SowinskiBraeden/3d-cube
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add small sphere thats broken inside cube

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SowinskiBraeden committed 2026-01-09 13:56:23 -08:00
1 parent bd32748bbe
commit 47ad4e47bc
3 files changed
+165 -14
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main.c
+165 -14
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@@ -1,3 +1,6 @@
#ifndef M_PI
#define M_PI 3.141592653589793238462643383279502884 /* pi */
#endif
#include <SDL2/SDL.h>
#include <SDL2/SDL_render.h>
#include <math.h>
@@ -48,7 +51,8 @@ VEC3 rotate(VEC3 v, double angle)
{
return (VEC3) {
x: v.x * cos(angle) - v.z * sin(angle),
// y: v.y * cos(angle) - v.x * sin(angle),
// y: v.x * sin(angle) + v.y * cos(angle),
// z: v.z,
y: v.y,
z: v.x * sin(angle) + v.z * cos(angle),
};
@@ -63,6 +67,103 @@ VEC3 translate_z(VEC3 v)
};
}
void draw_point(SDL_Renderer *renderer, VEC2 v)
{
const float size = 2.0;
SDL_Rect point_rect;
// Adjust x and y to center the point visually, if desired
point_rect.x = v.x - size / 2;
point_rect.y = v.y - size / 2;
point_rect.w = size;
point_rect.h = size;
// Draw the filled rectangle
SDL_RenderFillRect(renderer, &point_rect);
}
void draw_circle(SDL_Renderer *renderer, VEC2 v, float r)
{
float x = r, y = 0.0;
// Initialising the value of P
int P = 1 - r;
while (x > y)
{
y++;
// Mid-point is inside or on the perimeter
if (P <= 0)
P = P + 2*y + 1;
// Mid-point is outside the perimeter
else
{
x--;
P = P + 2*y - 2*x + 1;
}
// All the perimeter points have already been printed
if (x < y)
break;
// Printing the generated point and its reflection
// in the other octants after translation
draw_point(renderer, (VEC2){x + v.x, y + v.y});
draw_point(renderer, (VEC2){-x + v.x, y + v.y});
draw_point(renderer, (VEC2){x + v.x, -y + v.y});
draw_point(renderer, (VEC2){-x + v.x, -y + v.y});
// If the generated point is on the line x = y then
// the perimeter points have already been printed
if (x != y)
{
draw_point(renderer, (VEC2){y + v.x, x + v.y});
draw_point(renderer, (VEC2){-y + v.x, x + v.y});
draw_point(renderer, (VEC2){y + v.x, -x + v.y});
draw_point(renderer, (VEC2){-y + v.x, -x + v.y});
}
}
}
void draw_ellipse_points(SDL_Renderer *renderer, VEC2 *points, size_t num_points)
{
for (size_t i = 0; i < num_points; ++i)
{
VEC2 a = points[i];
VEC2 b = points[(i + (size_t) sqrt(num_points)) % num_points];
SDL_RenderDrawLine(renderer, a.x, a.y, b.x, b.y);
}
}
void draw_2d_ellipse(SDL_Renderer *renderer, int x, int y, int rx, int ry) {
// Number of points to approximate the ellipse
const int num_points = 100;
VEC2 points[num_points];
for (int i = 0; i < num_points; ++i)
{
float angle = 2.0f * M_PI * i / num_points;
VEC2 p = (VEC2){
x + (int)(rx * cosf(angle)),
y + (int)(ry * sinf(angle)),
};
// printf("(%f, %f)\n" ,p.x, p.y);
// draw_point(renderer, p);
points[i] = p;
}
draw_ellipse_points(renderer, points, num_points);
for (int i = 0; i < num_points; ++i)
{
VEC2 a = points[i];
VEC2 b = points[(i + 1) % (num_points)];
SDL_RenderDrawLine(renderer, a.x, a.y, b.x, b.y);
}
}
int main(void)
{
if (SDL_Init(SDL_INIT_VIDEO) != 0)
@@ -110,16 +211,47 @@ int main(void)
double angle = 0;
VEC3 vertecies[8] = {
{x: 0.25, y: 0.25, z: 0.25},
{x: -0.25, y: 0.25, z: 0.25},
{x: -0.25, y: -0.25, z: 0.25},
{x: 0.25, y: -0.25, z: 0.25},
int stacks = 20;
int slices = 20;
float r = 0.175;
{x: 0.25, y: 0.25, z: -0.25},
{x: -0.25, y: 0.25, z: -0.25},
{x: -0.25, y: -0.25, z: -0.25},
{x: 0.25, y: -0.25, z: -0.25},
VEC3 sphere[(stacks) * (slices)];
for (int i = 0; i < stacks; i++) {
// Phi (angle of latitude, ranges from 0 to PI)
float phi = M_PI * (float)i / (float)stacks;
float sinPhi = sin(phi);
float cosPhi = cos(phi);
for (int j = 0; j < slices; j++) {
// Theta (angle of longitude, ranges from 0 to 2*PI)
float theta = 2.f * M_PI * (float)j / (float)slices;
float sinTheta = sin(theta);
float cosTheta = cos(theta);
// Convert spherical coordinates to Cartesian (x, y, z)
// The choice of axis mapping may vary. Here Y is vertical.
sphere[i * stacks + j] = (VEC3){
x: r * cosTheta * sinPhi,
y: r * cosPhi,
z: r * sinTheta * sinPhi,
};
}
}
size_t num_points = sizeof(sphere) / sizeof(sphere[0]);
// CUBE
VEC3 vertecies[8] = {
{x: 0.3, y: 0.3, z: 0.3},
{x: -0.3, y: 0.3, z: 0.3},
{x: -0.3, y: -0.3, z: 0.3},
{x: 0.3, y: -0.3, z: 0.3},
{x: 0.3, y: 0.3, z: -0.3},
{x: -0.3, y: 0.3, z: -0.3},
{x: -0.3, y: -0.3, z: -0.3},
{x: 0.3, y: -0.3, z: -0.3},
};
int faces[6][4] = {
@@ -150,7 +282,7 @@ int main(void)
delta = (now - last_time) / 1000.0f; // seconds
last_time = now;
angle += 3.141592654 * delta;
angle += M_PI * delta * 0.5;
// clear scren
SDL_SetRenderDrawColor(
@@ -172,7 +304,25 @@ int main(void)
RAINDROP_A
);
// Draw faces
// draw sphere
// draw_circle(renderer, (VEC2){WINDOW_W/2, WINDOW_H/2}, 150);
// draw_2d_ellipse(renderer, WINDOW_W/2, WINDOW_H/2, 150, 150);
VEC2 ellipse[num_points];
for (size_t i = 0; i < num_points; i++)
{
VEC3 v = sphere[i];
v = rotate(v, angle);
v = translate_z(v);
// v.y = v.y - 0.125;
VEC2 v2 = project(v);
v2 = toScreenCoord(v2);
ellipse[i] = v2;
}
draw_ellipse_points(renderer, ellipse, num_points);
// Draw faces of cube
// SDL_RenderDrawLine(renderer, x1, y1, x2, y2)
for (int i = 0; i < 6; i++)
{
@@ -181,8 +331,8 @@ int main(void)
VEC3 ao = vertecies[faces[i][j]];
VEC3 bo = vertecies[faces[i][(j + 1) % 4]];
ao = rotate(ao, angle);
bo = rotate(bo, angle);
ao = rotate(ao, -angle);
bo = rotate(bo, -angle);
ao = translate_z(ao);
bo = translate_z(bo);
@@ -197,6 +347,7 @@ int main(void)
}
}
// draw vertecies of cube
// for (int i = 0; i < sizeof(vertecies) / sizeof(vertecies[0]); i++)
// {
// VEC3 v3 = vertecies[i];