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render_lores.c
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render_lores.c
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#include "render.h"
#include <pico/stdlib.h>
#include "buffers.h"
#include "colors.h"
#include "vga.h"
static void render_lores_line(uint line);
#ifdef APPLE_MODEL_IIE
static void render_dlores_line(uint line);
#endif
static inline uint lores_line_to_mem_offset(uint line) {
return ((line & 0x7) << 7) + (((line >> 3) & 0x3) * 40);
}
void render_lores() {
vga_prepare_frame();
// Skip 48 lines to center vertically
vga_skip_lines(48);
#ifdef APPLE_MODEL_IIE
if(soft_80col && soft_dhires) {
for(uint line = 0; line < 24; line++) {
render_dlores_line(line);
}
} else
#endif
{
for(uint line = 0; line < 24; line++) {
render_lores_line(line);
}
}
}
void render_mixed_lores() {
vga_prepare_frame();
// Skip 48 lines to center vertically
vga_skip_lines(48);
#ifdef APPLE_MODEL_IIE
if(soft_80col && soft_dhires) {
for(uint line = 0; line < 20; line++) {
render_dlores_line(line);
}
} else
#endif
{
for(uint line = 0; line < 20; line++) {
render_lores_line(line);
}
}
for(uint line = 20; line < 24; line++) {
render_text_line(line, false);
}
}
static void render_lores_line(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;
const uint8_t *page = is_page2_display_enabled() ? text_mainmem_page2 : text_mainmem_page1;
const uint8_t *line_buf = page + lores_line_to_mem_offset(line);
// Pad 40 pixels on the left to center horizontally
sl1->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl_pos++;
sl1->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl_pos++;
sl1->data[sl_pos] = (0 | THEN_EXTEND_3) | ((0 | THEN_EXTEND_3) << 16); // 8 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_3) | ((0 | THEN_EXTEND_3) << 16); // 8 pixels per word
sl_pos++;
if(soft_monochrom) {
const uint32_t bits_to_pixels[4] = {
((uint32_t)mono_bg_color << 16) | mono_bg_color,
((uint32_t)mono_bg_color << 16) | mono_fg_color,
((uint32_t)mono_fg_color << 16) | mono_bg_color,
((uint32_t)mono_fg_color << 16) | mono_fg_color,
};
for(int i = 0; i < 40; i += 2) {
// Construct the bit patterns for both lines of the next two lores columns by extending each
// pixel's 4-bit color pattern to 14 bits
uint32_t bitpattern1 = (uint32_t)(line_buf[i] & 0xf) | ((uint32_t)(line_buf[i + 1] & 0xf) << 14);
uint32_t bitpattern2 = (uint32_t)((line_buf[i] >> 4) & 0xf) | ((uint32_t)((line_buf[i + 1] >> 4) & 0xf) << 14);
bitpattern1 |= (bitpattern1 << 4);
bitpattern1 |= (bitpattern1 & ~(uint32_t)0xc0) << 8;
bitpattern2 |= (bitpattern2 << 4);
bitpattern2 |= (bitpattern2 & ~(uint32_t)0xc0) << 8;
// Render out the pixels, least significant bit first
for(int j = 0; j < 14; j++) {
sl1->data[sl_pos] = bits_to_pixels[bitpattern1 & 0x03];
sl2->data[sl_pos] = bits_to_pixels[bitpattern2 & 0x03];
sl_pos++;
bitpattern1 >>= 2;
bitpattern2 >>= 2;
}
}
} else {
for(int i = 0; i < 40; i++) {
uint32_t color1 = ntsc_palette[line_buf[i] & 0xf];
uint32_t color2 = ntsc_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++;
}
}
if(soft_scanline_emulation) {
// Just insert a blank scanline between each rendered scanline
sl1->data[sl_pos] = THEN_WAIT_HSYNC;
sl2->data[sl_pos] = THEN_WAIT_HSYNC;
sl_pos++;
sl1->repeat_count = 3;
sl2->repeat_count = 3;
} else {
sl1->repeat_count = 7;
sl2->repeat_count = 7;
}
sl1->length = sl_pos;
sl2->length = sl_pos;
vga_submit_scanline(sl1);
vga_submit_scanline(sl2);
}
#ifdef APPLE_MODEL_IIE
static void render_dlores_line(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;
const uint8_t *page_main = is_page2_display_enabled() ? text_mainmem_page2 : text_mainmem_page1;
const uint8_t *page_aux = is_page2_display_enabled() ? text_auxmem_page2 : text_auxmem_page1;
const uint line_offset = lores_line_to_mem_offset(line);
const uint8_t *line_main = page_main + line_offset;
const uint8_t *line_aux = page_aux + line_offset;
// Pad 40 pixels on the left to center horizontally
sl1->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl_pos++;
sl1->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_7) | ((0 | THEN_EXTEND_7) << 16); // 16 pixels per word
sl_pos++;
sl1->data[sl_pos] = (0 | THEN_EXTEND_3) | ((0 | THEN_EXTEND_3) << 16); // 8 pixels per word
sl2->data[sl_pos] = (0 | THEN_EXTEND_3) | ((0 | THEN_EXTEND_3) << 16); // 8 pixels per word
sl_pos++;
if(soft_monochrom) {
const uint32_t bits_to_pixels[4] = {
((uint32_t)mono_bg_color << 16) | mono_bg_color,
((uint32_t)mono_bg_color << 16) | mono_fg_color,
((uint32_t)mono_fg_color << 16) | mono_bg_color,
((uint32_t)mono_fg_color << 16) | mono_fg_color,
};
for(int i = 0; i < 40; i++) {
// Construct the bit patterns for both lines of the next two lores columns by extending each
// pixel's 4-bit color pattern to 7 bits
uint32_t bitpattern1 = (uint32_t)(line_aux[i] & 0xf) | ((uint32_t)(line_main[i] & 0xf) << 7);
uint32_t bitpattern2 = (uint32_t)((line_aux[i] >> 4) & 0xf) | ((uint32_t)((line_main[i] >> 4) & 0xf) << 7);
bitpattern1 |= ((bitpattern1 & ~(uint32_t)0x7) << 4);
bitpattern2 |= ((bitpattern2 & ~(uint32_t)0x7) << 4);
// Render out the next 14 pixels, least significant bit first
for(int j = 0; j < 7; j++) {
sl1->data[sl_pos] = bits_to_pixels[bitpattern1 & 0x03];
sl2->data[sl_pos] = bits_to_pixels[bitpattern2 & 0x03];
sl_pos++;
bitpattern1 >>= 2;
bitpattern2 >>= 2;
}
}
} else {
for(int i = 0; i < 40; i++) {
// First pixel data is from aux memory
uint32_t color_aux1 = ntsc90_palette[line_aux[i] & 0xf];
uint32_t color_aux2 = ntsc90_palette[(line_aux[i] >> 4) & 0xf];
// Next pixel data is from main memory
uint32_t color_main1 = ntsc_palette[line_main[i] & 0xf];
uint32_t color_main2 = ntsc_palette[(line_main[i] >> 4) & 0xf];
// Each double-lores pixel is 3.5 hires pixels, or 7 VGA pixels wide
sl1->data[sl_pos] = (color_aux1 | THEN_EXTEND_6) | ((color_main1 | THEN_EXTEND_6) << 16);
sl2->data[sl_pos] = (color_aux2 | THEN_EXTEND_6) | ((color_main2 | THEN_EXTEND_6) << 16);
sl_pos++;
}
}
if(soft_scanline_emulation) {
// Just insert a blank scanline between each rendered scanline
sl1->data[sl_pos] = THEN_WAIT_HSYNC;
sl2->data[sl_pos] = THEN_WAIT_HSYNC;
sl_pos++;
sl1->repeat_count = 3;
sl2->repeat_count = 3;
} else {
sl1->repeat_count = 7;
sl2->repeat_count = 7;
}
sl1->length = sl_pos;
sl2->length = sl_pos;
vga_submit_scanline(sl1);
vga_submit_scanline(sl2);
}
#endif