shithub: choc

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video: Add support for OS X high-DPI rendering.

This gives extra resolution when using a Mac with a retina display, and
can actually make a significant difference in terms of quality,
especially when using small window sizes.

--- a/src/i_video.c

+++ b/src/i_video.c

@@ -436,14 +436,23 @@

 }

-static void CreateUpscaledTexture(int w, int h)

+static void CreateUpscaledTexture(void)

 {

     const int actualheight = aspect_ratio_correct ?

                              SCREENHEIGHT_4_3 :

                              SCREENHEIGHT;

+    int w, h;

     int h_upscale, w_upscale;

     static int h_upscale_old, w_upscale_old;

+    // Get the size of the renderer output. The units this gives us will be

+    // real world pixels, which are not necessarily equivalent to the screen's

+    // window size (because of highdpi).

+    if (SDL_GetRendererOutputSize(renderer, &w, &h) != 0)

+    {

+        I_Error("Failed to get renderer output size: %s", SDL_GetError());

+    }

+

     // When the screen or window dimensions do not match the aspect ratio

     // of the texture, the rendered area is scaled down to fit. Calculate

     // the actual dimensions of the rendered area.

@@ -461,35 +470,36 @@

         w = h * SCREENWIDTH / actualheight;

     }

+    // Pick texture size the next integer multiple of the screen dimensions.

     // If one screen dimension matches an integer multiple of the original

     // resolution, there is no need to overscale in this direction.

-    h_upscale = h / SCREENHEIGHT;

+    w_upscale = (w + SCREENWIDTH - 1) / SCREENWIDTH;

+    h_upscale = (h + SCREENHEIGHT - 1) / SCREENHEIGHT;

-    if (!h || h % SCREENHEIGHT)

+    // Minimum texture dimensions of 320x200.

+

+    if (w_upscale < 1)

     {

-        h_upscale++;

+        w_upscale = 1;

     }

-

-    w_upscale = w / SCREENWIDTH;

-

-    if (!w || w % SCREENWIDTH)

+    if (h_upscale < 1)

     {

-        w_upscale++;

+        h_upscale = 1;

     }

     // Limit maximum texture dimensions to 1600x1200.

+    // It's really diminishing returns at this point.

+    if (w_upscale > 5)

+    {

+        w_upscale = 5;

+    }

     if (h_upscale > 6)

     {

         h_upscale = 6;

     }

-    if (w_upscale > 5)

-    {

-        w_upscale = 5;

-    }

-

     // Create a new texture only if the upscale factors have actually changed.

     if (h_upscale == h_upscale_old && w_upscale == w_upscale_old)

@@ -535,7 +545,7 @@

     if (need_resize && SDL_GetTicks() > last_resize_time + 1000/TICRATE)

     {

-        CreateUpscaledTexture(resize_w, resize_h);

+        CreateUpscaledTexture();

         screen_width = resize_w;

         screen_height = resize_h;

         need_resize = false;

@@ -977,6 +987,10 @@

         flags |= SDL_WINDOW_RESIZABLE;

     }

+    // Set the highdpi flag - this makes a big difference on Macs with

+    // retina displays, especially when using small window sizes.

+    flags |= SDL_WINDOW_ALLOW_HIGHDPI;

+

     // Create window and renderer contexts. We set the window title

     // later anyway and leave the window position "undefined". If "flags"

     // contains the fullscreen flag (see above), then w and h are ignored.

@@ -1065,7 +1079,7 @@

     // Initially create the upscaled texture for rendering to screen

-    CreateUpscaledTexture(w, h);

+    CreateUpscaledTexture();

 }

 void I_InitGraphics(void)