void icetProjectTile(GLint tile)
{
GLint *viewports;
GLint physical_viewport[4];
GLint tile_width, tile_height;
GLint renderable_width, renderable_height;
/* Update tile projections. */
if (viewport_time != icetStateGetTime(ICET_TILE_VIEWPORTS)) {
update_tile_projections();
viewport_time = icetStateGetTime(ICET_TILE_VIEWPORTS);
}
if ((tile < 0) || (tile >= num_tiles)) {
icetRaiseError("Bad tile passed to icetProjectTile.",
ICET_INVALID_VALUE);
return;
}
viewports = icetUnsafeStateGet(ICET_TILE_VIEWPORTS);
tile_width = viewports[tile*4+2];
tile_height = viewports[tile*4+3];
glGetIntegerv(GL_VIEWPORT, physical_viewport);
renderable_width = physical_viewport[2];
renderable_height = physical_viewport[3];
if ((renderable_width != tile_width) || (renderable_height != tile_height)){
/* Compensate for fact that tile is smaller than actual window. */
glOrtho(-1.0, 2.0*renderable_width/tile_width - 1.0,
-1.0, 2.0*renderable_height/tile_height - 1.0,
1.0, -1.0);
}
glMultMatrixd(tile_projections + 16*tile);
if (projection_time != icetStateGetTime(ICET_PROJECTION_MATRIX)) {
icetGetDoublev(ICET_PROJECTION_MATRIX, global_projection);
projection_time = icetStateGetTime(ICET_PROJECTION_MATRIX);
}
glMultMatrixd(global_projection);
}
static void update_tile_projections(void)
{
IceTInt num_tiles;
const IceTInt *viewports;
IceTDouble *tile_projections;
IceTInt tile_idx;
if ( icetStateGetTime(ICET_TILE_VIEWPORTS)
< icetStateGetTime(ICET_TILE_PROJECTIONS) ) {
/* Projections already up to date. */
return;
}
icetGetIntegerv(ICET_NUM_TILES, &num_tiles);
tile_projections = icetStateAllocateDouble(ICET_TILE_PROJECTIONS,
num_tiles*16);
viewports = icetUnsafeStateGetInteger(ICET_TILE_VIEWPORTS);
for (tile_idx = 0; tile_idx < num_tiles; tile_idx++) {
icetGetViewportProject(viewports[tile_idx*4+0], viewports[tile_idx*4+1],
viewports[tile_idx*4+2], viewports[tile_idx*4+3],
tile_projections + 16*tile_idx);
}
}
