Effective Contour Creation with OpenGL Texture Mapping
By Wenfei Wu, December 01, 2000
In graphics applications, "let the hardware do it" is generally good advice. Today's graphics hardware keeps getting better and better, and OpenGL knows how to exploit its capabilities. Even producing contour plots can be a fairly painless operation.
Effective Contour Creation with OpenGL Texture Mapping/Listing 1
void CContoursDoc::CreateTextureObject()
{
// Define texture image
unsigned char Texture8[8][3] =
{
{ 0x00, 0x00, 0xa0 }, // Dark Blue
{ 0x00, 0x00, 0xff }, // Blue
{ 0x00, 0xa0, 0xff }, // Indigo
{ 0x00, 0xa0, 0x40 }, // Dark Green
{ 0x00, 0xff, 0x00 }, // Green
{ 0xff, 0xff, 0x00 }, // Yellow
{ 0xff, 0xcc, 0x00 }, // Orange
{ 0xff, 0x00, 0x00 } // Red
};
// Set pixel storage mode
::glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
// Generate a texture name
::glGenTextures(1, m_nTexName);
// Create a texture object
::glBindTexture(GL_TEXTURE_1D, m_nTexName[0]);
::glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER,
GL_NEAREST);
::glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER,
GL_NEAREST);
::glTexImage1D(GL_TEXTURE_1D, 0, 3, 8, 0, GL_RGB,
GL_UNSIGNED_BYTE, Texture8);
}
