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Implement scroll up operation #46

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merged 2 commits into from
Jul 13, 2024
Merged

Implement scroll up operation #46

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91a743c
Implement scroll up operation.
craigthomas Jul 10, 2024
a347737
Add integration test to make sure scroll up is called.
craigthomas Jul 10, 2024
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4 changes: 4 additions & 0 deletions chip8/cpu.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -317,6 +317,10 @@ def clear_return(self):
num_lines = self.operand & 0x000F
self.screen.scroll_down(num_lines, self.bitplane)
self.last_op = f"Scroll Down {num_lines:01X}"
elif sub_operation == 0x00D0:
num_lines = self.operand & 0x000F
self.screen.scroll_up(num_lines, self.bitplane)
self.last_op = f"Scroll Up {num_lines:01X}"
else:
try:
self.clear_routines[operation]()
Expand Down
48 changes: 47 additions & 1 deletion chip8/screen.py
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,7 @@ def scroll_down(self, num_lines, bitplane):
for y in range(max_y - num_lines, max_y):
self.draw_pixel(x, y, False, bitplane)

# Start copying pixels from the top to the bottom and shift by 4 pixels
# Start copying pixels from the top to the bottom and shift by n pixels
for x in range(max_x):
for y in range(max_y - num_lines - 1, -1, -1):
current_pixel = self.get_pixel(x, y, bitplane)
Expand All @@ -220,6 +220,52 @@ def scroll_down(self, num_lines, bitplane):
for y in range(num_lines):
self.draw_pixel(x, y, False, bitplane)

def scroll_up(self, num_lines, bitplane):
"""
Scroll the screen up by num_lines.

:param num_lines: the number of lines to scroll up
:param bitplane: the bitplane to scroll
"""
if bitplane == 0:
return

mode_scale = 1 if self.mode == SCREEN_MODE_EXTENDED else 2
actual_lines = num_lines * mode_scale * self.scale_factor
if bitplane == 3:
self.surface.scroll(0, -actual_lines)
self.surface.fill(
self.pixel_colors[0],
(
0,
self.height * mode_scale * self.scale_factor - actual_lines,
self.width * mode_scale * self.scale_factor,
self.height * mode_scale * self.scale_factor
)
)
self.update()
return

max_x = self.get_width()
max_y = self.get_height()

# Blank out any pixels in the top n lines that we will copy to
for x in range(max_x):
for y in range(num_lines):
self.draw_pixel(x, y, False, bitplane)

# Start copying pixels from the top to the bottom and shift up by n pixels
for x in range(max_x):
for y in range(num_lines, max_y):
current_pixel = self.get_pixel(x, y, bitplane)
self.draw_pixel(x, y, False, bitplane)
self.draw_pixel(x, y - num_lines, current_pixel, bitplane)

# Blank out any pixels in the bottom num_lines horizontal lines
for x in range(max_x):
for y in range(max_y - num_lines, max_y):
self.draw_pixel(x, y, False, bitplane)

def scroll_left(self, bitplane):
"""
Scroll the screen left 4 pixels.
Expand Down
5 changes: 5 additions & 0 deletions test/test_chip8cpu.py
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Original file line number Diff line number Diff line change
Expand Up @@ -852,6 +852,11 @@ def test_scroll_down_called(self):
self.cpu.clear_return()
self.screen.scroll_down.assert_called_with(4, 1)

def test_scroll_up_called(self):
self.cpu.operand = 0x00D4
self.cpu.clear_return()
self.screen.scroll_up.assert_called_with(4, 1)

def test_scroll_right_called(self):
self.cpu.operand = 0x00FB
self.cpu.clear_return()
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47 changes: 47 additions & 0 deletions test/test_chip8screen.py
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -123,6 +123,18 @@ def test_scroll_down_bitplane_0_does_nothing(self):
self.assertFalse(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))

def test_scroll_up_bitplane_0_does_nothing(self):
self.screen.init_display()
self.screen.draw_pixel(0, 1, 1, 1)
self.screen.draw_pixel(0, 1, 1, 2)
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))
self.screen.scroll_up(1, 0)
self.assertFalse(self.screen.get_pixel(0, 0, 1))
self.assertFalse(self.screen.get_pixel(0, 0, 2))
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))

def test_scroll_down_bitplane_1(self):
self.screen.init_display()
self.screen.draw_pixel(0, 0, 1, 1)
Expand All @@ -134,6 +146,17 @@ def test_scroll_down_bitplane_1(self):
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))

def test_scroll_up_bitplane_1(self):
self.screen.init_display()
self.screen.draw_pixel(0, 1, 1, 1)
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))
self.screen.scroll_up(1, 1)
self.assertTrue(self.screen.get_pixel(0, 0, 1))
self.assertFalse(self.screen.get_pixel(0, 0, 2))
self.assertFalse(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))

def test_scroll_down_bitplane_1_both_pixels_active(self):
self.screen.init_display()
self.screen.draw_pixel(0, 0, 1, 1)
Expand All @@ -146,6 +169,18 @@ def test_scroll_down_bitplane_1_both_pixels_active(self):
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))

def test_scroll_up_bitplane_1_both_pixels_active(self):
self.screen.init_display()
self.screen.draw_pixel(0, 1, 1, 1)
self.screen.draw_pixel(0, 1, 1, 2)
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))
self.screen.scroll_up(1, 1)
self.assertTrue(self.screen.get_pixel(0, 0, 1))
self.assertFalse(self.screen.get_pixel(0, 0, 2))
self.assertFalse(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))

def test_scroll_down_bitplane_3_both_pixels_active(self):
self.screen.init_display()
self.screen.draw_pixel(0, 0, 1, 1)
Expand All @@ -158,6 +193,18 @@ def test_scroll_down_bitplane_3_both_pixels_active(self):
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))

def test_scroll_up_bitplane_3_both_pixels_active(self):
self.screen.init_display()
self.screen.draw_pixel(0, 1, 1, 1)
self.screen.draw_pixel(0, 1, 1, 2)
self.assertTrue(self.screen.get_pixel(0, 1, 1))
self.assertTrue(self.screen.get_pixel(0, 1, 2))
self.screen.scroll_up(1, 3)
self.assertTrue(self.screen.get_pixel(0, 0, 1))
self.assertTrue(self.screen.get_pixel(0, 0, 2))
self.assertFalse(self.screen.get_pixel(0, 1, 1))
self.assertFalse(self.screen.get_pixel(0, 1, 2))

def test_scroll_right_bitplane_0_does_nothing(self):
self.screen.init_display()
self.screen.draw_pixel(0, 0, 1, 1)
Expand Down
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