Fermi2D: limit blit area to only available area

Normaly OpenGL does not care if the areas exceed the texture regions but
other backends such as Vulkan do care about the limits of this areas.
This PR crops the areas of the blit in order that they don't surpass the
limits of the textures. This should help Vulkan and faulty OpenGL
drivers

src/video_core/engines/fermi_2d.cpp

@@ -47,10 +47,20 @@ void Fermi2D::HandleSurfaceCopy() {
         src_blit_x2 = static_cast<u32>((regs.blit_src_x >> 32) + regs.blit_dst_width);
         src_blit_y2 = static_cast<u32>((regs.blit_src_y >> 32) + regs.blit_dst_height);
     }
-    const Common::Rectangle<u32> src_rect{src_blit_x1, src_blit_y1, src_blit_x2, src_blit_y2};
-    const Common::Rectangle<u32> dst_rect{regs.blit_dst_x, regs.blit_dst_y,
-                                          regs.blit_dst_x + regs.blit_dst_width,
-                                          regs.blit_dst_y + regs.blit_dst_height};
+    const u32 dst_blit_x2 = regs.blit_dst_x + regs.blit_dst_width;
+    const u32 dst_blit_y2 = regs.blit_dst_x + regs.blit_dst_height;
+    const u32 excess_src_x2 = std::max<s32>(0, dst_blit_x2 - regs.dst.width);
+    const u32 excess_src_y2 = std::max<s32>(0, dst_blit_y2 - regs.dst.height);
+    const u32 excess_dst_x2 = std::max<s32>(0, src_blit_x2 - regs.src.width);
+    const u32 excess_dst_y2 = std::max<s32>(0, src_blit_y2 - regs.src.height);
+
+    const Common::Rectangle<u32> src_rect{
+        src_blit_x1, src_blit_y1, std::min<u32>(regs.src.width, src_blit_x2) - excess_src_x2,
+        std::min<u32>(regs.src.height, src_blit_y2) - excess_src_y2};
+    const Common::Rectangle<u32> dst_rect{
+        regs.blit_dst_x, regs.blit_dst_y,
+        std::min<u32>(regs.dst.width, dst_blit_x2) - excess_dst_x2,
+        std::min<u32>(regs.dst.height, dst_blit_y2) - excess_dst_y2};
     Config copy_config;
     copy_config.operation = regs.operation;
     copy_config.filter = regs.blit_control.filter;