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/* Exercise 1D textures
*/
#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "glad/glad.h"
#include "glut_wrap.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");
gladLoadGL();
if (!Window) {
exit(1);
}
init();
glutReshapeFunc( reshape );
glutKeyboardFunc( key );
/* glutIdleFunc( idle ); */
glutDisplayFunc( draw );
glutMainLoop();
return 0;
}
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