Henri Verbeet : wined3d: Fix the half pixel offset.
Alexandre Julliard
julliard at winehq.org
Wed Sep 10 06:01:46 CDT 2008
Module: wine
Branch: master
Commit: 27b8f719ca7f26e1edbec6f7e46cc612dce12b41
URL: http://source.winehq.org/git/wine.git/?a=commit;h=27b8f719ca7f26e1edbec6f7e46cc612dce12b41
Author: Henri Verbeet <hverbeet at codeweavers.com>
Date: Wed Sep 10 11:08:10 2008 +0200
wined3d: Fix the half pixel offset.
Turns out the original fix was correct for fixed function, but for the
wrong reason. The shader path was already correct. This fixes a
regresssion introduced by 932e95c111118b643650d6643e47be0ddb5528a1.
---
dlls/wined3d/state.c | 32 ++++++++++++++++++++------------
1 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/dlls/wined3d/state.c b/dlls/wined3d/state.c
index 61ccab6..358ad14 100644
--- a/dlls/wined3d/state.c
+++ b/dlls/wined3d/state.c
@@ -3905,16 +3905,6 @@ static void transform_projection(DWORD state, IWineD3DStateBlockImpl *stateblock
divide by the Width/Height, so we need the half range(1.0) to translate by
half a pixel.
- Note that when rendering offscreen, we need to translate 1 pixel
- (2/h in normalized device coordinates) down after doing the flip,
- because of the way the viewport transformation works in OpenGL:
- (-1,1) in normalized device coordinates corresponds to the upper
- left corner of the upper left pixel in the viewport. (-1,-1)
- corresponds to lower left corner of the lower left pixel in the
- viewport. In other words, the upper left corner of the pixel
- *below* the lower left pixel in the viewport. See also section
- 2.11.1 "Controlling the Viewport" of the GL 2.1 spec.
-
The other fun is that d3d's output z range after the transformation is [0;1],
but opengl's is [-1;1]. Since the z buffer is in range [0;1] for both, gl
scales [-1;1] to [0;1]. This would mean that we end up in [0.5;1] and loose a lot
@@ -3922,6 +3912,24 @@ static void transform_projection(DWORD state, IWineD3DStateBlockImpl *stateblock
[0;1] to [-1;1], so when gl undoes that we utilize the full z range
*/
+ /*
+ * Careful with the order of operations here, we're essentially working backwards:
+ * x = x + 1/w;
+ * y = (y - 1/h) * flip;
+ * z = z * 2 - 1;
+ *
+ * Becomes:
+ * glTranslatef(0.0, 0.0, -1.0);
+ * glScalef(1.0, 1.0, 2.0);
+ *
+ * glScalef(1.0, flip, 1.0);
+ * glTranslatef(1/w, -1/h, 0.0);
+ *
+ * This is equivalent to:
+ * glTranslatef(1/w, -flip/h, -1.0)
+ * glScalef(1.0, flip, 2.0);
+ */
+
if (stateblock->wineD3DDevice->render_offscreen) {
/* D3D texture coordinates are flipped compared to OpenGL ones, so
* render everything upside down when rendering offscreen. */
@@ -4517,7 +4525,7 @@ static void vertexdeclaration(DWORD state, IWineD3DStateBlockImpl *stateblock, W
*/
if (useVertexShaderFunction) {
device->posFixup[1] = device->render_offscreen ? -1.0 : 1.0;
- device->posFixup[3] = -1.0 / stateblock->viewport.Height;
+ device->posFixup[3] = -device->posFixup[1] / stateblock->viewport.Height;
}
}
@@ -4649,7 +4657,7 @@ static void viewport_miscpart(DWORD state, IWineD3DStateBlockImpl *stateblock, W
static void viewport_vertexpart(DWORD state, IWineD3DStateBlockImpl *stateblock, WineD3DContext *context) {
stateblock->wineD3DDevice->posFixup[2] = 1.0 / stateblock->viewport.Width;
- stateblock->wineD3DDevice->posFixup[3] = -1.0 / stateblock->viewport.Height;
+ stateblock->wineD3DDevice->posFixup[3] = -stateblock->wineD3DDevice->posFixup[1] / stateblock->viewport.Height;
if(!isStateDirty(context, STATE_TRANSFORM(WINED3DTS_PROJECTION))) {
transform_projection(STATE_TRANSFORM(WINED3DTS_PROJECTION), stateblock, context);
}
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