2 * Test texture compression.
6 #define GL_GLEXT_PROTOTYPES
13 #define IMAGE_FILE "../images/arch.rgb"
15 static int ImgWidth, ImgHeight;
16 static GLenum ImgFormat;
17 static GLenum CompFormat;
18 static GLfloat EyeDist = 5.0;
19 static GLfloat Rot = 0.0;
20 const GLenum Target = GL_TEXTURE_2D;
26 GLenum err = glGetError();
28 printf("GL Error %d at line %d\n", (int) err, line);
34 LookupFormat(GLenum format)
37 case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
38 return "GL_COMPRESSED_RGB_S3TC_DXT1_EXT";
39 case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
40 return "GL_COMPRESSED_RGBA_S3TC_DXT1_EXT";
41 case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
42 return "GL_COMPRESSED_RGBA_S3TC_DXT3_EXT";
52 GLboolean all = 0*GL_TRUE;
57 glGetTexLevelParameteriv(Target, 0,
58 GL_TEXTURE_COMPRESSED_IMAGE_SIZE_ARB, &size);
59 glGetTexLevelParameteriv(Target, 0, GL_TEXTURE_INTERNAL_FORMAT, &fmt);
61 buffer = (GLubyte *) malloc(size);
62 glGetCompressedTexImageARB(Target, 0, buffer);
64 printf("Testing sub-texture replacement\n");
66 glCompressedTexImage2DARB(Target, 0,
67 fmt, ImgWidth, ImgHeight, 0,
71 glCompressedTexSubImage2DARB(Target, 0,
73 ImgWidth, ImgHeight / 2,
76 glCompressedTexSubImage2DARB(Target, 0,
77 0, ImgHeight / 2, /* pos */
78 ImgWidth, ImgHeight / 2,
79 fmt, size/2, buffer + size / 2);
87 LoadCompressedImage(const char *file)
89 const GLenum filter = GL_LINEAR;
93 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
94 glPixelStorei(GL_PACK_ALIGNMENT, 1);
97 * Load image and scale if needed.
99 image = LoadRGBImage( file, &ImgWidth, &ImgHeight, &ImgFormat );
101 printf("Couldn't read %s\n", IMAGE_FILE);
104 printf("Image is %d x %d\n", ImgWidth, ImgHeight);
107 assert(ImgWidth == 128 || ImgWidth == 256 || ImgWidth == 512);
108 assert(ImgWidth == 128 || ImgHeight == 256 || ImgHeight == 512);
110 if (ImgFormat == GL_RGB)
111 CompFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
113 CompFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
115 if (ImgFormat == GL_RGBA) {
117 for (i = 0; i < ImgWidth * ImgHeight; i++) {
118 if (image[i*4+3] != 0 && image[i*4+3] != 0xff) {
121 if (image[i*4+3] == 0)
122 image[i*4+3] = 4 * i / ImgWidth;
124 printf("Num Alpha !=0,255: %d\n", numAlpha);
127 CompFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
131 * Give image to OpenGL and have it compress it.
133 glTexImage2D(Target, 0, CompFormat, ImgWidth, ImgHeight, 0,
134 ImgFormat, GL_UNSIGNED_BYTE, image);
135 CheckError(__LINE__);
139 glGetTexLevelParameteriv(Target, 0, GL_TEXTURE_INTERNAL_FORMAT, &p);
140 printf("Compressed Internal Format: %s (0x%x)\n", LookupFormat(p), p);
141 assert(p == CompFormat);
143 printf("Original size: %d bytes\n", ImgWidth * ImgHeight * 3);
144 glGetTexLevelParameteriv(Target, 0, GL_TEXTURE_COMPRESSED_IMAGE_SIZE_ARB, &p);
145 printf("Compressed size: %d bytes\n", p);
147 glTexParameteri(Target, GL_TEXTURE_MIN_FILTER, filter);
148 glTexParameteri(Target, GL_TEXTURE_MAG_FILTER, filter);
156 Init(const char *file)
158 GLint numFormats, formats[100];
161 if (!glutExtensionSupported("GL_ARB_texture_compression")) {
162 printf("Sorry, GL_ARB_texture_compression is required.\n");
165 if (!glutExtensionSupported("GL_EXT_texture_compression_s3tc")) {
166 printf("Sorry, GL_EXT_texture_compression_s3tc is required.\n");
170 printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
171 printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
173 glGetIntegerv(GL_NUM_COMPRESSED_TEXTURE_FORMATS_ARB, &numFormats);
174 glGetIntegerv(GL_COMPRESSED_TEXTURE_FORMATS_ARB, formats);
175 printf("%d supported compression formats: ", numFormats);
176 for (p = 0; p < numFormats; p++)
177 printf("0x%x ", formats[p]);
180 LoadCompressedImage(file);
182 glEnable(GL_TEXTURE_2D);
184 if (ImgFormat == GL_RGBA) {
185 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
192 Reshape( int width, int height )
194 glViewport( 0, 0, width, height );
195 glMatrixMode( GL_PROJECTION );
197 glFrustum(-1, 1, -1, 1, 4, 100);
198 glMatrixMode( GL_MODELVIEW );
204 Key( unsigned char key, int x, int y )
234 glClearColor(0.3, 0.3, .8, 0);
235 glClear(GL_COLOR_BUFFER_BIT);
238 glTranslatef(0, 0, -(EyeDist+0.01));
239 glRotatef(Rot, 0, 0, 1);
241 glTexCoord2f(0, 0); glVertex2f(-1, -1);
242 glTexCoord2f(1, 0); glVertex2f( 1, -1);
243 glTexCoord2f(1, 1); glVertex2f( 1, 1);
244 glTexCoord2f(0, 1); glVertex2f(-1, 1);
253 main( int argc, char *argv[] )
255 glutInit( &argc, argv );
256 glutInitWindowSize( 600, 600 );
258 glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE);
260 glutCreateWindow(argv[0]);
262 glutReshapeFunc( Reshape );
263 glutKeyboardFunc( Key );
264 glutDisplayFunc( Draw );