+
+
+static void
+MipGenTexture( void )
+{
+ /* test auto mipmap generation */
+ GLint width, height, i;
+ GLenum format;
+ GLubyte *image = LoadRGBImage(TEXTURE_FILE, &width, &height, &format);
+ if (!image) {
+ printf("Error: could not load texture image %s\n", TEXTURE_FILE);
+ exit(1);
+ }
+ /* resize to TexWidth x TexHeight */
+ if (width != TexWidth || height != TexHeight) {
+ GLubyte *newImage = malloc(TexWidth * TexHeight * 4);
+
+ fprintf(stderr, "rescale %d %d to %d %d\n", width, height,
+ TexWidth, TexHeight);
+ fflush(stderr);
+
+ gluScaleImage(format, width, height, GL_UNSIGNED_BYTE, image,
+ TexWidth, TexHeight, GL_UNSIGNED_BYTE, newImage);
+ free(image);
+ image = newImage;
+ }
+ printf("Using GL_SGIS_generate_mipmap\n");
+ glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
+ glTexImage2D(GL_TEXTURE_2D, 0, format, TexWidth, TexHeight, 0,
+ format, GL_UNSIGNED_BYTE, image);
+ free(image);
+
+ /* make sure mipmap was really generated correctly */
+ width = TexWidth;
+ height = TexHeight;
+ for (i = 0; i < 9; i++) {
+ GLint w, h;
+ glGetTexLevelParameteriv(GL_TEXTURE_2D, i, GL_TEXTURE_WIDTH, &w);
+ glGetTexLevelParameteriv(GL_TEXTURE_2D, i, GL_TEXTURE_HEIGHT, &h);
+ printf("Level %d size: %d x %d\n", i, w, h);
+ assert(w == width);
+ assert(h == height);
+ width /= 2;
+ height /= 2;
+ }
+
+
+ glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_FALSE);
+}
+
+
+
+static void
+ResetTextureLevel( int i )
+{
+ GLubyte tex2d[SIZE*SIZE][4];
+
+ {
+ GLint Width = TexWidth / (1 << i);
+ GLint Height = TexHeight / (1 << i);
+ GLint s, t;
+
+ for (s = 0; s < Width; s++) {
+ for (t = 0; t < Height; t++) {
+ tex2d[t*Width+s][0] = ((s / 16) % 2) ? 0 : 255;
+ tex2d[t*Width+s][1] = ((t / 16) % 2) ? 0 : 255;
+ tex2d[t*Width+s][2] = 128;
+ tex2d[t*Width+s][3] = 255;
+ }
+ }
+
+ glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+
+ glTexImage2D(GL_TEXTURE_2D, i, GL_RGB, Width, Height, 0,
+ GL_RGBA, GL_UNSIGNED_BYTE, tex2d);
+ }
+}
+
+
+static void
+ResetTexture( void )
+{
+#if 0
+ /* This doesn't work so well as the arch texture is 512x512.
+ */
+ LoadRGBMipmaps(TEXTURE_FILE, GL_RGB);
+#else
+ {
+ int i;
+
+ for (i = 0; i <= LEVELS; i++)
+ {
+ ResetTextureLevel(i);
+ }
+ }
+#endif
+}
+
+
+
+
+
+
+
+static void
+RenderTexture( void )
+{
+ GLenum status;
+ GLuint MyFB;
+
+ fprintf(stderr, "RenderTextureLevel %d\n", RenderTextureLevel);
+ fflush(stderr);
+
+ /* gen framebuffer id, delete it, do some assertions, just for testing */
+ glGenFramebuffersEXT(1, &MyFB);
+ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, MyFB);
+ assert(glIsFramebufferEXT(MyFB));
+
+ CheckError(__LINE__);
+
+ /* Render color to texture */
+ glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT,
+ GL_COLOR_ATTACHMENT0_EXT,
+ GL_TEXTURE_2D, TexObj,
+ RenderTextureLevel);
+
+
+
+ CheckError(__LINE__);
+
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+ glTranslatef(0.0, 0.0, -15.0);
+
+ status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+ if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+ printf("Framebuffer incomplete!!!\n");
+ }
+
+ glViewport(0, 0,
+ TexWidth / (1 << RenderTextureLevel),
+ TexHeight / (1 << RenderTextureLevel));
+
+ glClearColor(0.5, 0.5, 1.0, 0.0);
+ glClear(GL_COLOR_BUFFER_BIT);
+
+ CheckError(__LINE__);
+
+ glBegin(GL_POLYGON);
+ glColor3f(1, 0, 0);
+ glVertex2f(-1, -1);
+ glColor3f(0, 1, 0);
+ glVertex2f(1, -1);
+ glColor3f(0, 0, 1);
+ glVertex2f(0, 1);
+ glEnd();
+
+
+ /* Bind normal framebuffer */
+ glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+ CheckError(__LINE__);
+
+ glDeleteFramebuffersEXT(1, &MyFB);
+ CheckError(__LINE__);
+
+ glClearColor(0, 0, 0, 0);
+}
+