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|
%% This is an example. Feel free to copy and reuse as you wish.
%%
%% This example was almost entirely generated by Grok 3 with
%% minor human-driven changes (such as fixing the position of
%% legs). The raster is imperfect, either missing sides or
%% sides being incorrectly defined.
%%
%% The conversation leading to this example can be found at
%% https://x.com/i/grok/share/IN1mWW5a4g1zcqYTInA4X8BXP
-module(duck_engine).
-export([run/0]).
run() ->
% Initialize SDL with video subsystem
case sdl:start([video]) of
ok ->
% Ensure SDL stops when this process exits
sdl:stop_on_exit(),
% Create a window (title, x, y, width, height, flags)
{ok, Window} = sdl_window:create(<<"Duck Engine">>, 100, 100, 800, 600, []),
% Create a renderer with acceleration and vsync
{ok, Renderer} = sdl_renderer:create(Window, -1, [accelerated, present_vsync]),
% Define initial duck vertices
Duck = duck_vertices(),
% Start the rendering loop with initial rotation angles
loop(Window, Renderer, Duck, {0.0, 0.0, 0.0});
{application_start_error, Reason} ->
io:format("Failed to start esdl2 application: ~p~n", [Reason]),
error;
{error, String} ->
io:format("SDL initialization failed: ~s~n", [String]),
error
end.
% Main rendering loop
loop(Window, Renderer, Duck, {XAngle, YAngle, ZAngle}) ->
% Set clear color to white (R, G, B, A)
sdl_renderer:set_draw_color(Renderer, 255, 255, 255, 255),
% Clear the renderer
sdl_renderer:clear(Renderer),
% Rotate the duck vertices
RotatedDuck = rotate_duck(Duck, XAngle, YAngle, ZAngle),
% Project and draw the rotated duck
project_and_draw(RotatedDuck, Renderer),
% Present the rendered frame
sdl_renderer:present(Renderer),
% Process all events and determine if we should quit
case handle_events() of
quit -> ok; % Exit if quit event is detected
continue ->
% Sleep for ~16ms (approx 60 FPS) and continue with updated angles
timer:sleep(16),
loop(Window, Renderer, Duck, {XAngle + 0.03, YAngle + 0.05, ZAngle + 0.04})
end.
% Handle all pending events in the queue
handle_events() ->
case sdl_events:poll() of
#{type := quit} -> quit; % Quit event detected
#{type := _} -> handle_events(); % Other event, keep processing
false -> continue % No more events, proceed with rendering
end.
% Rotate duck vertices around X, Y, and Z axes
rotate_duck(Vertices, XAngle, YAngle, ZAngle) ->
RotX = matrix3d:rotate_x(XAngle),
RotY = matrix3d:rotate_y(YAngle),
RotZ = matrix3d:rotate_z(ZAngle),
% Combine rotation matrices: X * (Y * Z)
TempMatrix = matrix3d:multiply(RotY, RotZ),
CombinedMatrix = matrix3d:multiply(RotX, TempMatrix),
[matrix3d:apply(CombinedMatrix, Vertex) || Vertex <- Vertices].
% Define duck vertices (unchanged from your description)
duck_vertices() ->
[
% Body: 0-11
{1.0, 1.4, 0.8}, {1.0, 1.4, -0.8}, {1.4, 0.6, 0.8}, {1.4, 0.6, -0.8},
{1.0, -1.0, 0.8}, {1.0, -1.0, -0.8}, {-1.0, 1.4, 0.8}, {-1.0, 1.4, -0.8},
{-1.4, 0.6, 0.8}, {-1.4, 0.6, -0.8}, {-1.0, -1.0, 0.8}, {-1.0, -1.0, -0.8},
% Head: 12-19
{-1.4, 2.0, 0.6}, {-1.4, 2.0, -0.6}, {-1.4, 1.2, 0.6}, {-1.4, 1.2, -0.6},
{-2.0, 2.0, 0.6}, {-2.0, 2.0, -0.6}, {-2.0, 1.2, 0.6}, {-2.0, 1.2, -0.6},
% Beak: 20-25
{-2.4, 1.8, 0.2}, {-2.4, 1.8, -0.2}, {-2.4, 1.4, 0.2}, {-2.4, 1.4, -0.2},
{-2.0, 1.6, 0.2}, {-2.0, 1.6, -0.2},
% Right Leg: 26-29
{-1.0, -1.0, -0.3}, {-1.0, -2.0, -0.3}, {-1.2, -2.0, -0.1}, {-1.2, -2.0, -0.5},
% Left Leg: 30-33
{-1.0, -1.0, 0.3}, {-1.0, -2.0, 0.3}, {-1.2, -2.0, 0.1}, {-1.2, -2.0, 0.5}
].
% Project 3D vertices to 2D and draw filled triangles
project_and_draw(Vertices, Renderer) ->
Projected = [project_vertex(V) || V <- Vertices],
% Body - Front (bright yellow)
sdl_renderer:set_draw_color(Renderer, 255, 255, 0, 255),
FrontTriangles = [
[0, 2, 4], [6, 8, 10], [0, 6, 10], [0, 4, 10]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- FrontTriangles],
% Body - Back (darker yellow)
sdl_renderer:set_draw_color(Renderer, 220, 220, 0, 255),
BackTriangles = [
[1, 3, 5], [7, 9, 11], [1, 7, 11], [1, 5, 11]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- BackTriangles],
% Body - Right (golden yellow)
sdl_renderer:set_draw_color(Renderer, 255, 215, 0, 255),
RightTriangles = [
[0, 1, 3], [3, 5, 4], [0, 2, 4]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- RightTriangles],
% Body - Left (pale yellow)
sdl_renderer:set_draw_color(Renderer, 255, 245, 0, 255),
LeftTriangles = [
[6, 7, 9], [9, 11, 10], [6, 8, 10]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- LeftTriangles],
% Body - Top (light yellow)
sdl_renderer:set_draw_color(Renderer, 255, 255, 100, 255),
TopTriangles = [
[0, 1, 6], [1, 7, 6]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- TopTriangles],
% Body - Bottom (deep yellow)
sdl_renderer:set_draw_color(Renderer, 255, 200, 0, 255),
BottomTriangles = [
[4, 5, 10], [5, 11, 10]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- BottomTriangles],
% Neck (match head color: slightly greenish yellow)
sdl_renderer:set_draw_color(Renderer, 245, 255, 0, 255),
NeckTriangles = [
[6, 7, 18], [7, 19, 18], % Left-back to head bottom
[0, 1, 14], [1, 15, 14] % Right-front to head bottom
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- NeckTriangles],
% Head (slightly greenish yellow)
sdl_renderer:set_draw_color(Renderer, 245, 255, 0, 255),
HeadTriangles = [
[12, 13, 15], [12, 14, 15], [16, 17, 19], [16, 18, 19],
[12, 16, 18], [12, 14, 18], [13, 17, 19], [13, 15, 19]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- HeadTriangles],
% Beak (orange-yellow)
sdl_renderer:set_draw_color(Renderer, 255, 235, 0, 255),
BeakTriangles = [
[20, 21, 23], [20, 22, 23], [20, 24, 25], [20, 21, 25],
[22, 24, 25], [22, 23, 25]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- BeakTriangles],
% Legs (muted yellow)
sdl_renderer:set_draw_color(Renderer, 235, 235, 0, 255),
LegTriangles = [
[26, 27, 28], [26, 27, 29], [30, 31, 32], [30, 31, 33]
],
[fill_triangle(Renderer, [lists:nth(A+1, Projected) || A <- Tri]) || Tri <- LegTriangles],
% Draw edges in black
sdl_renderer:set_draw_color(Renderer, 0, 0, 0, 255),
Edges = [
{0, 1}, {1, 3}, {3, 5}, {5, 4}, {4, 2}, {2, 0},
{6, 7}, {7, 9}, {9, 11}, {11, 10}, {10, 8}, {8, 6},
{0, 6}, {1, 7}, {2, 8}, {3, 9}, {4, 10}, {5, 11},
{12, 13}, {13, 15}, {15, 14}, {14, 12},
{16, 17}, {17, 19}, {19, 18}, {18, 16},
{12, 16}, {13, 17}, {14, 18}, {15, 19},
{6, 16}, {7, 17}, {8, 18}, {9, 19},
{20, 21}, {21, 23}, {23, 22}, {22, 20},
{20, 24}, {21, 25}, {22, 24}, {23, 25}, {24, 25},
{16, 24}, {17, 25},
{26, 27}, {27, 28}, {27, 29},
{30, 31}, {31, 32}, {31, 33}
],
[draw_line(Renderer, lists:nth(A+1, Projected), lists:nth(B+1, Projected)) || {A, B} <- Edges].
% Project a 3D vertex to 2D screen coordinates (unchanged)
project_vertex({X, Y, Z}) ->
ZOffset = Z + 10,
Scale = 800,
ScreenX = 400 + round((X / ZOffset) * Scale),
ScreenY = 300 + round((Y / ZOffset) * Scale),
{ScreenX, ScreenY}.
% Draw a line (unchanged)
draw_line(Renderer, {X1, Y1}, {X2, Y2}) ->
sdl_renderer:draw_line(Renderer, X1, Y1, X2, Y2).
% Fill a triangle with scanline approach, handling degenerate cases
fill_triangle(Renderer, Points) ->
[{X1, Y1}, {X2, Y2}, {X3, Y3}] = lists:sort(fun({_, YA}, {_, YB}) -> YA =< YB end, Points),
if
Y1 == Y3 -> % Degenerate case: all Ys equal
if
X1 == X2 andalso X2 == X3 -> ok; % Single point
true ->
XMin = lists:min([X1, X2, X3]),
XMax = lists:max([X1, X2, X3]),
sdl_renderer:draw_line(Renderer, XMin, Y1, XMax, Y1)
end;
true ->
case {Y1 == Y2, Y2 == Y3} of
{true, false} -> % Flat top
fill_flat_top_triangle(Renderer, X1, Y1, X2, Y2, X3, Y3);
{false, true} -> % Flat bottom
fill_flat_bottom_triangle(Renderer, X1, Y1, X2, Y2, X3, Y3);
{false, false} -> % General case
T = (Y2 - Y1) / (Y3 - Y1),
XMid = X1 + round(T * (X3 - X1)),
fill_flat_bottom_triangle(Renderer, X1, Y1, X2, Y2, XMid, Y2),
fill_flat_top_triangle(Renderer, X2, Y2, XMid, Y2, X3, Y3)
end
end.
% Fill a flat-bottom triangle
fill_flat_bottom_triangle(Renderer, X1, Y1, X2, Y2, X3, _) ->
lists:foreach(
fun(Y) ->
T = (Y - Y1) / (Y2 - Y1),
XA = X1 + round(T * (X2 - X1)),
XB = X1 + round(T * (X3 - X1)),
{XStart, XEnd} = if XA =< XB -> {XA, XB}; true -> {XB, XA} end,
sdl_renderer:draw_line(Renderer, XStart, Y, XEnd, Y)
end,
lists:seq(round(Y1), round(Y2))
).
% Fill a flat-top triangle
fill_flat_top_triangle(Renderer, X1, Y1, X2, _, X3, Y3) ->
lists:foreach(
fun(Y) ->
T = (Y - Y1) / (Y3 - Y1),
XA = X1 + round(T * (X3 - X1)),
XB = X2 + round(T * (X3 - X2)),
{XStart, XEnd} = if XA =< XB -> {XA, XB}; true -> {XB, XA} end,
sdl_renderer:draw_line(Renderer, XStart, Y, XEnd, Y)
end,
lists:seq(round(Y1), round(Y3))
).
|
