4 files changed, 33 insertions, 30 deletions
diff --git a/src/renderer/RSoftwareBackend.cpp b/src/renderer/RSoftwareBackend.cpp
index 217354b..7bcdd8f 100644
--- a/src/renderer/RSoftwareBackend.cpp
+++ b/src/renderer/RSoftwareBackend.cpp
@@ -75,8 +75,8 @@ RSoftwareBackend::Draw()
             DrawRectangle(entity.rect);
         } break;
 
-        case REntityType_MonoBitmap: {
-            DrawMonoBitmap(entity.bitmap);
+        case REntityType_AlphaBitmap: {
+            DrawAlphaBitmap(entity.bitmap);
         } break;
 
         default:;
@@ -146,7 +146,7 @@ RSoftwareBackend::DrawRectangle(REntity_Rectangle& entity)
 
 
 void
-RSoftwareBackend::DrawMonoBitmap(REntity_MonoBitmap& entity)
+RSoftwareBackend::DrawAlphaBitmap(REntity_AlphaBitmap& entity)
 {
     int32_t x0 = (int32_t)entity.pos.x;
     int32_t y0 = (int32_t)entity.pos.y;
@@ -176,34 +176,37 @@ RSoftwareBackend::DrawMonoBitmap(REntity_MonoBitmap& entity)
     uint32_t gshift = m_canvas.gshift;
     uint32_t bshift = m_canvas.bshift;
 
-    uint8_t* grayscale = (uint8_t*)entity.bitmap.pixels.get() + (-cut_bot * entity.bitmap.w) + (-cut_left);
-    uint32_t* rgba = m_canvas.pixels + y0 * m_canvas.w + x0;
+    uint8_t* alpha_row = (uint8_t*)entity.bitmap.pixels.get() + (-cut_bot * entity.bitmap.w) + (-cut_left);
+    uint32_t* rgba_row = m_canvas.pixels + y0 * m_canvas.w + x0;
     for (int32_t y = y0; y <= y1; y++) {
-        uint8_t *grayscale_pixels = grayscale;
-        uint32_t *rgba_pixels = rgba;
+        uint8_t* alpha = alpha_row;
+        uint32_t* rgba = rgba_row;
         for (int32_t x = x0; x <= x1; x++) {
-            float alpha = *grayscale_pixels / 255.0f;
+            if (*alpha == 0) {
+                alpha++;
+                rgba++;
+                continue;
+            }
 
-            // Todo: we do not want to blend with existing color!
+            float alphaf = *alpha / 255.0f;
 
-            uint32_t rgba_result = *rgba_pixels;
-            float r0 = (rgba_result >> rshift) & 0xff;
-            float g0 = (rgba_result >> gshift) & 0xff;
-            float b0 = (rgba_result >> bshift) & 0xff;
+            float r1 = entity.color.r * alphaf;
+            float g1 = entity.color.g * alphaf;
+            float b1 = entity.color.b * alphaf;
 
-            float r1 = r0 + (entity.color.r - r0)*alpha;
-            float g1 = g0 + (entity.color.g - g0)*alpha;
-            float b1 = b0 + (entity.color.b - b0)*alpha;
+            uint32_t r2 = uint32_t(r1 * 255.0f) << rshift;
+            uint32_t g2 = uint32_t(g1 * 255.0f) << gshift;
+            uint32_t b2 = uint32_t(b1 * 255.0f) << bshift;
 
-            rgba_result = (uint32_t)r1 << rshift | (uint32_t)g1 << gshift | (uint32_t)b1 << bshift;
-            *rgba_pixels = rgba_result;
+            uint32_t rgba_result = r2 | g2 | b2;
+            *rgba = rgba_result;
 
-            grayscale_pixels++;
-            rgba_pixels++;
+            alpha++;
+            rgba++;
         }
 
-        grayscale += entity.bitmap.w;
-        rgba += m_canvas.w;
+        alpha_row += entity.bitmap.w;
+        rgba_row += m_canvas.w;
     }
 }
 
diff --git a/src/renderer/RSoftwareBackend.hpp b/src/renderer/RSoftwareBackend.hpp
index 53cca9b..89d6a52 100644
--- a/src/renderer/RSoftwareBackend.hpp
+++ b/src/renderer/RSoftwareBackend.hpp
@@ -28,7 +28,7 @@ private:
     void SortRenderEntities();
 
     void DrawRectangle(REntity_Rectangle& entity);
-    void DrawMonoBitmap(REntity_MonoBitmap& entity);
+    void DrawAlphaBitmap(REntity_AlphaBitmap& entity);
 
 
 private:
diff --git a/src/renderer/Renderer.cpp b/src/renderer/Renderer.cpp
index f10319a..4e449ba 100644
--- a/src/renderer/Renderer.cpp
+++ b/src/renderer/Renderer.cpp
@@ -70,10 +70,10 @@ Renderer::Clear(Color color)
 }
 
 void
-Renderer::PushMonoBitmap(MonoBitmap& bitmap, V3F32 pos, Color color)
+Renderer::PushAlphaBitmap(AlphaBitmap& bitmap, V3F32 pos, Color color)
 {
     m_render_entities.emplace_back(REntity{.bitmap{
-            REntityType_MonoBitmap,
+            REntityType_AlphaBitmap,
             pos,
             bitmap,
             color
diff --git a/src/renderer/Renderer.hpp b/src/renderer/Renderer.hpp
index fc037d6..b825681 100644
--- a/src/renderer/Renderer.hpp
+++ b/src/renderer/Renderer.hpp
@@ -20,14 +20,14 @@ extern Renderer g_renderer;
 
 enum REntityType : int32_t {
     REntityType_Rectangle,
-    REntityType_MonoBitmap,
+    REntityType_AlphaBitmap,
     REntityType_Circle,
 };
 
-struct REntity_MonoBitmap {
+struct REntity_AlphaBitmap {
     REntityType type;
     V3F32 pos;
-    MonoBitmap& bitmap;
+    AlphaBitmap& bitmap;
     Color color;
 };
 
@@ -47,7 +47,7 @@ struct REntity_Circle {
 
 union REntity {
     REntityType type;
-    REntity_MonoBitmap bitmap;
+    REntity_AlphaBitmap bitmap;
     REntity_Rectangle rect;
     REntity_Circle circle;
 };
@@ -70,7 +70,7 @@ public:
 
     void Clear(Color color);
     void PushRectangle(Rectangle rect, float z, Color color);
-    void PushMonoBitmap(MonoBitmap& bitmap, V3F32 pos, Color color);
+    void PushAlphaBitmap(AlphaBitmap& bitmap, V3F32 pos, Color color);
     void PushCircle(Circle circle, float z, Color color);