space_game/src/draw.c

#include "draw.h"
#include "game.h"

Vect viewport_pos;
int width, height;

/* generic rendering functions */
int MAX_ONSCREEN_OBJECTS = 99;

int num_onscreen = 0;

void render_texture_at(struct SDL_Renderer * ren, struct SDL_Texture * texture,int x, int y) {
    /* draw a texture at x.y */

    SDL_Rect destination;
    destination.x = x;
    destination.y = y;

    SDL_QueryTexture(texture, NULL, NULL, &destination.w, &destination.h);

    SDL_RenderCopy(ren, texture, NULL, &destination);
}

/*SDL_Texture * load_image(SDL_Renderer * ren, char fname[]) {*/
    /*[> Load an image into a texture <]*/

    /*SDL_Surface * surface = IMG_Load(fname) ;*/
    /*if(!surface) {*/
        /*printf("IMG_Load: %s\n", IMG_GetError());*/
        /*// handle error*/
    /*}*/
    
    /*SDL_Texture * png_image = SDL_CreateTextureFromSurface(ren, surface);*/
    /*cleanup(surface, SURFACE);*/
    /*return (png_image);*/
/*}*/

Vect in_view(Vect V) {
    Vect ret;
    ret.x = V.x -viewport_pos.x;
    ret.y = V.y -viewport_pos.y;
    return ret;
}

/* Game Specific rendering functions */
void draw_player(SDL_Renderer * ren, int x, int y, bool red) {
    // translate to viewport

    Vect V;
    V.x = x; V.y = y;
    V = in_view(V);

    /* draw the player as a coloured rect */
    SDL_Rect player_rect;

    player_rect.x = V.x -10; 
    player_rect.y = V.y -10; 

    player_rect.w = 20;
    player_rect.h = 20;

    if (red) {
        SDL_SetRenderDrawColor(ren, 255, 0, 0, 255);
    } else {
        struct colour c = get_scene_at(viewport_pos, level).colours.bg;

        SDL_SetRenderDrawColor(ren, c.r, c.g, c.b, 255);
    }

    SDL_RenderDrawRect(ren, &player_rect);
    SDL_RenderFillRect(ren, &player_rect);
    // draw strings
    for (int i = 0; i < player.physics->num_strings; i++) {
        if (!player.physics->strings[i].attached) {
            continue;
        }
        Vect B;
        B = in_view(player.physics->position);
        Vect E;
        E = in_view(player.physics->strings[i].end_point);
        SDL_RenderDrawLine(ren, B.x, B.y, E.x, E.y);
    }


    SDL_SetRenderDrawColor(ren, 0,0,0, 255);

}

void draw_floor(SDL_Renderer *ren, FloorPoly *poly, bool down) {
    SDL_Point left;
    SDL_Point right;
    left.x = poly->left.x - viewport_pos.x;

    if (left.x > width) {
        return;
    }

    right.x = poly->right.x - viewport_pos.x;
    if (right.x < 0) {
        return;
    }

    left.y = poly->left.y - viewport_pos.y;
    right.y = poly->right.y - viewport_pos.y;

    if (left.y <= 0 && right.y <= 0) {
        return;
    }
    if (left.y >= height && right.y >= height) {
        return;
    }

    SDL_SetRenderDrawColor(ren, 100,100,100, 255);

    int end = down ? height : 0;

    double m = (double)(right.y - left.y) / (double)(right.x - left.x);
    double c = (double)left.y - ((double)left.x * m);

    for (int i = left.x; i <= right.x; i++) {
        int y = (int)(m * i + c);
        if (y > 0) {
            SDL_RenderDrawLine(ren, i, y, i, end);
        }
    }

    SDL_SetRenderDrawColor(ren, 0,0,0, 255);
}

// draw collision poly
void draw_collision_poly(SDL_Renderer* ren, Body *body) {
    if (!SHOWCOLLISION) {
        return;
    }

    if (body->colliding) {
        SDL_SetRenderDrawColor(ren, 255, 0, 0, 255);
    } else {
        SDL_SetRenderDrawColor(ren, 0, 255, 0, 255);
    }

    // draw strings
    for (int i = 0; i < body->num_strings; i++) {
        if (!body->strings[i].attached) {
            continue;
        }
        Vect B;
        B = in_view(body->position);
        Vect E;
        E = in_view(body->strings[i].end_point);
        SDL_RenderDrawLine(ren, B.x, B.y, E.x, E.y);
    }

    if (body->collision_poly_size == 1) {
        SDL_Rect dot;
        Vect V;
        V.x = body->collision_poly[0].x;
        V.y = body->collision_poly[0].y;
        Vect T = in_view(V);
        dot.x = T.x;
        dot.y = T.y;
        dot.w = 4;
        dot.h = 4;
        SDL_RenderDrawRect(ren, &dot);
        SDL_RenderFillRect(ren, &dot);
    } else if (body->collision_poly_size == 2) {
        int x_st = body->collision_poly[0].x -viewport_pos.x;
        int y_st = body->collision_poly[0].y -viewport_pos.y;
        int x_en = body->collision_poly[1].x -viewport_pos.x;
        int y_en = body->collision_poly[1].y -viewport_pos.y;
        SDL_RenderDrawLine(ren, x_st, y_st, x_en, y_en);
    } else if (body->collision_poly_size > 2) {
        int x_st = body->collision_poly[0].x -viewport_pos.x;
        int y_st = body->collision_poly[0].y -viewport_pos.y;
        int x_en, y_en;
        for (int i = 1; i < body->collision_poly_size; i++) {
            x_en = body->collision_poly[i].x -viewport_pos.x;
            y_en = body->collision_poly[i].y -viewport_pos.y;
            SDL_RenderDrawLine(ren, x_st, y_st, x_en, y_en);
            x_st = x_en;
            y_st = y_en;
        }
        x_en = body->collision_poly[0].x-viewport_pos.x;
        y_en = body->collision_poly[0].y-viewport_pos.y;
        SDL_RenderDrawLine(ren, x_st, y_st, x_en, y_en);
    }
    SDL_SetRenderDrawColor(ren, 0,0,0, 255);
}

// draw indicator of forces acting on an object
void draw_forces(SDL_Renderer *ren, Body *body) {
    if (!SHOWFORCES) {
        return;
    }
    Vect start;
    start.x = (int)body->position.x -viewport_pos.x;
    start.y = (int)body->position.y -viewport_pos.y;

    Vect F;
    for (int i = 0; i < body->num_motors; i++) {
        if (!get_motor_active(body, i)) {
            continue;
        }
        F.x += body->motors[i].x;
        F.y += body->motors[i].y;
        Vect end = vect_add(start, F);
        SDL_SetRenderDrawColor(ren, 255,0,0, 255);
        SDL_RenderDrawLine(ren, start.x, start.y, start.x, end.y);
        SDL_SetRenderDrawColor(ren, 0,0,255, 255);
        SDL_RenderDrawLine(ren, start.x, start.y, end.x, start.y);
    }

    SDL_SetRenderDrawColor(ren, 0,0,0, 255);
}

void draw_wall(SDL_Renderer *ren, Wall *wall) {
    SDL_SetRenderDrawColor(ren, 120, 85, 188, 255);
    int x_st, x_en, y_st, y_en;
    x_st = wall->nodes[0].x + wall->physics->position.x -viewport_pos.x;
    y_st = wall->nodes[0].y + wall->physics->position.y -viewport_pos.y;
    for (int i = 1; i < wall->numNodes; i++) {
         x_en = wall->nodes[i].x + wall->physics->position.x -viewport_pos.x;
         y_en = wall->nodes[i].y + wall->physics->position.y -viewport_pos.y;
         SDL_RenderDrawLine(ren, x_st, y_st, x_en, y_en);
         x_st = x_en;
         y_st = y_en;
    }
     x_en = wall->nodes[0].x + wall->physics->position.x -viewport_pos.x;
     y_en = wall->nodes[0].y + wall->physics->position.y -viewport_pos.y;
     SDL_RenderDrawLine(ren, x_st, y_st, x_en, y_en);

     SDL_SetRenderDrawColor(ren, 0,0,0, 255);
}

int distance_colour(int x, int y, int x2, int y2, int blackpoint) {

    int dist = (int) sqrt((x2 - x)*(x2 - x)  + (y2 - y)*(y2 - y) );

    if (dist == 0) {
        return 255;
    }
	if (dist > blackpoint) {
		return 0;
	}

    int frac = blackpoint / dist;

//    int frac = 255 * (int) sin((double)dist / blackpoint);
    if (frac > 255) {
        return 255;
    }
    
    return frac;
}

void update_viewport(double x, double y) {
    float xmargin = 0.5;
    float ymargin = 0.2;

    if (player.physics->position.x - viewport_pos.x > (1-xmargin) * width) {
        viewport_pos.x =  - ((1-xmargin) * width - player.physics->position.x);
    }

    if (player.physics->position.x - viewport_pos.x < xmargin * width) {
        viewport_pos.x =  -(xmargin * width - player.physics->position.x);
    }

    if (player.physics->position.y - viewport_pos.y > (1-ymargin) * height) {
        viewport_pos.y =  -((1-ymargin) * height - player.physics->position.y);
    }

    if (player.physics->position.y - viewport_pos.y < ymargin * height) {
        viewport_pos.y =  -(ymargin * height - player.physics->position.y);
    }
}

double interpolate_h(Vect left, Vect right, double x) {
    static Vect v;

    double m = (double)(right.y - left.y) / (double)(right.x - left.x); 
    double c = (double)left.y - ((double)left.x * m); 

    return x * m + c;
}

void draw_environment(SDL_Renderer * ren, struct environment *scene) {
    struct colour c1 = scene->colours.bg;
    struct colour c2 = scene->colours.fg1;
    struct colour c3 = scene->colours.fg2;
    struct colour c4 = scene->colours.fg3;

    /*c1->r = 255;*/
    /*c2->g = 255;*/
    /*c3->b = 255;*/
    /*c4->g = 255;*/
    /*c4->b = 255;*/

    // background colour
    SDL_SetRenderDrawColor(ren, c1.r, c1.g, c1.b, 255);
    /*SDL_SetRenderDrawColor(ren, 255, 0, 0, 255);*/

    SDL_Rect rect; 
    rect.x = 0;
    rect.y = 0;
    rect.w = width;
    rect.h = height;
    SDL_RenderFillRect(ren, &rect);

/*
 *    double m = (double)(right.y - left.y) / (double)(right.x - left.x);
 *    double c = (double)left.y - ((double)left.x * m);
 *
 *    for (int i = left.x; i <= right.x; i++) {
 *        int y = (int)(m * i + c);
 *        if (y > 0) {
 *            SDL_RenderDrawLine(ren, i, y, i, end);
 *        }
 *    }
 */

    int k = 0;
//    printf("from 0 to (room tiles) %d - 1, res %d width %d\n", E_ROOM_TILES, E_ROOM_RES, E_ROOM_WIDTH);
    for (int i = 0; i < E_ROOM_TILES - 1; i++) {
        for (int j = 0; j < E_ROOM_RES; j++) {
            k++;
            Vect *left;
            Vect *right;

            int x = (i * E_ROOM_RES) + j;
            if (x - viewport_pos.x > width) {
                break;
            }
            if (x - viewport_pos.x < 0) {
                continue;
            }

            left = arlst_get(&scene->ceil, i);
            right = arlst_get(&scene->ceil, i+1);

            int y0 = interpolate_h(*left, *right, x) - viewport_pos.y;

            left = arlst_get(&scene->bg1, i);
            right = arlst_get(&scene->bg1, i+1);

            int y1 = interpolate_h(*left, *right, x) - viewport_pos.y;

            left = arlst_get(&scene->bg2, i);
            right = arlst_get(&scene->bg2, i+1);

            int y2 = interpolate_h(*left, *right, x) - viewport_pos.y;

            left = arlst_get(&scene->floor, i);
            right = arlst_get(&scene->floor, i+1);

            int y3 = interpolate_h(*left, *right, x) - viewport_pos.y;

            x = x - viewport_pos.x;
            /*printf("x: %d, ", x);*/
            /*printf("y: %d %d %d %d\n", y0, y1, y2, y3);*/

            // 3. bg2 to floor
            SDL_SetRenderDrawColor(ren, c4.r, c4.g, c4.b, 255);
            SDL_RenderDrawLine(ren, x, y2, x, y3);
            
            // 1. ceil to bg1
            SDL_SetRenderDrawColor(ren, c2.r, c2.g, c2.b, 255);
            SDL_RenderDrawLine(ren, x, y0, x, y1);

            // 2. bg1 to bg2
            SDL_SetRenderDrawColor(ren, c3.r, c3.g, c3.b, 255);
            SDL_RenderDrawLine(ren, x, y1, x, y2);
             


        }
    }
}


void draw_level_time(SDL_Renderer *ren, struct environment * e) {
    static TTF_Font* font = NULL;
    if (!font) {
        font = TTF_OpenFont("TerminusTTF.ttf", 18);
        const char *err = SDL_GetError();
        if (err) {
            printf("%s\n", err);
        }
    }
    
    int margin = height / 10;
    SDL_Rect position = {.x = margin, .y = height - margin};
    struct colour colour = e->colours.fg1;

    int minutes = level_time / 60000;
    float seconds = level_time * 0.001;
    char time_string[250];
    snprintf(time_string, 250, "%d:%.4f", minutes, seconds);

    SDL_Colour sdl_col = {colour.r, colour.g, colour.b, 255}; 

    SDL_SetRenderDrawColor(ren, colour.r, colour.g, colour.b, 255);
    SDL_Surface *surf =  TTF_RenderText_Solid(font, time_string, sdl_col);

    SDL_Texture *texture = SDL_CreateTextureFromSurface(ren, surf);
    SDL_QueryTexture(texture, NULL, NULL, &position.w, &position.h);
    SDL_RenderCopy(ren, texture, NULL, &position);

    SDL_DestroyTexture(texture);
    SDL_FreeSurface(surf);

}

void redraw_buffer(SDL_Renderer * ren) {
	static int mousex = 0;
	static int mousey = 0;
	static int newmousex = 0;	
	static int newmousey = 0;
    static SDL_Point *bgPixels[256];
    static int numpixels[256];

    /*if (!width && !height) {*/
        /*for (int i = 0; i < 256; i++) {*/
            /*bgPixels[i] = malloc(sizeof(SDL_Point) * width * height);*/
            /*memset(bgPixels[i], 0, sizeof(SDL_Point) * width * height);*/
            /*memset(numpixels, 0, (sizeof(int) * 256));*/
        /*}*/
    /*}*/

	//SDL_GetMouseState(&newmousex, &newmousey);
    update_viewport(player.physics->position.x, player.physics->position.y);

    struct environment scene = get_scene_at(viewport_pos, level);
    draw_environment(ren, &scene);
    draw_level_time(ren, &scene);

    for (int i=0; i < world.items.size; i++) {
        world_thing thing;
        thing = world.get(i);

        switch (thing.kind) {
            case PLAYER:
                draw_player(ren, (*thing.player).physics->position.x, (*thing.player).physics->position.y, thing.player->colliding);
                draw_collision_poly(ren, thing.player->physics);
                draw_forces(ren, thing.player->physics);
                continue;
            case STATIC_WALL_W:
                draw_wall(ren, thing.wall);
                draw_collision_poly(ren, thing.wall->physics);
                continue;
            case FLOOR:
                for (int i = 0; i < thing.floor->numPolys; i++) {
                    draw_floor(ren, &thing.floor->polys[i], true);
                    draw_collision_poly(ren, thing.floor->polys[i].physics);
                }
                continue;
            case CEILING:
                for (int i = 0; i < thing.floor->numPolys; i++) {
                    draw_floor(ren, &thing.floor->polys[i], false);
                    draw_collision_poly(ren, thing.floor->polys[i].physics);
                }
                continue;
            case ROOM_W:
                for (int i = 0; i < thing.room->ceil.numItems; i++) {
                    draw_collision_poly(ren, thing.room->ceil.items[i]);
                }
                for (int i = 0; i < thing.room->floor.numItems; i++) {
                    draw_collision_poly(ren, thing.room->floor.items[i]);
                }
            default:
                continue;
        }
    }

	/*if (newmousex != mousex || newmousey != mousey) {*/ /*mousey = newmousey;*/
		/*mousex = newmousex;*/
        /*for (int i = 0; i < 256; i++) {*/
            /*memset(bgPixels[i], 0, sizeof(SDL_Point) * width * height);*/
            /*memset(numpixels, 0, (sizeof(int) * 256));*/
        /*}*/
        /*for (int i=0; i < width; i++) {*/
            /*for (int j = 0; j < height; j++) {*/
                /*col = distance_colour(i, j, mousex, mousey, 10000);*/

                /*SDL_Point *row = bgPixels[col];*/
                /*SDL_Point point;*/
                /*point.x = i;*/
                /*point.y = j;*/
                /*row[numpixels[col]] = point;*/
                /*numpixels[col] += 1;*/

            /*}*/
        /*}*/
	/*}*/

    /*for (int i = 0; i < 255; i++) {*/
        /*SDL_Point *row = bgPixels[i];*/
        /*col = i;*/
        /*SDL_SetRenderDrawColor(ren, col, col, col, 255);*/
        /*SDL_RenderDrawPoints(ren, row, numpixels[i]);*/
    /*}*/

}