--disable_framebuffer_readback

src/xenia/gpu/gl4/command_processor.cc

@@ -2396,6 +2396,7 @@ bool CommandProcessor::IssueCopy() {
   uint32_t w = copy_dest_pitch;
   uint32_t h = copy_dest_height;
 
+  if (!FLAGS_disable_framebuffer_readback) {
     // Make active so glReadPixels reads from us.
     glBindFramebuffer(GL_READ_FRAMEBUFFER, source_framebuffer->framebuffer);
     switch (copy_command) {
@@ -2419,6 +2420,7 @@ bool CommandProcessor::IssueCopy() {
         return false;
     }
     glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+  }
 
   // Perform any requested clears.
   uint32_t copy_depth_clear = regs[XE_GPU_REG_RB_DEPTH_CLEAR].u32;

src/xenia/gpu/gl4/gl4_gpu-private.h

@@ -22,6 +22,7 @@ DECLARE_bool(gl_debug_output_synchronous);
 
 DECLARE_bool(vendor_gl_extensions);
 
+DECLARE_bool(disable_framebuffer_readback);
 DECLARE_bool(disable_textures);
 
 namespace xe {

src/xenia/gpu/gl4/gl4_gpu.cc

@@ -22,6 +22,8 @@ DEFINE_bool(gl_debug_output_synchronous, true,
 DEFINE_bool(vendor_gl_extensions, true,
             "Enable vendor-specific (NV, AMD, etc) GL extensions.");
 
+DEFINE_bool(disable_framebuffer_readback, false,
+            "Disable framebuffer readback.");
 DEFINE_bool(disable_textures, false, "Disable textures and use colors only.");
 
 namespace xe {