Hi folks,
I want to start learning OpenGL. So I got myself the Superbible (5th edition) and followed all instructions. Here’s the first code sample:
// Triangle.cpp
// Our first OpenGL program that will just draw a triangle on the screen.
#include <GLTools.h> // OpenGL toolkit
#include <GLShaderManager.h> // Shader Manager Class
#ifdef __APPLE__
#include <glut/glut.h> // OS X version of GLUT
#else
#define FREEGLUT_STATIC
#include <GL/glut.h> // Windows FreeGlut equivalent
#endif
GLBatch triangleBatch;
GLShaderManager shaderManager;
///////////////////////////////////////////////////////////////////////////////
// Window has changed size, or has just been created. In either case, we need
// to use the window dimensions to set the viewport and the projection matrix.
void ChangeSize(int w, int h)
{
glViewport(0, 0, w, h);
}
///////////////////////////////////////////////////////////////////////////////
// This function does any needed initialization on the rendering context.
// This is the first opportunity to do any OpenGL related tasks.
void SetupRC()
{
// Blue background
glClearColor(0.0f, 0.0f, 1.0f, 1.0f );
shaderManager.InitializeStockShaders();
// Load up a triangle
GLfloat vVerts[] = { -0.5f, 0.0f, 0.0f,
0.5f, 0.0f, 0.0f,
0.0f, 0.5f, 0.0f };
triangleBatch.Begin(GL_TRIANGLES, 3);
triangleBatch.CopyVertexData3f(vVerts);
triangleBatch.End();
}
///////////////////////////////////////////////////////////////////////////////
// Called to draw scene
void RenderScene(void)
{
// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
GLfloat vRed[] = { 1.0f, 0.0f, 0.0f, 1.0f };
shaderManager.UseStockShader(GLT_SHADER_IDENTITY, vRed);
triangleBatch.Draw();
// Perform the buffer swap to display back buffer
glutSwapBuffers();
}
///////////////////////////////////////////////////////////////////////////////
// Main entry point for GLUT based programs
int main(int argc, char* argv[])
{
gltSetWorkingDirectory(argv[0]);
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL);
glutInitWindowSize(800,600);
glutCreateWindow("Triangle");
glutReshapeFunc(ChangeSize);
glutDisplayFunc(RenderScene);
GLenum err = glewInit();
if(GLEW_OK != err){
fprintf(stderr, "GLEW Error: %s
", glewGetErrorString(err));
return 1;
}
SetupRC();
glutMainLoop();
return 0;
}
But somehow I alway run into a “Unhandled exception at 0x00000000 in Triangle.exe: 0x00000005: Access violation reading location 0x00000000”.
Using the debugger it seems the problem lies in SetupRC(). The error occurs when the triangleBatch code is executed. If I comment out trianglebatch.Begin(); + …CopyVertexData3f(vVerts); + triangleBatch.end(); It works and shows the “scene”.
Another issue was that after loading “freeglut_static.lib” I got a message from VS-2008, that there are no rules defined for reading this library. Could this be the problem? If so how could I solve it?
Thanks in advance!