analog-firmware/vga/render_lores.c

#include <pico/stdlib.h>
#include "common/config.h"
#include "vga/vgabuf.h"
#include "vga/render.h"
#include "vga/vgaout.h"

uint16_t DELAYED_COPY_DATA(lores_dot_pattern)[16] = {
    0x0000,
    0x2222,
    0x1111,
    0x3333,
    0x0888,
    0x2AAA,
    0x1999,
    0x3BBB,
    0x0444,
    0x2666,
    0x1555,
    0x3777,
    0x0CCC,
    0x2EEE,
    0x1DDD,
    0x3FFF,
};

uint16_t DELAYED_COPY_DATA(lores_palette)[16] = {
    RGB_BLACK,   RGB_MAGENTA, RGB_DBLUE,   RGB_HVIOLET,
    RGB_DGREEN,  RGB_DGRAY,   RGB_HBLUE,   RGB_LBLUE,
    RGB_BROWN,   RGB_HORANGE, RGB_LGRAY,   RGB_PINK,
    RGB_HGREEN,  RGB_YELLOW,  RGB_AQUA,    RGB_WHITE
};


static void render_lores_line(bool p2, uint line);

//#define PAGE2SEL (!(soft_switches & SOFTSW_80STORE) && (soft_switches & SOFTSW_PAGE_2))
#define PAGE2SEL ((soft_switches & (SOFTSW_80STORE | SOFTSW_PAGE_2)) == SOFTSW_PAGE_2)

void DELAYED_COPY_CODE(render_lores)() {
    for(uint line=0; line < 24; line++) {
        render_lores_line(PAGE2SEL, line);
    }
}


void DELAYED_COPY_CODE(render_mixed_lores)() {
    for(uint line=0; line < 20; line++) {
        render_lores_line(PAGE2SEL, line);
    }

    for(uint line=20; line < 24; line++) {
        if(soft_switches & SOFTSW_80COL) {
            render_text80_line(PAGE2SEL, line);
        } else {
            render_text40_line(PAGE2SEL, line);
        }
    }
}


static void DELAYED_COPY_CODE(render_lores_line)(bool p2, uint line) {
    // Construct two scanlines for the two different colored cells at the same time
    struct vga_scanline *sl1 = vga_prepare_scanline();
    struct vga_scanline *sl2 = vga_prepare_scanline();
    uint sl_pos = 0;
    uint i, j;
    uint32_t color1, color2;

    const uint8_t *line_buf = (const uint8_t *)((p2 ? text_p2 : text_p1) + ((line & 0x7) << 7) + (((line >> 3) & 0x3) * 40));

    // Pad 40 pixels on the left to center horizontally
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl_pos++;
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl_pos++;
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_3) | ((text_border|THEN_EXTEND_3) << 16); // 8 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_3) | ((text_border|THEN_EXTEND_3) << 16); // 8 pixels per word
    sl_pos++;

    if((soft_switches & SOFTSW_MONOCHROME) || (mono_palette & 0x8)) {
        for(i = 0; i < 40; i+=2) {
            color1 = lores_dot_pattern[line_buf[i] & 0xf] << 14;
            color2 = lores_dot_pattern[(line_buf[i] >> 4) & 0xf] << 14;
            color1 |= lores_dot_pattern[line_buf[i+1] & 0xf];
            color2 |= lores_dot_pattern[(line_buf[i+1] >> 4) & 0xf];

            for(j = 0; j < 14; j++) {
                uint32_t pixeldata;

                pixeldata = (color1 & 0x8000000) ? (text_fore) : (text_back);
                pixeldata |= (color1 & 0x4000000) ? ((text_fore) << 16) : ((text_back) << 16);
                color1 <<= 2;
                sl1->data[sl_pos] = pixeldata;

                pixeldata = (color2 & 0x8000000) ? (text_fore) : (text_back);
                pixeldata |= (color2 & 0x4000000) ? ((text_fore) << 16) : ((text_back) << 16);
                sl2->data[sl_pos] = pixeldata;
                color2 <<= 2;

                sl_pos++;
            }
        }
    } else {
        for(i = 0; i < 40; i++) {
            color1 = lores_palette[line_buf[i] & 0xf];
            color2 = lores_palette[(line_buf[i] >> 4) & 0xf];

            // Each lores pixel is 7 hires pixels, or 14 VGA pixels wide
            sl1->data[sl_pos] = (color1|THEN_EXTEND_6) | ((color1|THEN_EXTEND_6) << 16);
            sl2->data[sl_pos] = (color2|THEN_EXTEND_6) | ((color2|THEN_EXTEND_6) << 16);
            sl_pos++;
        }
    }

    // Pad 40 pixels on the right to center horizontally
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl_pos++;
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_7) | ((text_border|THEN_EXTEND_7) << 16); // 16 pixels per word
    sl_pos++;
    sl1->data[sl_pos] = (text_border|THEN_EXTEND_3) | ((text_border|THEN_EXTEND_3) << 16); // 8 pixels per word
    sl2->data[sl_pos] = (text_border|THEN_EXTEND_3) | ((text_border|THEN_EXTEND_3) << 16); // 8 pixels per word
    sl_pos++;

    sl1->length = sl_pos;
    sl1->repeat_count = 7;
    vga_submit_scanline(sl1);

    sl2->length = sl_pos;
    sl2->repeat_count = 7;
    vga_submit_scanline(sl2);
}