--- /dev/null
+/*
+ * Compressed texture demo. Written by Daniel Borca.
+ * This program is in the public domain.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+#define GL_GLEXT_PROTOTYPES 1
+#include <GL/glut.h>
+
+#include "readtex.c" /* I know, this is a hack. */
+#define TEXTURE_FILE "../images/tree2.rgba"
+
+
+static float Rot = 0.0;
+static GLboolean Anim = 1;
+
+typedef struct {
+ GLubyte *data;
+ GLuint size;
+ GLenum format;
+ GLuint w, h;
+
+ GLenum TC;
+
+ GLubyte *cData;
+ GLuint cSize;
+ GLenum cFormat;
+} TEXTURE;
+
+static TEXTURE *Tx, t1, t2, t3;
+static GLboolean fxt1, dxtc, s3tc;
+
+
+static const char *TextureName (GLenum TC)
+{
+ switch (TC) {
+ case GL_RGBA:
+ return "RGBA";
+ case GL_COMPRESSED_RGB:
+ return "COMPRESSED_RGB";
+ case GL_COMPRESSED_RGBA:
+ return "COMPRESSED_RGBA";
+ case GL_COMPRESSED_RGB_FXT1_3DFX:
+ return "GL_COMPRESSED_RGB_FXT1_3DFX";
+ case GL_COMPRESSED_RGBA_FXT1_3DFX:
+ return "GL_COMPRESSED_RGBA_FXT1_3DFX";
+ case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+ return "GL_COMPRESSED_RGB_S3TC_DXT1_EXT";
+ case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+ return "GL_COMPRESSED_RGBA_S3TC_DXT1_EXT";
+ case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+ return "GL_COMPRESSED_RGBA_S3TC_DXT3_EXT";
+ case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+ return "GL_COMPRESSED_RGBA_S3TC_DXT5_EXT";
+ case GL_RGB_S3TC:
+ return "GL_RGB_S3TC";
+ case GL_RGB4_S3TC:
+ return "GL_RGB4_S3TC";
+ case GL_RGBA_S3TC:
+ return "GL_RGBA_S3TC";
+ case GL_RGBA4_S3TC:
+ return "GL_RGBA4_S3TC";
+ default:
+ return "?";
+ }
+}
+
+
+static void
+PrintString(const char *s)
+{
+ while (*s) {
+ glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+ s++;
+ }
+}
+
+
+static void Idle( void )
+{
+ float t = glutGet(GLUT_ELAPSED_TIME) * 0.001; /* in seconds */
+ Rot = t * 360 / 4; /* 1 rotation per 4 seconds */
+ glutPostRedisplay();
+}
+
+
+static void Display( void )
+{
+ /* draw background gradient */
+ glDisable(GL_TEXTURE_2D);
+ glBegin(GL_POLYGON);
+ glColor3f(1.0, 0.0, 0.2); glVertex2f(-1.5, -1.0);
+ glColor3f(1.0, 0.0, 0.2); glVertex2f( 1.5, -1.0);
+ glColor3f(0.0, 0.0, 1.0); glVertex2f( 1.5, 1.0);
+ glColor3f(0.0, 0.0, 1.0); glVertex2f(-1.5, 1.0);
+ glEnd();
+
+ glPushMatrix();
+ glRotatef(Rot, 0, 0, 1);
+
+ glEnable(GL_TEXTURE_2D);
+ glBegin(GL_POLYGON);
+ glTexCoord2f(0, 1); glVertex2f(-1, -0.5);
+ glTexCoord2f(1, 1); glVertex2f( 1, -0.5);
+ glTexCoord2f(1, 0); glVertex2f( 1, 0.5);
+ glTexCoord2f(0, 0); glVertex2f(-1, 0.5);
+ glEnd();
+
+ glPopMatrix();
+
+ /* info */
+ glColor4f(1, 1, 1, 1);
+
+ glRasterPos3f(-1.2, -0.7, 0);
+ PrintString("Selected: ");
+ PrintString(TextureName(Tx->TC));
+ if (Tx->cData) {
+ char tmp[64];
+ glRasterPos3f(-1.2, -0.8, 0);
+ PrintString("Internal: ");
+ PrintString(TextureName(Tx->cFormat));
+ glRasterPos3f(-1.2, -0.9, 0);
+ PrintString("Size : ");
+ sprintf(tmp, "%d (%d%% of %d)", Tx->cSize, Tx->cSize * 100 / Tx->size, Tx->size);
+ PrintString(tmp);
+ }
+
+ glutSwapBuffers();
+}
+
+
+static void Reshape( int width, int height )
+{
+ glViewport( 0, 0, width, height );
+ glMatrixMode( GL_PROJECTION );
+ glLoadIdentity();
+ glOrtho( -1.5, 1.5, -1.0, 1.0, -1.0, 1.0 );
+ glMatrixMode( GL_MODELVIEW );
+ glLoadIdentity();
+}
+
+
+static void ReInit( GLenum TC, TEXTURE *Tx )
+{
+ GLint rv;
+
+ if ((Tx->TC == TC) && (Tx->cData != NULL)) {
+ glCompressedTexImage2DARB(GL_TEXTURE_2D, /* target */
+ 0, /* level */
+ Tx->cFormat, /* real format */
+ Tx->w, /* original width */
+ Tx->h, /* original height */
+ 0, /* border */
+ Tx->cSize, /* compressed size*/
+ Tx->cData); /* compressed data*/
+ } else {
+ glTexImage2D(GL_TEXTURE_2D, /* target */
+ 0, /* level */
+ TC, /* internal format */
+ Tx->w, Tx->h, /* width, height */
+ 0, /* border */
+ Tx->format, /* texture format */
+ GL_UNSIGNED_BYTE, /* texture type */
+ Tx->data); /* the texture */
+
+ /* okay, now cache the compressed texture */
+ Tx->TC = TC;
+ if (Tx->cData != NULL) {
+ free(Tx->cData);
+ Tx->cData = NULL;
+ }
+ glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_ARB, &rv);
+ if (rv) {
+ glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, (GLint *)&Tx->cFormat);
+ glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_COMPRESSED_IMAGE_SIZE_ARB, (GLint *)&Tx->cSize);
+ if ((Tx->cData = malloc(Tx->cSize)) != NULL) {
+ glGetCompressedTexImageARB(GL_TEXTURE_2D, 0, Tx->cData);
+ }
+ }
+ }
+}
+
+
+static void Init( void )
+{
+ /* HEIGHT * WIDTH + 1 (for trailing '\0') */
+ static char pattern[8 * 32 + 1] = {"\
+ \
+ MMM EEEE SSS AAA \
+ M M M E S S A A \
+ M M M EEEE SS A A \
+ M M M E SS AAAAA \
+ M M E S S A A \
+ M M EEEE SSS A A \
+ "
+ };
+
+ GLuint i, j;
+
+ GLubyte (*texture1)[8 * 32][4];
+ GLubyte (*texture2)[256][256][4];
+
+ t1.w = 32;
+ t1.h = 8;
+ t1.size = t1.w * t1.h * 4;
+ t1.data = malloc(t1.size);
+ t1.format = GL_RGBA;
+ t1.TC = GL_RGBA;
+
+ texture1 = (GLubyte (*)[8 * 32][4])t1.data;
+ for (i = 0; i < sizeof(pattern) - 1; i++) {
+ switch (pattern[i]) {
+ default:
+ case ' ':
+ (*texture1)[i][0] = 255;
+ (*texture1)[i][1] = 255;
+ (*texture1)[i][2] = 255;
+ (*texture1)[i][3] = 64;
+ break;
+ case 'M':
+ (*texture1)[i][0] = 255;
+ (*texture1)[i][1] = 0;
+ (*texture1)[i][2] = 0;
+ (*texture1)[i][3] = 255;
+ break;
+ case 'E':
+ (*texture1)[i][0] = 0;
+ (*texture1)[i][1] = 255;
+ (*texture1)[i][2] = 0;
+ (*texture1)[i][3] = 255;
+ break;
+ case 'S':
+ (*texture1)[i][0] = 0;
+ (*texture1)[i][1] = 0;
+ (*texture1)[i][2] = 255;
+ (*texture1)[i][3] = 255;
+ break;
+ case 'A':
+ (*texture1)[i][0] = 255;
+ (*texture1)[i][1] = 255;
+ (*texture1)[i][2] = 0;
+ (*texture1)[i][3] = 255;
+ break;
+ }
+ }
+
+ t2.w = 256;
+ t2.h = 256;
+ t2.size = t2.w * t2.h * 4;
+ t2.data = malloc(t2.size);
+ t2.format = GL_RGBA;
+ t2.TC = GL_RGBA;
+
+ texture2 = (GLubyte (*)[256][256][4])t2.data;
+ for (j = 0; j < t2.h; j++) {
+ for (i = 0; i < t2.w; i++) {
+ (*texture2)[j][i][0] = sqrt(i * j * 255 * 255 / (t2.w * t2.h));
+ (*texture2)[j][i][1] = 0;
+ (*texture2)[j][i][2] = 0;
+ (*texture2)[j][i][3] = 255;
+ }
+ }
+
+ t3.data = LoadRGBImage(TEXTURE_FILE, (GLint *)&t3.w, (GLint *)&t3.h, &t3.format);
+ t3.size = t3.w * t3.h * ((t3.format == GL_RGB) ? 3 : 4);
+ t3.TC = GL_RGBA;
+
+ ReInit(GL_RGBA, Tx = &t1);
+
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
+ glEnable(GL_TEXTURE_2D);
+
+ glEnable(GL_BLEND);
+ glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+}
+
+
+static void Key( unsigned char key, int x, int y )
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 27:
+ exit(0);
+ break;
+ case ' ':
+ Anim = !Anim;
+ if (Anim)
+ glutIdleFunc( Idle );
+ else
+ glutIdleFunc( NULL );
+ break;
+ case 't':
+ if (Tx == &t1) {
+ Tx = &t2;
+ } else if (Tx == &t2) {
+ Tx = &t3;
+ } else {
+ Tx = &t1;
+ }
+ ReInit(Tx->TC, Tx);
+ break;
+ case '0':
+ ReInit(GL_RGBA, Tx);
+ break;
+ case '1':
+ ReInit(GL_COMPRESSED_RGB, Tx);
+ break;
+ case '2':
+ ReInit(GL_COMPRESSED_RGBA, Tx);
+ break;
+ case '3':
+ if (fxt1) ReInit(GL_COMPRESSED_RGB_FXT1_3DFX, Tx);
+ break;
+ case '4':
+ if (fxt1) ReInit(GL_COMPRESSED_RGBA_FXT1_3DFX, Tx);
+ break;
+ case '5':
+ if (dxtc) ReInit(GL_COMPRESSED_RGB_S3TC_DXT1_EXT, Tx);
+ break;
+ case '6':
+ if (dxtc) ReInit(GL_COMPRESSED_RGBA_S3TC_DXT1_EXT, Tx);
+ break;
+ case '7':
+ if (dxtc) ReInit(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT, Tx);
+ break;
+ case '8':
+ if (dxtc) ReInit(GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, Tx);
+ break;
+ case 'a':
+ if (s3tc) ReInit(GL_RGB_S3TC, Tx);
+ break;
+ case 's':
+ if (s3tc) ReInit(GL_RGB4_S3TC, Tx);
+ break;
+ case 'd':
+ if (s3tc) ReInit(GL_RGBA_S3TC, Tx);
+ break;
+ case 'f':
+ if (s3tc) ReInit(GL_RGBA4_S3TC, Tx);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+int main( int argc, char *argv[] )
+{
+ glutInit( &argc, argv );
+ glutInitWindowPosition( 0, 0 );
+ glutInitWindowSize( 400, 300 );
+
+ glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
+
+ if (glutCreateWindow(argv[0]) <= 0) {
+ printf("Couldn't create window\n");
+ exit(0);
+ }
+
+ if (!glutExtensionSupported("GL_ARB_texture_compression")) {
+ printf("Sorry, GL_ARB_texture_compression not supported\n");
+ exit(0);
+ }
+ if (glutExtensionSupported("GL_3DFX_texture_compression_FXT1")) {
+ fxt1 = GL_TRUE;
+ }
+ if (glutExtensionSupported("GL_EXT_texture_compression_s3tc")) {
+ dxtc = GL_TRUE;
+ }
+ if (glutExtensionSupported("GL_S3_s3tc")) {
+ s3tc = GL_TRUE;
+ }
+
+ Init();
+
+ glutReshapeFunc( Reshape );
+ glutKeyboardFunc( Key );
+ glutDisplayFunc( Display );
+ if (Anim)
+ glutIdleFunc( Idle );
+
+ glutMainLoop();
+ return 0;
+}