initial check-in

progs/demos/lodbias.c

@@ -0,0 +1,217 @@
+/*
+ * 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 <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <GL/glut.h>
+#include <GL/glext.h>
+
+#include "../util/readtex.c"   /* I know, this is a hack. */
+
+#define TEXTURE_FILE "../images/girl.rgb"
+
+static GLfloat Xrot = 0, Yrot = -30, Zrot = 0;
+static GLboolean Anim = GL_TRUE;
+static GLint Bias = 0, DeltaBias = 10;  /* ints avoid fp precision problem */
+static GLint BiasMin = -200, BiasMax = 300;
+
+
+
+static void
+PrintString(const char *s)
+{
+   while (*s) {
+      glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+      s++;
+   }
+}
+
+static void Idle( void )
+{
+   Bias += DeltaBias;
+   if (Bias < BiasMin) {
+      Bias = BiasMin;
+      DeltaBias = 10;
+   }
+   else if (Bias > BiasMax) {
+      Bias = BiasMax;
+      DeltaBias = -10;
+   }
+
+   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 )
+{
+   const char *exten = (const char *) glGetString(GL_EXTENSIONS);
+   if (!strstr(exten, "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 (!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);
+}
+
+
+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;
+}