' We suggest the use the most coloured ' resolution (up to 16 colors). BITMAP ENABLE(16) ' This is the number of stars to be displayed. ' Currenly there is a maximum number of 32 sprites multiplexed. CONST starCount = 24 ' This data structure will hold, in one place, the information ' related to each individual star we'll draw. Specifically, ' we'll keep the (x,y) coordinates, the animation frame ' (frame), and the reference to the multiplexed sprite ' displayed (sprite). TYPE starType x AS POSITION y AS POSITION sprite AS MSPRITE frame AS BYTE END TYPE ' This directive allows you to disable the control over image ' height constraints, where they are present. In fact, the ' conversion of images from the modern format to the native format ' of the target must guarantee some specific constraints. However, ' where it is ensured that the dimensions of the graphic resources ' are consistent, it is possible to disable this type of control. ' This is in order to be able to load graphic resources that do not ' need to respect these constraints, such as resources linked ' to sprites. DEFINE IMAGE FREE HEIGHT ' This pragma allow to delay the refresh of the changes made ' to multiplexed sprites. They will be stored and reflected ' on the screen only when the instruction MSPRITE UPDATE ' will be executed. DEFINE MSPRITE ASYNC ' Let's change the border and background color. COLOR BORDER BLUE CLS BLUE ' Let's wait for a key press. This trick will ' allow to initialize the TIMER variable to a really ' random value, that depends on the key press delay. INK WHITE VHCENTER "PRESS ANY KEY" WAIT KEY RELEASE ' Let's initialize the random number generator ' using the time passed from the execution start. RANDOMIZE TIMER ' Load from the host the (degrated quality of the) image ' of the opening titles of the videogame. ' ' Note that the original image has been converted to ' match at best each target, and moved the result into ' each folder with the same target name. In particular: ' ' c64 : 160x200 pixel, 16 colors background := LOAD IMAGE("vdg_orville.png") ' Load from the host the (degrated quality of the) image ' of the animated sprites of the rotating stars. star := LOAD ATLAS("vdg_orville_star.png") FRAME SIZE (24,21) ' Finally, load from the host the music track, in MIDI ' format. It will be converted to the native format, as well. music := LOAD MUSIC("vdg_orville.mid") ' Let's create an array that will hold separate ' information for each star. DIM stars(starCount) AS starType ' Now let's initialize each individual star... FOR i = LBOUND(stars) TO UBOUND(stars) ' The horizontal starting position is from 0 to 319. stars(i).x = RND(320) ' The vertical starting position starts from 52 ' and go down of 8 pixel for each star. Note that ' the vertical screen resolution could be not high ' enough to keep all the sprites. stars(i).y = 52+i*8 ' Assign the sprite resource to this sspecific star. ' We use the IMAGE( ) function to extract the image ' from the loaded ATLAS (using the FRAME 0 for the ' first one). Then, we use the MSPRITE instruction to ' convert the bitmap into a sprite resource, and using ' the IGNORE COLOR LIGHT GREEN we are saying that ' that color will be used as "transparency" for the ' sprite. stars(i).sprite = MSPRITE( IMAGE( star FRAME 0 ) IGNORE COLOR LIGHT GREEN ) ' Each star starts from a random frame (0..3). stars(i).frame = RND(4) ' We can enable the sprite. SPRITE stars(i).sprite ENABLE NEXT i ' Put the titles on the screen. PUT IMAGE background AT 0, 0 ' Let's start the music. MUSIC music ' This is an infinite loop, which will update ' the stars' positions at each cycle. DO ' For each star inside the array... FOR i = LBOUND(stars) TO UBOUND(stars) ' Increment the horizontal position, up to the ' end of the screen. ADD stars(i).x, 1+RND(4) IF stars(i).x > 350 THEN stars(i).x = 0 ' Based on the current frame, we are going ' to convert the bitmap from the specific ' frame of the ATLAS into a sprite. Note that ' we are going to indicate the previous ' sprite, in order to "replace" the image. SELECT CASE stars(i).frame CASE 0 stars(i).sprite = MSPRITE( IMAGE( star FRAME 0 ), stars(i).sprite IGNORE COLOR LIGHT GREEN ) CASE 1 stars(i).sprite = MSPRITE( IMAGE( star FRAME 1 ), stars(i).sprite IGNORE COLOR LIGHT GREEN ) CASE 2 stars(i).sprite = MSPRITE( IMAGE( star FRAME 2 ), stars(i).sprite IGNORE COLOR LIGHT GREEN ) CASE 3 stars(i).sprite = MSPRITE( IMAGE( star FRAME 3 ), stars(i).sprite IGNORE COLOR LIGHT GREEN ) ENDSELECT ' Increment the frame, up to the ' end of the ATLAS' frames. INC stars(i).frame IF stars(i).frame = FRAMES( star ) THEN stars(i).frame = 0 ' Move the star to the specific position. SPRITE stars(i).sprite AT stars(i).x, stars(i).y NEXT i ' Update every sprite at once. MSPRITE UPDATE LOOP