Attachment 104697 Details for Bug 82683 – code example consistently demonstrating the segfault

code example consistently demonstrating the segfault

opengl-segfault.c (text/plain), 4.31 KB, created by Ben Foppa on 2014-08-15 22:24:12 UTC

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Creator: Ben Foppa

Created: 2014-08-15 22:24:12 UTC

Size: 4.31 KB

patch

obsolete

>#include <stdio.h>
>#include "GL/gl.h"
>#include "GL/glext.h"
>#include "SDL2/SDL.h"
>
>// this section is for loading OpenGL things from later versions.
>
>typedef void (APIENTRY *GLGenVertexArrays) (GLsizei n, GLuint *arrays);
>typedef void (APIENTRY *GLGenBuffers) (GLsizei n, GLuint *buffers);
>typedef void (APIENTRY *GLBindVertexArray) (GLuint array);
>typedef void (APIENTRY *GLBindBuffer) (GLenum target, GLuint buffer);
>typedef void (APIENTRY *GLBufferData) (GLenum target, GLsizeiptr size, const GLvoid* data, GLenum usage);
>typedef void (APIENTRY *GLBufferSubData) (GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid* data);
>typedef void (APIENTRY *GLGetBufferSubData) (GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid* data);
>typedef void (APIENTRY *GLFlush) (void);
>typedef void (APIENTRY *GLFinish) (void);
>
>GLGenVertexArrays glGenVertexArrays = NULL;
>GLGenBuffers glGenBuffers = NULL;
>GLBindVertexArray glBindVertexArray = NULL;
>GLBindBuffer glBindBuffer = NULL;
>GLBufferData glBufferData = NULL;
>GLBufferSubData glBufferSubData = NULL;
>GLGetBufferSubData glGetBufferSubData = NULL;
>
>void load_gl_pointers() {
>  glGenVertexArrays = (GLGenVertexArrays)SDL_GL_GetProcAddress("glGenVertexArrays");
>  glGenBuffers = (GLGenBuffers)SDL_GL_GetProcAddress("glGenBuffers");
>  glBindVertexArray = (GLBindVertexArray)SDL_GL_GetProcAddress("glBindVertexArray");
>  glBindBuffer = (GLBindBuffer)SDL_GL_GetProcAddress("glBindBuffer");
>  glBufferData = (GLBufferData)SDL_GL_GetProcAddress("glBufferData");
>  glBufferSubData = (GLBufferSubData)SDL_GL_GetProcAddress("glBufferSubData");
>  glGetBufferSubData = (GLGetBufferSubData)SDL_GL_GetProcAddress("glGetBufferSubData");
>}
>
>// end OpenGL loading stuff
>
>
>#define CAPACITY (1 << 8)
>
>// return nonzero if an OpenGL error has occurred.
>int opengl_checkerr(const char* const label) {
>  GLenum err;
>  switch(err = glGetError()) {
>    case GL_INVALID_ENUM:
>      printf("GL_INVALID_ENUM");
>      break;
>    case GL_INVALID_VALUE:
>      printf("GL_INVALID_VALUE");
>      break;
>    case GL_INVALID_OPERATION:
>      printf("GL_INVALID_OPERATION");
>      break;
>    case GL_INVALID_FRAMEBUFFER_OPERATION:
>      printf("GL_INVALID_FRAMEBUFFER_OPERATION");
>      break;
>    case GL_OUT_OF_MEMORY:
>      printf("GL_OUT_OF_MEMORY");
>      break;
>    case GL_STACK_UNDERFLOW:
>      printf("GL_STACK_UNDERFLOW");
>      break;
>    case GL_STACK_OVERFLOW:
>      printf("GL_STACK_OVERFLOW");
>      break;
>    default: return 0;
>  }
>
>  printf(" %s\n", label);
>  return 1;
>}
>
>int main(int nargs, const char* args[]) {
>  printf("initializing..\n");
>  SDL_Init(SDL_INIT_EVERYTHING);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
>
>  SDL_Window* const w =
>    SDL_CreateWindow(
>      "broken",
>      SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
>      1, 1,
>      SDL_WINDOW_OPENGL
>    );
>
>  if(w == NULL) {
>    printf("window was null\n");
>    return 0;
>  }
>
>  SDL_GLContext context = SDL_GL_CreateContext(w);
>
>  if(context == NULL) {
>    printf("context was null\n");
>    return 0;
>  }
>
>  load_gl_pointers();
>
>  if(opengl_checkerr("init")) {
>    return 1;
>  }
>
>  printf("GL_VENDOR: %s\n", glGetString(GL_VENDOR));
>  printf("GL_RENDERER: %s\n", glGetString(GL_RENDERER));
>
>  float* const vs = malloc(CAPACITY * sizeof(float));
>  memset(vs, 0, CAPACITY * sizeof(float));
>
>  unsigned int i = 0;
>  while(i < 128000) {
>    GLuint vertex_array, vertex_buffer;
>    glGenVertexArrays(1, &vertex_array);
>    glGenBuffers(1, &vertex_buffer);
>
>    glBindVertexArray(vertex_array);
>    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
>
>    if(opengl_checkerr("gen/binding")) {
>      return 1;
>    }
>
>    glBufferData(
>      GL_ARRAY_BUFFER,
>      CAPACITY * sizeof(float),
>      vs, // initialize with `vs` just to make sure it's allocated.
>      GL_DYNAMIC_DRAW
>    );
>
>    // verify that the memory is allocated by reading it back into `vs`.
>    glGetBufferSubData(
>      GL_ARRAY_BUFFER,
>      0,
>      CAPACITY * sizeof(float),
>      vs
>    );
>
>    if(opengl_checkerr("creating buffer")) {
>      return 1;
>    }
>
>    glFlush();
>    glFinish();
>
>    // segfault occurs here..
>    glBufferSubData(
>      GL_ARRAY_BUFFER,
>      0,
>      CAPACITY * sizeof(float),
>      vs
>    );
>
>    glFlush();
>    glFinish();
>
>    ++i;
>  }
>
>  return 0;
>}

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Attachments on bug 82683: 104697 | 104766 | 106164

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