From 757b2b61e1781fbc903413f8703628468fd6c2f9 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Jos=C3=A9=20Fonseca?= <jose.r.fonseca@gmail.com>
Date: Mon, 19 Sep 2011 10:09:53 +0100
Subject: [PATCH] Infer the drawable size from glBlitFramebuffer too

---
 glretrace.hpp      |  1 +
 glretrace.py       | 22 ++++++----------------
 glretrace_main.cpp | 31 +++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/glretrace.hpp b/glretrace.hpp
index 255dd6f..5b93f2d 100644
--- a/glretrace.hpp
+++ b/glretrace.hpp
@@ -69,6 +69,7 @@ void retrace_call_wgl(Trace::Call &call);
 void snapshot(unsigned call_no);
 void frame_complete(unsigned call_no);
 
+void updateDrawable(int width, int height);
 
 } /* namespace glretrace */
 
diff --git a/glretrace.py b/glretrace.py
index 53afdbe..356659a 100644
--- a/glretrace.py
+++ b/glretrace.py
@@ -207,23 +207,13 @@ class GlRetracer(Retracer):
 
 
     def call_function(self, function):
+        # Infer the drawable size from GL calls
         if function.name == "glViewport":
-            print '    GLint draw_framebuffer = 0;'
-            print '    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &draw_framebuffer);'
-            print '    if (draw_framebuffer == 0) {'
-            print '        if (glretrace::drawable) {'
-            print '            int drawable_width  = x + width;'
-            print '            int drawable_height = y + height;'
-            print '            if (drawable_width  > (int)glretrace::drawable->width ||'
-            print '                drawable_height > (int)glretrace::drawable->height) {'
-            print '                glretrace::drawable->resize(drawable_width, drawable_height);'
-            print '                if (!glretrace::drawable->visible) {'
-            print '                    glretrace::drawable->show();'
-            print '                }'
-            print '                glScissor(0, 0, drawable_width, drawable_height);'
-            print '            }'
-            print '        }'
-            print '    }'
+            print '    glretrace::updateDrawable(x + width, y + height);'
+        if function.name in ('glBlitFramebuffer', 'glBlitFramebufferEXT'):
+            # Some applications do all their rendering in a framebuffer, and
+            # then just blit to the drawable without ever calling glViewport.
+            print '    glretrace::updateDrawable(std::max(dstX0, dstX1), std::max(dstY0, dstY1));'
 
         if function.name == "glEnd":
             print '    glretrace::insideGlBeginEnd = false;'
diff --git a/glretrace_main.cpp b/glretrace_main.cpp
index 3a90092..cd35889 100644
--- a/glretrace_main.cpp
+++ b/glretrace_main.cpp
@@ -103,6 +103,37 @@ checkGlError(Trace::Call &call) {
     std::cerr << "\n";
 }
 
+/**
+ * Grow the current drawble.
+ *
+ * We need to infer the drawable size from GL calls because the drawable sizes
+ * are specified by OS specific calls which we do not trace.
+ */
+void
+updateDrawable(int width, int height) {
+    if (!drawable) {
+        return;
+    }
+
+    if (width  <= glretrace::drawable->width &&
+        height <= glretrace::drawable->height) {
+        return;
+    }
+
+    // Check for bound framebuffer last, as this may have a performance impact.
+    GLint draw_framebuffer = 0;
+    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &draw_framebuffer);
+    if (draw_framebuffer != 0) {
+        return;
+    }
+
+    glretrace::drawable->resize(width, height);
+    if (!drawable->visible) {
+        drawable->show();
+    }
+    glScissor(0, 0, width, height);
+}
+
 
 void snapshot(unsigned call_no) {
     if (!drawable ||
-- 
2.43.0