[Mesa-dev] [Mesa-bug] Mesa 3.1 bug?: glDrawRangeElements with GL_LINES

[Scott McMillan]

Attached is a test program that renders an indexed GL_LINES
primitive using both glDrawElements and glDrawRangeElements
(selected by pressing the 'v' key).  There seems to be a
problem with glDrawRangeElements when the (min, max) range is
(0, 1) and I am only drawing one line. If I increase the max
range it seems to have no problem (even though I am still only
rendering the first line.

scott

P.S. Happy New Year everyone.

-- 
Scott McMillan                        mailto:[EMAIL PROTECTED]
Cambridge Research Associates         http://www.cambridge.com
1430 Spring Hill Road, Ste. 200       Voice: (703) 790-0505 x7235
McLean, VA 22102                      Fax:   (703) 790-0370
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>

int vertex_arrays_flag = 1;
GLfloat vertices[8][3] = {{-3, 1, -10},
                          {-3,-1, -10},
                          {-1, 1, -10},
                          {-1,-1, -10},
                          { 1, 1, -10},
                          { 1,-1, -10},
                          { 3, 1, -10},
                          { 3,-1, -10}};

unsigned int indices[8] = {0,1,2,3,4,5,6,7};

void init(void)
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glPolygonMode(GL_FRONT, GL_LINE);
}

float num = 3.0;

void display(void)
{
    int i;
    glClear(GL_COLOR_BUFFER_BIT);

    if (vertex_arrays_flag == 1)
    {
       glEnableClientState(GL_VERTEX_ARRAY);
       glVertexPointer(3, GL_FLOAT, 0, vertices);
       glDrawRangeElements(GL_LINES,
                           0,
                           1,   /* HERE: Change this to 7 and things work */
                           2, GL_UNSIGNED_INT, indices);
       glDisableClientState(GL_VERTEX_ARRAY);
    }
    else
    {
       glEnableClientState(GL_VERTEX_ARRAY);
       glVertexPointer(3, GL_FLOAT, 0, vertices);
       glDrawElements(GL_LINES, 2, GL_UNSIGNED_INT, indices);
       glDisableClientState(GL_VERTEX_ARRAY);
    }

    glutSwapBuffers();
}

void reshape(int w, int h)
{
    glViewport(0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, (GLfloat)w/(GLfloat)h, 1.0, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
    switch (key)
    {
       case 27:
          exit(0);
          break;

       case 'v':
          vertex_arrays_flag = 1 - vertex_arrays_flag;
          fprintf(stderr, "Using glDrawRangeElements: %d\n",
                  vertex_arrays_flag);
          break;
    }
}

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(50,50);
    glutCreateWindow(argv[0]);
    init();
    glutDisplayFunc(display);
    glutIdleFunc(display);
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
    glutMainLoop();
    return 0;
}