Now have a basic sprite system that uses SFML's sprites, but the algorithm for determining how much of a sprite to display is wrong. Need to use the alternate algorithm from LODE's tutorial that draws sprites after rendering.

constants.hpp

@@ -1,5 +1,7 @@
 #pragma once
 
+constexpr const int TEXTURE_WIDTH=256;
+constexpr const int TEXTURE_HEIGHT=256;
 constexpr const int RAY_VIEW_WIDTH=960;
 constexpr const int RAY_VIEW_HEIGHT=720;
 constexpr const int RAY_VIEW_X=(1280 - RAY_VIEW_WIDTH);

main.cpp

@@ -67,7 +67,6 @@ int main() {
     auto elapsed = std::chrono::duration<double>(end - start);
     stats.sample(1/elapsed.count());
 
-
     draw_gui(window, text, stats);
     window.display();
 

raycaster.cpp

@@ -17,7 +17,7 @@ union ColorConv {
 };
 
 inline uint32_t dumb_lighting(uint32_t pixel, double distance) {
-  if(distance < 1) return pixel;
+  if(distance < 1.0) return pixel;
 
   ColorConv conv{.as_int=pixel};
   conv.as_color.r /= distance;
@@ -84,7 +84,8 @@ void Raycaster::sprite_casting() {
   for(int i = 0; i < $textures.NUM_SPRITES; i++) {
     int sprite_index = spriteOrder[i];
     Sprite& sprite_rec = $textures.get_sprite(sprite_index);
-    auto& sprite_texture = $textures.get_texture(sprite_rec.texture);
+    // auto& sprite_texture = $textures.get_texture(sprite_rec.texture);
+    sf::Sprite *sf_sprite = sprite_rec.sprite;
 
     double spriteX = sprite_rec.x - $posX;
     double spriteY = sprite_rec.y - $posY;
@@ -103,18 +104,10 @@ void Raycaster::sprite_casting() {
 
     int spriteScreenX = int(($width / 2) * (1 + transformX / transformY));
 
-    int vMoveScreen = int(sprite_rec.elevation * -1 / transformY);
-
     // calculate the height of the sprite on screen
     //using "transformY" instead of the real distance prevents fisheye
     int spriteHeight = abs(int($height / transformY)) / sprite_rec.vDiv;
 
-    //calculate lowest and highest pixel to fill in current stripe
-    int drawStartY = -spriteHeight / 2 + $height / 2 + vMoveScreen;
-    if(drawStartY < 0) drawStartY = 0;
-    int drawEndY = spriteHeight / 2 + $height / 2 + vMoveScreen;
-    if(drawEndY >= $height) drawEndY = $height - 1;
-
     // calculate width the the sprite
     // same as height of sprite, given that it's square
     int spriteWidth = abs(int($height / transformY)) / sprite_rec.uDiv;
@@ -123,29 +116,29 @@ void Raycaster::sprite_casting() {
     int drawEndX = spriteWidth / 2 + spriteScreenX;
     if(drawEndX > $width) drawEndX = $width;
 
-    //loop through every vertical stripe of the sprite on screen
-    for(int stripe = drawStartX; stripe < drawEndX; stripe++) {
-      int texX = int(256 * (stripe - (-spriteWidth / 2 + spriteScreenX)) * textureWidth / spriteWidth) / 256;
-      // the conditions in the if are:
-      // 1) it's in front of the camera plane so you don't see things behind you
-      // 2) ZBuffer, with perpendicular distance
-      if(transformY > 0 && transformY < ZBuffer[stripe]) {
-        for(int y = drawStartY; y < drawEndY; y++) {
-          //256 and 128 factors to avoid floats
-          int d = (y - vMoveScreen) * 256 - $height * 128 + spriteHeight * 128;
-          int texY = ((d * textureHeight) / spriteHeight) / 256;
-          //get current color from the texture
-          // BUG: this crashes sometimes when the math goes out of bounds
-          int index = textureWidth * texY + texX;
-          if(index < 0 || (size_t)index >= sprite_texture.size()) continue;
-          uint32_t color = sprite_texture[index];
-          // poor person's transparency, get current color from the texture
-          if((color & 0x00FFFFFF) != 0) {
-            RGBA pixel = color;
-            $pixels[pixcoord(stripe, y)] = pixel;
-          }
-        }
-      }
+
+    if(drawStartX < drawEndX && transformY > 0 && transformY < ZBuffer[drawStartX]) {
+      int vMoveScreen = int(sprite_rec.elevation * -1 / transformY);
+      //calculate lowest and highest pixel to fill in current stripe
+      int drawStartY = -spriteHeight / 2 + $height / 2 + vMoveScreen;
+      if(drawStartY < 0) drawStartY = 0;
+      int drawEndY = spriteHeight / 2 + $height / 2 + vMoveScreen;
+      if(drawEndY >= $height) drawEndY = $height - 1;
+
+      float x = float(drawStartX + RAY_VIEW_X);
+      float y = float(drawStartY + RAY_VIEW_Y);
+      float sprite_w = float(spriteWidth) / float(textureWidth);
+      float sprite_h = float(spriteHeight) / float(textureHeight);
+      int texX = int(256 * (drawStartX - (-spriteWidth / 2 + spriteScreenX)) * textureWidth / spriteWidth) / 256;
+      int texX_end = int(256 * (drawEndX - (-spriteWidth / 2 + spriteScreenX)) * textureWidth / spriteWidth) / 256;
+
+      int d = (y - vMoveScreen) * 256 - $height * 128 + spriteHeight * 128;
+      int texY = ((d * textureHeight) / spriteHeight) / 256;
+
+      sf_sprite->setScale({sprite_h, sprite_w});
+      sf_sprite->setTextureRect(sf::IntRect({texX, texY}, {texX_end, textureHeight}));
+      sf_sprite->setPosition({x, y});
+      $window.draw(*sf_sprite);
     }
   }
 }
@@ -328,8 +321,8 @@ void Raycaster::draw_ceiling_floor() {
 void Raycaster::render() {
   draw_ceiling_floor();
   cast_rays();
-  sprite_casting();
   draw_pixel_buffer();
+  sprite_casting();
 }
 
 bool Raycaster::empty_space(int new_x, int new_y) {

texture.cpp

@@ -28,6 +28,11 @@ void TexturePack::load_textures() {
 
   floor = load_image(assets["floor"]);
   ceiling = load_image(assets["ceiling"]);
+
+  sf::Texture* sprite_texture = new sf::Texture("assets/undead_peasant-256.png");
+  sf::Sprite* sf_sprite = new sf::Sprite(*sprite_texture);
+
+  sprites.push_back({4.0, 3.55, 6, sf_sprite, sprite_texture});
 }
 
 Image& TexturePack::get_texture(size_t num) {

texture.hpp

@@ -3,11 +3,14 @@
 #include <cstdint>
 #include <vector>
 #include <string>
+#include <SFML/Graphics.hpp>
 
 struct Sprite {
   double x;
   double y;
   int texture;
+  sf::Sprite *sprite = nullptr;
+  sf::Texture *sprite_texture = nullptr;
   // ZED: this should be a separate transform parameter
   double elevation=0;
   int uDiv=1;
@@ -22,7 +25,7 @@ struct TexturePack {
   constexpr static const int TEXTURE_HEIGHT=256; // must be power of two
 
   std::vector<Image> images;
-  std::vector<Sprite> sprites{{4.0, 3.55, 6}};
+  std::vector<Sprite> sprites;
   Image floor;
   Image ceiling;