snark13
737c974400
- Split tests/ (libc feature tests) and examples/ (real apps); shared
app.mk in repo root, was examples/example.mk
- libc/io/* split into libc/{conio,env,errno,file,mouse,string,sys,
time,video}/ — clearer module boundaries
- New examples/mdview/: markdown viewer (Phases 1-5 + light nested
lists). Headers (H1-H4), HR, ulist/olist/quote with nesting via
leading spaces, fenced code blocks, inline emphasis (bold/italic/
underscore/code), wrap/unwrap mode with soft wrap (F2), horizontal
pan (← →) with '>' truncation indicator
- libc additions: scroll() in conio (ESTEX SCROLL), strlwr/strupr,
gets() test
- Makefile updates across tests/ for the new shared app.mk path
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
121 lines
3.8 KiB
C
121 lines
3.8 KiB
C
/*
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* gfx_dbuf — double-buffering demo.
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*
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* Renders a moving rectangle by alternating between page 0 and page 1:
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* - Each frame: draw to the HIDDEN page, then flip visible to it.
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* - The page currently being displayed is never written to, so the
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* user only sees fully-rendered frames (no half-drawn artefacts,
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* no flicker from the per-frame clear).
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*
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* Indicators help verify the swap is actually happening:
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* - A small colour swatch in the top-right alternates each frame:
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* one shade when page 0 is shown, another when page 1. If the
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* box motion looks smooth and the swatch flickers between the two
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* shades at the animation rate, the swap is working.
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*
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* NOTE: each graphics screen has its OWN palette page (screen 0 →
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* palette 0, screen 1 → palette 1). We load the same palette into
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* both so the colours look identical regardless of which page is
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* currently visible. See memory/sprinter_graphics.md.
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*
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* Press any key to exit.
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*/
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#include <stdio.h>
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#include <conio.h>
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#include <gfx.h>
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#include <stdint.h>
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static uint8_t palette[256 * 4];
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#define COL_BLACK 0x00
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#define COL_BG 0x20
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#define COL_STRIPE 0x60
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#define COL_TEXT 0xC0
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#define COL_BOX 0xFF
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#define COL_PAGE0 0x40
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#define COL_PAGE1 0xE0
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static void make_palette(void)
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{
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for (int i = 0; i < 256; i++) {
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palette[i*4+0] = (uint8_t)i;
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palette[i*4+1] = (uint8_t)i;
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palette[i*4+2] = (uint8_t)i;
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palette[i*4+3] = 0;
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}
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}
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static void draw_frame(int box_x, int box_y, uint8_t page_indicator)
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{
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gfx_clear256(COL_BG);
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/* Static decoration — identical on both pages so the swap doesn't
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* flicker the chrome. */
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gfx_fill_rect256(0, 0, GFX_WIDTH, 8, COL_STRIPE);
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gfx_fill_rect256(0, GFX_HEIGHT - 8, GFX_WIDTH, 8, COL_STRIPE);
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gfx_text256(8, 16, "double-buffering demo", COL_TEXT, COL_BG);
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gfx_text256(8, GFX_HEIGHT - 24,
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"press a key to exit", COL_TEXT, COL_BG);
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/* Page indicator — different shade for each page so a flickering
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* box here proves the swap is happening. */
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gfx_fill_rect256(GFX_WIDTH - 24, 16, 12, 12,
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page_indicator ? COL_PAGE1 : COL_PAGE0);
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/* The animated box. */
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gfx_fill_rect256(box_x, box_y, 40, 30, COL_BOX);
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gfx_rect256 (box_x, box_y, 40, 30, COL_BLACK);
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}
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int main(void)
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{
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make_palette();
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uint8_t prev = gfx_init(GFX_MODE_320x256x256, 0);
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/* Each graphics screen has its own palette page (0→pal 0, 1→pal 1).
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* Load the same data into both so the visual swap is seamless. */
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gfx_pal_load(0, 0, 0, palette);
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gfx_pal_load(1, 0, 0, palette);
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/* Clear both pages so the very first flip doesn't reveal garbage. */
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gfx_set_draw_page(0);
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gfx_clear256(COL_BG);
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gfx_set_draw_page(1);
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gfx_clear256(COL_BG);
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/* Bouncing rect state. */
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int box_x = 10;
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int box_y = 100;
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int dx = 3;
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int dy = 2;
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const int box_w = 40, box_h = 30;
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while (!kbhit()) {
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uint8_t hidden = 1 - gfx_get_visible_page();
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gfx_set_draw_page(hidden);
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draw_frame(box_x, box_y, hidden);
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/* Wait for the next frame interrupt before flipping, so the
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* page swap lands during vertical retrace and the user never
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* sees a half-drawn frame. */
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gfx_wait_vsync();
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gfx_set_visible_page(hidden);
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/* Step the box; bounce off all four walls. */
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box_x += dx;
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if (box_x < 0) { box_x = 0; dx = -dx; }
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if (box_x + box_w > GFX_WIDTH) { box_x = GFX_WIDTH - box_w; dx = -dx; }
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box_y += dy;
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if (box_y < 8) { box_y = 8; dy = -dy; }
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if (box_y + box_h > GFX_HEIGHT-8) { box_y = GFX_HEIGHT-8 - box_h; dy = -dy; }
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}
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(void)getch();
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gfx_done(prev);
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puts("done");
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return 0;
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}
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