add support for texture-to-texture blits.master

per Holger's suggestion, texture-to-texture blits are implemented as
texture-to-framebuffer followed by framebuffer-to-texture blits.

1 files changed, 71 insertions, 89 deletions

diff --git a/src/libgame/sdl.c b/src/libgame/sdl.c
index 29e2254..96c3a99 100644
--- a/src/libgame/sdl.c
+++ b/src/libgame/sdl.c
@@ -213,11 +213,8 @@ void SDLInitVideoBuffer(DrawBuffer **backbuffer, DrawWindow **window,
   /* set window and icon title */
   SDL_WM_SetCaption(program.window_title, program.window_title);
 
-  /* create additional (symbolic) buffer for double-buffering */
-  /* GL-TODO: remove all uses of 'window'. 'window' is never drawn to.
-   * the only reason we create a Bitmap and not just use '*window = NULL'
-   * is that a lot of code still uses 'window == NULL' to check if video
-   * is available. */
+  /* create additional (symbolic) buffers for double-buffering */
+  *backbuffer = CreateBitmap(video.width, video.height, video.depth);
   *window = CreateBitmapStruct();
 }
 
@@ -229,9 +226,6 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
   int video_yoffset_bottom;
   SDL_Surface *new_surface = NULL;
 
-  if (*backbuffer == NULL)
-    *backbuffer = CreateBitmapStruct();
-
   /* GL-TODO: this should be placed immediately before SDL_SetVideoMode. */
   SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 
@@ -258,8 +252,6 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
     }
     else
     {
-      (*backbuffer)->surface = new_surface;
-
       video.fullscreen_enabled = TRUE;
       video.fullscreen_mode_current = setup.fullscreen_mode;
 
@@ -285,8 +277,6 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
     }
     else
     {
-      (*backbuffer)->surface = new_surface;
-
       video.fullscreen_enabled = FALSE;
       success = TRUE;
     }
@@ -294,7 +284,7 @@ boolean SDLSetVideoMode(DrawBuffer **backbuffer, boolean fullscreen)
 
   if (success)
   {
-    glClearColor(0, 0, 0, 0);
+    glClearColor(0, 0, 0, 0); glClear(GL_COLOR_BUFFER_BIT);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glViewport(video_xoffset, video_yoffset_bottom, video.width, video.height);
     glMatrixMode(GL_PROJECTION); glLoadIdentity();
@@ -354,7 +344,9 @@ void SDLCreateBitmapContent(Bitmap *new_bitmap, int width, int height,
     depth = 4;
   /* GL-TODO: is it possible to set size without allocating this memory? */
   pixels = checked_calloc(realw * realh * depth);   /* zeroes */
+#if 0
   memset(pixels, 128, realw * realh * depth);   /* GL-TODO: REMOVE DEBUG */
+#endif
   glTexImage2D(GL_TEXTURE_2D, 0, depth, realw, realh, 0,
     depth == 3 ? GL_RGB : GL_RGBA, GL_UNSIGNED_BYTE, pixels);
   checked_free(pixels);
@@ -382,60 +374,23 @@ void SDLFreeBitmapPointers(Bitmap *bitmap)
   bitmap->texture_name = 0;
 }
 
-void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
-		 int src_x, int src_y, int width, int height,
-		 int dst_x, int dst_y, int mask_mode)
+static void SDLBlitToWindow(Bitmap *src_bitmap,
+			    int src_x, int src_y, int width, int height,
+			    int dst_x, int dst_y, int mask_mode)
 {
-  if (dst_bitmap != backbuffer && dst_bitmap != window)
-  {
-    if (src_bitmap == backbuffer)
-    {
-      if (dst_bitmap->texture_name == 0)
-        return;
-      glBindTexture(GL_TEXTURE_2D, dst_bitmap->texture_name);
-      /* GL-TODO: this assumes video_yoffset is the same on the top and
-       * the bottom of the screen. is that correct? (i.e. are video.height
-       * and fullscreen_height always even?) */
-      glCopyTexSubImage2D(GL_TEXTURE_2D, 0,
-        dst_x, dst_bitmap->height - dst_y - height,
-	src_x + video_xoffset, video.height + video_yoffset - src_y - height,
-        width, height);
-    }
-    else
-    {
-      Error(ERR_WARN, "SDLCopyArea() from bitmap to bitmap is deprecated");
-    }
-    return;
-  }
-
-  if (src_bitmap == backbuffer && dst_bitmap == window)
-  {
-    SDL_GL_SwapBuffers();
-#if 0
-    /* this draws a yellow layer on the backbuffer, showing which regions
-     * of the screen were recently redrawn. if the whole screen was always
-     * redrawn, no yellow layer would be visible. */
-    glBindTexture(GL_TEXTURE_2D, 0);
-    glEnable(GL_BLEND);
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-    glColor4f(1, 1, 0, 0.01);
-    glBegin(GL_QUADS);
-    glVertex2i(0, 0); glVertex2i(800, 0); glVertex2i(800, 600); glVertex2i(0, 600);
-    glEnd();
-#endif
-    return;
-  }
-
   if(src_bitmap->texture_name == 0)
     return;
-  if (mask_mode == BLIT_MASKED)
+  if (mask_mode == BLIT_MASKED || mask_mode == BLIT_INVERSE)
     glEnable(GL_BLEND);
   else
     glDisable(GL_BLEND);
   /* GL-TODO: don't allow blitting from outside src_bitmap */
   glEnable(GL_TEXTURE_2D);
   glBindTexture(GL_TEXTURE_2D, src_bitmap->texture_name);
-  glColor3f(1, 1, 1);   /* GL-TODO: allow black for SDLCopyInverseMasked */
+  if (mask_mode == BLIT_INVERSE)
+    glColor3f(0, 0, 0);
+  else
+    glColor3f(1, 1, 1);
   glBegin(GL_QUADS);
   /* all the Vertex() arguments are in traditional coordinates (0 is up). */
 #define Vertex(sx, sy, dx, dy)                                               \
@@ -448,31 +403,78 @@ void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
   Vertex(src_x, src_y, dst_x, dst_y);                             /* upper left */
 #undef Vertex
   glEnd();
+}
+
+static void SDLBlitFromWindow(Bitmap *dst_bitmap,
+			      int src_x, int src_y, int width, int height,
+			      int dst_x, int dst_y)
+{
+  if (dst_bitmap->texture_name == 0)
+    return;
+  glBindTexture(GL_TEXTURE_2D, dst_bitmap->texture_name);
+  /* GL-TODO: this assumes video_yoffset is the same on the top and
+   * the bottom of the screen. is that correct? (i.e. are video.height
+   * and fullscreen_height always even?) */
+  glCopyTexSubImage2D(GL_TEXTURE_2D, 0,
+    dst_x, dst_bitmap->height - dst_y - height,
+    src_x + video_xoffset, video.height + video_yoffset - src_y - height,
+    width, height);
+}
 
-  if (dst_bitmap == window)
+void SDLCopyArea(Bitmap *src_bitmap, Bitmap *dst_bitmap,
+		 int src_x, int src_y, int width, int height,
+		 int dst_x, int dst_y, int mask_mode)
+{
+  Bitmap *real_dst_bitmap = (dst_bitmap == window ? backbuffer : dst_bitmap);
+
+  if (src_bitmap != backbuffer || dst_bitmap != window) {
+    if (mask_mode == BLIT_OPAQUE)
+      SDLBlitToWindow(src_bitmap, src_x, src_y, width, height, 0, 0, BLIT_OPAQUE);
+    else {
+      SDLBlitToWindow(real_dst_bitmap, dst_x, dst_y, width, height, 0, 0, BLIT_OPAQUE);
+      SDLBlitToWindow(src_bitmap, src_x, src_y, width, height, 0, 0, mask_mode);
+    }
+    SDLBlitFromWindow(real_dst_bitmap, 0, 0, width, height, dst_x, dst_y);
+  }
+  if (dst_bitmap == window) {
+    /* window is used as a temporary buffer for blits, so partial screen updates
+     * aren't supported */
+    SDLBlitToWindow(backbuffer, 0, 0, video.width, video.height, 0, 0, BLIT_OPAQUE);
     SDL_GL_SwapBuffers();
+#if 1
+    /* this draws a yellow layer on the backbuffer, showing which regions
+     * of the screen were recently redrawn. if the whole screen was always
+     * redrawn, no yellow layer would be visible. */
+    glBindTexture(GL_TEXTURE_2D, 0);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glColor4f(1, 1, 0, 0.01);
+    glBegin(GL_QUADS);
+    glVertex2i(0, 0); glVertex2i(800, 0); glVertex2i(800, 600); glVertex2i(0, 600);
+    glEnd();
+#endif
+  }
 }
 
 void SDLFillRectangle(Bitmap *dst_bitmap, int x, int y, int width, int height,
 		      Uint32 color)
 {
-  if (dst_bitmap != backbuffer && dst_bitmap != window)
+  if (dst_bitmap != backbuffer)
   {
-    Error(ERR_WARN, "SDLFilLRectangle() to a bitmap is deprecated");
+    Error(ERR_WARN, "SDLFillRectangle() to bitmaps other than backbuffer is deprecated");
     return;
   }
 
   glBindTexture(GL_TEXTURE_2D, 0);
   glColor3ub((color>>16)&0xFF, (color>>8)&0xFF, color&0xFF);
   glBegin(GL_QUADS);
-  glVertex2i(x, video.height-y);
-  glVertex2i(x+width, video.height-y);
-  glVertex2i(x+width, video.height-y-height);
-  glVertex2i(x, video.height-y-height);
+  glVertex2i(0, 0);
+  glVertex2i(0, video.height);
+  glVertex2i(video.width, video.height);
+  glVertex2i(video.width, 0);
   glEnd();
 
-  if (dst_bitmap == window)
-    SDL_GL_SwapBuffers();
+  SDLBlitFromWindow(backbuffer, 0, 0, width, height, x, y);
 }
 
 void SDLFadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
@@ -738,21 +740,7 @@ void SDLDrawSimpleLine(Bitmap *dst_bitmap, int from_x, int from_y,
 void SDLDrawLine(Bitmap *dst_bitmap, int from_x, int from_y,
 		 int to_x, int to_y, Uint32 color)
 {
-  if (dst_bitmap != backbuffer && dst_bitmap != window)
-  {
-    Error(ERR_WARN, "SDLDrawLine() to a bitmap is deprecated");
-    return;
-  }
-
-  glBindTexture(GL_TEXTURE_2D, 0);
-  glColor3ub((color>>16)&0xFF, (color>>8)&0xFF, color&0xFF);
-  glBegin(GL_LINES);
-  glVertex2i(from_x, video.height-from_y);
-  glVertex2i(to_x, video.height-to_y);
-  glEnd();
-
-  if (dst_bitmap == window)
-    SDL_GL_SwapBuffers();
+  Error(ERR_WARN, "SDLDrawLine() is deprecated");
 }
 
 Pixel SDLGetPixel(Bitmap *src_bitmap, int x, int y)
@@ -777,12 +765,7 @@ void SDLCopyInverseMasked(Bitmap *src_bitmap, Bitmap *dst_bitmap,
 			  int src_x, int src_y, int width, int height,
 			  int dst_x, int dst_y)
 {
-  Error(ERR_WARN, "SDLCopyInverseMasked() is deprecated");
-  /* GL-TODO: implement this.
-   * for each non-black pixel in src_bitmap, this function draws a black
-   * pixel in dst_bitmap. this is used for text cursors in DrawTextExt.
-   * this can be trivially reimplemented by setting glColor to black
-   * before doing BlitBitmap, but SDLCopyArea sets glColor(1,1,1) ATM. */
+  SDLCopyArea(src_bitmap, dst_bitmap, src_x, src_y, width, height, dst_x, dst_y, BLIT_INVERSE);
 }
 
 void SDLZoomBitmap(Bitmap *src_bitmap, Bitmap *dst_bitmap)
@@ -869,7 +852,6 @@ Bitmap *SDLLoadImage(char *filename)
   {
     for (x = 0; x < sdl_image_tmp->w; x++)
     {
-      Uint8 pixel[4];
       SDL_GetRGBA(SDLGetSurfacePixel(sdl_image_tmp, x, y), sdl_image_tmp->format,
         line+x*4+0, line+x*4+1, line+x*4+2, line+x*4+3);
       /* simulate colorkey */