/* * Test mipmap generation and lod bias. * * Brian Paul * 17 March 2008 */ #include <assert.h> #include <stdlib.h> #include <stdio.h> #include <math.h> #include <GL/glut.h> #include <GL/glext.h> #include "readtex.h" #define TEXTURE_FILE "../images/arch.rgb" static int TexWidth = 256, TexHeight = 256; static int WinWidth = 1044, WinHeight = 900; static GLfloat Bias = 0.0; static GLboolean ScaleQuads = GL_FALSE; static GLint Win = 0; static void PrintString(const char *s) { while (*s) { glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s); s++; } } static void Display(void) { int x, y, bias; char str[100]; int texWidth = TexWidth, texHeight = TexHeight; glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0, WinWidth, 0, WinHeight, -1, 1); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glColor3f(1,1,1); y = WinHeight - 300; x = 4; for (bias = -1; bias < 11; bias++) { if (ScaleQuads) { if (bias > 0) { if (texWidth == 1 && texHeight == 1) break; texWidth = TexWidth >> bias; texHeight = TexHeight >> bias; if (texWidth < 1) texWidth = 1; if (texHeight < 1) texHeight = 1; } glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, 0.0); } else { glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, bias); } glRasterPos2f(x, y + TexHeight + 5); if (ScaleQuads) sprintf(str, "Texture Level %d: %d x %d", (bias < 0 ? 0 : bias), texWidth, texHeight); else sprintf(str, "Texture LOD Bias = %d", bias); PrintString(str); glPushMatrix(); glTranslatef(x, y, 0); glEnable(GL_TEXTURE_2D); glBegin(GL_POLYGON); glTexCoord2f(0, 0); glVertex2f(0, 0); glTexCoord2f(1, 0); glVertex2f(texWidth, 0); glTexCoord2f(1, 1); glVertex2f(texWidth, texHeight); glTexCoord2f(0, 1); glVertex2f(0, texHeight); glEnd(); glPopMatrix(); glDisable(GL_TEXTURE_2D); x += TexWidth + 4; if (x >= WinWidth) { x = 4; y -= 300; } } glutSwapBuffers(); } static void Reshape(int width, int height) { WinWidth = width; WinHeight = height; glViewport(0, 0, width, height); } static void Key(unsigned char key, int x, int y) { (void) x; (void) y; switch (key) { case 'b': Bias -= 10; break; case 'B': Bias += 10; break; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': Bias = 100.0 * (key - '0'); break; case 's': ScaleQuads = !ScaleQuads; break; case 27: glutDestroyWindow(Win); exit(0); break; } glutPostRedisplay(); } static void Init(void) { GLfloat maxBias; if (!glutExtensionSupported("GL_EXT_texture_lod_bias")) { printf("Sorry, GL_EXT_texture_lod_bias not supported by this renderer.\n"); exit(1); } if (!glutExtensionSupported("GL_SGIS_generate_mipmap")) { printf("Sorry, GL_SGIS_generate_mipmap not supported by this renderer.\n"); exit(1); } glPixelStorei(GL_UNPACK_ALIGNMENT, 1); if (1) { /* 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); 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; } } else { if (LoadRGBMipmaps(TEXTURE_FILE, GL_RGB)) { printf("Using gluBuildMipmaps()\n"); } else { printf("Error: could not load texture image %s\n", TEXTURE_FILE); exit(1); } } /* mipmapping required for this extension */ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glGetFloatv(GL_MAX_TEXTURE_LOD_BIAS_EXT, &maxBias); printf("GL_RENDERER: %s\n", (char*) glGetString(GL_RENDERER)); printf("LOD bias range: [%g, %g]\n", -maxBias, maxBias); printf("Press 's' to toggle quad scaling\n"); } int main(int argc, char *argv[]) { glutInit(&argc, argv); glutInitWindowPosition(0, 0); glutInitWindowSize(WinWidth, WinHeight); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); Win = glutCreateWindow(argv[0]); glutReshapeFunc(Reshape); glutKeyboardFunc(Key); glutDisplayFunc(Display); Init(); glutMainLoop(); return 0; }