mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-11-26 10:49:17 +00:00
88 lines
2.2 KiB
Verilog
88 lines
2.2 KiB
Verilog
|
|
`include "hvsync_generator.v"
|
|
|
|
/*
|
|
A bouncing ball using absolute coordinates.
|
|
*/
|
|
|
|
module ball_absolute_top(clk, reset, hsync, vsync, rgb);
|
|
|
|
input clk;
|
|
input reset;
|
|
output hsync, vsync;
|
|
output [2:0] rgb;
|
|
wire display_on;
|
|
wire [8:0] hpos;
|
|
wire [8:0] vpos;
|
|
|
|
reg [8:0] ball_hpos; // ball current X position
|
|
reg [8:0] ball_vpos; // ball current Y position
|
|
|
|
reg [8:0] ball_horiz_move = -2; // ball current X velocity
|
|
reg [8:0] ball_vert_move = 2; // ball current Y velocity
|
|
|
|
localparam ball_horiz_initial = 128; // ball initial X position
|
|
localparam ball_vert_initial = 128; // ball initial Y position
|
|
|
|
localparam BALL_SIZE = 4; // ball size (in pixels)
|
|
|
|
// video sync generator
|
|
hvsync_generator hvsync_gen(
|
|
.clk(clk),
|
|
.reset(reset),
|
|
.hsync(hsync),
|
|
.vsync(vsync),
|
|
.display_on(display_on),
|
|
.hpos(hpos),
|
|
.vpos(vpos)
|
|
);
|
|
|
|
// update horizontal timer
|
|
always @(posedge vsync or posedge reset)
|
|
begin
|
|
if (reset) begin
|
|
// reset ball position to center
|
|
ball_hpos <= ball_horiz_initial;
|
|
ball_vpos <= ball_vert_initial;
|
|
end else begin
|
|
// add velocity vector to ball position
|
|
ball_hpos <= ball_hpos + ball_horiz_move;
|
|
ball_vpos <= ball_vpos + ball_vert_move;
|
|
end
|
|
end
|
|
|
|
// vertical bounce
|
|
always @(posedge ball_vert_collide)
|
|
begin
|
|
ball_vert_move <= -ball_vert_move;
|
|
end
|
|
|
|
// horizontal bounce
|
|
always @(posedge ball_horiz_collide)
|
|
begin
|
|
ball_horiz_move <= -ball_horiz_move;
|
|
end
|
|
|
|
// offset of ball position from video beam
|
|
wire [8:0] ball_hdiff = hpos - ball_hpos;
|
|
wire [8:0] ball_vdiff = vpos - ball_vpos;
|
|
|
|
// ball graphics output
|
|
wire ball_hgfx = ball_hdiff < BALL_SIZE;
|
|
wire ball_vgfx = ball_vdiff < BALL_SIZE;
|
|
wire ball_gfx = ball_hgfx && ball_vgfx;
|
|
|
|
// collide with vertical and horizontal boundaries
|
|
// these are set when the ball touches a border
|
|
wire ball_vert_collide = ball_vpos >= 240 - BALL_SIZE;
|
|
wire ball_horiz_collide = ball_hpos >= 256 - BALL_SIZE;
|
|
|
|
// combine signals to RGB output
|
|
wire grid_gfx = (((hpos&7)==0) && ((vpos&7)==0));
|
|
wire r = display_on && (ball_hgfx | ball_gfx);
|
|
wire g = display_on && (grid_gfx | ball_gfx);
|
|
wire b = display_on && (ball_vgfx | ball_gfx);
|
|
assign rgb = {b,g,r};
|
|
|
|
endmodule
|