAP_METHOD_ARB            0x2007
#define WGL_SUPPORT_OPENGL_ARB         0x2010
#define WGL_DOUBLE_BUFFER_ARB          0x2011
#define WGL_PIXEL_TYPE_ARB             0x2013
#define WGL_COLOR_BITS_ARB             0x2014
#define WGL_DEPTH_BITS_ARB             0x2022
#define WGL_STENCIL_BITS_ARB           0x2023
#define WGL_FULL_ACCELERATION_ARB      0x2027
#define WGL_SWAP_EXCHANGE_ARB          0x2028
#define WGL_TYPE_RGBA_ARB              0x202B
#define WGL_CONTEXT_MAJOR_VERSION_ARB  0x2091
#define WGL_CONTEXT_MINOR_VERSION_ARB  0x2092
#define GL_ARRAY_BUFFER                   0x8892
#define GL_STATIC_DRAW                    0x88E4
#define GL_FRAGMENT_SHADER                0x8B30
#define GL_VERTEX_SHADER                  0x8B31
#define GL_COMPILE_STATUS                 0x8B81
#define GL_LINK_STATUS                    0x8B82
#define GL_INFO_LOG_LENGTH                0x8B84
#define GL_TEXTURE0                       0x84C0
#define GL_BGRA                           0x80E1
#define GL_ELEMENT_ARRAY_BUFFER           0x8893

PROC glCreateProgram;
PROC glCreateShader;
PROC glShaderSource;
PROC glCompileShader;
PROC glAttachShader;
PROC glLinkProgram;
PROC glUseProgram;
PROC glGetShaderInfoLog;
PROC glDeleteShader;
PROC glDetachShader;
PROC glIsProgram;
PROC glGenBuffers;
PROC glBindBuffer;
PROC glBufferData;
PROC glEnableVertexAttribArray;
PROC glVertexAttribPointer;
PROC glGenVertexArrays;
PROC glBindVertexArray;

void GLEInit(int);

这是 c 文件，glExtions.c

#include "glExtensions.h"
#include <windows.h>
#include <gl/gl.h>
#include "consoleUtil.h"

extern PROC glCreateProgram;
extern PROC glCreateShader;
extern PROC glShaderSource;
extern PROC glCompileShader;
extern PROC glAttachShader;
extern PROC glLinkProgram;
extern PROC glUseProgram;
extern PROC glGetShaderInfoLog;
extern PROC glDeleteShader;
extern PROC glDetachShader;
extern PROC glIsProgram;
extern PROC glGenBuffers;
extern PROC glBindBuffer;
extern PROC glBufferData;
extern PROC glEnableVertexAttribArray;
extern PROC glVertexAttribPointer;
extern PROC glGenVertexArrays;
extern PROC glBindVertexArray;

PROC getProc(int hOut, const char* name) {
    PROC p = wglGetProcAddress(name);
    if(p == 0 ||
        (p == (void*)0x1) || (p == (void*)0x2) || (p == (void*)0x3) ||
        (p == (void*)-1) )
    {
        HMODULE module = LoadLibraryA("opengl32.dll");
        p = GetProcAddress(module, name);
    }

    return p;
}

void GLEInit(int hOut) {
    glCreateProgram = getProc(hOut, "glCreateProgram");
    glCreateShader = getProc(hOut, "glCreateShader");
    glShaderSource = getProc(hOut, "glShaderSource");
    glCompileShader = getProc(hOut, "glCompileShader");
    glAttachShader = getProc(hOut, "glAttachShader");
    glLinkProgram = getProc(hOut, "glLinkProgram");
    glUseProgram = getProc(hOut, "glUseProgram");
    glGetShaderInfoLog = getProc(hOut, "glGetShaderInfoLog");
    glDeleteShader = getProc(hOut, "glDeleteShader");
    glDetachShader = getProc(hOut, "glDetachShader");
    glIsProgram = getProc(hOut, "glIsProgram");
    glGenBuffers = getProc(hOut, "glGenBuffers");
    glBindBuffer = getProc(hOut, "glBindBuffer");
    glBufferData = getProc(hOut, "glBufferData");
    glEnableVertexAttribArray = getProc(hOut, "glEnableVertexAttribArray");
    glVertexAttribPointer = getProc(hOut, "glVertexAttribPointer");
    glGenVertexArrays = getProc(hOut, "glGenVertexArrays");
    glBindVertexArray = getProc(hOut, "glBindVertexArray");
}

GLEInit 在创建窗口后立即运行，然后运行此代码

int createBasicProgram(int hOut) {
    //vertex shader bullcrap
    FILE* basicVSFile = getFile("shaders/basic.vs");
    FILEDATA* vsfd = getFileData(hOut, basicVSFile);
    close(basicVSFile);

    int vs = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vs, vsfd->numLines, vsfd->lines, vsfd->lengths);
    glCompileShader(vs);

    int actualLength = 0;
    glGetShaderInfoLog(vs, ERROR_BUFFER_SIZE, &actualLength, errorBuffer);
    if (actualLength > 0) {
        print(hOut, "deleting vertex shader\n");
        glDeleteShader(vs);
        print(hOut, errorBuffer);
        return -1;
    }
    freeFileData(vsfd);


    //fragment shader bullcrap
    FILE* basicFSFile = getFile("shaders/basic.fs");
    FILEDATA* fsfd = getFileData(hOut, basicFSFile);
    int fs = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fs, fsfd->numLines, fsfd->lines, fsfd->lengths);
    glCompileShader(fs);

    glGetShaderInfoLog(fs, ERROR_BUFFER_SIZE, &actualLength, errorBuffer);
    if (actualLength > 0) {
        print(hOut, "deleting fragment shader\n");
        glDeleteShader(fs);
        print(hOut, errorBuffer);
        return -1;
    }
    freeFileData(fsfd);

    int progId = glCreateProgram();
    glAttachShader(progId, vs);
    glAttachShader(progId, fs);
    glLinkProgram(progId);
    glGetShaderInfoLog(progId, ERROR_BUFFER_SIZE, &actualLength, errorBuffer);
    if (actualLength > 0) {
        print(hOut, errorBuffer);
    }

    glDetachShader(progId, vs);
    glDetachShader(progId, fs);
    glDeleteShader(vs);
    glDeleteShader(fs);

    return progId;
}

void init(hOut) {
    bp = createBasicProgram(hOut);

    glGenVertexArrays(1, &vaoId);
    glBindVertexArray(vaoId);
    glGenBuffers(1, &vboId);
    glBindBuffer(GL_ARRAY_BUFFER, vboId);
    glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_STATIC_DRAW);
}

这段代码不会导致错误，但是当我添加简单的语句时:

glUseProgram(bp);

进入显示函数，该函数每帧都会被调用，程序运行一秒钟，控制台和程序窗口打开并呈黑色大约 3 秒，然后崩溃，没有构建错误或输出错误可跟踪。这个 glUseProgram 有什么原因会导致我的程序崩溃吗？

堆栈转储显示:“异常:STATUS_ACCESS_VIOLATION at rip=001004016E6”，带有一堆内存位置和我不明白的东西。

Answer 1

我又花了 7 个小时在这个项目上，我终于弄清楚了。我所说的“它”是指我的旧代码有一些问题。前两个问题是glExtensions.c和glExtensions.h，最初我所做的只是调用使用getProc来获取函数指针并将其放入PROC宏中，这根本不是它所需要的。 PROC 不使用正确的调用约定或指定正确的参数，而是需要包含 glext.h，它由 khronos 维护，可以在此处找到:https://www.khronos.org/registry/OpenGL/api/GL/glext.h 。关于这些函数的作用的描述也可以在这里找到:https://www.khronos.org/opengl/wiki/Load_OpenGL_Functions 。需要更改的另一件事是在创建程序之前调用 glUseProgram。程序创建代码是正确的，但是我在 WM_PAINT 和 WM_SIZE 上调用显示，并且两者都被放入消息队列并在调用 GLEInit 之前进行处理。相反，如果 PeekMessage 找不到任何消息，则应在消息循环中调用 display。

这是自上次以来更改的相关代码:

glExtensions.h:

#include <windows.h>
#include "glext.h"
#include "wglext.h"

PFNGLCREATEPROGRAMPROC glCreateProgram;
PFNGLCREATESHADERPROC glCreateShader;
PFNGLSHADERSOURCEPROC glShaderSource;
PFNGLCOMPILESHADERPROC glCompileShader;
PFNGLATTACHSHADERPROC glAttachShader;
PFNGLLINKPROGRAMPROC glLinkProgram;
PFNGLUSEPROGRAMPROC glUseProgram;
PFNGLGETSHADERINFOLOGPROC glGetShaderInfoLog;
PFNGLGETPROGRAMINFOLOGPROC glGetProgramInfoLog;
PFNGLDELETESHADERPROC glDeleteShader;
PFNGLDETACHSHADERPROC glDetachShader;
PFNGLISPROGRAMPROC glIsProgram;
PFNGLGENBUFFERSPROC glGenBuffers;
PFNGLBINDBUFFERPROC glBindBuffer;
PFNGLBUFFERDATAPROC glBufferData;
PFNGLENABLEVERTEXATTRIBARRAYPROC glEnableVertexAttribArray;
PFNGLVERTEXATTRIBPOINTERPROC glVertexAttribPointer;
PFNGLGENVERTEXARRAYSPROC glGenVertexArrays;
PFNGLBINDVERTEXARRAYPROC glBindVertexArray;
PFNGLGETINTEGERI_VPROC glGetIntegeri_v;
PFNGLGETSTRINGIPROC glGetStringi;
PFNWGLSWAPINTERVALEXTPROC wglSwapIntervalEXT;
PFNWGLGETSWAPINTERVALEXTPROC wglGetSwapIntervalEXT;

void GLEInit(HANDLE);

void checkGLError(HANDLE, char*);

glExtensions.c:

#include "glExtensions.h"

#include <windows.h>
#include <gl/gl.h>
#include "consoleUtil.h"

void* getProc(HANDLE hOut, const char* name) {
    print(hOut, "loading %s\n", name);
    void* p = wglGetProcAddress(name);
    if (p == NULL) {
        int e = GetLastError();
        print(hOut, "error loading %s: %i\n", name, e);
        return NULL;
    }
    if(p == 0 ||
        (p == (void*)0x1) || (p == (void*)0x2) || (p == (void*)0x3) ||
        (p == (void*)-1) )
    {
        HMODULE module = LoadLibraryA("opengl32.dll");
        if (module == NULL) {
            int e = GetLastError();
            print(hOut, "error loading library \"opengl32.dll\" for function pointer %s: %i\n", name, e);
            return NULL;
        }
        p = GetProcAddress(module, name);
        if (p == NULL) {
            int e = GetLastError();
            print(hOut, "error loading %s with getProcAddress: %i\n", name, e);
            return NULL;
        }
    }

    print(hOut, "success loading\n");
    return p;
}

void checkGLError(HANDLE hOut, char* desc) {
    GLenum e = glGetError();
    if (e > 0) {
        print(hOut, "Error %i: %s\n", e, desc);
        return;
    }
    print(hOut, "%s completed with no errors\n", desc);
}

void GLEInit(HANDLE hOut) {
    glCreateProgram = (PFNGLCREATEPROGRAMPROC)getProc(hOut, "glCreateProgram");
    glCreateShader = (PFNGLCREATESHADERPROC)getProc(hOut, "glCreateShader");
    glShaderSource = (PFNGLSHADERSOURCEPROC)getProc(hOut, "glShaderSource");
    glCompileShader = (PFNGLCOMPILESHADERPROC)getProc(hOut, "glCompileShader");
    glAttachShader = (PFNGLATTACHSHADERPROC)getProc(hOut, "glAttachShader");
    glLinkProgram = (PFNGLLINKPROGRAMPROC)getProc(hOut, "glLinkProgram");
    glUseProgram = (PFNGLUSEPROGRAMPROC)getProc(hOut, "glUseProgram");
    glGetShaderInfoLog = (PFNGLGETSHADERINFOLOGPROC)getProc(hOut, "glGetShaderInfoLog");
    glGetProgramInfoLog = (PFNGLGETPROGRAMINFOLOGPROC)getProc(hOut, "glGetProgramInfoLog");
    glDeleteShader = (PFNGLDELETESHADERPROC)getProc(hOut, "glDeleteShader");
    glDetachShader = (PFNGLDETACHSHADERPROC)getProc(hOut, "glDetachShader");
    glIsProgram = (PFNGLISPROGRAMPROC)getProc(hOut, "glIsProgram");
    glGenBuffers = (PFNGLGENBUFFERSPROC)getProc(hOut, "glGenBuffers");
    glBindBuffer = (PFNGLBINDBUFFERPROC)getProc(hOut, "glBindBuffer");
    glBufferData = (PFNGLBUFFERDATAPROC)getProc(hOut, "glBufferData");
    glEnableVertexAttribArray = (PFNGLENABLEVERTEXATTRIBARRAYPROC)getProc(hOut, "glEnableVertexAttribArray");
    glVertexAttribPointer = (PFNGLVERTEXATTRIBPOINTERPROC)getProc(hOut, "glVertexAttribPointer");
    glGenVertexArrays = (PFNGLGENVERTEXARRAYSPROC)getProc(hOut, "glGenVertexArrays");
    glBindVertexArray = (PFNGLBINDVERTEXARRAYPROC)getProc(hOut, "glBindVertexArray");
    glGetIntegeri_v = (PFNGLGETINTEGERI_VPROC)getProc(hOut, "glGetIntegeri_v");
    glGetStringi = (PFNGLGETSTRINGIPROC)getProc(hOut, "glGetStringi");
    wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)getProc(hOut, "wglSwapIntervalEXT");
    wglGetSwapIntervalEXT = (PFNWGLGETSWAPINTERVALEXTPROC)getProc(hOut, "wglGetSwapIntervalEXT");
}