I posted about 2 weeks ago trying to find a solution to quads being broken into triangles when texturing. Because quads are broken into triangles, a "line" exists on the shared edge of the triangles. I do not want a perspective texture, rather, the checkerboard texture I apply to the quad should be evenly spaced along the borders of the quad (i.e. each square along an edge should have the same width). I have included some sample code this time (most of which was taken from the OpenGL Programming Guide) - I am working in Linux: #include #include #include #define checkImageWidth 64 #define checkImageHeight 64 static GLubyte checkImage[checkImageHeight][checkImageWidth][4]; static GLubyte otherImage[checkImageHeight][checkImageWidth][4]; static GLuint texName[2]; void makeCheckImages(void) { int i, j, c; for(i=0; i[j][0] = (GLubyte) c; checkImage[j][1] = (GLubyte) c; checkImage[j][2] = (GLubyte) c; checkImage[j][3] = 255; c = (((i&0x10)==0)^((j&0x10)==0))*255; otherImage[j][0] = (GLubyte) c; otherImage[j][1] = (GLubyte) 0; otherImage[j][2] = (GLubyte) 0; otherImage[j][3] = 255; } } } void init(void) { glClearColor(0.0, 0.0, 0.0, 0.0); glShadeModel(GL_FLAT); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LESS); glClearDepth(1.0); makeCheckImages(); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glGenTextures(2, texName); glBindTexture(GL_TEXTURE_2D, texName[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage); glBindTexture(GL_TEXTURE_2D, texName[1]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage); glEnable(GL_TEXTURE_2D); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-3.0, 3.0, -3.0, 3.0, -3.0, 3.0); } void display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glBindTexture(GL_TEXTURE_2D, texName[0]); glBegin(GL_QUADS); glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, -1.0, 0.0); glTexCoord2f(0.0, 1.0); glVertex3f(-2.0, 1.0, 0.0); glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 1.0, 0.0); glTexCoord2f(1.0, 0.0); glVertex3f(0.0, -1.0, 0.0); glEnd(); glBindTexture(GL_TEXTURE_2D, texName[1]); glBegin(GL_QUADS); glTexCoord2f(0.0, 0.0); glVertex3f(1.5, -1.0, 0.0); glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0); glTexCoord2f(1.0, 1.0); glVertex3f(0.5, 1.0, 0.0); glTexCoord2f(1.0, 0.0); glVertex3f(0.5, -1.0, 0.0); glEnd(); glFlush(); } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(700, 700); glutInitWindowPosition(100, 100); glutCreateWindow("hello"); init(); glutDisplayFunc(display); glutMainLoop(); return 0; } Thanks </i>

Sorry about the code thing...

I replaced GL_FLAT with GL_SMOOTH and still get the same problem.

Using floats did not change the results.

I have posted a better description of my problem at

http://www-viz.tamu.edu/students/kevbogsp/quadtexture.html

This is a rough page with a few images I threw together. Can you let me know if my reasoning is correct and if there is a way to fix it?

Thanks