fix wierd render issues with black background

[e2dk4r]

When there is black background, renderer doesn't correctly display generated or loaded bitmaps.

Steps to reproduce:

1. git clone --depth 1 https://github.com/e2dk4r/handmadehero -b day-157 handmadehero-issue-3
2. patch -p1 < issue-3.patch

diff --git a/src/handmadehero.c b/src/handmadehero.c
index 35285be..2d719fe 100644
--- a/src/handmadehero.c
+++ b/src/handmadehero.c
@@ -1520,9 +1520,9 @@ GameUpdateAndRender(struct game_memory *memory, struct game_input *input, struct
 
     // render
 
-    // BitmapWithColor(renderGroup, &state->testDiffuse, particle->position, 1.0f, color);
-    BitmapAsset(renderGroup, BitmapGetFirstId(transientState->assets, ASSET_TYPE_HEAD), particle->position, 1.0f,
-                color);
+    BitmapWithColor(renderGroup, &state->testDiffuse, particle->position, 1.0f, color);
+    //BitmapAsset(renderGroup, BitmapGetFirstId(transientState->assets, ASSET_TYPE_HEAD), particle->position, 1.0f,
+     //           color);
   }
 
   TiledDrawRenderGroup(transientState->highPriorityQueue, renderGroup, &drawBuffer);

3. Build and run

Actual result:

Expected result:

Blacks blended without blue artifacts