65 lines
2.9 KiB
Plaintext
65 lines
2.9 KiB
Plaintext
;;;; raylib [core] example - scissor test
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;;;;
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;;;; examples/core/core_scissor_test.c. Needed begin-scissor-mode and
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;;;; end-scissor-mode, now hand-written in vendor/raylib/raylib.fln: they are
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;;;; a begin/end pair inside a frame, which is the class docs/PORTING.md §1 says
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;;;; belongs in the hand-written half and not in the importer's. get-mouse-x
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;;;; and get-mouse-y come from the generated half — their Flan face is the C
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;;;; one, two plain i32s, and there is nothing for a hand-written line to say
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;;;; about them that the header does not already say.
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;;;;
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;;;; The scissor rectangle is a Rectangle of floats in the C and stays one
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;;;; here, even though every use of it casts back to i32, because the one call
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;;;; that takes it whole — draw-rectangle-lines-ex — wants a Rectangle. That
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;;;; is also why the mouse is read through get-mouse-x/get-mouse-y rather than
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;;;; get-mouse-position: the C does the arithmetic in floats from integer
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;;;; readings, and doing it the other way round would round differently on the
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;;;; odd pixel.
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;;;;
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;;;; What this example is really a test of, and what no headless case could
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;;;; be: raylib's scissor rectangle is in screen pixels with y growing DOWN,
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;;;; and the GL call underneath measures from the bottom. raylib flips it. If
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;;;; the binding or the flip were wrong the clip would appear mirrored about
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;;;; the middle of the window — a perfectly plausible picture, in the wrong
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;;;; place — so the only check is the outline drawn around it afterwards
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;;;; landing on the revealed patch.
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import rl "vendor:raylib"
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const screen-width = 800
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const screen-height = 450
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once scissor: rl/Rectangle
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once scissor-mode: bool
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fn main() -> ()
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rl/init-window(screen-width, screen-height,
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"raylib [core] example - scissor test")
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defer rl/close-window()
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scissor = rl/Rectangle{.x 0.0 .y 0.0 .width 300.0 .height 300.0}
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scissor-mode = true
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rl/set-target-fps(60)
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until rl/window-should-close()
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;; Update
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if rl/is-key-pressed(:key-s)
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scissor-mode = not scissor-mode
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;; Centre the scissor area on the mouse.
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scissor.x = f32(rl/get-mouse-x()) - scissor.width / 2.0
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scissor.y = f32(rl/get-mouse-y()) - scissor.height / 2.0
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;; Draw
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rl/with-drawing:
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rl/clear-background(rl/raywhite)
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if scissor-mode
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rl/begin-scissor-mode(i32(scissor.x), i32(scissor.y),
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i32(scissor.width), i32(scissor.height))
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;; A full-screen rectangle and a line of text. Only the part inside the
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;; scissor rectangle reaches the framebuffer, which is the whole example.
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rl/draw-rectangle(0, 0, rl/get-screen-width(), rl/get-screen-height(),
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rl/red)
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rl/draw-text("Move the mouse around to reveal this text!", 190, 200, 20,
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rl/lightgray)
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if scissor-mode
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rl/end-scissor-mode()
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rl/draw-rectangle-lines-ex(scissor, 1.0, rl/black)
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rl/draw-text("Press S to toggle scissor test", 10, 10, 20, rl/black)
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