You can now set a shader for a slide.

Makefile

@@ -1,4 +1,4 @@
-SAMPLE=./sample/about-bezos.md
+SAMPLE=./no-stream.md
 ROOT_DIR=$(dir $(firstword $(MAKEFILE_LIST)))
 
 all: build

assets/layouts.json

@@ -30,11 +30,11 @@
         "[_|_|_|_|_]"
   ],
   "centered": [
-        "[=*%(300,200)title|_|_|_|_]",
+        "[=*%(300,400)title|_|_|_|_]",
         "[_|_|_]",
-        "[=*%(300,600)content]",
         "[_|_|_]",
         "[_|_|_]",
+        "[=*%(300,400)content]",
         "[_|_|_]",
         "[_|_|_]",
         "[_|_|_]"

assets/shaders.json

@@ -6,5 +6,21 @@
   "ERROR": {
     "file_name": "assets/shaders/ui_error.frag",
     "type": "fragment"
+  },
+  "rayview_sprites": {
+    "file_name": "assets/shaders/rayview_sprites.frag",
+    "type": "fragment"
+  },
+  "flame": {
+    "file_name": "assets/shaders/flame_trash.frag",
+    "type": "fragment"
+  },
+  "lightning": {
+    "file_name": "assets/shaders/lightning_attack.frag",
+    "type": "fragment"
+  },
+  "boss_hit": {
+    "file_name": "assets/shaders/flame_trash.frag",
+    "type": "fragment"
   }
 }

assets/shaders/flame_trash.frag

@@ -0,0 +1,79 @@
+#version 120
+uniform vec2 u_resolution;
+uniform float u_time;
+uniform sampler2D source;
+uniform float u_mouse;
+uniform float value = 0.2;
+uniform int octaves=8;
+
+float random (in vec2 st) {
+    return fract(sin(dot(st.xy,
+                         vec2(12.9898,78.233)))*
+        43758.5453123);
+}
+
+float noise(in vec2 st) {
+  vec2 i = floor(st);
+  vec2 f = fract(st);
+
+  float a = random(i);
+  float b = random(i + vec2(1.0, 0.0));
+  float c = random(i + vec2(0.0, 1.0));
+  float d = random(i + vec2(1.0, 1.0));
+
+  vec2 u = f * f * (3.0 - 2.0 * f);
+
+  return mix(a, b, u.x) +
+    (c - a) * u.y * (1.0 - u.x) +
+    (d - b) * u.x * u.y;
+}
+
+float fbm(in vec2 st) {
+  float v = 0.0;
+  float a = 0.5;
+  vec2 shift = vec2(100.0);
+  mat2 rot = mat2(cos(0.5), sin(0.5),
+      -sin(0.5), cos(0.5));
+
+  for(int i = 0; i < octaves; i++) {
+    v += a * noise(st);
+    st = rot * st * 2.0 + shift;
+    a *= 0.5;
+  }
+
+  return v;
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution.xy * 3.0;
+  vec3 color = vec3(0.0);
+
+  float speed = u_time * 10.0;
+  float value = 0.8; // cos(u_time) * cos(u_time);
+
+  vec2 q = vec2(0.0);
+  q.x = fbm(st + 0.00 * speed);
+  q.y = fbm(st + vec2(1.0));
+
+  vec2 r = vec2(0,0);
+  r.x += fbm( st + 1.0*q + vec2(1.0, 0.0)+ 0.15* speed );
+  r.y += fbm( st + 1.0*q + vec2(-1.0, 0.0)+ 0.126* speed);
+
+  float f = fbm(st * r);
+
+  color = mix(vec3(0.666667,0.619608, 0.122777),
+                vec3(0.666667,0.666667,0.498039),
+                clamp((f*f)*4.0,0.0,1.0));
+
+  color = mix(color,
+       vec3(0.666667, 0.122222, 0.0666667),
+       clamp(length(r.x), 0.0, 1.0));
+
+  color *= (f*f*f+0.5*f*f+0.6*f) * value;
+
+  vec4 pixel = texture2D(source, gl_TexCoord[0].xy);
+
+  float mask = color.r * pixel.a;
+
+  gl_FragColor = gl_Color * vec4(color, mask) + pixel;
+}

assets/shaders/lightning_attack.frag

@@ -0,0 +1,79 @@
+#version 120
+uniform vec2 u_resolution;
+uniform float u_time;
+uniform sampler2D source;
+uniform float u_mouse;
+uniform float value = 0.2;
+uniform int octaves=8;
+
+float random (in vec2 st) {
+    return fract(sin(dot(st.xy,
+                         vec2(12.9898,78.233)))*
+        43758.5453123);
+}
+
+float noise(in vec2 st) {
+  vec2 i = floor(st);
+  vec2 f = fract(st);
+
+  float a = random(i);
+  float b = random(i + vec2(1.0, 0.0));
+  float c = random(i + vec2(0.0, 1.0));
+  float d = random(i + vec2(1.0, 1.0));
+
+  vec2 u = f * f * (3.0 - 2.0 * f);
+
+  return mix(a, b, u.x) +
+    (c - a) * u.y * (1.0 - u.x) +
+    (d - b) * u.x * u.y;
+}
+
+float fbm(in vec2 st) {
+  float v = 0.0;
+  float a = 0.5;
+  vec2 shift = vec2(100.0);
+  mat2 rot = mat2(cos(0.5), sin(0.5),
+      -sin(0.5), cos(0.5));
+
+  for(int i = 0; i < octaves; i++) {
+    v += a * noise(st);
+    st = rot * st * 2.0 + shift;
+    a *= 0.5;
+  }
+
+  return v;
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution.xy * 3.0;
+  vec3 color = vec3(0.0);
+
+  float speed = u_time * 40.0;
+  float value = cos(u_time) * cos(u_time);
+
+  vec2 q = vec2(0.0);
+  q.x = fbm(st + 0.00 * speed);
+  q.y = fbm(st + vec2(1.0));
+
+  vec2 r = vec2(0,0);
+  r.x += fbm( st + 1.0*q + vec2(1.0, 0.0)+ 0.15* speed );
+  r.y += fbm( st + 1.0*q + vec2(-1.0, 0.0)+ 0.126* speed);
+
+  float f = fbm(st / r);
+
+  color = mix(vec3(0.122777,0.619608, 0.666667),
+                vec3(0.498039,0.666667,0.666667),
+                clamp((f*f)*4.0,0.0,1.0));
+
+  color = mix(color,
+       vec3(0.0666667, 0.122222, 0.666667),
+       clamp(length(r.x), 0.0, 1.0));
+
+  color *= (f*f*f+0.5*f*f+0.6*f) * value;
+
+  vec4 pixel = texture2D(source, gl_TexCoord[0].xy);
+
+  float mask = color.r * pixel.a;
+
+  gl_FragColor = gl_Color * vec4(color, mask) + pixel;
+}

assets/shaders/rayview_sprites.frag

@@ -0,0 +1,25 @@
+uniform sampler2D source;
+uniform sampler2D bloom;
+uniform vec2 offsetFactor;
+uniform float darkness;
+
+void main()
+{
+	vec2 textureCoordinates = gl_TexCoord[0].xy;
+	vec4 color = vec4(0.0);
+	color += texture2D(source, textureCoordinates - 4.0 * offsetFactor) * 0.0162162162;
+	color += texture2D(source, textureCoordinates - 3.0 * offsetFactor) * 0.0540540541;
+	color += texture2D(source, textureCoordinates - 2.0 * offsetFactor) * 0.1216216216;
+	color += texture2D(source, textureCoordinates - offsetFactor) * 0.1945945946;
+	color += texture2D(source, textureCoordinates) * 0.2270270270;
+	color += texture2D(source, textureCoordinates + offsetFactor) * 0.1945945946;
+	color += texture2D(source, textureCoordinates + 2.0 * offsetFactor) * 0.1216216216;
+	color += texture2D(source, textureCoordinates + 3.0 * offsetFactor) * 0.0540540541;
+	color += texture2D(source, textureCoordinates + 4.0 * offsetFactor) * 0.0162162162;
+
+    vec4 sourceFragment = texture2D(source, gl_TexCoord[0].xy);
+    vec4 bloomFragment = texture2D(bloom, gl_TexCoord[0].xy);
+    float alpha = color.a;
+    gl_FragColor = (color + sourceFragment - bloomFragment) * darkness;
+    gl_FragColor.a = alpha;
+}

sample/about-bezos.md

@@ -40,6 +40,14 @@ Bare content like this
 * { "bg_image": "file_path" }
 * You don't even need text
 ---
+{
+  "shader": "flame",
+  "bg_color": [100, 20, 10, 255]
+}
+# Shaders
+* Use "shader": "flame"
+* Shaders configured in assets/shaders.json
+---
 {
  "bg_color": [10, 10, 25, 255],
  "font_color": [255, 146, 0, 255],
@@ -68,14 +76,14 @@ One Word
 {
 "layout": "image_left",
 "image_stretch": false,
-"title_size": 100,
+"title_size": 150,
 "font_size": 50
 }
 # Specific Positions
 ![image](assets/sample_bg.jpg)
 * ![image](assets/sample_bg.jpg)
 * Places in image cell in layout.
-* Can combine with
+  can combine with
   image_stretch and layout
   to place it anywhere.
 ---

src/backend.cpp

@@ -1,6 +1,7 @@
 #include "backend.hpp"
 #include "dbc.hpp"
 #include <string>
+#include <guecs/sfml/shaders.hpp>
 
 using std::string;
 
@@ -31,13 +32,20 @@ namespace gui {
   }
 
   std::shared_ptr<sf::Shader> Backend::get_shader(const std::string& name) {
-    dbc::log("Backend::get_shader not implemented");
-    return nullptr;
+    return shaders::get(name);
   }
 
   bool Backend::shader_updated() {
-    dbc::log("Backend::shader_updated not implemented");
-    return false;
+    if(shaders::updated($shaders_version)) {
+      $shaders_version = shaders::version();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  Backend::Backend() {
+    shaders::init();
   }
 
   guecs::Theme Backend::theme() {

src/backend.hpp

@@ -5,9 +5,12 @@
 
 namespace gui {
   class Backend : public guecs::Backend {
+    int $shaders_version = 0;
+
   public:
     std::string $font_file = "assets/text.otf";
 
+    Backend();
     guecs::SpriteTexture get_sprite(const std::string& name);
     guecs::SpriteTexture get_icon(const std::string& name);
     void sound_play(const std::string& name);

src/main.cpp

@@ -9,10 +9,11 @@
 #include <filesystem>
 #include <chrono>
 #include <SFML/System/Clock.hpp>
+#include <memory>
 
 using namespace std::chrono_literals;
 
-std::optional<SlidesUI> load_slides(const std::string& input_md, std::shared_ptr<gui::Backend> backend) {
+std::shared_ptr<SlidesUI> load_slides(const std::string& input_md, std::shared_ptr<gui::Backend> backend) {
   try {
     auto data = parse_slides(input_md, [&](nlohmann::json& config) {
         backend->set_font(config["font_file"]);
@@ -21,13 +22,13 @@ std::optional<SlidesUI> load_slides(const std::string& input_md, std::shared_ptr
 
     fmt::println("FONT FILE: {}", backend->$font_file);
 
-    SlidesUI slides(data);
-    slides.init();
+    auto slides = std::make_shared<SlidesUI>(data, sf::Vector2u{WINDOW_WIDTH, WINDOW_HEIGHT});
+    slides->init();
 
     return slides;
   } catch(...) {
     fmt::println("ERROR!");
-    return std::nullopt;
+    return nullptr;
   }
 }
 
@@ -76,43 +77,45 @@ int main(int argc, char *argv[]) {
 
   auto backend = std::make_shared<gui::Backend>();
 
-  auto new_slides = load_slides(argv[1], backend);
+  auto slides = load_slides(argv[1], backend);
 
-  if(!new_slides) {
+  if(!slides) {
     fmt::println("ERROR in your .md file");
     return 1;
   }
 
-  SlidesUI slides = *new_slides;
   ControlUI control_ui(presenter);
   control_ui.init();
 
   dbc::check(control_ui.$status != nullptr, "bad ptr");
 
   ChangeDetector slides_reloader{argv[1]};
-  ChangeDetector layout_reloader{slides.$deck->config["layouts"]};
+  ChangeDetector layout_reloader{slides->$deck->config["layouts"]};
 
   while(controller.isOpen()) {
     while (const auto event = presenter.pollEvent()) {
-      if(event) slides.handle_events(presenter, *event);
+      if(event) slides->handle_events(presenter, *event);
     }
 
     while (const auto event = controller.pollEvent()) {
       if(event) control_ui.handle_events(controller, *event);
     }
 
-    slides.render(presenter);
+    slides->render(presenter);
     control_ui.render(controller);
 
     presenter.display();
     controller.display();
 
     if(slides_reloader.changed() || layout_reloader.changed()) {
+      // save the current slide
+      auto current_slide = slides->$current;
+      // load the new one
       auto new_slides = load_slides(argv[1], backend);
 
       if(new_slides) {
-        new_slides->set_slide(slides.$current);
-        slides = *new_slides;
+        new_slides->set_slide(current_slide);
+        slides = new_slides;
       }
     }
   }

src/slides_ui.cpp

@@ -68,12 +68,15 @@ void Slide::config_text(guecs::Text &result, nlohmann::json& config, std::string
   if(config.contains(prefix + "_centered")) result.centered = config[prefix + "_centered"];
 }
 
-void Slide::render(sf::RenderWindow& window) {
-  $gui.render(window);
-  // $gui.debug_layout(window);
+void Slide::render(sf::RenderTarget& view) {
+  $gui.render(view);
+  // $gui.debug_layout(view);
 }
 
-SlidesUI::SlidesUI(shared_ptr<SlideDeck> deck) {
+SlidesUI::SlidesUI(shared_ptr<SlideDeck> deck, sf::Vector2u size) :
+  $view_texture{size},
+  $view_sprite($view_texture.getTexture())
+{
   dbc::check(deck != nullptr, "deck is null");
   dbc::check(deck->slides.size() > 0, "slide deck is empy");
   $deck = deck;
@@ -156,6 +159,13 @@ void SlidesUI::show_slide() {
     color = {color_conf[0], color_conf[1], color_conf[2], color_conf[3]};
   }
 
+  if(slide.$config.contains("shader")) {
+    $view_shader = shaders::get(slide.$config["shader"]);
+    $view_shader->setUniform("u_resolution", sf::Vector2f{WINDOW_WIDTH, WINDOW_HEIGHT});
+  } else {
+    $view_shader = nullptr;
+  }
+
   std::string layout_name{"default_slide"};
 
   if(slide.$config.contains("layout")) {
@@ -168,13 +178,22 @@ void SlidesUI::show_slide() {
   bg.init();
 
   auto& cell = $gui.cell_for("slide");
+
   slide.init(cell, layout);
 }
 
-void SlidesUI::render(sf::RenderWindow& window) {
-  $gui.render(window);
+void SlidesUI::render(sf::RenderTarget& window) {
+  $gui.render($view_texture);
   auto& slide = current();
-  slide.render(window);
+  slide.render($view_texture);
+  $view_texture.display();
+
+  if($view_shader) {
+    $view_shader->setUniform("u_time", $clock.getElapsedTime().asSeconds());
+    window.draw($view_sprite, $view_shader.get());
+  } else {
+    window.draw($view_sprite);
+  }
 
   // $gui.debug_layout(window);
 }

src/slides_ui.hpp

@@ -1,7 +1,8 @@
 #pragma once
 
-#include "guecs/sfml/components.hpp"
-#include "guecs/ui.hpp"
+#include <guecs/sfml/components.hpp>
+#include <guecs/sfml/shaders.hpp>
+#include <guecs/ui.hpp>
 #include <nlohmann/json.hpp>
 #include <memory>
 #include "constants.hpp"
@@ -22,7 +23,7 @@ struct Slide {
   Slide() {}
 
   void init(lel::Cell& cell, const std::string& layout);
-  void render(sf::RenderWindow& window);
+  void render(sf::RenderTarget& view);
   void config_text(guecs::Text &result, nlohmann::json& config, std::string prefix);
 };
 
@@ -37,9 +38,13 @@ struct SlidesUI {
   guecs::UI $gui;
   std::shared_ptr<SlideDeck> $deck = nullptr;
   std::unordered_map<std::string, std::string> $layouts;
+  sf::RenderTexture $view_texture;
+  sf::Sprite $view_sprite;
+  std::shared_ptr<sf::Shader> $view_shader = nullptr;
+  sf::Clock $clock;
   size_t $current = 0;
 
-  SlidesUI(std::shared_ptr<SlideDeck> deck);
+  SlidesUI(std::shared_ptr<SlideDeck> deck,  sf::Vector2u size);
   void init();
   Slide& current();
 
@@ -47,7 +52,7 @@ struct SlidesUI {
   void prev_slide();
   void show_slide();
   void set_slide(size_t index);
-  void render(sf::RenderWindow& window);
+  void render(sf::RenderTarget& window);
   void mouse(float x, float y, guecs::Modifiers mods);
   void set_text(const std::string& name);
   void handle_events(sf::RenderWindow& presenter, const sf::Event& event);