[Mesa-dev] [Mesa-bug] Texture object/vertex array bug in Mesa 3.1b3

[Scott McMillan]

While I can texture an polygon using a texture object with
the traditional approach: glBegin(GL_TRIANGLE_STRIP)....glEnd(),
Mesa 3.1b3 gets it wrong when I use a texture object with
an equivalent glVertexArray approach as shown in the attached
program (press any key but ESC to toggle between modes).

-- 
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 <stdlib.h>
#include <stdio.h>

#define checkImageSize 64

static GLubyte checkImage[checkImageSize][checkImageSize][4];
static GLuint texName;
int vertex_arrays_flag = 1;

void makeCheckImage(void)
{
    int i,j;
    GLubyte c;
    for (i=0; i<checkImageSize; i++)
    {
        for (j=0; j<checkImageSize; j++)
        {
            c = 255;
            if ((i&0x8) != (j&0x8)) c = 100;
            checkImage[i][j][0] = c;
            checkImage[i][j][1] = c;
            checkImage[i][j][2] = c;
            checkImage[i][j][3] = 255;
        }
    }
}


void init(void)
{
    glClearColor(0.0, 0.0, 0.0, 0.0);

    makeCheckImage();

    glGenTextures(1, &texName);
    glBindTexture(GL_TEXTURE_2D, texName);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    /* Changing wrap modes alters vertex array rendering */
    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,
                 checkImageSize, checkImageSize, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, checkImage);

    glEnable(GL_TEXTURE_2D);
}

GLfloat vertices[4][3] = {{-2, 2, -10},
                          {-2,-2, -10},
                          { 2, 2, -10},
                          { 2,-2, -10}};
GLfloat texcoords[4][2] = {{0, 1},
                           {0, 0},
                           {1, 1},
                           {1, 0}};

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

    if (vertex_arrays_flag == 0)
    {
       glBegin(GL_TRIANGLE_STRIP);
       for (i=0; i<4; i++)
       {
          glTexCoord2fv(texcoords[i]); glVertex3fv(vertices[i]);
       }
       glEnd();
    }
    else
    {
       glEnableClientState(GL_VERTEX_ARRAY);
       glEnableClientState(GL_TEXTURE_COORD_ARRAY);
       glVertexPointer(3, GL_FLOAT, 0, vertices);
       glTexCoordPointer(2, GL_FLOAT, 0, texcoords);
       glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
       glDisableClientState(GL_VERTEX_ARRAY);
       glDisableClientState(GL_TEXTURE_COORD_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;
        default:
            vertex_arrays_flag = 1 - vertex_arrays_flag;
            fprintf(stderr, "Using vertex arrays: %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;
}