WIP: pico: handle rgb555 blits for PicoVision

Missing Surface::alpha handling and using the wrong format.

32blit-pico/display_picovision.cpp

@@ -166,6 +166,34 @@ static void pen_rgba_rgb555_picovision(const blit::Pen* pen, const blit::Surface
   }
 }
 
+template<int h_repeat = 1>
+static void blit_rgb555(uint16_t *s, const blit::Surface* dest, uint32_t doff, uint32_t cnt, int32_t src_step) {
+  if(h_repeat == 1 && src_step == 1 && !dest->mask && dest->alpha == 255) {
+    // copy
+    ram.write(base_address + doff * 2, (uint32_t *)s, cnt * 2);
+    return;
+  }
+
+  do {
+    auto step = std::min(cnt, uint32_t(std::size(blend_buf)));
+
+    auto *ptr = blend_buf;
+    for(unsigned i = 0; i < step; i += h_repeat) {
+      // TODO if dest->alpha, blend
+
+      auto col = *s;
+      for(int j = 0; j < h_repeat; j++)
+        *ptr++ = col;
+
+      s += src_step;
+    }
+
+    ram.write(base_address + doff * 2, (uint32_t *)blend_buf, step * 2);
+    doff += step;
+    cnt -= step;
+  } while(cnt);
+}
+
 template<int h_repeat = 1>
 static void blit_rgba_rgb555_picovision(const blit::Surface* src, uint32_t soff, const blit::Surface* dest, uint32_t doff, uint32_t cnt, int32_t src_step) {
   uint8_t* s = src->palette ? src->data + soff : src->data + (soff * src->pixel_stride);
@@ -176,6 +204,9 @@ static void blit_rgba_rgb555_picovision(const blit::Surface* src, uint32_t soff,
 
   flush_batch();
 
+  if(src->format == blit::PixelFormat::RGB565) // still a lie
+    return blit_rgb555<h_repeat>((uint16_t *)s, dest, doff, cnt, src_step);
+
   do {
     auto step = std::min(cnt, uint32_t(std::size(blend_buf)));