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CLK/Components/9918/Implementation/Draw.hpp
2023-01-26 21:34:56 -05:00

327 lines
10 KiB
C++

//
// Draw.hpp
// Clock Signal
//
// Created by Thomas Harte on 05/01/2023.
// Copyright © 2023 Thomas Harte. All rights reserved.
//
#ifndef Draw_hpp
#define Draw_hpp
// MARK: - TMS9918
template <Personality personality>
void Base<personality>::draw_tms_character(int start, int end) {
LineBuffer &line_buffer = line_buffers_[output_pointer_.row];
// Paint the background tiles.
const int pixels_left = end - start;
if(this->screen_mode_ == ScreenMode::MultiColour) {
for(int c = start; c < end; ++c) {
pixel_target_[c] = palette[
(line_buffer.patterns[c >> 3][0] >> (((c & 4)^4))) & 15
];
}
} else {
const int shift = start & 7;
int byte_column = start >> 3;
int length = std::min(pixels_left, 8 - shift);
int pattern = Numeric::bit_reverse(line_buffer.patterns[byte_column][0]) >> shift;
uint8_t colour = line_buffer.patterns[byte_column][1];
uint32_t colours[2] = {
palette[(colour & 15) ? (colour & 15) : background_colour_],
palette[(colour >> 4) ? (colour >> 4) : background_colour_]
};
int background_pixels_left = pixels_left;
while(true) {
background_pixels_left -= length;
for(int c = 0; c < length; ++c) {
pixel_target_[c] = colours[pattern&0x01];
pattern >>= 1;
}
pixel_target_ += length;
if(!background_pixels_left) break;
length = std::min(8, background_pixels_left);
byte_column++;
pattern = Numeric::bit_reverse(line_buffer.patterns[byte_column][0]);
colour = line_buffer.patterns[byte_column][1];
colours[0] = palette[(colour & 15) ? (colour & 15) : background_colour_];
colours[1] = palette[(colour >> 4) ? (colour >> 4) : background_colour_];
}
}
// Paint sprites and check for collisions, but only if at least one sprite is active
// on this line.
if(line_buffer.active_sprite_slot) {
const int shift_advance = sprites_magnified_ ? 1 : 2;
// If this is the start of the line clip any part of any sprites that is off to the left.
if(!start) {
for(int index = 0; index < line_buffer.active_sprite_slot; ++index) {
LineBuffer::ActiveSprite &sprite = line_buffer.active_sprites[index];
if(sprite.x < 0) sprite.shift_position -= shift_advance * sprite.x;
}
}
int sprite_buffer[256];
int sprite_collision = 0;
memset(&sprite_buffer[start], 0, size_t(end - start)*sizeof(sprite_buffer[0]));
constexpr uint32_t sprite_colour_selection_masks[2] = {0x00000000, 0xffffffff};
constexpr int colour_masks[16] = {0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
// Draw all sprites into the sprite buffer.
const int shifter_target = sprites_16x16_ ? 32 : 16;
for(int index = line_buffer.active_sprite_slot - 1; index >= 0; --index) {
LineBuffer::ActiveSprite &sprite = line_buffer.active_sprites[index];
if(sprite.shift_position < shifter_target) {
const int pixel_start = std::max(start, sprite.x);
for(int c = pixel_start; c < end && sprite.shift_position < shifter_target; ++c) {
const int shift = (sprite.shift_position >> 1) ^ 7;
int sprite_colour = (sprite.image[shift >> 3] >> (shift & 7)) & 1;
// A colision is detected regardless of sprite colour ...
sprite_collision |= sprite_buffer[c] & sprite_colour;
sprite_buffer[c] |= sprite_colour;
// ... but a sprite with the transparent colour won't actually be visible.
sprite_colour &= colour_masks[sprite.image[2]&15];
pixel_origin_[c] =
(pixel_origin_[c] & sprite_colour_selection_masks[sprite_colour^1]) |
(palette[sprite.image[2]&15] & sprite_colour_selection_masks[sprite_colour]);
sprite.shift_position += shift_advance;
}
}
}
status_ |= sprite_collision << StatusSpriteCollisionShift;
}
}
template <Personality personality>
void Base<personality>::draw_tms_text(int start, int end) {
LineBuffer &line_buffer = line_buffers_[output_pointer_.row];
const uint32_t colours[2] = { palette[background_colour_], palette[text_colour_] };
const int shift = start % 6;
int byte_column = start / 6;
int pattern = Numeric::bit_reverse(line_buffer.patterns[byte_column][0]) >> shift;
int pixels_left = end - start;
int length = std::min(pixels_left, 6 - shift);
while(true) {
pixels_left -= length;
for(int c = 0; c < length; ++c) {
pixel_target_[c] = colours[pattern&0x01];
pattern >>= 1;
}
pixel_target_ += length;
if(!pixels_left) break;
length = std::min(6, pixels_left);
byte_column++;
pattern = Numeric::bit_reverse(line_buffer.patterns[byte_column][0]);
}
}
// MARK: - Master System
template <Personality personality>
void Base<personality>::draw_sms(int start, int end, uint32_t cram_dot) {
if constexpr (is_sega_vdp(personality)) {
LineBuffer &line_buffer = line_buffers_[output_pointer_.row];
int colour_buffer[256];
/*
Add extra border for any pixels that fall before the fine scroll.
*/
int tile_start = start, tile_end = end;
int tile_offset = start;
if(output_pointer_.row >= 16 || !Storage<personality>::horizontal_scroll_lock_) {
for(int c = start; c < (line_buffer.latched_horizontal_scroll & 7); ++c) {
colour_buffer[c] = 16 + background_colour_;
++tile_offset;
}
// Remove the border area from that to which tiles will be drawn.
tile_start = std::max(start - (line_buffer.latched_horizontal_scroll & 7), 0);
tile_end = std::max(end - (line_buffer.latched_horizontal_scroll & 7), 0);
}
uint32_t pattern;
uint8_t *const pattern_index = reinterpret_cast<uint8_t *>(&pattern);
/*
Add background tiles; these will fill the colour_buffer with values in which
the low five bits are a palette index, and bit six is set if this tile has
priority over sprites.
*/
if(tile_start < end) {
const int shift = tile_start & 7;
int byte_column = tile_start >> 3;
int pixels_left = tile_end - tile_start;
int length = std::min(pixels_left, 8 - shift);
pattern = *reinterpret_cast<const uint32_t *>(line_buffer.patterns[byte_column]);
if(line_buffer.names[byte_column].flags&2)
pattern >>= shift;
else
pattern <<= shift;
while(true) {
const int palette_offset = (line_buffer.names[byte_column].flags&0x18) << 1;
if(line_buffer.names[byte_column].flags&2) {
for(int c = 0; c < length; ++c) {
colour_buffer[tile_offset] =
((pattern_index[3] & 0x01) << 3) |
((pattern_index[2] & 0x01) << 2) |
((pattern_index[1] & 0x01) << 1) |
((pattern_index[0] & 0x01) << 0) |
palette_offset;
++tile_offset;
pattern >>= 1;
}
} else {
for(int c = 0; c < length; ++c) {
colour_buffer[tile_offset] =
((pattern_index[3] & 0x80) >> 4) |
((pattern_index[2] & 0x80) >> 5) |
((pattern_index[1] & 0x80) >> 6) |
((pattern_index[0] & 0x80) >> 7) |
palette_offset;
++tile_offset;
pattern <<= 1;
}
}
pixels_left -= length;
if(!pixels_left) break;
length = std::min(8, pixels_left);
byte_column++;
pattern = *reinterpret_cast<const uint32_t *>(line_buffer.patterns[byte_column]);
}
}
/*
Apply sprites (if any).
*/
if(line_buffer.active_sprite_slot) {
const int shift_advance = sprites_magnified_ ? 1 : 2;
// If this is the start of the line clip any part of any sprites that is off to the left.
if(!start) {
for(int index = 0; index < line_buffer.active_sprite_slot; ++index) {
LineBuffer::ActiveSprite &sprite = line_buffer.active_sprites[index];
if(sprite.x < 0) sprite.shift_position -= shift_advance * sprite.x;
}
}
int sprite_buffer[256];
int sprite_collision = 0;
memset(&sprite_buffer[start], 0, size_t(end - start)*sizeof(sprite_buffer[0]));
// Draw all sprites into the sprite buffer.
for(int index = line_buffer.active_sprite_slot - 1; index >= 0; --index) {
LineBuffer::ActiveSprite &sprite = line_buffer.active_sprites[index];
if(sprite.shift_position < 16) {
const int pixel_start = std::max(start, sprite.x);
// TODO: it feels like the work below should be simplifiable;
// the double shift in particular, and hopefully the variable shift.
for(int c = pixel_start; c < end && sprite.shift_position < 16; ++c) {
const int shift = (sprite.shift_position >> 1);
const int sprite_colour =
(((sprite.image[3] << shift) & 0x80) >> 4) |
(((sprite.image[2] << shift) & 0x80) >> 5) |
(((sprite.image[1] << shift) & 0x80) >> 6) |
(((sprite.image[0] << shift) & 0x80) >> 7);
if(sprite_colour) {
sprite_collision |= sprite_buffer[c];
sprite_buffer[c] = sprite_colour | 0x10;
}
sprite.shift_position += shift_advance;
}
}
}
// Draw the sprite buffer onto the colour buffer, wherever the tile map doesn't have
// priority (or is transparent).
for(int c = start; c < end; ++c) {
if(
sprite_buffer[c] &&
(!(colour_buffer[c]&0x20) || !(colour_buffer[c]&0xf))
) colour_buffer[c] = sprite_buffer[c];
}
if(sprite_collision)
status_ |= StatusSpriteCollision;
}
// Map from the 32-colour buffer to real output pixels, applying the specific CRAM dot if any.
pixel_target_[start] = Storage<personality>::colour_ram_[colour_buffer[start] & 0x1f] | cram_dot;
for(int c = start+1; c < end; ++c) {
pixel_target_[c] = Storage<personality>::colour_ram_[colour_buffer[c] & 0x1f];
}
// If the VDP is set to hide the left column and this is the final call that'll come
// this line, hide it.
if(end == 256) {
if(Storage<personality>::hide_left_column_) {
pixel_origin_[0] = pixel_origin_[1] = pixel_origin_[2] = pixel_origin_[3] =
pixel_origin_[4] = pixel_origin_[5] = pixel_origin_[6] = pixel_origin_[7] =
Storage<personality>::colour_ram_[16 + background_colour_];
}
}
}
}
// MARK: - Yamaha
template <Personality personality>
template <ScreenMode mode>
void Base<personality>::draw_yamaha(LineBuffer &buffer, int start, int end) {
// TODO: sprites. And all other graphics modes.
if constexpr (mode == ScreenMode::YamahaGraphics5) {
// TODO: a much smarter loop.
for(int c = start >> 1; c < end >> 1; c++) {
pixel_target_[c] = Storage<personality>::palette_[
buffer.bitmap[c >> 2] >> ((((c & 3) ^ 3) << 1)) & 3
];
}
return;
}
}
template <Personality personality>
void Base<personality>::draw_yamaha(int start, int end) {
LineBuffer &line_buffer = line_buffers_[output_pointer_.row];
if constexpr (is_yamaha_vdp(personality)) {
switch(line_buffer.screen_mode) {
case ScreenMode::YamahaGraphics5: draw_yamaha<ScreenMode::YamahaGraphics5>(line_buffer, start, end); break;
default: break;
}
}
}
// MARK: - Mega Drive
// TODO.
#endif /* Draw_hpp */