143 lines
3.9 KiB
Python
143 lines
3.9 KiB
Python
# fx-92 Scientifique Collège+ language interpreter: On-screen drawing
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from sdl2 import *
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class Window:
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"""
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An SDL window with pixel scaling.
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"""
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BLACK = (0, 0, 0, 255)
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WHITE = (255, 255, 255, 255)
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def __init__(self, width, height, scale, quiet=False):
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self.width = width
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self.height = height
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self.scale = scale
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self.quiet = quiet
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def __enter__(self):
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"""
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Enter window context: allocate and create a window.
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"""
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if SDL_WasInit(SDL_INIT_VIDEO):
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raise Exception("Cannot create two windows")
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if SDL_Init(SDL_INIT_VIDEO) < 0:
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raise Exception("Failed to initialize SDL")
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# Create the window
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mode = SDL_WINDOW_HIDDEN if self.quiet else SDL_WINDOW_SHOWN
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self.w = SDL_CreateWindow("fx-92 Scientifique Collège+".encode(),
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SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
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self.width*self.scale, self.height*self.scale, mode)
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if self.w is None:
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raise Exception("Failed to create window")
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# Create the renderer
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self.r = SDL_CreateRenderer(self.w, -1, SDL_RENDERER_ACCELERATED)
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if self.r is None:
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SDL_DestroyWindow(self.w)
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raise Exception("Failed to create renderer")
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# Create the base texture where things will be rendered at scale 1
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self.t = SDL_CreateTexture(self.r, SDL_PIXELFORMAT_ARGB8888,
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SDL_TEXTUREACCESS_TARGET, self.width, self.height)
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if self.t is None:
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SDL_DestroyRenderer(r)
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SDL_DestroyWindow(w)
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raise Exception("Failed to create texture")
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SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, b'0')
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SDL_SetRenderTarget(self.r, self.t)
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self.clear(self.WHITE)
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self.update()
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return self
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def __exit__(self, *args):
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"""
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Exit context: close and destroy window.
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"""
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if self.t is not None:
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SDL_SetRenderTarget(self.r, None)
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SDL_DestroyTexture(self.t)
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if self.r is not None:
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SDL_DestroyRenderer(self.r)
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if self.w is not None:
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SDL_DestroyWindow(self.w)
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SDL_Quit()
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def clear(self, color):
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"""Clear screen in a uniform color."""
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SDL_SetRenderDrawColor(self.r, *color)
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SDL_RenderClear(self.r)
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def line(self, x1, y1, x2, y2, color):
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"""Draw a straight line."""
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SDL_SetRenderDrawColor(self.r, *color)
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# Bresenham line drawing algorithm
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sgn = lambda x: -1 if x < 0 else (1 if x > 0 else 0)
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x, y = x1, y1
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dx, dy = x2 - x1, y2 - y1
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sx, sy = sgn(dx), sgn(dy)
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dx, dy = abs(dx), abs(dy)
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cumul = 0
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SDL_RenderDrawPoint(self.r, x, y)
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if dx >= dy:
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cumul = dx // 2
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for i in range(dx):
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x += sx
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cumul += dy
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if cumul > dx:
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cumul -= dx
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y += sy
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SDL_RenderDrawPoint(self.r, x, y)
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else:
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cumul = dy // 2
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for i in range(dy):
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y += sy
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cumul += dx
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if cumul > dy:
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cumul -= dy
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x += sx
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SDL_RenderDrawPoint(self.r, x, y)
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def wait(self):
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"""Wait for the window to be closed."""
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if self.quiet:
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return
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event = SDL_Event()
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while 1:
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SDL_WaitEvent(event)
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if event.type == SDL_QUIT:
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break
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def update(self):
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"""Push window contents on-screen."""
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# Target the window with scaling
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SDL_SetRenderTarget(self.r, None)
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SDL_RenderSetScale(self.r, self.scale, self.scale)
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# Push that to the screen
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SDL_RenderCopy(self.r, self.t, None, None)
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SDL_RenderPresent(self.r)
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# Go back to the texture
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SDL_SetRenderTarget(self.r, self.t)
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SDL_RenderSetScale(self.r, 1, 1)
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