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apply textures to the walls

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Dmitry V. Sokolov
2019-02-09 17:05:45 +01:00
parent df8fb12a3e
commit 8e221cbc89
1 changed files with 31 additions and 3 deletions
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34
tinyraycaster.cpp
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@@ -79,6 +79,18 @@ bool load_texture(const std::string filename, std::vector<uint32_t> &texture, si
return true;
}
std::vector<uint32_t> texture_column(const std::vector<uint32_t> &img, const size_t texsize, const size_t ntextures, const size_t texid, const size_t texcoord, const size_t column_height) {
const size_t img_w = texsize*ntextures;
const size_t img_h = texsize;
assert(img.size()==img_w*img_h && texcoord<texsize && texid<ntextures);
std::vector<uint32_t> column(column_height);
for (size_t y=0; y<column_height; y++) {
size_t pix_x = texid*texsize + texcoord;
size_t pix_y = (y*texsize)/column_height;
column[y] = img[pix_x + pix_y*img_w];
}
return column;
}
int main() {
const size_t win_w = 1024; // image width
@@ -136,15 +148,31 @@ int main() {
float cx = player_x + t*cos(angle);
float cy = player_y + t*sin(angle);
size_t pix_x = cx*rect_w;
size_t pix_y = cy*rect_h;
int pix_x = cx*rect_w;
int pix_y = cy*rect_h;
framebuffer[pix_x + pix_y*win_w] = pack_color(160, 160, 160); // this draws the visibility cone
if (map[int(cx)+int(cy)*map_w]!=' ') { // our ray touches a wall, so draw the vertical column to create an illusion of 3D
size_t texid = map[int(cx)+int(cy)*map_w] - '0';
assert(texid<walltext_cnt);
size_t column_height = win_h/(t*cos(angle-player_a));
draw_rectangle(framebuffer, win_w, win_h, win_w/2+i, win_h/2-column_height/2, 1, column_height, walltext[texid*walltext_size]);
float hitx = cx - floor(cx+.5); // hitx and hity contain (signed) fractional parts of cx and cy,
float hity = cy - floor(cy+.5); // they vary between -0.5 and +0.5, and one of them is supposed to be very close to 0
int x_texcoord = hitx*walltext_size;
if (std::abs(hity)>std::abs(hitx)) { // we need to determine whether we hit a "vertical" or a "horizontal" wall (w.r.t the map)
x_texcoord = hity*walltext_size;
}
if (x_texcoord<0) x_texcoord += walltext_size; // do not forget x_texcoord can be negative, fix that
assert(x_texcoord>=0 && x_texcoord<(int)walltext_size);
std::vector<uint32_t> column = texture_column(walltext, walltext_size, walltext_cnt, texid, x_texcoord, column_height);
pix_x = win_w/2+i;
for (size_t j=0; j<column_height; j++) {
pix_y = j + win_h/2-column_height/2;
if (pix_y<0 || pix_y>=(int)win_h) continue;
framebuffer[pix_x + pix_y*win_w] = column[j];
}
break;
}
}