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/*
* Test texture compression.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <GL/glew.h>
#include <GL/glut.h>
#include "texcomp_image.h"
static int ImgWidth = 512;
static int ImgHeight = 512;
static GLenum CompFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
static GLfloat EyeDist = 5.0;
static GLfloat Rot = 0.0;
const GLenum Target = GL_TEXTURE_2D;
static void
CheckError(int line)
{
GLenum err = glGetError();
if (err) {
printf("GL Error %d at line %d\n", (int) err, line);
}
}
static void
LoadCompressedImage(void)
{
unsigned char ImgDataTemp[ImgSize / 4];
unsigned i;
const GLenum filter = GL_LINEAR;
glTexImage2D(Target, 0, CompFormat, ImgWidth, ImgHeight, 0,
GL_RGB, GL_UNSIGNED_BYTE, NULL);
/* bottom half */
glCompressedTexSubImage2DARB(Target, 0,
0, 0, /* pos */
ImgWidth, ImgHeight / 2,
CompFormat, ImgSize / 2, ImgData + ImgSize / 2);
/* top left */
for (i = 0; i < ImgHeight / 8; i++) {
memcpy(&ImgDataTemp[i * ImgWidth], &ImgData[i * 2 * ImgWidth], ImgWidth);
}
glCompressedTexSubImage2DARB(Target, 0,
0, ImgHeight / 2, /* pos */
ImgWidth / 2, ImgHeight / 2,
CompFormat, ImgSize / 4, ImgDataTemp);
/* top right */
for (i = 0; i < ImgHeight / 8; i++) {
memcpy(&ImgDataTemp[i * ImgWidth], &ImgData[i * 2 * ImgWidth + ImgWidth], ImgWidth);
}
glCompressedTexSubImage2DARB(Target, 0,
ImgWidth / 2, ImgHeight / 2, /* pos */
ImgWidth / 2, ImgHeight / 2,
CompFormat, ImgSize / 4, ImgDataTemp);
glTexParameteri(Target, GL_TEXTURE_MIN_FILTER, filter);
glTexParameteri(Target, GL_TEXTURE_MAG_FILTER, filter);
}
static void
Init()
{
GLint numFormats, formats[100];
GLint p;
if (!glutExtensionSupported("GL_ARB_texture_compression")) {
printf("Sorry, GL_ARB_texture_compression is required.\n");
exit(1);
}
if (!glutExtensionSupported("GL_EXT_texture_compression_s3tc")) {
printf("Sorry, GL_EXT_texture_compression_s3tc is required.\n");
exit(1);
}
printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
glGetIntegerv(GL_NUM_COMPRESSED_TEXTURE_FORMATS_ARB, &numFormats);
glGetIntegerv(GL_COMPRESSED_TEXTURE_FORMATS_ARB, formats);
printf("%d supported compression formats: ", numFormats);
for (p = 0; p < numFormats; p++)
printf("0x%x ", formats[p]);
printf("\n");
glEnable(GL_TEXTURE_2D);
LoadCompressedImage();
}
static void
Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum(-1, 1, -1, 1, 4, 100);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
static void
Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 'd':
EyeDist -= 1.0;
if (EyeDist < 4.0)
EyeDist = 4.0;
break;
case 'D':
EyeDist += 1.0;
break;
case 'z':
Rot += 5.0;
break;
case 'Z':
Rot -= 5.0;
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void
Draw( void )
{
glClearColor(0.3, 0.3, .8, 0);
glClear(GL_COLOR_BUFFER_BIT);
CheckError(__LINE__);
glPushMatrix();
glTranslatef(0, 0, -(EyeDist+0.01));
glRotatef(Rot, 0, 0, 1);
glBegin(GL_POLYGON);
glTexCoord2f(0, 0); glVertex2f(-1, -1);
glTexCoord2f(1, 0); glVertex2f( 1, -1);
glTexCoord2f(1, 1); glVertex2f( 1, 1);
glTexCoord2f(0, 1); glVertex2f(-1, 1);
glEnd();
glPopMatrix();
glutSwapBuffers();
}
int
main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowSize( 600, 600 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE);
glutCreateWindow(argv[0]);
glewInit();
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutDisplayFunc( Draw );
Init();
glutMainLoop();
return 0;
}
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