/* Exercise 1D textures */ #include <assert.h> #include <math.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include "GL/glut.h" static GLuint Window = 0; static GLuint TexObj[2]; static GLfloat Angle = 0.0f; static void draw( void ) { glClear( GL_COLOR_BUFFER_BIT ); glColor3f( 1.0, 1.0, 1.0 ); /* draw first polygon */ glPushMatrix(); glTranslatef( -1.0, 0.0, 0.0 ); glRotatef( Angle, 0.0, 0.0, 1.0 ); glBindTexture( GL_TEXTURE_1D, TexObj[0] ); glBegin( GL_POLYGON ); glTexCoord1f( 0.0 ); glVertex2f( -1.0, -1.0 ); glTexCoord1f( 1.0 ); glVertex2f( 1.0, -1.0 ); glTexCoord1f( 1.0 ); glVertex2f( 1.0, 1.0 ); glTexCoord1f( 0.0 ); glVertex2f( -1.0, 1.0 ); glEnd(); glPopMatrix(); glutSwapBuffers(); } static void idle( void ) { Angle += 2.0; glutPostRedisplay(); } /* change view Angle, exit upon ESC */ static void key(unsigned char k, int x, int y) { (void) x; (void) y; switch (k) { case 27: exit(0); } } /* new window size or exposure */ static void reshape( int width, int height ) { glViewport(0, 0, (GLint)width, (GLint)height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); /* glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/ glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 ); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef( 0.0, 0.0, -8.0 ); } static void init( void ) { GLubyte tex[256][3]; GLint i; glDisable( GL_DITHER ); /* Setup texturing */ glEnable( GL_TEXTURE_1D ); glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL ); /* generate texture object IDs */ glGenTextures( 2, TexObj ); /* setup first texture object */ glBindTexture( GL_TEXTURE_1D, TexObj[0] ); for (i = 0; i < 256; i++) { GLfloat f; /* map 0..255 to -PI .. PI */ f = ((i / 255.0) - .5) * (3.141592 * 2); f = sin(f); /* map -1..1 to 0..255 */ tex[i][0] = (f+1.0)/2.0 * 255.0; tex[i][1] = 0; tex[i][2] = 0; } glTexImage1D( GL_TEXTURE_1D, 0, 3, 256, 0, GL_RGB, GL_UNSIGNED_BYTE, tex ); glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT ); glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_REPEAT ); } int main( int argc, char *argv[] ) { glutInit(&argc, argv); glutInitWindowPosition(0, 0); glutInitWindowSize(300, 300); glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE ); Window = glutCreateWindow("Texture Objects"); if (!Window) { exit(1); } init(); glutReshapeFunc( reshape ); glutKeyboardFunc( key ); /* glutIdleFunc( idle ); */ glutDisplayFunc( draw ); glutMainLoop(); return 0; }