/*  * Generate a VGA signal using a PIC32 microcontroller.  *  * Copyright (C) 2017, 2018 Paul Boddie <paul@boddie.org.uk>  *  * This program is free software: you can redistribute it and/or modify  * it under the terms of the GNU General Public License as published by  * the Free Software Foundation, either version 3 of the License, or  * (at your option) any later version.  *  * This program is distributed in the hope that it will be useful,  * but WITHOUT ANY WARRANTY; without even the implied warranty of  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  * GNU General Public License for more details.  *  * You should have received a copy of the GNU General Public License  * along with this program.  If not, see <http://www.gnu.org/licenses/>.  */   #include "debug.h" #include "display.h" #include "font.h" #include "image.h" #include "init.h" #include "pic32_c.h" #include "utils.h" #include "viewport.h"  /* Specific functionality. */  #include "devconfig.h" #include "main.h" #include "vga_display.h"    /* Define the scroll increment depending on how many DMA channels are used.    CPU-driven transfers permit an increment of 1. */  #ifdef TRANSFER_CPU #define SCROLL_XSTEP    1 #else #define SCROLL_XSTEP    LINE_CHANNELS #endif    /* Define timers if not indicated in the build configuration. */  #ifndef LINE_TIMER #define LINE_TIMER      2 #endif  #ifndef TRANSFER_TIMER #define TRANSFER_TIMER  0 #endif  /* Define different output ports and pins for parallel mode. */  #ifndef PARALLEL_MODE #define VGA_OUTPUT      PORTB #define OC1_PIN         RPA0R #define OC2_PIN         RPA1R #define LED_PIN         (1 << 3) #else #define VGA_OUTPUT      PM_REG(0, PMxDIN) #define OC1_PIN         RPB4R #define OC2_PIN         RPB5R #define LED_PIN         (1 << 2) #endif    /* Initialise memory for a multi-frame display. */  static Display(banner_config, LINE_LENGTH, 10, 1); static Display(display_config, LINE_LENGTH, LINE_COUNT - 10, FRAME_COUNT);    /* Bundled image and font data. */  extern image_t screendata; extern image_t sprite;  static SpriteOverwriting(scr, &screendata, &display_config, FRAME_COUNT, -1);  extern uint8_t fontchars[]; extern font_range_t fontbase;  static Font(font_config, fontchars, &fontbase);    /* Plot the revealed region at the edge of the screen after scrolling. */  static void plot_screen_edge(int xorigin, int yorigin, int xstep, int ystep) {     image_update_scrolled_tiled_image(&scr, xorigin, yorigin, xstep, ystep); }    /* Update the sprite position. */  static void update_sprite_position(sprite_t *s, int *xdir, int *ydir) {     position_t *last = image_get_stored_position(s, wrap_value(display_config.frame - 1, display_config.frames));     position_t *next = image_get_sprite_position(s);      if (((*xdir > 0) && (last->x < display_config.line_length - s->image->width - *xdir)) ||         ((*xdir < 0) && (last->x > -*xdir)))     {         next->x = last->x + *xdir;     }     else     {         next->x = last->x;         if (*xdir)             *xdir = -*xdir;     }      if (((*ydir > 0) && (last->y < display_config.line_count - s->image->height - *ydir)) ||         ((*ydir < 0) && (last->y > -*ydir)))     {         next->y = last->y + *ydir;     }     else     {         next->y = last->y;         if (*ydir)             *ydir = -*ydir;     } }  /* Move a sprite around on the framebuffer. */  static void animate(uint32_t delay) {     /* Stores of background details, replotted when moving the sprite. */      Sprite(s1, &sprite, &display_config, FRAME_COUNT, 0x0c);     Sprite(s2, &sprite, &display_config, FRAME_COUNT, 0x0c);     Sprite(s3, &sprite, &display_config, FRAME_COUNT, 0x0c);      /* Scrolling viewport. */      Viewport(v, &display_config, SCROLL_XSTEP, 1, plot_screen_edge);      /* Reset the viewport to a well-defined state. */      viewport_set_origin(&v, 0, 0);      /* Sprite and scrolling directions. */      int xdir[] = {1, -1, 0}, ydir[] = {1, 0, -1};      /* Sprite positions. */      image_set_sprite_position(&s1, 0, 0);     image_set_sprite_position(&s2, display_config.line_length - s2.image->width, 0);     image_set_sprite_position(&s3, 0, display_config.line_count - s3.image->height);      /* Animation loop. */      while (1)     {         image_plot_sprite(&s1);         image_plot_sprite(&s2);         image_plot_sprite(&s3);          /* Update the display with the frame details. */          vga_set_frame(&display_config, 1);         wait(delay);          /* Select the next frame to plot to. */          display_select_next_frame(&display_config);          /* Prepare the frame for updates. */          viewport_unplot_sprite_from_image(&v, &s1, &scr);         viewport_unplot_sprite_from_image(&v, &s2, &scr);         viewport_unplot_sprite_from_image(&v, &s3, &scr);          /* Update the origin to scroll the screen. */          /* Due to the effect of a simple screen start increment in the            dual channel configuration, horizontal scrolling involves two            pixel increments and thus requires a two-pixel column to be            plotted per scrolling increment. */          /* For vertically-scaled backgrounds, the full resolution image            is traversed by multiples of the scrolling increment. */          viewport_update_origin(&v, xdir[0] * SCROLL_XSTEP,                                    ydir[0]);          /* Update the position of the sprite being plotted. */          update_sprite_position(&s1, &xdir[0], &ydir[0]);         update_sprite_position(&s2, &xdir[1], &ydir[1]);         update_sprite_position(&s3, &xdir[2], &ydir[2]);     } }  /* Set up a banner. */  static void setup_banner(void) {     int frame, x = 0, y = 0;      for (frame = 0; frame < banner_config.frames; frame++)     {         /* Obtain the frame. */          display_select_frame(&banner_config, frame);          write_string(&banner_config, &font_config, "VGA display example", &x, &y, 0xff);     }      display_select_frame(&banner_config, 0); }  /* Set up a background. */  static void setup_background(void) {     int frame;      for (frame = 0; frame < display_config.frames; frame++)     {         /* Obtain the frame. */          display_select_frame(&display_config, frame);          /* Tile the image on the screen. */          image_tile_sprite(&scr, 0, 0, display_config.line_length,                                       display_config.line_count,                                       0, 0);     }      display_select_frame(&display_config, 0); }  static void setup(void) {     setup_banner();     setup_background(); }    /* Main program. */  void main(void) {     init_memory();     init_pins();     init_outputs();      unlock_config();     config_oc();     config_uart();     lock_config();  #ifndef TRANSFER_CPU     init_dma(); #endif  #ifdef PARALLEL_MODE     init_pm();      /* Configure parallel master mode. */      pm_init(0, 0b10);     pm_set_output(0, 1, 0);     pm_on(0); #endif      uart_init(1, FPB, 115200);     uart_on(1);      /* Set the display to a well-defined state. */      init_display(&banner_config);     init_display(&display_config);      /* Initialise VGA output with one or two line channels, configuring a line        timer and any transfer timer, with an initiating channel being introduced        if a transfer timer is specified. */      init_vga_with_timers(&banner_config, LINE_CHANNELS, LINE_TIMER, TRANSFER_TIMER);     vga_add_window(&display_config);      /* Configure VGA output transfer to the output register, also configuring        output compare units for horizontal and vertical sync. */      vga_configure_transfer(VGA_OUTPUT);     vga_configure_sync(1, 2);      interrupts_on();      /* Move a sprite around on the screen with a delay between each movement. */      setup();     animate(1); }    /* Exception and interrupt handlers. */  void exception_handler(void) {     blink(1 << 22, PORTA, LED_PIN); }  void interrupt_handler(void) {     vga_interrupt_handler(); }    /* Peripheral pin configuration. */  void config_oc(void) {     /* Map OC1. */      REG(OC1_PIN) = 0b0101;      /* Map OC2. */      REG(OC2_PIN) = 0b0101; }  void config_uart(void) {     /* Map U1RX to RPB13. */      REG(U1RXR) = 0b0011;        /* U1RXR<3:0> = 0011 (RPB13) */      /* Map U1TX to RPB15. */      REG(RPB15R) = 0b0001;       /* RPB15R<3:0> = 0001 (U1TX) */      /* Set RPB13 to input. */      SET_REG(TRISB, 1 << 13); }