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attempt to fix charset rendering (no success)

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This commit is contained in:
Franco Colmenarez
2023-07-10 21:43:01 -05:00
parent 703e819e80
commit 265da3470f
1 changed files with 50 additions and 13 deletions
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63
snes-frontend/src/ppu.rs
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@@ -61,21 +61,58 @@ fn render_background(bgdebug: &mut BgDebug, registers: &PPURegisters) {
fn render_background_char_2bpp(bgdebug: &mut BgDebug, registers: &PPURegisters) {
let vram_base_address = registers.get_bg_char_base_address(bgdebug.background) as usize;
let vram = registers.vram();
let width = 8 * 16;
let height = 8 * 8;
for x in 0..width {
for y in 0..height {
let width: usize = 8 * 16;
let height: usize = 8 * 8;
for y in 0..height {
for x in 0..width {
let current_char = (x / 8) + ((y / 8) * 16);
let current_char_column = x.rem_euclid(8);
let current_char_row = y.rem_euclid(8);
// 8x8 pixels, 2 bitplanes, each word (16bit) holds 8 pixels
// so 1 char is 8 bytes x 2
let char_base_vram_address = current_char * 8 * 2;
let vram_address = vram_base_address + (
char_base_vram_address + (current_char_row * 2)
);
let current_pixel = x + (y * width);
let vram_address = vram_base_address + (current_pixel / 4);
let byte = vram[vram_address];
let lsb_bitplane= vram[vram_address];
let msb_bitplane= vram[vram_address + 1];
let pixels = [
(byte >> 6) & 0b11,
(byte >> 4) & 0b11,
(byte >> 2) & 0b11,
byte & 0b11,
(
(lsb_bitplane >> 7) |
((msb_bitplane >> 7) << 1)
),
(
((lsb_bitplane >> 6) & 1) |
(((msb_bitplane >> 6) & 1) << 1)
),
(
((lsb_bitplane >> 5) & 1) |
(((msb_bitplane >> 5) & 1) << 1)
),
(
((lsb_bitplane >> 4) & 1) |
(((msb_bitplane >> 4) & 1) << 1)
),
(
((lsb_bitplane >> 3) & 1) |
(((msb_bitplane >> 3) & 1) << 1)
),
(
((lsb_bitplane >> 2) & 1) |
(((msb_bitplane >> 2) & 1) << 1)
),
(
((lsb_bitplane >> 1) & 1) |
(((msb_bitplane >> 1) & 1) << 1)
),
(
(lsb_bitplane & 1) |
((msb_bitplane & 1) << 1)
),
];
let pixel_index = current_pixel.rem_euclid(4);
let effective_pixel = pixels[pixel_index];
let effective_pixel = pixels[current_char_column];
let fb_index = current_pixel * 4;
let r = fb_index;
@@ -130,7 +167,7 @@ pub fn background_window(bgdebug: &mut BgDebug, registers: &PPURegisters, ui: &i
.opened(&mut bgdebug.is_enabled)
.build(ui, || {
ui.text("Charset:");
let charset_image = imgui::Image::new(char_texture_id, [16.0 * 8.0, 8.0 * 8.0]);
let charset_image = imgui::Image::new(char_texture_id, [16.0 * 8.0 * 2.0, 8.0 * 8.0 * 2.0]);
charset_image.build(&ui);
ui.separator();
ui.text("Background:");