Fix negative surface zooming.

3 files changed, 17 insertions, 7 deletions

diff --git a/tests/runner.py b/tests/runner.py
index 4bd4b806..ddef3568 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -13183,8 +13183,8 @@ Press any key to continue.'''
       self.btest('sdl_maprgba.c', reference='sdl_maprgba.png', reference_slack=3)
 
     def test_sdl_rotozoom(self):
-      shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'example.png'))
-      self.btest('sdl_rotozoom.c', reference='sdl_rotozoom.png', args=['--preload-file', 'example.png'])
+      shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'screenshot.png'))
+      self.btest('sdl_rotozoom.c', reference='sdl_rotozoom.png', args=['--preload-file', 'screenshot.png'], reference_slack=3)
 
     def test_sdl_canvas_palette_2(self):
       open(os.path.join(self.get_dir(), 'pre.js'), 'w').write('''
diff --git a/tests/sdl_rotozoom.c b/tests/sdl_rotozoom.c
index b3970f6c..e81258d9 100644
--- a/tests/sdl_rotozoom.c
+++ b/tests/sdl_rotozoom.c
@@ -6,15 +6,18 @@
 #include "emscripten.h"
 #endif
 
+const int numSprites = 8;
 SDL_Surface *screen;
-SDL_Surface *sprite[6];
+SDL_Surface *sprite[numSprites];
 
 void mainloop() {
     int i;
+    int row = 0;
     SDL_Rect rect = { 0, 0, 100, 100 };
-    for (i = 0; i < 6; i++) {
+    for (i = 0; i < numSprites; i++) {
         rect.x = i & 1 ? 200 : 0;
-        rect.y = i & 2 ? 200 : 0;
+        rect.y = row * 200;
+        row += i & 1;
         SDL_BlitSurface(sprite[i], 0, screen, &rect);
         SDL_UpdateRect(screen, 0, 0, 0, 0);
     }
@@ -23,20 +26,27 @@ void mainloop() {
 int main(int argc, char **argv) {
     SDL_Init(SDL_INIT_VIDEO);
 
-    screen = SDL_SetVideoMode(400, 400, 32, SDL_SWSURFACE);
+    const int width = 400;
+    const int height = 200 * (numSprites + 1) / 2;
+    screen = SDL_SetVideoMode(width, height, 32, SDL_SWSURFACE);
+    SDL_Rect rect = { 0, 0, width, height };
+    SDL_FillRect(screen, &rect, SDL_MapRGBA(screen->format, 0, 0, 0, 0xff));
 
-    sprite[0] = IMG_Load("example.png");
+    sprite[0] = IMG_Load("screenshot.png");
     sprite[1] = SDL_CreateRGBSurface(SDL_SWSURFACE, 100, 100, 32, 0xFF000000, 0xFF0000, 0xFF00, 0xFF);
     SDL_FillRect(sprite[1], 0, 0xA0A0A0A0);
     sprite[2] = zoomSurface(sprite[0], 0.5, 0.5, SMOOTHING_ON);
     sprite[3] = zoomSurface(sprite[1], 0.5, 0.5, SMOOTHING_ON);
     sprite[4] = rotozoomSurface(sprite[0], -20, 0.3, SMOOTHING_ON);
     sprite[5] = rotozoomSurface(sprite[1], 45, 0.5, SMOOTHING_ON);
+    sprite[6] = zoomSurface(sprite[0], -0.5, 0.5, SMOOTHING_ON);
+    sprite[7] = zoomSurface(sprite[0], -0.5, -0.5, SMOOTHING_ON);
 
     mainloop();
 
 #ifndef EMSCRIPTEN
     SDL_Event evt;
+    SDL_SaveBMP(screen, "native_output.bmp");
     while (1) {
        if (SDL_PollEvent(&evt) != 0 && evt.type == SDL_QUIT) break;
        //mainloop();
diff --git a/tests/sdl_rotozoom.png b/tests/sdl_rotozoom.png
index 3ca8da70..5c5dec2f 100644
--- a/tests/sdl_rotozoom.png
+++ b/tests/sdl_rotozoom.png