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-rw-r--r--progs/demos/lodbias.c217
1 files changed, 217 insertions, 0 deletions
diff --git a/progs/demos/lodbias.c b/progs/demos/lodbias.c
new file mode 100644
index 00000000000..e36acc67cdf
--- /dev/null
+++ b/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;
+}