SomeGameEngineV2/engine/tests/geometry/samples/collision_sample2.c

#include "cute_c2_ext.h"
#include "raylib.h"
#include "raymath.h"

#include <stdio.h>

const int screenWidth = 800;
const int screenHeight = 450;

typedef struct Shape {
    Vector2 pos;
    Vector2 center;
    Vector2 vel;
    C2_TYPE type;
    union {
        c2v boxDim;
        c2Circle circle;
        c2Poly poly;
    } shape;
    Color colour;
} Shape;


void DrawShape(const Shape* shape) {
    switch (shape->type) 
    {
        case C2_TYPE_AABB:
            DrawRectangle(
                shape->center.x - shape->shape.boxDim.x / 2,
                shape->center.y - shape->shape.boxDim.y / 2,
                shape->shape.boxDim.x,
                shape->shape.boxDim.y,
                shape->colour
            );
        break;
        case C2_TYPE_CIRCLE:
            DrawCircle(
                shape->center.x,
                shape->center.y, shape->shape.circle.r,
                shape->colour
            );
        break;
        case C2_TYPE_POLY:
            for (int i = 0; i < shape->shape.poly.count; ++i) {
                int next = (i + 1 + shape->shape.poly.count) % shape->shape.poly.count;
                DrawLineV(
                    (Vector2){shape->shape.poly.verts[i].x, shape->shape.poly.verts[i].y},
                    (Vector2){shape->shape.poly.verts[next].x, shape->shape.poly.verts[next].y},
                    shape->colour
                );
            }
        break;
        default:
        break;
    }
}

struct TOIInfo {
    double toi;
    c2v contact;
    c2v normal;
};

void draw_toi_info(const struct TOIInfo* info)
{
    if (info->toi != INFINITY)
    {
        DrawCircle(info->contact.x, info->contact.y, 4, GREEN);
        DrawLineEx(
            (Vector2){info->contact.x, info->contact.y},
            (Vector2){
                info->contact.x + info->normal.x * 12,
                info->contact.y + info->normal.y * 12
            },
            2, GREEN
        );
    }
}

int main(void)
{
    InitWindow(screenWidth, screenHeight, "raylib");
    SetTargetFPS(60);


    Shape A = {
        .pos = {300,150},
        .center = {300,150},
        .type = C2_TYPE_AABB,
        .shape.boxDim = {32, 32},
        .colour = BLUE,
    };

    Shape B = {
        .pos = {400,300},
        .center = {400,300},
        .type = C2_TYPE_AABB,
        .shape.boxDim = {256, 64},
        .colour = RED,
    };

    //Shape C = {
    //    .pos = {200,250},
    //    .center = {250,266.666},
    //    .type = C2_TYPE_POLY,
    //    .shape.poly = {
    //        .count = 3,
    //        .verts = {
    //            {0,0},
    //            {100, 0},
    //            {50,50},
    //        },
    //    },
    //    .colour = RED,
    //};
    //c2MakePoly(&C.shape.poly);
    //for (int i = 0; i < C.shape.poly.count; ++i) {
    //    C.shape.poly.verts[i].x += C.pos.x;
    //    C.shape.poly.verts[i].y += C.pos.y;
    //}

    while (!WindowShouldClose())
    {
        float frame_time = GetFrameTime();
        Vector2 move_dir = {0};

        if (IsKeyDown(KEY_LEFT)) {
            move_dir.x += -1;
        }
        if (IsKeyDown(KEY_RIGHT)) {
            move_dir.x += 1;
        }
        if (IsKeyDown(KEY_UP)) {
            move_dir.y += -1;
        }
        if (IsKeyDown(KEY_DOWN)) {
            move_dir.y += 1;
        }

        move_dir = Vector2Normalize(move_dir);
        A.vel = Vector2Scale(move_dir, 200);

        c2AABB Abox= {
            {A.center.x - A.shape.boxDim.x / 2, A.center.y - A.shape.boxDim.y / 2},
            {A.center.x + A.shape.boxDim.x / 2, A.center.y + A.shape.boxDim.y / 2},
        };
        c2AABB Bbox= {
            {B.center.x - B.shape.boxDim.x / 2, B.center.y - B.shape.boxDim.y / 2},
            {B.center.x + B.shape.boxDim.x / 2, B.center.y + B.shape.boxDim.y / 2},
        };


        struct TOIInfo toi0 = {0};
        toi0.toi = AABBToAABBTOI(
            Abox, (c2v){A.vel.x *frame_time, A.vel.y * frame_time},
            Bbox, (c2v){0,0},
            &toi0.normal, &toi0.contact
        );


        A.pos = Vector2Add(
            A.pos , Vector2Scale(A.vel, frame_time)
        );
        A.center = A.pos;

        BeginDrawing();
            ClearBackground(RAYWHITE);
            DrawShape(&B);
            if (toi0.toi <= 1 && toi0.toi > 0)
            {
                draw_toi_info(&toi0);
            }
            DrawShape(&A);
        EndDrawing();
    }
    return 0;
}