71 lines
3.0 KiB
Plaintext
71 lines
3.0 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.flan: 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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(defconst screen-width 800)
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(defconst screen-height 450)
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(defvar scissor rl/Rectangle)
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(defvar scissor-mode bool)
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(defn 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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(set scissor (rl/Rectangle {.x 0.0 .y 0.0 .width 300.0 .height 300.0}))
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(set 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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(when (rl/key-pressed? :s) (set scissor-mode (not scissor-mode)))
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;; Centre the scissor area on the mouse.
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(set (.x scissor) (- (f32 (rl/get-mouse-x)) (/ (.width scissor) 2.0)))
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(set (.y scissor) (- (f32 (rl/get-mouse-y)) (/ (.height scissor) 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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(when scissor-mode
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(rl/begin-scissor-mode (i32 (.x scissor)) (i32 (.y scissor))
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(i32 (.width scissor)) (i32 (.height scissor))))
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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) 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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(when scissor-mode (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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