Well I was expecting an opengl program that draws a red triangle on a white background using programmable shaders and does work on both ATI and GeForce cards.
Anyway here is the code that works on ATI and crashes on GeForce:
test.cpp
// Two-Dimensional Sierpinski Gasket
// Generated using randomly selected vertices and bisection
#include "Angel.h"
//----------------------------------------------------------------------------
void
init( void )
{
// Specifiy the vertices for a triangle
vec4 vertices[3] = {
vec4( -1.0, -1.0, 0.0, 1.0 ), vec4( 0.0, 1.0, 0.0, 1.0 ), vec4( 1.0, -1.0, 0.0, 1.0 )
};
// Create a vertex array object
GLuint vao;
glGenVertexArrays( 1, &vao );
glBindVertexArray( vao );
// Create and initialize a buffer object
GLuint buffer;
glGenBuffers( 1, &buffer );
glBindBuffer( GL_ARRAY_BUFFER, buffer );
glBufferData( GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW );
// Load shaders and use the resulting shader program
GLuint program = InitShader( "vshader21.glsl", "fshader21.glsl" );
glUseProgram( program );
// Initialize the vertex position attribute from the vertex shader
GLuint loc = glGetAttribLocation( program, "vPosition" );
glEnableVertexAttribArray( loc );
glVertexAttribPointer( loc, 4, GL_FLOAT, GL_FALSE, 0,
BUFFER_OFFSET(0) );
glClearColor( 1.0, 1.0, 1.0, 1.0 ); // white background
}
//----------------------------------------------------------------------------
void
display( void )
{
glClear( GL_COLOR_BUFFER_BIT ); // clear the window
glDrawArrays( GL_TRIANGLES, 0, 3 ); // draw the points
glFlush();
}
//----------------------------------------------------------------------------
void
keyboard( unsigned char key, int x, int y )
{
switch ( key ) {
case 033:
exit( EXIT_SUCCESS );
break;
}
}
//----------------------------------------------------------------------------
int
main( int argc, char **argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_RGBA );
glutInitWindowSize( 512, 512 );
// If you are using freeglut, the next two lines will check if
// the code is truly 3.2. Otherwise, comment them out
glutInitContextVersion( 3, 2 );
glutInitContextProfile( GLUT_CORE_PROFILE );
glutCreateWindow( "Sierpinski Gasket" );
glewInit();
init();
glutDisplayFunc( display );
glutKeyboardFunc( keyboard );
glutMainLoop();
return 0;
}
vshader21.glsl:
#version 150
in vec4 vPosition;
void
main()
{
gl_Position = vPosition;
}
fshader21.glsl:
#version 150
out vec4 fColor;
void
main()
{
fColor = vec4( 1.0, 0.0, 0.0, 1.0 );
}
Finally InitShader.cpp:
#include "Angel.h"
namespace Angel {
// Create a NULL-terminated string by reading the provided file
static char*
readShaderSource(const char* shaderFile)
{
FILE* fp = fopen(shaderFile, "r");
if ( fp == NULL ) { return NULL; }
fseek(fp, 0L, SEEK_END);
long size = ftell(fp);
fseek(fp, 0L, SEEK_SET);
char* buf = new char[size + 1];
fread(buf, 1, size, fp);
buf[size] = '\0';
fclose(fp);
return buf;
}
// Create a GLSL program object from vertex and fragment shader files
GLuint
InitShader(const char* vShaderFile, const char* fShaderFile)
{
struct Shader {
const char* filename;
GLenum type;
GLchar* source;
} shaders[2] = {
{ vShaderFile, GL_VERTEX_SHADER, NULL },
{ fShaderFile, GL_FRAGMENT_SHADER, NULL }
};
GLuint program = glCreateProgram();
for ( int i = 0; i < 2; ++i ) {
Shader& s = shaders[i];
s.source = readShaderSource( s.filename );
if ( shaders[i].source == NULL ) {
std::cerr << "Failed to read " << s.filename << std::endl;
exit( EXIT_FAILURE );
}
GLuint shader = glCreateShader( s.type );
glShaderSource( shader, 1, (const GLchar**) &s.source, NULL );
glCompileShader( shader );
GLint compiled;
glGetShaderiv( shader, GL_COMPILE_STATUS, &compiled );
if ( !compiled ) {
std::cerr << s.filename << " failed to compile:" << std::endl;
GLint logSize;
glGetShaderiv( shader, GL_INFO_LOG_LENGTH, &logSize );
char* logMsg = new char[logSize];
glGetShaderInfoLog( shader, logSize, NULL, logMsg );
std::cerr << logMsg << std::endl;
delete [] logMsg;
exit( EXIT_FAILURE );
}
delete [] s.source;
glAttachShader( program, shader );
}
/* link and error check */
glLinkProgram(program);
GLint linked;
glGetProgramiv( program, GL_LINK_STATUS, &linked );
if ( !linked ) {
std::cerr << "Shader program failed to link" << std::endl;
GLint logSize;
glGetProgramiv( program, GL_INFO_LOG_LENGTH, &logSize);
char* logMsg = new char[logSize];
glGetProgramInfoLog( program, logSize, NULL, logMsg );
std::cerr << logMsg << std::endl;
delete [] logMsg;
exit( EXIT_FAILURE );
}
/* use program object */
glUseProgram(program);
return program;
}
} // Close namespace Angel block