From 202d4c3dc8cfa931c66bb9a1f887825dce54dc20 Mon Sep 17 00:00:00 2001
From: redstrate <54911369+redstrate@users.noreply.github.com>
Date: Wed, 13 May 2020 17:19:21 -0400
Subject: [PATCH] Show render in progress

---
 include/image.h |  7 ++++++-
 src/main.cpp    | 28 +++++++++++++++++++---------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/include/image.h b/include/image.h
index 51182fd..09d9c1c 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1,10 +1,15 @@
 #pragma once
 
 #include <glm/glm.hpp>
+#include <array>
 
 template<class T, int Width, int Height>
 class Image {
 public:
+    void reset() {
+        array = {};
+    }
+    
     T& get(const int32_t x, const int32_t y) {
         return array[y * Width + x];
     }
@@ -13,5 +18,5 @@ public:
         return array[y * Width + x];
     }
     
-    T array[Width * Height] = {};
+    std::array<T, Width * Height> array = {};
 };
diff --git a/src/main.cpp b/src/main.cpp
index 2409440..fdb670e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -42,6 +42,7 @@ constexpr int32_t num_tiles_y = height / tile_size;
 // globals
 Scene scene = {};
 Image<glm::vec4, width, height> colors = {};
+bool image_dirty = false;
 
 bool calculate_tile(const int32_t from_x, const int32_t to_width, const int32_t from_y, const int32_t to_height) {
     for (int32_t y = from_y; y < (from_y + to_height); y++) {
@@ -64,6 +65,8 @@ bool calculate_tile(const int32_t from_x, const int32_t to_width, const int32_t
                 
                 const glm::vec3 finalColor = model_color * diffuse * (1.0f - shadow);
                 colors.get(x, y) = glm::vec4(finalColor, 1.0f);
+                
+                image_dirty = true;
             }
         }
     }
@@ -158,20 +161,22 @@ void setup_gfx() {
 
 void update_texture() {
     glBindTexture(GL_TEXTURE_2D, pixels_texture);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_FLOAT, colors.array);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_FLOAT, colors.array.data());
     glBindTexture(GL_TEXTURE_2D, 0);
 }
 
+std::vector<std::future<bool>> futures;
+
 void render() {
-    std::vector<std::future<bool>> futures;
-    for(int32_t y = 0; y < num_tiles_y; y++)
-        for(int32_t x = 0; x < num_tiles_x; x++)
-            futures.push_back(std::async(std::launch::async, calculate_tile, x * tile_size, tile_size, y * tile_size, tile_size));
+    futures.clear();
+    colors.reset();
     
-    for(auto& future : futures)
-        future.wait();
-    
-    update_texture();
+    for(int32_t y = 0; y < num_tiles_y; y++) {
+        for(int32_t x = 0; x < num_tiles_x; x++) {
+            auto f = std::async(std::launch::async, calculate_tile, x * tile_size, tile_size, y * tile_size, tile_size);
+            futures.push_back(std::move(f));
+        }
+    }
 }
 
 void dump_to_file() {
@@ -244,6 +249,11 @@ int main(int, char*[]) {
         if(ImGui::Button("Dump to file"))
             dump_to_file();
         
+        if(image_dirty) {
+            update_texture();
+            image_dirty = false;
+        }
+        
         ImGui::Render();
         
         auto& io = ImGui::GetIO();