From a05046026ec9edb1e528fac2c70f887239302237 Mon Sep 17 00:00:00 2001
From: Nicolay Korslund <korslund@gmail.com>
Date: Sun, 19 Sep 2010 12:36:19 +0200
Subject: [PATCH] More direct pixel functions.

---
 rend2d/servers/sdl_driver.cpp | 30 +++++++++++++++++++++++++++++-
 rend2d/servers/sdl_driver.hpp |  6 ++++++
 rend2d/sprite.hpp             | 18 ++++++++++++++++++
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/rend2d/servers/sdl_driver.cpp b/rend2d/servers/sdl_driver.cpp
index d86cf53e4d..aa1ff6c6dc 100644
--- a/rend2d/servers/sdl_driver.cpp
+++ b/rend2d/servers/sdl_driver.cpp
@@ -7,7 +7,34 @@
 
 using namespace Mangle::Rend2D;
 
-// This is a really crappy and slow implementation
+const SpriteData *SDL_Sprite::lock()
+{
+  // Make sure we aren't already locked
+  assert(!data.pixels);
+
+  // Lock the surface and set up the data structure
+  SDL_LockSurface(surface);
+
+  data.pixels = surface->pixels;
+  data.w = surface->w;
+  data.h = surface->h;
+  data.pitch = surface->pitch;
+  data.bypp = surface->format->BytesPerPixel;
+
+  return &data;
+}
+
+void SDL_Sprite::unlock()
+{
+  if(data.pixels)
+    {
+      SDL_UnlockSurface(surface);
+      data.pixels = NULL;
+    }
+}
+
+// This is a really crappy and slow implementation, only intended for
+// testing purposes. Use lock/unlock for faster pixel drawing.
 void SDL_Sprite::pixel(int x, int y, int color)
 {
   SDL_LockSurface(surface);
@@ -83,6 +110,7 @@ SDL_Sprite::SDL_Sprite(SDL_Surface *s, bool autoDelete)
   : surface(s), autoDel(autoDelete)
 {
   assert(surface != NULL);
+  data.pixels = NULL;
 }
 
 SDL_Sprite::~SDL_Sprite()
diff --git a/rend2d/servers/sdl_driver.hpp b/rend2d/servers/sdl_driver.hpp
index 4cab45c2e8..0f205ba34c 100644
--- a/rend2d/servers/sdl_driver.hpp
+++ b/rend2d/servers/sdl_driver.hpp
@@ -37,10 +37,16 @@ namespace Mangle
       // Set one pixel
       void pixel(int x, int y, int value);
 
+      const SpriteData *lock();
+      void unlock();
+
     private:
       // The SDL surface
       SDL_Surface* surface;
 
+      // Used for locking
+      SpriteData data;
+
       // If true, delete this surface when the canvas is destructed
       bool autoDel;
     };
diff --git a/rend2d/sprite.hpp b/rend2d/sprite.hpp
index 7f6b9a2206..f49da6cb6d 100644
--- a/rend2d/sprite.hpp
+++ b/rend2d/sprite.hpp
@@ -5,6 +5,17 @@ namespace Mangle
 {
   namespace Rend2D
   {
+    /**
+       A pointer to sprite data for direct drawing. Only to be used
+       while the corresponding sprite is locked.
+     */
+    struct SpriteData
+    {
+      void *pixels;     // Pixel data
+      int w, h;         // Width and height
+      int pitch, bypp;  // Pitch (bytes) and bytes per pixel
+    };
+
     /**
        A Sprite is either a bitmap to be drawn or an output of area
        for blitting other bitmaps, or both. They are created by the
@@ -33,6 +44,13 @@ namespace Mangle
       /// format. This is not expected to be fast, and in some
       /// implementations may not work at all.
       virtual void pixel(int x, int y, int value) {}
+
+      /// Lock sprite for direct drawing, and return a struct
+      /// containing the necessary pointer.  When finished, unlock the
+      /// sprite with unlock(). May return NULL, if so then direct
+      /// drawing is not possible.
+      virtual const SpriteData *lock() { return NULL; }
+      virtual void unlock() {}
     };
   }
 }