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8bitworkshop/presets/verilog-vga/ball_paddle.v
2019-01-27 15:29:37 -05:00

245 lines
7.4 KiB
Verilog

`include "hvsync_generator.v"
`include "digits10.v"
`include "scoreboard.v"
/*
A brick-smashing ball-and-paddle game.
*/
module ball_paddle_top(clk, reset, hpaddle, hsync, vsync, rgb);
input clk;
input reset;
input hpaddle;
output hsync, vsync;
output [2:0] rgb;
wire display_on;
wire [9:0] hpos;
wire [9:0] vpos;
reg [9:0] paddle_pos; // paddle X position
reg [9:0] ball_x; // ball X position
reg [9:0] ball_y; // ball Y position
reg ball_dir_x; // ball X direction (0=left, 1=right)
reg ball_speed_x; // ball speed (0=1 pixel/frame, 1=2 pixels/frame)
reg ball_dir_y; // ball Y direction (0=up, 1=down)
reg brick_array [0:BRICKS_H*BRICKS_V-1]; // 16*8 = 128 bits
wire [3:0] score0; // score right digit
wire [3:0] score1; // score left digit
wire [3:0] lives; // # lives remaining
reg incscore; // incscore signal
reg declives = 0; // TODO
localparam BRICKS_H = 16; // # of bricks across
localparam BRICKS_V = 8; // # of bricks down
localparam BALL_DIR_LEFT = 0;
localparam BALL_DIR_RIGHT = 1;
localparam BALL_DIR_DOWN = 1;
localparam BALL_DIR_UP = 0;
localparam PADDLE_WIDTH = 63; // horizontal paddle size
localparam BALL_SIZE = 12; // square ball size
// video sync generator
hvsync_generator hvsync_gen(
.clk(clk),
.reset(reset),
.hsync(hsync),
.vsync(vsync),
.display_on(display_on),
.hpos(hpos),
.vpos(vpos)
);
// scoreboard
wire score_gfx; // output from score generator
player_stats stats(
.reset(reset),
.score0(score0),
.score1(score1),
.incscore(incscore),
.lives(lives),
.declives(declives)
);
scoreboard_generator score_gen(
.score0(score0),
.score1(score1),
.lives(lives),
.vpos(vpos),
.hpos(hpos),
.board_gfx(score_gfx)
);
wire [5:0] hcell = hpos[9:4]; // horizontal brick index
wire [5:0] vcell = vpos[9:4]; // vertical brick index
wire lr_border = hcell==0 || hcell==31; // along horizontal border?
// TODO: unsigned compare doesn't work in JS
wire [9:0] paddle_rel_x = ((hpos-paddle_pos) & 10'h3ff);
// player paddle graphics signal
wire paddle_gfx = (vcell == 28) && (paddle_rel_x < PADDLE_WIDTH);
// difference between ball position and video beam
wire [9:0] ball_rel_x = (hpos - ball_x);
wire [9:0] ball_rel_y = (vpos - ball_y);
// ball graphics signal
wire ball_gfx = ball_rel_x < BALL_SIZE
&& ball_rel_y < BALL_SIZE;
reg main_gfx; // main graphics signal (bricks and borders)
reg brick_present; // 1 when we are drawing a brick
reg [6:0] brick_index;// index into array of current brick
// brick graphics signal
wire brick_gfx = lr_border || (brick_present && vpos[3:1] != 0 && hpos[4:2] != 4);
// scan bricks: compute brick_index and brick_present flag
always @(posedge clk)
// see if we are scanning brick area
if (vpos[9:7] == 1 && !lr_border)
begin
// every 16th pixel, starting at 8
if (hpos[4:0] == 8) begin
// compute brick index
brick_index <= {vpos[6:4], hpos[8:5]};
end
// every 17th pixel
else if (hpos[4:0] == 9) begin
// load brick bit from array
brick_present <= !brick_array[brick_index];
end
end else begin
brick_present <= 0;
end
// only works when paddle at bottom of screen!
// (we don't want to mess w/ paddle position during visible portion)
always @(posedge hsync)
if (!hpaddle)
paddle_pos <= vpos;
// 1 when ball signal intersects main (brick + border) signal
wire ball_pixel_collide = main_gfx & ball_gfx;
reg ball_collide_paddle = 0;
reg [3:0] ball_collide_bits = 0;
// compute ball collisions with paddle and playfield
always @(posedge clk)
// clear all collide bits for frame
if (vsync) begin
ball_collide_bits <= 0;
ball_collide_paddle <= 0;
end else begin
if (ball_pixel_collide) begin
// did we collide w/ paddle?
if (paddle_gfx) begin
ball_collide_paddle <= 1;
end
// ball has 4 collision quadrants
if (!ball_rel_x[2] & !ball_rel_y[2]) ball_collide_bits[0] <= 1;
if (ball_rel_x[2] & !ball_rel_y[2]) ball_collide_bits[1] <= 1;
if (!ball_rel_x[2] & ball_rel_y[2]) ball_collide_bits[2] <= 1;
if (ball_rel_x[2] & ball_rel_y[2]) ball_collide_bits[3] <= 1;
end
end
// compute ball collisions with brick and increment score
always @(posedge clk)
if (ball_pixel_collide && brick_present) begin
brick_array[brick_index] <= 1;
incscore <= 1; // increment score
end else begin
incscore <= 0; // reset incscore
end
// computes position of ball in relation to center of paddle
wire signed [9:0] ball_paddle_dx = ball_x - paddle_pos + 8;
// ball bounce: determine new velocity/direction
always @(posedge vsync or posedge reset)
begin
if (reset) begin
ball_dir_y <= BALL_DIR_DOWN;
end else
// ball collided with paddle?
if (ball_collide_paddle) begin
// bounces upward off of paddle
ball_dir_y <= BALL_DIR_UP;
// which side of paddle, left/right?
ball_dir_x <= (ball_paddle_dx < 20) ? BALL_DIR_LEFT : BALL_DIR_RIGHT;
// hitting with edge of paddle makes it fast
ball_speed_x <= ball_collide_bits[3:0] != 4'b1100;
end else begin
// collided with playfield
// TODO: can still slip through corners
// compute left/right bounce
casez (ball_collide_bits[3:0])
4'b01?1: ball_dir_x <= BALL_DIR_RIGHT; // left edge/corner
4'b1101: ball_dir_x <= BALL_DIR_RIGHT; // left corner
4'b101?: ball_dir_x <= BALL_DIR_LEFT; // right edge/corner
4'b1110: ball_dir_x <= BALL_DIR_LEFT; // right corner
default: ;
endcase
// compute top/bottom bounce
casez (ball_collide_bits[3:0])
4'b1011: ball_dir_y <= BALL_DIR_DOWN;
4'b0111: ball_dir_y <= BALL_DIR_DOWN;
4'b001?: ball_dir_y <= BALL_DIR_DOWN;
4'b0001: ball_dir_y <= BALL_DIR_DOWN;
4'b0100: ball_dir_y <= BALL_DIR_UP;
4'b1?00: ball_dir_y <= BALL_DIR_UP;
4'b1101: ball_dir_y <= BALL_DIR_UP;
4'b1110: ball_dir_y <= BALL_DIR_UP;
default: ;
endcase
end
end
// ball motion: update ball position
always @(negedge vsync or posedge reset)
begin
if (reset) begin
// reset ball position to top center
ball_x <= 256;
ball_y <= 320;
end else begin
// move ball horizontal and vertical position
if (ball_dir_x == BALL_DIR_RIGHT)
ball_x <= ball_x + (ball_speed_x?1:0) + 1;
else
ball_x <= ball_x - (ball_speed_x?1:0) - 1;
ball_y <= ball_y + (ball_dir_y==BALL_DIR_DOWN?1:-1);
end
end
// compute main_gfx
always @(*)
begin
case (vpos[9:4])
0,1,2: main_gfx = score_gfx; // scoreboard
3: main_gfx = 0;
4: main_gfx = 1; // top border
8,9,10,11,12,13,14,15: main_gfx = brick_gfx; // brick rows 1-8
28: main_gfx = paddle_gfx | lr_border; // paddle
29: main_gfx = hpos[0] ^ vpos[0]; // bottom border
default: main_gfx = lr_border; // left/right borders
endcase
end
// combine signals to RGB output
wire grid_gfx = (((hpos&15)==0) || ((vpos&15)==0));
wire r = display_on && (ball_gfx | paddle_gfx);
wire g = display_on && (main_gfx | ball_gfx);
wire b = display_on && (grid_gfx | ball_gfx | brick_present);
assign rgb = {b,g,r};
endmodule