272 lines
7.1 KiB
C
272 lines
7.1 KiB
C
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/*
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* Paletted texture demo. Written by Brian Paul.
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* This program is in the public domain.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#ifdef _WIN32
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#include <windows.h>
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#endif
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#include <GL/glew.h>
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#include <GL/glut.h>
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static float Rot = 0.0;
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static GLboolean Anim = 1;
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static void Idle( void )
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{
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float t = glutGet(GLUT_ELAPSED_TIME) * 0.001; /* in seconds */
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Rot = t * 360 / 4; /* 1 rotation per 4 seconds */
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glutPostRedisplay();
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}
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static void Display( void )
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{
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/* draw background gradient */
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glDisable(GL_TEXTURE_2D);
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glBegin(GL_POLYGON);
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glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
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glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
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glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5, 1.0);
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glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5, 1.0);
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glEnd();
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glPushMatrix();
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glRotatef(Rot, 0, 0, 1);
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glEnable(GL_TEXTURE_2D);
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glBegin(GL_POLYGON);
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glTexCoord2f(0, 1); glVertex2f(-1, -0.5);
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glTexCoord2f(1, 1); glVertex2f( 1, -0.5);
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glTexCoord2f(1, 0); glVertex2f( 1, 0.5);
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glTexCoord2f(0, 0); glVertex2f(-1, 0.5);
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glEnd();
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glPopMatrix();
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glutSwapBuffers();
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}
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static void Reshape( int width, int height )
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{
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glViewport( 0, 0, width, height );
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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}
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static void Key( unsigned char key, int x, int y )
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{
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(void) x;
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(void) y;
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switch (key) {
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case 27:
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exit(0);
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break;
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case 's':
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Rot += 0.5;
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break;
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case ' ':
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Anim = !Anim;
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if (Anim)
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glutIdleFunc( Idle );
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else
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glutIdleFunc( NULL );
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break;
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}
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glutPostRedisplay();
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}
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static void Init( void )
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{
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#define HEIGHT 8
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#define WIDTH 32
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/* 257 = HEIGHT * WIDTH + 1 (for trailing '\0') */
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static char texture[257] = {"\
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\
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MMM EEEE SSS AAA \
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M M M E S S A A \
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M M M EEEE SS A A \
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M M M E SS AAAAA \
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M M E S S A A \
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M M EEEE SSS A A \
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"
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};
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GLubyte table[256][4];
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if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
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printf("Sorry, GL_EXT_paletted_texture not supported\n");
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exit(0);
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}
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/* load the color table for each texel-index */
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memset(table, 0, 256*4);
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table[' '][0] = 255;
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table[' '][1] = 255;
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table[' '][2] = 255;
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table[' '][3] = 64;
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table['M'][0] = 255;
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table['M'][1] = 0;
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table['M'][2] = 0;
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table['M'][3] = 255;
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table['E'][0] = 0;
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table['E'][1] = 255;
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table['E'][2] = 0;
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table['E'][3] = 255;
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table['S'][0] = 0;
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table['S'][1] = 0;
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table['S'][2] = 255;
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table['S'][3] = 255;
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table['A'][0] = 255;
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table['A'][1] = 255;
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table['A'][2] = 0;
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table['A'][3] = 255;
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#ifdef GL_EXT_paletted_texture
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#if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
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printf("Using shared palette\n");
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glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT, /* target */
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GL_RGBA, /* internal format */
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256, /* table size */
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GL_RGBA, /* table format */
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GL_UNSIGNED_BYTE, /* table type */
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table); /* the color table */
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glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
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#else
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glColorTableEXT(GL_TEXTURE_2D, /* target */
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GL_RGBA, /* internal format */
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256, /* table size */
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GL_RGBA, /* table format */
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GL_UNSIGNED_BYTE, /* table type */
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table); /* the color table */
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#endif
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glTexImage2D(GL_TEXTURE_2D, /* target */
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0, /* level */
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GL_COLOR_INDEX8_EXT, /* internal format */
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WIDTH, HEIGHT, /* width, height */
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0, /* border */
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GL_COLOR_INDEX, /* texture format */
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GL_UNSIGNED_BYTE, /* texture type */
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texture); /* the texture */
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#endif
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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#undef HEIGHT
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#undef WIDTH
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}
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/*
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* Color ramp test
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*/
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static void Init2( void )
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{
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#define HEIGHT 32
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#define WIDTH 256
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static char texture[HEIGHT][WIDTH];
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GLubyte table[256][4];
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int i, j;
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if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
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printf("Sorry, GL_EXT_paletted_texture not supported\n");
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exit(0);
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}
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for (j = 0; j < HEIGHT; j++) {
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for (i = 0; i < WIDTH; i++) {
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texture[j][i] = i;
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}
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}
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for (i = 0; i < 255; i++) {
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table[i][0] = i;
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table[i][1] = 0;
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table[i][2] = 0;
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table[i][3] = 255;
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}
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#ifdef GL_EXT_paletted_texture
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#if defined(GL_EXT_shared_texture_palette) && defined(USE_SHARED_PALETTE)
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printf("Using shared palette\n");
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glColorTableEXT(GL_SHARED_TEXTURE_PALETTE_EXT, /* target */
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GL_RGBA, /* internal format */
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256, /* table size */
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GL_RGBA, /* table format */
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GL_UNSIGNED_BYTE, /* table type */
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table); /* the color table */
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glEnable(GL_SHARED_TEXTURE_PALETTE_EXT);
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#else
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glColorTableEXT(GL_TEXTURE_2D, /* target */
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GL_RGBA, /* internal format */
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256, /* table size */
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GL_RGBA, /* table format */
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GL_UNSIGNED_BYTE, /* table type */
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table); /* the color table */
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#endif
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glTexImage2D(GL_TEXTURE_2D, /* target */
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0, /* level */
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GL_COLOR_INDEX8_EXT, /* internal format */
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WIDTH, HEIGHT, /* width, height */
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0, /* border */
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GL_COLOR_INDEX, /* texture format */
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GL_UNSIGNED_BYTE, /* texture type */
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texture); /* teh texture */
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#endif
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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}
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int main( int argc, char *argv[] )
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{
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glutInit( &argc, argv );
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glutInitWindowPosition( 0, 0 );
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glutInitWindowSize( 400, 300 );
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glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
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glutCreateWindow(argv[0]);
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glewInit();
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Init();
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(void) Init2; /* silence warning */
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glutReshapeFunc( Reshape );
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glutKeyboardFunc( Key );
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glutDisplayFunc( Display );
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if (Anim)
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glutIdleFunc( Idle );
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glutMainLoop();
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return 0;
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}
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