92 lines
4.7 KiB
Plaintext
92 lines
4.7 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.fln 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 :camera-third-person mode also takes the mouse, which
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;;;; is why the C calls DisableCursor: the cursor is locked to the window and
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;;;; its 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.fln, 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.fln"
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const screen-width = 800
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const screen-height = 450
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once camera: rl/Camera3D
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once cube: rl/Vector3
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fn 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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camera = rl/Camera3D{.position rl/Vector3{.x 10.0 .y 10.0 .z 10.0} .target rl/Vector3{.x 0.0 .y 0.0 .z 0.0} .up rl/Vector3{.x 0.0 .y 1.0 .z 0.0} .fovy 45.0 .projection :projection-perspective}
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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), :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(rl/Vector3{.x cube.x, .y cube.y + 2.5, .z cube.z},
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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(label-pos.x) - rl/measure-text("Enemy: 100/100", 20) / 2,
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i32(label-pos.y), 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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x += rl/measure-text("Cube position in screen space coordinates: [", 20)
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x += d/draw-int(i32(label-pos.x), x, 10, 20, rl/lime)
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rl/draw-text(", ", x, 10, 20, rl/lime)
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x += rl/measure-text(", ", 20)
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x += d/draw-int(i32(label-pos.y), 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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