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-rw-r--r--src/main.zig214
-rw-r--r--src/sdl.zig5
2 files changed, 147 insertions, 72 deletions
diff --git a/src/main.zig b/src/main.zig
index 9a26a6c..89ce7d8 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -3,107 +3,175 @@ const matrix = @import("matrix.zig");
const sdl = @import("sdl.zig");
const Cube = struct {
- points: [8][3]f32,
+ points: [8]Point,
+};
+
+pub const Point = struct {
+ x: f32,
+ y: f32,
+ z: f32,
};
pub fn draw_cube(instance: sdl.instance, cube: Cube) void {
- var c = cube.points;
sdl.draw_color(instance, 255, 255, 255, 0);
- sdl.draw_line(instance, &c[0], &c[1]);
- sdl.draw_line(instance, &c[0], &c[2]);
- sdl.draw_line(instance, &c[0], &c[4]);
+ sdl.draw_line(instance, cube.points[0], cube.points[1]);
+ sdl.draw_line(instance, cube.points[0], cube.points[2]);
+ sdl.draw_line(instance, cube.points[0], cube.points[4]);
- sdl.draw_line(instance, &c[7], &c[6]);
- sdl.draw_line(instance, &c[7], &c[5]);
- sdl.draw_line(instance, &c[7], &c[3]);
+ sdl.draw_line(instance, cube.points[7], cube.points[6]);
+ sdl.draw_line(instance, cube.points[7], cube.points[5]);
+ sdl.draw_line(instance, cube.points[7], cube.points[3]);
- sdl.draw_line(instance, &c[2], &c[3]);
- sdl.draw_line(instance, &c[4], &c[5]);
- sdl.draw_line(instance, &c[1], &c[5]);
+ sdl.draw_line(instance, cube.points[2], cube.points[3]);
+ sdl.draw_line(instance, cube.points[4], cube.points[5]);
+ sdl.draw_line(instance, cube.points[1], cube.points[5]);
- sdl.draw_line(instance, &c[6], &c[2]);
- sdl.draw_line(instance, &c[3], &c[1]);
- sdl.draw_line(instance, &c[4], &c[6]);
+ sdl.draw_line(instance, cube.points[6], cube.points[2]);
+ sdl.draw_line(instance, cube.points[3], cube.points[1]);
+ sdl.draw_line(instance, cube.points[4], cube.points[6]);
}
-pub fn get_shifted_cube(cube: Cube, x: f32, y: f32, z: f32) Cube {
+pub fn shift_cube(cube: Cube, x: f32, y: f32, z: f32) Cube {
var shifted_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
- shifted_cube.points[i][0] = point[0] + x;
- shifted_cube.points[i][1] = point[1] + y;
- shifted_cube.points[i][2] = point[2] + z;
+ shifted_cube.points[i].x = point.x + x;
+ shifted_cube.points[i].y = point.y + y;
+ shifted_cube.points[i].z = point.z + z;
}
-
return shifted_cube;
}
-pub fn get_centered_cube(cube: Cube, offset: f32) Cube {
+pub fn center_cube(cube: Cube, offset: f32) Cube {
var centered_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
- for (point) |dimension, j| {
- centered_cube.points[i][j] = dimension + offset;
- }
+ centered_cube.points[i] = center_point(point, offset);
}
return centered_cube;
}
-pub fn get_projected_cube(cube: Cube, alpha: f32, beta: f32) Cube {
+pub fn center_point(point: Point, offset: f32) Point {
+ return Point{
+ .x = point.x + offset,
+ .y = point.y + offset,
+ .z = 0,
+ };
+}
+
+pub fn rotate_cube(cube: Cube, alpha: f32, beta: f32) Cube {
+ var rotated_cube = Cube{ .points = undefined };
+
+ var a = matrix.new(
+ 3,
+ 3,
+ &[_]f32{
+ 1, 0, 0,
+ 0, @cos(alpha), @sin(alpha),
+ 0, -@sin(alpha), @cos(alpha),
+ },
+ );
+
+ var b = matrix.new(
+ 3,
+ 3,
+ &[_]f32{
+ @cos(beta), 0, -@sin(beta),
+ 0, 1, 0,
+ @sin(beta), 0, @cos(beta),
+ },
+ );
+
+ for (cube.points) |point, i| {
+ var m = matrix.multiply(
+ matrix.multiply(a, b),
+ matrix.new(3, 1, &[3]f32{ point.x, point.y, point.z }),
+ ).x.items;
+ rotated_cube.points[i].x = m[0];
+ rotated_cube.points[i].y = m[1];
+ rotated_cube.points[i].z = m[2];
+ }
+
+ return rotated_cube;
+}
+
+pub fn project_cube(cube: Cube) Cube {
var projected_cube = Cube{ .points = undefined };
- var ax = [_]f32{
- 1, 0, 0,
- 0, @cos(alpha), @sin(alpha),
- 0, -@sin(alpha), @cos(alpha),
- };
- var a = matrix.new(3, 3, &ax);
+ for (cube.points) |point, i| {
+ projected_cube.points[i] = project_point(point);
+ }
- var bx = [_]f32{
- @cos(beta), 0, -@sin(beta),
- 0, 1, 0,
- @sin(beta), 0, @cos(beta),
- };
- var b = matrix.new(3, 3, &bx);
+ return projected_cube;
+}
+pub fn project_point(p: Point) Point {
var cx = [_]f32{
1, 0, 0,
0, 1, 0,
0, 0, 0,
};
var c = matrix.new(3, 3, &cx);
+ var m = matrix.multiply(c, matrix.new(3, 1, &[3]f32{ p.x, p.y, p.z })).x.items;
- for (cube.points) |point, i| {
- var p = point;
- var x = matrix.multiply(c, matrix.multiply(matrix.multiply(a, b), matrix.new(3, 1, &p))).x.items;
- projected_cube.points[i][0] = x[0];
- projected_cube.points[i][1] = x[1];
- }
+ var projected_point = Point{
+ .x = m[0],
+ .y = m[1],
+ .z = m[2],
+ };
- return projected_cube;
+ return projected_point;
}
-pub fn get_scaled_cube(cube: Cube, scale: f32) Cube {
+pub fn scale_cube(cube: Cube, scale: f32) Cube {
var scaled_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
- for (point) |dimension, j| {
- scaled_cube.points[i][j] = dimension * scale;
- }
+ scaled_cube.points[i].x = point.x * scale;
+ scaled_cube.points[i].y = point.y * scale;
+ scaled_cube.points[i].z = point.z * scale;
}
return scaled_cube;
}
+pub fn draw_axis(instance: sdl.instance) void {
+ var o = center_point(
+ project_point(Point{ .x = 00, .y = 00, .z = 00 }),
+ 250,
+ );
+ var x = center_point(
+ project_point(Point{ .x = 50, .y = 00, .z = 00 }),
+ 250,
+ );
+ var y = center_point(
+ project_point(Point{ .x = 00, .y = 50, .z = 00 }),
+ 250,
+ );
+ var z = center_point(
+ project_point(Point{ .x = 00, .y = 00, .z = 50 }),
+ 250,
+ );
+
+ sdl.draw_color(instance, 255, 0, 0, 0);
+ sdl.draw_line(instance, o, x);
+
+ sdl.draw_color(instance, 0, 255, 0, 0);
+ sdl.draw_line(instance, o, y);
+
+ sdl.draw_color(instance, 0, 0, 255, 0);
+ sdl.draw_line(instance, o, z);
+}
+
pub fn main() anyerror!void {
var instance = sdl.init();
const unit_cube = Cube{
- .points = [8][3]f32{
- [3]f32{ 01, 01, 01 },
- [3]f32{ 01, 01, -1 },
- [3]f32{ 01, -1, 01 },
- [3]f32{ 01, -1, -1 },
- [3]f32{ -1, 01, 01 },
- [3]f32{ -1, 01, -1 },
- [3]f32{ -1, -1, 01 },
- [3]f32{ -1, -1, -1 },
+ .points = [8]Point{
+ Point{ .x = 01, .y = 01, .z = 01 },
+ Point{ .x = 01, .y = 01, .z = -1 },
+ Point{ .x = 01, .y = -1, .z = 01 },
+ Point{ .x = 01, .y = -1, .z = -1 },
+ Point{ .x = -1, .y = 01, .z = 01 },
+ Point{ .x = -1, .y = 01, .z = -1 },
+ Point{ .x = -1, .y = -1, .z = 01 },
+ Point{ .x = -1, .y = -1, .z = -1 },
},
};
@@ -123,28 +191,34 @@ pub fn main() anyerror!void {
sdl.draw_color(instance, 0, 0, 0, 0);
sdl.clear(instance);
- var cube = get_projected_cube(unit_cube, alpha, beta);
- cube = get_scaled_cube(cube, 50);
- cube = get_centered_cube(cube, 250);
+ var cube = rotate_cube(unit_cube, alpha, beta);
+ cube = scale_cube(cube, 50);
+ cube = project_cube(cube);
+ cube = center_cube(cube, 250);
draw_cube(instance, cube);
- cube = get_projected_cube(unit_cube, alpha + 90, beta + 90);
- cube = get_scaled_cube(cube, 25);
- cube = get_centered_cube(cube, 250);
+ cube = rotate_cube(unit_cube, alpha + 90, beta + 90);
+ cube = scale_cube(cube, 25);
+ cube = project_cube(cube);
+ cube = center_cube(cube, 250);
draw_cube(instance, cube);
- cube = get_shifted_cube(unit_cube, 5, 0, 0);
- cube = get_projected_cube(cube, alpha, beta);
- cube = get_scaled_cube(cube, 25);
- cube = get_centered_cube(cube, 250);
+ cube = shift_cube(unit_cube, 5, 0, 0);
+ cube = rotate_cube(cube, 2 * alpha, 2 * beta);
+ cube = scale_cube(cube, 25);
+ cube = project_cube(cube);
+ cube = center_cube(cube, 250);
draw_cube(instance, cube);
- cube = get_shifted_cube(unit_cube, -5, 0, 0);
- cube = get_projected_cube(cube, alpha, beta);
- cube = get_scaled_cube(cube, 25);
- cube = get_centered_cube(cube, 250);
+ cube = shift_cube(unit_cube, -5, 0, 0);
+ cube = rotate_cube(cube, 2 * alpha, 2 * beta);
+ cube = scale_cube(cube, 25);
+ cube = project_cube(cube);
+ cube = center_cube(cube, 250);
draw_cube(instance, cube);
+ draw_axis(instance);
+
beta += 0.01;
alpha += 0.01;
diff --git a/src/sdl.zig b/src/sdl.zig
index c7b9906..b84bbfb 100644
--- a/src/sdl.zig
+++ b/src/sdl.zig
@@ -1,5 +1,6 @@
const std = @import("std");
const sdl = @cImport(@cInclude("SDL2/SDL.h"));
+const Point = @import("main.zig").Point;
pub const instance = struct {
renderer: ?*sdl.SDL_Renderer,
@@ -29,8 +30,8 @@ pub fn init() instance {
};
}
-pub fn draw_line(i: instance, p1: []f32, p2: []f32) void {
- _ = sdl.SDL_RenderDrawLineF(i.renderer, p1[0], p1[1], p2[0], p2[1]);
+pub fn draw_line(i: instance, p1: Point, p2: Point) void {
+ _ = sdl.SDL_RenderDrawLineF(i.renderer, p1.x, p1.y, p2.x, p2.y);
}
pub fn delay(t: u32) void {
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 21:29:00 +0000