   Billboarding Problem
  I''ve just put the finishing touches on my sky and but one small problem remains. I''ve looked at several billboarding posts and implemented a billboard for my sun. However, when rendered, the sun does ugly things when the view direction changes. How can I correct this, code is below:float matrix[16];glGetFloatv(GL_MODELVIEW_MATRIX, (GLfloat *)matrix); // get modelview matrixglEnable(GL_TEXTURE_2D);glBindTexture(GL_TEXTURE_2D, texture[4]);// Set sun texturesunCoord[0] *= 5.0f; // multiply sun position to make it further awaysunCoord[1] *= 5.0f;sunCoord[2] *= 5.0f;glBegin(GL_QUADS);   // Draw sunglColor4f(1.0f, 1.0f, 1.0f, 1.0f);glTexCoord2f(0.0f, 0.0f);glVertex3f(sunCoord[0] - matrix[0] - matrix[4], sunCoord[1] - matrix[1] - matrix[5], sunCoord[2] - matrix[2] - matrix[6]);glTexCoord2f(1.0f, 0.0f);glVertex3f(sunCoord[0] + matrix[0] - matrix[4], sunCoord[1] + matrix[1] - matrix[5], sunCoord[2] + matrix[2] - matrix[6]);glTexCoord2f(1.0f, 1.0f);glVertex3f(sunCoord[0] + matrix[0] + matrix[4], sunCoord[1] + matrix[1] + matrix[5], sunCoord[2] + matrix[2] + matrix[6]);glTexCoord2f(0.0f, 1.0f);glVertex3f(sunCoord[0] - matrix[0] + matrix[4], sunCoord[1] - matrix[1] + matrix[5], sunCoord[2] - matrix[2] + matrix[6]);glEnd();
  Try this... glBegin(GL_QUADS); // Draw sunglColor4f(1.0f, 1.0f, 1.0f, 1.0f);glTexCoord2f(0.0f, 0.0f);glVertex3f(sunCoord[0] - matrix[0] - matrix[1], sunCoord[1] - matrix[4] - matrix[5], sunCoord[2] - matrix[8] - matrix[9]);glTexCoord2f(1.0f, 0.0f);glVertex3f(sunCoord[0] + matrix[0] - matrix[1], sunCoord[1] + matrix[4] - matrix[5], sunCoord[2] + matrix[8] - matrix[9]);glTexCoord2f(1.0f, 1.0f);glVertex3f(sunCoord[0] + matrix[0] + matrix[1], sunCoord[1] + matrix[4] + matrix[5], sunCoord[2] + matrix[8] + matrix[9]);glTexCoord2f(0.0f, 1.0f);glVertex3f(sunCoord[0] - matrix[0] + matrix[1], sunCoord[1] - matrix[4] + matrix[5], sunCoord[2] - matrix[8] + matrix[9]);glEnd();;  Works great now thanks! Heres a sky screenshot (no sun sorry, didn't want to take another pic). EDIT: fixed link--===LITHIC===----===WWW.Decimation.TK===--   [edited by - Lithic on February 9, 2004 12:27:34 AM];  Aww... but I want a sun...   "Remember:  Silly is a state of Mind, Stupid is a way of Life." -- Dave Butler