[4/7] WineD3D: Use an aux buffer as blitting helper if available

[Stefan Dösinger]

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From a2ca4ad261f1e100108159dc8a4dc3d016629673 Mon Sep 17 00:00:00 2001
From: Stefan Doesinger <stefan at codeweavers.com>
Date: Sun, 4 Mar 2007 23:47:57 +0100
Subject: [PATCH] WineD3D: Use an aux buffer as blitting helper if available

This helps performance a bit because the function does not have to wait for the 2nd read to finish before
returning. Only do that if we have an aux buffer to mess with for free though.
---
 dlls/wined3d/surface.c |   48 ++++++++++++++++++++++++++++++++++--------------
 1 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/dlls/wined3d/surface.c b/dlls/wined3d/surface.c
index 2a1cc60..c4eefc9 100644
--- a/dlls/wined3d/surface.c
+++ b/dlls/wined3d/surface.c
@@ -2261,12 +2261,24 @@ static inline void fb_copy_to_texture_hwstretch(IWineD3DSurfaceImpl *This, IWine
     float left, right, top, bottom; /* Texture coordinates */
     UINT fbwidth = Src->currentDesc.Width;
     UINT fbheight = Src->currentDesc.Height;
+    GLenum drawBuffer = GL_BACK;
 
     TRACE("Using hwstretch blit\n");
     /* Activate the Proper context for reading from the source surface, set it up for blitting */
     ENTER_GL();
     ActivateContext(myDevice, SrcSurface, CTXUSAGE_BLIT);
 
+    /* Try to use an aux buffer for drawing the rectangle. This way it doesn't need restoring.
+     * This way we don't have to wait for the 2nd readback to finish to leave this function.
+     */
+    if(GL_LIMITS(aux_buffers) >= 2) {
+        /* Got more than one aux buffer? Use the 2nd aux buffer */
+        drawBuffer = GL_AUX1;
+    } else if((swapchain || myDevice->offscreenBuffer == GL_BACK) && GL_LIMITS(aux_buffers) >= 1) {
+        /* Only one aux buffer, but it isn't used (Onscreen rendering, or non-aux orm)? Use it! */
+        drawBuffer = GL_AUX0;
+    }
+
     if(!swapchain && wined3d_settings.offscreen_rendering_mode == ORM_FBO) {
         glGenTextures(1, &backup);
         checkGLcall("glGenTextures\n");
@@ -2350,6 +2362,9 @@ static inline void fb_copy_to_texture_hwstretch(IWineD3DSurfaceImpl *This, IWine
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 
+    glDrawBuffer(drawBuffer);
+    glReadBuffer(drawBuffer);
+
     glBegin(GL_QUADS);
         /* bottom left */
         glTexCoord2f(left, bottom);
@@ -2383,23 +2398,28 @@ static inline void fb_copy_to_texture_hwstretch(IWineD3DSurfaceImpl *This, IWine
     glBindTexture(GL_TEXTURE_2D, backup ? backup : Src->glDescription.textureName);
     checkGLcall("glBindTexture(GL_TEXTURE_2D, Src->glDescription.textureName)");
 
-    glBegin(GL_QUADS);
-        /* top left */
-        glTexCoord2f(0.0, (float) fbheight / (float) Src->pow2Height);
-        glVertex2i(0, 0);
+    if(drawBuffer == GL_BACK) {
+        glBegin(GL_QUADS);
+            /* top left */
+            glTexCoord2f(0.0, (float) fbheight / (float) Src->pow2Height);
+            glVertex2i(0, 0);
 
-        /* bottom left */
-        glTexCoord2f(0.0, 0.0);
-        glVertex2i(0, fbheight);
+            /* bottom left */
+            glTexCoord2f(0.0, 0.0);
+            glVertex2i(0, fbheight);
 
-        /* bottom right */
-        glTexCoord2f((float) fbwidth / (float) Src->pow2Width, 0.0);
-        glVertex2i(fbwidth, Src->currentDesc.Height);
+            /* bottom right */
+            glTexCoord2f((float) fbwidth / (float) Src->pow2Width, 0.0);
+            glVertex2i(fbwidth, Src->currentDesc.Height);
 
-        /* top right */
-        glTexCoord2f((float) fbwidth / (float) Src->pow2Width, (float) fbheight / (float) Src->pow2Height);
-        glVertex2i(fbwidth, 0);
-    glEnd();
+            /* top right */
+            glTexCoord2f((float) fbwidth / (float) Src->pow2Width, (float) fbheight / (float) Src->pow2Height);
+            glVertex2i(fbwidth, 0);
+        glEnd();
+    } else {
+        /* Restore the old draw buffer */
+        glDrawBuffer(GL_BACK);
+    }
 
     /* Cleanup */
     if(src != Src->glDescription.textureName && src != backup) {
-- 
1.4.4.3