diff --git a/progs/osdemos/Makefile b/progs/osdemos/Makefile
index 03ab78a..7d1bc08 100644
--- a/progs/osdemos/Makefile
+++ b/progs/osdemos/Makefile
@@ -14,7 +14,8 @@
 LIB_DEP = $(LIB_DIR)/$(GL_LIB_NAME) $(LIB_DIR)/$(GLU_LIB_NAME) $(LIB_DIR)/$(GLUT_LIB_NAME)
 
 PROGS = \
-	osdemo 
+	osdemo \
+	ostest1
 
 
 ##### RULES #####
@@ -57,6 +58,10 @@
 osdemo: osdemo.c
 	$(CC) -I$(INCDIR) $(CFLAGS) osdemo.c $(OSMESA_LIBS) -o $@
 
+# special case: need the -lOSMesa library:
+ostest1: ostest1.c
+	$(CC) -I$(INCDIR) $(CFLAGS) ostest1.c $(OSMESA_LIBS) -o $@
+
 # another special case: need the -lOSMesa16 library:
 osdemo16: osdemo16.c
 	$(CC) -I$(INCDIR) $(CFLAGS) osdemo16.c $(OSMESA16_LIBS) -o $@
diff --git a/progs/osdemos/ostest1.c b/progs/osdemos/ostest1.c
new file mode 100644
index 0000000..61f0f3d
--- /dev/null
+++ b/progs/osdemos/ostest1.c
@@ -0,0 +1,344 @@
+/*
+ * Test OSMesa interface at 8, 16 and 32 bits/channel.
+ *
+ * Usage: osdemo [options]
+ *
+ * Options:
+ *   -f   generate image files
+ *   -g   render gradient and print color values
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "GL/osmesa.h"
+#include "GL/glut.h"
+
+
+#define WIDTH 600
+#define HEIGHT 600
+
+static GLboolean WriteFiles = GL_FALSE;
+static GLboolean Gradient = GL_FALSE;
+
+
+/**
+ * Draw red/green gradient across bottom of image.
+ * Read pixels to check deltas.
+ */
+static void
+render_gradient(void)
+{
+   GLfloat row[WIDTH][4];
+   int i;
+
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glOrtho(-1, 1, -1, 1, -1, 1);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+
+   glBegin(GL_POLYGON);
+   glColor3f(1, 0, 0);
+   glVertex2f(-1, -1.0);
+   glVertex2f(-1, -0.9);
+   glColor3f(0, 1, 0);
+   glVertex2f(1, -0.9);
+   glVertex2f(1, -1.0);
+   glEnd();
+   glFinish();
+
+   glReadPixels(0, 0, WIDTH, 1, GL_RGBA, GL_FLOAT, row);
+   for (i = 0; i < 4; i++) {
+      printf("row[i] = %f, %f, %f\n", row[i][0], row[i][1], row[i][2]);
+   }
+}
+
+
+static void
+render_image(void)
+{
+   static const GLfloat light_ambient[4] = { 0.0, 0.0, 0.0, 1.0 };
+   static const GLfloat light_diffuse[4] = { 1.0, 1.0, 1.0, 1.0 };
+   static const GLfloat light_specular[4] = { 1.0, 1.0, 1.0, 1.0 };
+   static const GLfloat light_position[4] = { 1.0, 1.0, 1.0, 0.0 };
+   static const GLfloat red_mat[4]   = { 1.0, 0.2, 0.2, 1.0 };
+   static const GLfloat green_mat[4] = { 0.2, 1.0, 0.2, 1.0 };
+   static const GLfloat blue_mat[4]  = { 0.2, 0.2, 1.0, 1.0 };
+   static const GLfloat yellow_mat[4]  = { 0.8, 0.8, 0.0, 1.0 };
+   static const GLfloat purple_mat[4]  = { 0.8, 0.4, 0.8, 0.6 };
+
+   glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
+   glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
+   glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
+   glLightfv(GL_LIGHT0, GL_POSITION, light_position);
+    
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_LIGHT0);
+
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-1.0, 1.0, -1.0, 1.0, 2.0, 50.0);
+   glMatrixMode(GL_MODELVIEW);
+   glTranslatef(0, 0.5, -7);
+
+   glClearColor(0.3, 0.3, 0.7, 0.0);
+   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+   glPushMatrix();
+   glRotatef(20.0, 1.0, 0.0, 0.0);
+
+   /* ground */
+   glEnable(GL_TEXTURE_2D);
+   glBegin(GL_POLYGON);
+   glNormal3f(0, 1, 0);
+   glTexCoord2f(0, 0);  glVertex3f(-5, -1, -5);
+   glTexCoord2f(1, 0);  glVertex3f( 5, -1, -5);
+   glTexCoord2f(1, 1);  glVertex3f( 5, -1,  5);
+   glTexCoord2f(0, 1);  glVertex3f(-5, -1,  5);
+   glEnd();
+   glDisable(GL_TEXTURE_2D);
+
+   glEnable(GL_LIGHTING);
+
+   glPushMatrix();
+   glTranslatef(-1.5, 0.5, 0.0); 
+   glRotatef(90.0, 1.0, 0.0, 0.0);
+   glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red_mat );
+   glutSolidTorus(0.275, 0.85, 20, 20);
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(-1.5, -0.5, 0.0); 
+   glRotatef(270.0, 1.0, 0.0, 0.0);
+   glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, green_mat );
+   glutSolidCone(1.0, 2.0, 16, 1);
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(0.75, 0.0, -1.0); 
+   glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue_mat );
+   glutSolidSphere(1.0, 20, 20);
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(0.75, 0.0, 1.3); 
+   glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, yellow_mat );
+   glutWireTeapot(1.0);
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(-0.5, 0.0, 2.5);
+   glRotatef(40, 0, 1, 0);
+   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+   glEnable(GL_BLEND);
+   glEnable(GL_CULL_FACE);
+   glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, purple_mat );
+   glutSolidCube(1.0);
+   glDisable(GL_BLEND);
+   glDisable(GL_CULL_FACE);
+   glPopMatrix();
+
+   glDisable(GL_LIGHTING);
+
+   glPopMatrix();
+
+   glDisable(GL_DEPTH_TEST);
+}
+
+
+static void
+init_context(void)
+{
+   const GLint texWidth = 64, texHeight = 64;
+   GLubyte *texImage;
+   int i, j;
+
+   /* checker image */
+   texImage = malloc(texWidth * texHeight * 4);
+   for (i = 0; i < texHeight; i++) {
+      for (j = 0; j < texWidth; j++) {
+         int k = (i * texWidth + j) * 4;
+         if ((i % 5) == 0 || (j % 5) == 0) {
+            texImage[k+0] = 200;
+            texImage[k+1] = 200;
+            texImage[k+2] = 200;
+            texImage[k+3] = 255;
+         }
+         else {
+            if ((i % 5) == 1 || (j % 5) == 1) {
+               texImage[k+0] = 50;
+               texImage[k+1] = 50;
+               texImage[k+2] = 50;
+               texImage[k+3] = 255;
+            }
+            else {
+               texImage[k+0] = 100;
+               texImage[k+1] = 100;
+               texImage[k+2] = 100;
+               texImage[k+3] = 255;
+            }
+         }
+      }
+   }
+
+   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0,
+                GL_RGBA, GL_UNSIGNED_BYTE, texImage);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+   free(texImage);
+}
+
+
+static void
+write_ppm(const char *filename, const GLubyte *buffer, int width, int height)
+{
+   const int binary = 0;
+   FILE *f = fopen( filename, "w" );
+   if (f) {
+      int i, x, y;
+      const GLubyte *ptr = buffer;
+      if (binary) {
+         fprintf(f,"P6\n");
+         fprintf(f,"# ppm-file created by osdemo.c\n");
+         fprintf(f,"%i %i\n", width,height);
+         fprintf(f,"255\n");
+         fclose(f);
+         f = fopen( filename, "ab" );  /* reopen in binary append mode */
+         for (y=height-1; y>=0; y--) {
+            for (x=0; x<width; x++) {
+               i = (y*width + x) * 4;
+               fputc(ptr[i], f);   /* write red */
+               fputc(ptr[i+1], f); /* write green */
+               fputc(ptr[i+2], f); /* write blue */
+            }
+         }
+      }
+      else {
+         /*ASCII*/
+         int counter = 0;
+         fprintf(f,"P3\n");
+         fprintf(f,"# ascii ppm file created by osdemo.c\n");
+         fprintf(f,"%i %i\n", width, height);
+         fprintf(f,"255\n");
+         for (y=height-1; y>=0; y--) {
+            for (x=0; x<width; x++) {
+               i = (y*width + x) * 4;
+               fprintf(f, " %3d %3d %3d", ptr[i], ptr[i+1], ptr[i+2]);
+               counter++;
+               if (counter % 5 == 0)
+                  fprintf(f, "\n");
+            }
+         }
+      }
+      fclose(f);
+   }
+}
+
+
+static GLboolean
+test(GLenum type, GLint bits, const char *filename)
+{
+   const GLint z = 16, stencil = 0, accum = 0;
+   OSMesaContext ctx;
+   void *buffer;
+   GLint cBits;
+
+   assert(bits == 8 ||
+          bits == 16 ||
+          bits == 32);
+
+   assert(type == GL_UNSIGNED_BYTE ||
+          type == GL_UNSIGNED_SHORT ||
+          type == GL_FLOAT);
+
+   ctx = OSMesaCreateContextExt(OSMESA_RGBA, z, stencil, accum, NULL );
+   if (!ctx) {
+      printf("OSMesaCreateContextExt() failed!\n");
+      return 0;
+   }
+
+   /* Allocate the image buffer */
+   buffer = malloc(WIDTH * HEIGHT * 4 * bits / 8);
+   if (!buffer) {
+      printf("Alloc image buffer failed!\n");
+      return 0;
+   }
+
+   /* Bind the buffer to the context and make it current */
+   if (!OSMesaMakeCurrent( ctx, buffer, type, WIDTH, HEIGHT )) {
+      printf("OSMesaMakeCurrent (%d bits/channel) failed!\n", bits);
+      return 0;
+   }
+
+   /* sanity checks */
+   glGetIntegerv(GL_RED_BITS, &cBits);
+   assert(cBits == bits);
+   glGetIntegerv(GL_GREEN_BITS, &cBits);
+   assert(cBits == bits);
+   glGetIntegerv(GL_BLUE_BITS, &cBits);
+   assert(cBits == bits);
+   glGetIntegerv(GL_ALPHA_BITS, &cBits);
+   assert(cBits == bits);
+
+   printf("Rendering %d bit/channel image: %s\n", bits, filename);
+
+   init_context();
+   render_image();
+   if (Gradient)
+      render_gradient();
+
+   /* Make sure buffered commands are finished! */
+   glFinish();
+
+
+   if (WriteFiles && filename != NULL) {
+      if (type == GL_UNSIGNED_SHORT) {
+         GLushort *buffer16 = (GLushort *) buffer;
+         GLubyte *buffer8 = malloc(WIDTH * HEIGHT * 4);
+         int i;
+         for (i = 0; i < WIDTH * HEIGHT * 4; i++)
+            buffer8[i] = buffer16[i] >> 8;
+         write_ppm(filename, buffer8, WIDTH, HEIGHT);
+         free(buffer8);
+      }
+      else if (type == GL_FLOAT) {
+         GLfloat *buffer32 = (GLfloat *) buffer;
+         GLubyte *buffer8 = malloc(WIDTH * HEIGHT * 4);
+         int i;
+         for (i = 0; i < WIDTH * HEIGHT * 4; i++)
+            buffer8[i] = (GLubyte) (buffer32[i] * 255.0);
+         write_ppm(filename, buffer8, WIDTH, HEIGHT);
+         free(buffer8);
+      }
+      else {
+         write_ppm(filename, buffer, WIDTH, HEIGHT);
+      }
+   }
+
+   OSMesaDestroyContext(ctx);
+
+   return 1;
+}
+
+
+int
+main( int argc, char *argv[] )
+{
+   int i;
+
+   for (i = 1; i < argc; i++) {
+      if (strcmp(argv[i], "-f") == 0)
+         WriteFiles = GL_TRUE;
+      else if (strcmp(argv[i], "-g") == 0)
+         Gradient = GL_TRUE;
+   }
+
+   test(GL_UNSIGNED_BYTE, 8, "image8.ppm");
+   test(GL_UNSIGNED_SHORT, 16, "image16.ppm");
+   test(GL_FLOAT, 32, "image32.ppm");
+
+   return 0;
+}