112 lines
5.0 KiB
Plaintext
112 lines
5.0 KiB
Plaintext
;;;; raylib [core] example - world to screen
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;;;;
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;;;; examples/core/core_world_screen.c, and the first thing in this directory
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;;;; to draw in 3D at all. That is why it is here: before it, vendor/raylib
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;;;; described no Vector3, no Camera3D and not one call that takes either, so
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;;;; the importer refused every 3D function in raylib.h by name — "Vector3 is
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;;;; a struct the package does not describe". Two defstructs later it refuses
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;;;; none of them, and the generated half grew the cubes, spheres, cylinders
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;;;; and billboards along with the eight lines this example needs.
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;;;;
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;;;; Hand-written in raylib.flan rather than generated, and why each:
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;;;;
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;;;; begin-mode-3d / end-mode-3d a begin/end pair inside a frame, the
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;;;; class docs/PORTING.md §1 names, and taken
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;;;; together the way begin-mode-2d is
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;;;; draw-cube / draw-cube-wires / draw-grid drawn every frame
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;;;; update-camera the Flan face differs: (Ptr Camera3D),
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;;;; because it mutates, and a CameraMode
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;;;; rather than the header's int
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;;;; get-world-to-screen it reads the same camera as the mode
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;;;;
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;;;; What is NOT pinned by anything, and cannot be: Camera3D's first three
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;;;; fields are all Vector3, so every permutation of position, target and up
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;;;; has the identical layout and no computed test can tell them apart. A
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;;;; camera looking from the wrong place is a picture, not a number. The same
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;;;; is true of Vector3's own x, y and z. Only the screen catches those.
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;;;;
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;;;; update-camera in :third-person mode also takes the mouse, which is why
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;;;; the C calls DisableCursor: the cursor is locked to the window and its
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;;;; movement becomes camera rotation rather than a pointer. disable-cursor
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;;;; comes from the generated half — it is called once, before the loop.
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;;;;
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;;;; The C's two TextFormats go through examples/digits.flan, as in the other
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;;;; ports, because Flan has no TextFormat and i64->bytes has no field width.
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(import rl "vendor:raylib")
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(import d "digits.flan")
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(defconst screen-width 800)
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(defconst screen-height 450)
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(defvar camera rl/Camera3D)
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(defvar cube rl/Vector3)
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(defn main [] ()
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(rl/init-window screen-width screen-height
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"raylib [core] example - core world screen")
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(defer (rl/close-window))
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;; `projection` is a CameraProjection, so the keyword resolves against the
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;; enum's members right here and a misspelt projection is a compile error
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;; rather than a 0. raylib's field is `int` and the layout is unchanged —
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;; an enum is four bytes either way.
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(set camera
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(rl/Camera3D {.position (rl/Vector3 {.x 10.0 .y 10.0 .z 10.0})
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.target (rl/Vector3 {.x 0.0 .y 0.0 .z 0.0})
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.up (rl/Vector3 {.x 0.0 .y 1.0 .z 0.0})
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.fovy 45.0
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.projection :perspective}))
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(set cube (rl/Vector3 {.x 0.0 .y 0.0 .z 0.0}))
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;; The mouse becomes the camera's, not a pointer's.
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(rl/disable-cursor)
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(rl/set-target-fps 60)
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(until (rl/window-should-close?)
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;; Update. The camera is passed by address because update-camera writes
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;; to it — a global is an assignable place, so it has an address to take.
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(rl/update-camera (addr camera) :third-person)
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;; Where the point 2.5 units above the cube lands on the screen. This is
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;; the whole example: the same transform raylib is about to draw with,
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;; asked in advance, so a label can be put on a thing in the world.
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(let [label-pos (rl/get-world-to-screen
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(rl/Vector3 {.x (.x cube)
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.y (+ (.y cube) 2.5)
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.z (.z cube)})
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camera)]
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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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(rl/with-mode-3d camera
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(rl/draw-cube cube 2.0 2.0 2.0 rl/red)
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(rl/draw-cube-wires cube 2.0 2.0 2.0 rl/maroon)
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(rl/draw-grid 10 1.0))
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;; And the 2D half, drawn after end-mode-3d and therefore on top of the
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;; cube whatever the depth buffer says — which is the second half of
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;; what the example demonstrates.
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(rl/draw-text "Enemy: 100 / 100"
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(- (i32 (.x label-pos))
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(/ (rl/measure-text "Enemy: 100/100" 20) 2))
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(i32 (.y label-pos)) 20 rl/black)
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(let [x 10]
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(rl/draw-text "Cube position in screen space coordinates: [" x 10 20
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rl/lime)
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(set x (+ x (rl/measure-text
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"Cube position in screen space coordinates: [" 20)))
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(set x (+ x (d/draw-int (i32 (.x label-pos)) x 10 20 rl/lime)))
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(rl/draw-text ", " x 10 20 rl/lime)
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(set x (+ x (rl/measure-text ", " 20)))
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(set x (+ x (d/draw-int (i32 (.y label-pos)) x 10 20 rl/lime)))
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(rl/draw-text "]" x 10 20 rl/lime))
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(rl/draw-text "Text 2d should be always on top of the cube" 10 40 20
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rl/gray)))))
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