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/* $Id: texwrap.c,v 1.2 2001/04/12 20:50:26 brianp Exp $ */
/*
* Test texture wrap modes.
* Press 'b' to toggle texture image borders. You should see the same
* rendering whether or not you're using borders.
*
* Brian Paul March 2001
*/
#define GL_GLEXT_PROTOTYPES
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
#ifndef GL_CLAMP_TO_BORDER_ARB
#define GL_CLAMP_TO_BORDER_ARB 0x812D
#endif
#define BORDER_TEXTURE 1
#define NO_BORDER_TEXTURE 2
#define SIZE 8
static GLubyte BorderImage[SIZE+2][SIZE+2][4];
static GLubyte NoBorderImage[SIZE][SIZE][4];
static GLuint Border = 1;
static void
PrintString(const char *s)
{
while (*s) {
glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
s++;
}
}
static void Display( void )
{
static const GLenum modes[] = {
GL_REPEAT,
GL_CLAMP,
GL_CLAMP_TO_EDGE,
GL_CLAMP_TO_BORDER_ARB
};
static const char *names[] = {
"GL_REPEAT",
"GL_CLAMP",
"GL_CLAMP_TO_EDGE",
"GL_CLAMP_TO_BORDER_ARB"
};
GLint i, j;
GLint numModes;
numModes = glutExtensionSupported("GL_ARB_texture_border_clamp") ? 4 : 3;
glClearColor(0.5, 0.5, 0.5, 1.0);
glClear( GL_COLOR_BUFFER_BIT );
#if 0
/* draw texture as image */
glDisable(GL_TEXTURE_2D);
glWindowPos2iMESA(1, 1);
glDrawPixels(6, 6, GL_RGBA, GL_UNSIGNED_BYTE, (void *) TexImage);
#endif
glBindTexture(GL_TEXTURE_2D, Border ? BORDER_TEXTURE : NO_BORDER_TEXTURE);
/* loop over min/mag filters */
for (i = 0; i < 2; i++) {
if (i) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}
else {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}
/* loop over border modes */
for (j = 0; j < numModes; j++) {
const GLfloat x0 = 0, y0 = 0, x1 = 140, y1 = 140;
const GLfloat b = 0.2;
const GLfloat s0 = -b, t0 = -b, s1 = 1.0+b, t1 = 1.0+b;
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, modes[j]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, modes[j]);
glPushMatrix();
glTranslatef(j * 150 + 10, i * 150 + 25, 0);
glEnable(GL_TEXTURE_2D);
glColor3f(1, 1, 1);
glBegin(GL_POLYGON);
glTexCoord2f(s0, t0); glVertex2f(x0, y0);
glTexCoord2f(s1, t0); glVertex2f(x1, y0);
glTexCoord2f(s1, t1); glVertex2f(x1, y1);
glTexCoord2f(s0, t1); glVertex2f(x0, y1);
glEnd();
/* draw red outline showing bounds of texture at s=0,1 and t=0,1 */
glDisable(GL_TEXTURE_2D);
glColor3f(1, 0, 0);
glBegin(GL_LINE_LOOP);
glVertex2f(x0 + b * (x1-x0) / (s1-s0), y0 + b * (y1-y0) / (t1-t0));
glVertex2f(x1 - b * (x1-x0) / (s1-s0), y0 + b * (y1-y0) / (t1-t0));
glVertex2f(x1 - b * (x1-x0) / (s1-s0), y1 - b * (y1-y0) / (t1-t0));
glVertex2f(x0 + b * (x1-x0) / (s1-s0), y1 - b * (y1-y0) / (t1-t0));
glEnd();
glPopMatrix();
}
}
glDisable(GL_TEXTURE_2D);
glColor3f(1, 1, 1);
for (i = 0; i < numModes; i++) {
glWindowPos2iMESA( i * 150 + 10, 5);
PrintString(names[i]);
}
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho(0, width, 0, height, -1, 1);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 'b':
Border = !Border;
printf("Texture Border Size = %d\n", Border);
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void Init( void )
{
static const GLubyte border[4] = { 0, 255, 0, 255 };
static const GLfloat borderf[4] = { 0, 1.0, 0, 1.0 };
GLint i, j;
for (i = 0; i < SIZE+2; i++) {
for (j = 0; j < SIZE+2; j++) {
if (i == 0 || j == 0 || i == SIZE+1 || j == SIZE+1) {
/* border color */
BorderImage[i][j][0] = border[0];
BorderImage[i][j][1] = border[1];
BorderImage[i][j][2] = border[2];
BorderImage[i][j][3] = border[3];
}
else if ((i + j) & 1) {
/* white */
BorderImage[i][j][0] = 255;
BorderImage[i][j][1] = 255;
BorderImage[i][j][2] = 255;
BorderImage[i][j][3] = 255;
}
else {
/* black */
BorderImage[i][j][0] = 0;
BorderImage[i][j][1] = 0;
BorderImage[i][j][2] = 0;
BorderImage[i][j][3] = 0;
}
}
}
glBindTexture(GL_TEXTURE_2D, BORDER_TEXTURE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, SIZE+2, SIZE+2, 1,
GL_RGBA, GL_UNSIGNED_BYTE, (void *) BorderImage);
for (i = 0; i < SIZE; i++) {
for (j = 0; j < SIZE; j++) {
if ((i + j) & 1) {
/* white */
NoBorderImage[i][j][0] = 255;
NoBorderImage[i][j][1] = 255;
NoBorderImage[i][j][2] = 255;
NoBorderImage[i][j][3] = 255;
}
else {
/* black */
NoBorderImage[i][j][0] = 0;
NoBorderImage[i][j][1] = 0;
NoBorderImage[i][j][2] = 0;
NoBorderImage[i][j][3] = 0;
}
}
}
glBindTexture(GL_TEXTURE_2D, NO_BORDER_TEXTURE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, SIZE, SIZE, 0,
GL_RGBA, GL_UNSIGNED_BYTE, (void *) NoBorderImage);
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderf);
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 650, 340 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Display );
Init();
glutMainLoop();
return 0;
}
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