/* * GL_EXT_texture_lod_bias demo * * Thanks to Michael Vance for implementing this extension in Mesa. * * Brian Paul * 20 March 2000 * * Copyright (C) 2000 Brian Paul All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #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/girl.rgb" static GLfloat Xrot = 0, Yrot = -30, Zrot = 0; static GLboolean Anim = GL_TRUE; static GLint Bias = 0, BiasStepSign = +1; /* ints avoid fp precision problem */ static GLint BiasMin = -400, BiasMax = 400; static void PrintString(const char *s) { while (*s) { glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s); s++; } } static void Idle( void ) { static int lastTime = 0; int time = glutGet(GLUT_ELAPSED_TIME); int step; if (lastTime == 0) lastTime = time; else if (time - lastTime < 10) return; step = (time - lastTime) / 10 * BiasStepSign; lastTime = time; Bias += step; if (Bias < BiasMin) { Bias = BiasMin; BiasStepSign = +1; } else if (Bias > BiasMax) { Bias = BiasMax; BiasStepSign = -1; } glutPostRedisplay(); } static void Display( void ) { char str[100]; glClear( GL_COLOR_BUFFER_BIT ); glMatrixMode( GL_PROJECTION ); glLoadIdentity(); glOrtho(-1, 1, -1, 1, -1, 1); glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); glDisable(GL_TEXTURE_2D); glColor3f(1,1,1); glRasterPos3f(-0.9, -0.9, 0.0); sprintf(str, "Texture LOD Bias = %4.1f", Bias * 0.01); PrintString(str); glMatrixMode( GL_PROJECTION ); glLoadIdentity(); glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 ); glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); glTranslatef( 0.0, 0.0, -8.0 ); glPushMatrix(); glRotatef(Xrot, 1, 0, 0); glRotatef(Yrot, 0, 1, 0); glRotatef(Zrot, 0, 0, 1); glEnable(GL_TEXTURE_2D); glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, 0.01 * Bias); glBegin(GL_POLYGON); glTexCoord2f(0, 0); glVertex2f(-1, -1); glTexCoord2f(2, 0); glVertex2f( 1, -1); glTexCoord2f(2, 2); glVertex2f( 1, 1); glTexCoord2f(0, 2); glVertex2f(-1, 1); glEnd(); glPopMatrix(); glutSwapBuffers(); } static void Reshape( int width, int height ) { glViewport( 0, 0, width, height ); } static void Key( unsigned char key, int x, int y ) { const GLfloat step = 3.0; (void) x; (void) y; switch (key) { case 'a': Anim = !Anim; if (Anim) glutIdleFunc(Idle); else glutIdleFunc(NULL); break; case 'z': Zrot -= step; break; case 'Z': Zrot += step; break; case 'b': Bias -= 10; break; case 'B': Bias += 10; break; case 27: exit(0); break; } glutPostRedisplay(); } static void SpecialKey( int key, int x, int y ) { const GLfloat step = 3.0; (void) x; (void) y; switch (key) { case GLUT_KEY_UP: Xrot -= step; break; case GLUT_KEY_DOWN: Xrot += step; break; case GLUT_KEY_LEFT: Yrot -= step; break; case GLUT_KEY_RIGHT: Yrot += step; 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); } glPixelStorei(GL_UNPACK_ALIGNMENT, 1); if (glutExtensionSupported("GL_SGIS_generate_mipmap")) { /* 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 256 x 256 */ if (width != 256 || height != 256) { GLubyte *newImage = malloc(256 * 256 * 4); gluScaleImage(format, width, height, GL_UNSIGNED_BYTE, image, 256, 256, 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, 256, 256, 0, format, GL_UNSIGNED_BYTE, image); free(image); /* make sure mipmap was really generated correctly */ width = height = 256; 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("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("LOD bias range: [%g, %g]\n", -maxBias, maxBias); BiasMin = -100 * maxBias; BiasMax = 100 * maxBias; /* Since we have (about) 8 mipmap levels, no need to bias beyond * the range [-1, +8]. */ if (BiasMin < -100) BiasMin = -100; if (BiasMax > 800) BiasMax = 800; } int main( int argc, char *argv[] ) { glutInit( &argc, argv ); glutInitWindowPosition( 0, 0 ); glutInitWindowSize( 350, 350 ); glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE ); glutCreateWindow(argv[0]); glutReshapeFunc( Reshape ); glutKeyboardFunc( Key ); glutSpecialFunc( SpecialKey ); glutDisplayFunc( Display ); if (Anim) glutIdleFunc(Idle); Init(); glutMainLoop(); return 0; }