static void cwk2_terrain_render_patch (Shape *terrain,
	int x, int y, int size)
{
	Cwk2TerrainData *data = terrain->private_data;
	int i, index = (y*data->size)+x;
	
	if (data->textured)
		glBindTexture (GL_TEXTURE_2D, data->texture);
	glBegin (GL_TRIANGLE_FAN);
	/* Centre */
	if (data->textured)
		glTexCoord2f (size/2, size/2);
	glColor3fv (terrain->vcolours[index]);
	glNormal3fv (terrain->vnormals[index]);
	glVertex3fv (terrain->vertices[index]);
	/* Top-right -> Top-left */
	index -= (size * data->size) - size;
	for (i = 0; i < size * 2; i++, index--) {
		if (terrain->vertices[index][3] > 0) {
			if (data->textured)
				glTexCoord2f (size - (i/2), 0);
			glColor3fv (terrain->vcolours[index]);
			glNormal3fv (terrain->vnormals[index]);
			glVertex3fv (terrain->vertices[index]);
		}
	}
	/* Top-left -> Bottom-left */
	for (i = 0; i < size * 2; i++, index+=data->size) {
		if (terrain->vertices[index][3] > 0) {
			if (data->textured)
				glTexCoord2f (0, i/2);
			glColor3fv (terrain->vcolours[index]);
			glNormal3fv (terrain->vnormals[index]);
			glVertex3fv (terrain->vertices[index]);
		}
	}
	/* Bottom-left -> Bottom-right */
	for (i = 0; i < size * 2; i++, index++) {
		if (terrain->vertices[index][3] > 0) {
			if (data->textured)
				glTexCoord2f (i/2, size);
			glColor3fv (terrain->vcolours[index]);
			glNormal3fv (terrain->vnormals[index]);
			glVertex3fv (terrain->vertices[index]);
		}
	}
	/* Bottom-right -> Top-right */
	for (i = 0; i <= size * 2; i++, index-=data->size) {
		if (terrain->vertices[index][3] > 0) {
			if (data->textured)
				glTexCoord2f (size, size - (i/2));
			glColor3fv (terrain->vcolours[index]);
			glNormal3fv (terrain->vnormals[index]);
			glVertex3fv (terrain->vertices[index]);
		}
	}
	glEnd ();
}