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program picking;
{$L build/cone.bin.o}
{$L build/cylinder.bin.o}
{$L build/sphere.bin.o}
{$mode objfpc}
uses
ctypes, nds9;
{$include inc/cone.bin.inc}
{$include inc/cylinder.bin.inc}
{$include inc/sphere.bin.inc}
type
TClickable = ( clNothing, clCone, clCylinder, clSphere);
var
clicked: TClickable; // what is being clicked
closeW: integer; // closest distace to camera
polyCount: integer; // keeps track of the number of polygons drawn
// run before starting to draw an object while picking
procedure startCheck();
begin
while PosTestBusy() do; // wait for the position test to finish
while GFX_BUSY do; // wait for all the polygons from the last object to be drawn
PosTest_Asynch(0,0,0); // start a position test at the current translated position
polyCount := GFX_POLYGON_RAM_USAGE^; // save the polygon count
end;
// run afer drawing an object while picking
procedure endCheck(obj: TClickable);
begin
while GFX_BUSY do; // wait for all the polygons to get drawn
while PosTestBusy() do; // wait for the position test to finish
if (GFX_POLYGON_RAM_USAGE^ > polyCount) then // if a polygon was drawn
begin
if PosTestWresult() <= closeW then
begin
// this is currently the closest object under the cursor!
closeW := PosTestWresult();
clicked := obj;
end;
end;
end;
var
rotateX: cuint32 = 0;
rotateY: cuint32 = 0;
touchXY: touchPosition;
viewport: array [0..3] of cint32 = (0,0,255,191); // used later for gluPickMatrix()
keys: u16;
begin
// initialize gl
glInit();
//set mode 0, enable BG0 and set it to 3D
videoSetMode(MODE_0_3D);
lcdMainOnBottom(); // we are going to be touching the 3D display
// enable edge outlining, this will be used to show which object is selected
glEnable(GL_OUTLINE);
//set the first outline color to white
glSetOutlineColor(0,RGB15(31,31,31));
// setup the rear plane
glClearColor(0,0,0,0); // set BG to black and clear
glClearPolyID(0); // the BG and polygons will have the same ID unless a polygon is highlighted
glClearDepth($7FFF);
// setup the camera
gluLookAt( 0.0, 0.0, 1.0, //camera possition
0.0, 0.0, 0.0, //look at
0.0, 1.0, 0.0); //up
glLight(0, RGB15(31,31,31) , 0, floattov10(-1.0), 0); // setup the light
while true do
begin
// handle key input
scanKeys();
keys := keysHeld();
if ((keys and KEY_UP)) = 0 then rotateX := rotateX +3;
if((keys and KEY_DOWN)) = 0 then rotateX := rotateX -3;
if((keys and KEY_LEFT)) = 0 then rotateY := rotateY +3;
if((keys and KEY_RIGHT)) = 0 then rotateY := rotateY -3;
// get touchscreen position
touchXY := touchReadXY();
glViewPort(0,0,255,191); // set the viewport to fullscreen
// setup the projection matrix for regular drawing
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60, 256.0 / 192.0, 0.1, 20);
glMatrixMode(GL_MODELVIEW); // use the modelview matrix while drawing
glPushMatrix(); // save the state of the current matrix(the modelview matrix)
glTranslate3f32(0,0,floattof32(-6));
glRotateXi(rotateX); // add X rotation to the modelview matrix
glRotateYi(rotateY); // add Y rotation to the modelview matrix
glPushMatrix(); // save the state of the modelview matrix while making the first pass
// draw the scene for displaying
glTranslatef32(floattof32(2.9),floattof32(0),floattof32(0)); // translate the modelview matrix to the drawing location
if (clicked = clCone) then
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(1)) // set a poly ID for outlining
else
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(0)); // set a poly ID for no outlining (same as BG)
glCallList((@cone_bin)); // draw a green cone from a predefined packed command list
glTranslatef32(floattof32(-3),floattof32(1.8),floattof32(2)); // translate the modelview matrix to the drawing location
if (clicked = clCylinder) then
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(1)) // set a poly ID for outlining
else
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(0)); // set a poly ID for no outlining (same as BG)
glCallList((@cylinder_bin)); // draw a blue cylinder from a predefined packed command list
glTranslatef32(floattof32(0.5),floattof32(-2.6),floattof32(-4)); // translate the modelview matrix to the drawing location
if(clicked = clSphere) then
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(1)) // set a poly ID for outlining
else
glPolyFmt(POLY_ALPHA(31) or POLY_CULL_BACK or POLY_FORMAT_LIGHT0 or POLY_ID(0)); // set a poly ID for no outlining (same as BG)
glCallList((@sphere_bin)); // draw a red sphere from a predefined packed command list
glPopMatrix(1); // restores the modelview matrix to where it was just rotated
// draw the scene again for picking
clicked := clNothing; //reset what was clicked on
closeW := $7FFFFFFF; //reset the distance
//set the viewport to just off-screen, this hides all rendering that will be done during picking
glViewport(0,192,0,192);
// setup the projection matrix for picking
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPickMatrix((touchXY.px),(191-touchXY.py),4,4,viewport); // render only what is below the cursor
gluPerspective(60, 256.0 / 192.0, 0.1, 20); // this must be the same as the original perspective matrix
glMatrixMode(GL_MODELVIEW); // switch back to modifying the modelview matrix for drawing
glTranslatef32(floattof32(2.9),floattof32(0),floattof32(0)); // translate the modelview matrix to the drawing location
startCheck();
glCallList((@cone_bin)); // draw a cone from a predefined packed command list
endCheck(clCone);
glTranslatef32(floattof32(-3),floattof32(1.8),floattof32(2)); // translate the modelview matrix to the drawing location
startCheck();
glCallList((@cylinder_bin)); // draw a cylinder from a predefined packed command list
endCheck(clCylinder);
glTranslatef32(floattof32(0.5),floattof32(-2.6),floattof32(-4)); // translate the modelview matrix to the drawing location
startCheck();
glCallList((@sphere_bin)); // draw a sphere from a predefined packed command list
endCheck(clSphere);
glPopMatrix(1); // restores the modelview matrix to its original state
glFlush(0); // wait for everything to be drawn before starting on the next frame
end;
end.
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