From df892ff67d8ae2c0f46b222f219b55029158c391 Mon Sep 17 00:00:00 2001
From: Roderick Colenbrander <thunderbird2k@gmx.net>
Date: Tue, 6 Nov 2007 01:11:35 +0100
Subject: [PATCH] wined3d: Rewrite the draw buffer selection code.

Before it was done in findContext, before selecting the new context
which is bad (it doesn't always work). The new code works and this
change also fixes some draw buffer regressions that happened during
the surface rewrite from the last couple of days.
---
 dlls/wined3d/context.c         | 33 +++++++++++++++++++--------------
 dlls/wined3d/wined3d_private.h |  1 +
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/dlls/wined3d/context.c b/dlls/wined3d/context.c
index dc64a5cb0ea..8311ab5be9d 100644
--- a/dlls/wined3d/context.c
+++ b/dlls/wined3d/context.c
@@ -674,7 +674,7 @@ static WineD3DContext *findThreadContextForSwapChain(IWineD3DSwapChain *swapchai
  * Returns: The needed context
  *
  *****************************************************************************/
-static inline WineD3DContext *FindContext(IWineD3DDeviceImpl *This, IWineD3DSurface *target, DWORD tid) {
+static inline WineD3DContext *FindContext(IWineD3DDeviceImpl *This, IWineD3DSurface *target, DWORD tid, GLint *buffer) {
     IWineD3DSwapChain *swapchain = NULL;
     HRESULT hr;
     BOOL readTexture = wined3d_settings.offscreen_rendering_mode != ORM_FBO && This->render_offscreen;
@@ -693,15 +693,12 @@ static inline WineD3DContext *FindContext(IWineD3DDeviceImpl *This, IWineD3DSurf
          * rendering. No context change is needed in that case
          */
 
-        if (wined3d_settings.offscreen_rendering_mode == ORM_BACKBUFFER) {
-            if(((IWineD3DSwapChainImpl *) swapchain)->backBuffer) {
-                glDrawBuffer(GL_BACK);
-                checkGLcall("glDrawBuffer(GL_BACK)");
-            } else {
-                glDrawBuffer(GL_FRONT);
-                checkGLcall("glDrawBuffer(GL_FRONT)");
-            }
-        } else if(wined3d_settings.offscreen_rendering_mode == ORM_PBUFFER) {
+        if(((IWineD3DSwapChainImpl *) swapchain)->frontBuffer == target) {
+            *buffer = GL_FRONT;
+        } else {
+            *buffer = GL_BACK;
+        }
+        if(wined3d_settings.offscreen_rendering_mode == ORM_PBUFFER) {
             if(This->pbufferContext && tid == This->pbufferContext->tid) {
                 This->pbufferContext->tid = 0;
             }
@@ -719,6 +716,7 @@ static inline WineD3DContext *FindContext(IWineD3DDeviceImpl *This, IWineD3DSurf
     } else {
         TRACE("Rendering offscreen\n");
         This->render_offscreen = TRUE;
+        *buffer = This->offscreenBuffer;
 
         switch(wined3d_settings.offscreen_rendering_mode) {
             case ORM_FBO:
@@ -784,8 +782,6 @@ static inline WineD3DContext *FindContext(IWineD3DDeviceImpl *This, IWineD3DSurf
                      */
                     context = findThreadContextForSwapChain(This->swapchains[0], tid);
                 }
-                glDrawBuffer(This->offscreenBuffer);
-                checkGLcall("glDrawBuffer(This->offscreenBuffer)");
                 break;
         }
 
@@ -849,11 +845,11 @@ void ActivateContext(IWineD3DDeviceImpl *This, IWineD3DSurface *target, ContextU
     DWORD                         dirtyState, idx;
     BYTE                          shift;
     WineD3DContext                *context;
+    GLint                         drawBuffer=0;
 
     TRACE("(%p): Selecting context for render target %p, thread %d\n", This, target, tid);
-
     if(This->lastActiveRenderTarget != target || tid != This->lastThread) {
-        context = FindContext(This, target, tid);
+        context = FindContext(This, target, tid, &drawBuffer);
         This->lastActiveRenderTarget = target;
         This->lastThread = tid;
     } else {
@@ -874,6 +870,15 @@ void ActivateContext(IWineD3DDeviceImpl *This, IWineD3DSurface *target, ContextU
 
     /* We only need ENTER_GL for the gl calls made below and for the helper functions which make GL calls */
     ENTER_GL();
+    /* Select the right draw buffer. It is selected in FindContext. */
+    if(drawBuffer && context->last_draw_buffer != drawBuffer) {
+        TRACE("Drawing to buffer: %#x\n", drawBuffer);
+        context->last_draw_buffer = drawBuffer;
+
+        glDrawBuffer(drawBuffer);
+        checkGLcall("glDrawBuffer");
+    }
+
     switch(usage) {
         case CTXUSAGE_RESOURCELOAD:
             /* This does not require any special states to be set up */
diff --git a/dlls/wined3d/wined3d_private.h b/dlls/wined3d/wined3d_private.h
index 7e2eec152e6..89688fcf897 100644
--- a/dlls/wined3d/wined3d_private.h
+++ b/dlls/wined3d/wined3d_private.h
@@ -493,6 +493,7 @@ struct WineD3DContext {
     DWORD                   tid;    /* Thread ID which owns this context at the moment */
 
     /* Stores some inforation about the context state for optimization */
+    GLint                   last_draw_buffer;
     BOOL                    last_was_rhw;      /* true iff last draw_primitive was in xyzrhw mode */
     BOOL                    last_was_pshader;
     BOOL                    last_was_vshader;