sdl: Add support for SDL2

Now we only support using pkg-config to find SDL, and prefer SDL2 over SDL.
For compatibility between versions, the render surface is now cleared on flip.
And closing the window now results in a JIM_EXIT return code from flip.
Also supports [sdl clear] to clear the background to a given colour.

Signed-off-by: Steve Bennett <steveb@workware.net.au>

1 files changed, 28 insertions, 0 deletions

diff --git a/examples/sdltest.tcl b/examples/sdltest.tcl
new file mode 100644
index 0000000..6607574
--- /dev/null
+++ b/examples/sdltest.tcl
@@ -0,0 +1,28 @@
+package require sdl
+
+set xres 1024
+set yres 768
+set s [sdl.screen $xres $yres]
+
+proc drawlist {s list} {
+    foreach item $list {
+        $s {*}$item
+    }
+}
+
+proc rand_circle {xres yres maxradius alpha} {
+    list fcircle [rand $xres] [rand $yres] [rand $maxradius] [rand 256] [rand 256] [rand 256] $alpha
+}
+
+loop i 0 200 {
+    set commands {}
+    loop j 0 1000 {
+        lappend commands [rand_circle $xres $yres 40 100]
+        if {$j % 50 == 0} {
+            #$s clear 200 200 200
+            drawlist $s $commands
+            $s flip
+            sleep 0.1
+        }
+    }
+}