61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
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/*
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Displays a bitmap using the TMS9928A's Mode 2.
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In Mode 2, the screen is horizontally divided into three
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256×64 pixel areas, each of which gets its own character
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set. By sequentially printing the characters 0 through 255
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in all three areas, the program can simulate a graphics mode
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where each pixel can be set individually.
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The limitation is that every horizontal run of 8 pixels
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can only have two colors (a foreground and background color.)
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The included Mode 2 bitmap was converted with a web utility:
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http://msx.jannone.org/conv/
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*/
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#include <stdlib.h>
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#include <cv.h>
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#include <cvu.h>
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#include "common.h"
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/* link in MODE 2 bitmap data */
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//#link "sailboat.s"
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extern const unsigned char msx_bitmap[0x3807];
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void setup_mode2() {
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cvu_vmemset(0, 0, 0x4000);
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cv_set_screen_mode(CV_SCREENMODE_BITMAP); // mode 2
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cv_set_image_table(IMAGE);
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cv_set_character_pattern_t(PATTERN|0x1fff); // AND mask
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cv_set_color_table(COLOR|0x1fff); // AND mask
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cv_set_sprite_attribute_table(SPRITES);
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}
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void main() {
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// turn off screen
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cv_set_screen_active(false);
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// setup mode 2 grpahics
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setup_mode2();
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// copy pattern and color tables
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cvu_memtovmemcpy(PATTERN, msx_bitmap+7, 0x1800);
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cvu_memtovmemcpy(COLOR, msx_bitmap+7+COLOR, 0x1800);
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// set IMAGE table to incrementing values
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for (int i=0; i<0x300; i++) {
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cvu_voutb(i, IMAGE+i);
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}
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// clear sprite table
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cvu_vmemset(SPRITES, 0, 0x100);
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// turn off screen
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cv_set_screen_active(true);
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while (1) {
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//cv_set_character_pattern_t(PATTERN|rand()); // AND mask
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//cv_set_color_table(COLOR|rand()); // AND mask
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}
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}
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