mirror of https://github.com/pevans/erc-c.git
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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* apple2.draw.c
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*
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* Draw pretty pixels on the screen in the way that Apple II would work.
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* NB: this code is pretty rough, and I expect some changes as we get
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* further into development.
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*/
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#include "apple2/apple2.h"
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#include "apple2/hires.h"
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#include "apple2/lores.h"
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#include "apple2/text.h"
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/*
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* Draw a pixel on screen at the given address.
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* FIXME: we do not draw anything D:
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*/
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void
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apple2_draw_pixel(apple2 *mach, vm_16bit addr)
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{
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}
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/*
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* In single lo-res mode, pixels are 40x40 on the screen. But since our
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* single mode has 280 pixels that _we_ show, this means that a pixel in
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* single lo-res is really 7 columns wide. (Confusing yet?) Each "row" in
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* text page 1 is just a row of visible dots, and 4 rows are equivalent
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* to one "pixel" in lo-res mode.
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*
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* Without text, you get 40x48 pixels.
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*/
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void
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apple2_draw_pixel_lores(apple2 *mach, vm_16bit addr)
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{
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#if 0
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vm_8bit color = vm_segment_get(mach->main, addr);
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vm_8bit top, bottom;
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vm_area loc;
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int *colors;
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// The top color is the low order nibble, so we can blank out the
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// high order nibble by AND-ing a mask of 0x0f (which is b00001111,
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// 15 decimal). The bottom color, ergo, is the high order nibble;
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// for that, we simply shift the color 4 positions to the right.
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top = color & 0x0F;
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bottom = color >> 4;
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// The next thing we need to consider is where we draw the pixel
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loc.xoff = (addr & 0xff) * mach->sysfont->width;
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loc.yoff = (addr >> 8) * mach->sysfont->height;
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loc.width = mach->sysfont->width;
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loc.height = mach->sysfont->height / 2;
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colors = lores_colors[top];
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vm_screen_set_color(mach->screen, colors[0], colors[1], colors[2], 255);
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vm_screen_draw_rect(mach->screen, &loc);
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// The bottom pixel we need to draw now must be offset by the height
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// of the pixel we just drew. (Remember, positive equals down in the
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// y-axis.)
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loc.yoff += loc.height;
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colors = lores_colors[bottom];
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vm_screen_set_color(mach->screen, colors[0], colors[1], colors[2], 255);
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vm_screen_draw_rect(mach->screen, &loc);
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#endif
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}
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/*
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* Draw the 40-column text necessary to render everything on the screen
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* with the machine in its current state.
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*/
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void
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apple2_draw_40col(apple2 *mach)
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{
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size_t addr;
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vm_screen_prepare(mach->screen);
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for (addr = 0x400; addr < 0x800; addr++) {
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apple2_text_draw(mach, addr);
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}
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}
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/*
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* Draw low-resolution graphics on the screen
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*/
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void
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apple2_draw_lores(apple2 *mach)
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{
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size_t addr;
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vm_screen_prepare(mach->screen);
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for (addr = 0x400; addr < 0x800; addr++) {
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apple2_lores_draw(mach, addr);
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}
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}
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/*
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* Draw high-resolution graphics on the screen
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*/
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void
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apple2_draw_hires(apple2 *mach)
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{
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vm_screen_prepare(mach->screen);
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for (int row = 0; row < 192; row++) {
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apple2_hires_draw(mach, row);
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}
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}
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/*
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* Find the right draw method for the machine, based on its display
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* mode, and use that to refresh the screen.
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*/
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void
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apple2_draw(apple2 *mach)
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{
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if (mach->display_mode & DISPLAY_TEXT) {
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apple2_draw_40col(mach);
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return;
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} else if (mach->memory_mode & MEMORY_HIRES) {
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apple2_draw_hires(mach);
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return;
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}
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// The fallback mode is to draw lores graphics
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apple2_draw_lores(mach);
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}
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