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Hello this code seems so well done and yet I'm getting this weird access violation error when I use anything but 0 in glShaderSources 2nd argument :

glShaderSource( fragshader, 0, fragfilebuff, NULL );

If I use lenofstr or any other number then 0 it calls up an error like this :

error

I have no idea for the life of me why this is happpening I've updated my drivers , I've even tried messing around with glewInit(); too see if it's something to do with that but no luck what so ever.

This nvidia dll has some problem with my code and I don't know why?...

void LoadShaders(const char *fragshaderfn, const char *vertshaderfn) { FILE *fragfile; const GLchar *fragfilebuff[256] = { 0 }; fopen_s(&fragfile, fragshaderfn, "r"); fread(fragfilebuff, sizeof(char), sizeof(char) * 256, fragfile); printf(fragfilebuff); GLsizei lenofstr = strlen(fragfilebuff); printf("this is the length -> %d", lenofstr); GLuint fragshader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragshader, 0, fragfilebuff, NULL); glCompileShader(fragshader); };

Here's the complete source : 

#include <SDL.h> #include <GL/glew.h> #include <SDL_opengl.h> #include <stdio.h> #include <conio.h> #define SCREEN_HEIGHT 480 #define SCREEN_WIDTH 640 SDL_Renderer *mainrenderer; SDL_Window *mainwindow; SDL_Event event; bool running = true; void LoadShaders(const char *fragshaderfn, const char *vertshaderfn) { FILE *fragfile; const GLchar *fragfilebuff[256] = { 0 }; fopen_s(&fragfile, fragshaderfn, "r"); fread(fragfilebuff, sizeof(char), sizeof(char) * 256, fragfile); printf(fragfilebuff); GLsizei lenofstr = strlen(fragfilebuff); printf("this is the length -> %d", lenofstr); GLuint fragshader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragshader, lenofstr, fragfilebuff, NULL); glCompileShader(fragshader); }; int main(int argc , char **argv) { SDL_Init(SDL_INIT_EVERYTHING); mainwindow = SDL_CreateWindow( "C OpenGL Engine", 300, 300, 640, 480, SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL ); SDL_GLContext maincontext = SDL_GL_CreateContext(mainwindow); SDL_GL_MakeCurrent(mainwindow, maincontext); glewExperimental = GL_TRUE; GLenum err = glewInit(); if (GLEW_OK != err) { /* Problem: glewInit failed, something is seriously wrong. */ fprintf(stderr, "Error: %s\n", glewGetErrorString(err)); } fprintf(stdout, "Status: Using GLEW %s\n", glewGetString(GLEW_VERSION)); if (SDL_GL_SetSwapInterval(1) < 0) { printf("Warning: Unable to set VSync! SDL Error: %s\n", SDL_GetError()); } LoadShaders("ffile.frag", ""); glClearColor(0.0, 0.0, 0.0, 1.0); while (running == true) { while (SDL_PollEvent(&event)) { switch (event.type) { case SDL_QUIT: SDL_GL_DeleteContext(maincontext); SDL_Quit(); return 0; break; } } glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); SDL_GL_SwapWindow(mainwindow); } SDL_GL_DeleteContext(maincontext); SDL_DestroyWindow(mainwindow); SDL_Quit(); return 0; }

All help would be appreciated I am using C , SDL 2.0 and OpenGL 3.3+ , MSVC 2015 , Win10 64bit

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  • \$\begingroup\$ Easy: glShaderSource( fragshader, 1, &fragfilebuff, NULL ); if your string has a 0x00 at the end. Replace NULL with &fragfilelen if not. \$\endgroup\$ Commented Apr 14, 2016 at 0:21

1 Answer 1

Reset to default
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void glShaderSource(GLuint shader, GLsizei count, const GLchar **string, const GLint *length);

Okay, I guess you didn't understand what these values mean. string is an "array"(pointer is more correct since a pointer is not an array) of "char const*" (I advice you to put all your code in one and only one char const *.

length is an "array" of int. Each values inside this "array" should be set at the length of the respective "char const*" in "string".

Count is just the number of char const* and int you have in both array above.

So, I'd go for that :

char const *code = getStringFromFile(path); int length = strlen(code); glShaderSource(shader, 1, &code, &length);

That should work :)

the getStringFromFile(path) could be done like this:

const char *getStringFromFile(char const *path) { FILE *file = fopen(path, "ab"); // open the file at the end and binary int length = ftell(file); // Ask the size of the file fseek(file, 0, SEEK_SET); // return to the beginning of the file char *buffer = calloc(length + 1, sizeof(char)); // alloc the buffer with the end 0 fread(buffer, sizeof(char), length, file); // read the file fclose(file); return buffer; }

This code may countain error, I didn't test it, but the idea is here

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  • \$\begingroup\$ omg someone answered : D , I'll study this so much and see if I can make it work. I should say that I did know an array might be needed however wasn't entirely shore how strict it was about that so good for clarifying. \$\endgroup\$ Commented Apr 13, 2016 at 23:11
  • \$\begingroup\$ Good luck, if you did not understand something, please, let me know. Btw, by getStringFromFile, I mean a function which put all the file into one buffer and return it. (Don't forget to free it) \$\endgroup\$ Commented Apr 13, 2016 at 23:13
  • \$\begingroup\$ It is a c++ code I made, but maybe it could help you github.com/qnope/GLTools/blob/master/System/GL/Pipeline/… \$\endgroup\$ Commented Apr 13, 2016 at 23:15
  • \$\begingroup\$ I'll check it and yes if i do not understand something I'll defiantly without a shadow of a doubt be right here again : ). \$\endgroup\$ Commented Apr 13, 2016 at 23:15
  • \$\begingroup\$ Antonie Morrier I must say I'm confused as why this code works , I'm glad that it is by the way just wanted too know why exactly I needed too make a const char *getstringfromfile function and use that in glshadersource instead of just giving it the buffer, is this because OpenGL can't read the buffer and needs you to do it for it? \$\endgroup\$ Commented Apr 13, 2016 at 23:25

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