[PATCH 6/6] wined3d: Set z = 0.0 via the projection matrix instead of depth clamping.

[Stefan Dösinger]

This works on cards that don't implement ARB_depth_clamp like r500
cards.

Note that texturing is influenced by position.w, not position.z.
---
 dlls/wined3d/directx.c    |  7 -------
 dlls/wined3d/state.c      | 33 ++++++++++-----------------------
 dlls/wined3d/wined3d_gl.h |  2 --
 3 files changed, 10 insertions(+), 32 deletions(-)

diff --git a/dlls/wined3d/directx.c b/dlls/wined3d/directx.c
index bacddc9..5fa9355 100644
--- a/dlls/wined3d/directx.c
+++ b/dlls/wined3d/directx.c
@@ -112,7 +112,6 @@ static const struct wined3d_extension_map gl_extension_map[] =
     {"GL_ARB_color_buffer_float",           ARB_COLOR_BUFFER_FLOAT        },
     {"GL_ARB_debug_output",                 ARB_DEBUG_OUTPUT              },
     {"GL_ARB_depth_buffer_float",           ARB_DEPTH_BUFFER_FLOAT        },
-    {"GL_ARB_depth_clamp",                  ARB_DEPTH_CLAMP               },
     {"GL_ARB_depth_texture",                ARB_DEPTH_TEXTURE             },
     {"GL_ARB_draw_buffers",                 ARB_DRAW_BUFFERS              },
     {"GL_ARB_draw_elements_base_vertex",    ARB_DRAW_ELEMENTS_BASE_VERTEX },
@@ -204,7 +203,6 @@ static const struct wined3d_extension_map gl_extension_map[] =
     {"GL_EXT_vertex_array_bgra",            EXT_VERTEX_ARRAY_BGRA         },
 
     /* NV */
-    {"GL_NV_depth_clamp",                   NV_DEPTH_CLAMP                },
     {"GL_NV_fence",                         NV_FENCE                      },
     {"GL_NV_fog_distance",                  NV_FOG_DISTANCE               },
     {"GL_NV_fragment_program",              NV_FRAGMENT_PROGRAM           },
@@ -3446,11 +3444,6 @@ static BOOL wined3d_adapter_init_gl_caps(struct wined3d_adapter *adapter)
         TRACE(" IMPLIED: NVIDIA (NV) Texture Gen Reflection support.\n");
         gl_info->supported[NV_TEXGEN_REFLECTION] = TRUE;
     }
-    if (!gl_info->supported[ARB_DEPTH_CLAMP] && gl_info->supported[NV_DEPTH_CLAMP])
-    {
-        TRACE(" IMPLIED: ARB_depth_clamp support (by NV_depth_clamp).\n");
-        gl_info->supported[ARB_DEPTH_CLAMP] = TRUE;
-    }
     if (!gl_info->supported[ARB_VERTEX_ARRAY_BGRA] && gl_info->supported[EXT_VERTEX_ARRAY_BGRA])
     {
         TRACE(" IMPLIED: ARB_vertex_array_bgra support (by EXT_vertex_array_bgra).\n");
diff --git a/dlls/wined3d/state.c b/dlls/wined3d/state.c
index f333603..961f651 100644
--- a/dlls/wined3d/state.c
+++ b/dlls/wined3d/state.c
@@ -103,7 +103,6 @@ static void state_zenable(struct wined3d_context *context, const struct wined3d_
 {
     enum wined3d_depth_buffer_type zenable = state->render_states[WINED3D_RS_ZENABLE];
     const struct wined3d_gl_info *gl_info = context->gl_info;
-    static UINT once;
 
     /* No z test without depth stencil buffers */
     if (!state->fb->depth_stencil)
@@ -132,21 +131,8 @@ static void state_zenable(struct wined3d_context *context, const struct wined3d_
             break;
     }
 
-    if (context->gl_info->supported[ARB_DEPTH_CLAMP])
-    {
-        if (!zenable && context->stream_info.position_transformed)
-        {
-            gl_info->gl_ops.gl.p_glEnable(GL_DEPTH_CLAMP);
-            checkGLcall("glEnable(GL_DEPTH_CLAMP)");
-        }
-        else
-        {
-            gl_info->gl_ops.gl.p_glDisable(GL_DEPTH_CLAMP);
-            checkGLcall("glDisable(GL_DEPTH_CLAMP)");
-        }
-    }
-    else if (!zenable && !once++)
-        FIXME("Z buffer disabled, but ARB_depth_clamp isn't supported.\n");
+    if (context->last_was_rhw && !isStateDirty(context, STATE_TRANSFORM(WINED3D_TS_PROJECTION)))
+        transform_projection(context, state, STATE_TRANSFORM(WINED3D_TS_PROJECTION));
 }
 
 static void state_cullmode(struct wined3d_context *context, const struct wined3d_state *state, DWORD state_id)
@@ -4105,12 +4091,16 @@ void transform_projection(struct wined3d_context *context, const struct wined3d_
         double y_offset = context->render_offscreen
                 ? ((63.0 / 64.0) - (2.0 * y) - h) / h
                 : ((63.0 / 64.0) - (2.0 * y) - h) / -h;
+        enum wined3d_depth_buffer_type zenable = state->fb->depth_stencil ?
+                state->render_states[WINED3D_RS_ZENABLE] : WINED3D_ZB_FALSE;
+        double z_scale = zenable ? 2.0f : 0.0f;
+        double z_offset = zenable ? -1.0f : 0.0f;
         const GLdouble projection[] =
         {
-             x_scale,      0.0,  0.0, 0.0,
-                 0.0,  y_scale,  0.0, 0.0,
-                 0.0,      0.0,  2.0, 0.0,
-            x_offset, y_offset, -1.0, 1.0,
+             x_scale,      0.0,  0.0,      0.0,
+                 0.0,  y_scale,  0.0,      0.0,
+                 0.0,      0.0,  z_scale,  0.0,
+            x_offset, y_offset,  z_offset, 1.0,
         };
 
         gl_info->gl_ops.gl.p_glLoadMatrixd(projection);
@@ -4775,9 +4765,6 @@ void vertexdeclaration(struct wined3d_context *context, const struct wined3d_sta
                 && state->shader[WINED3D_SHADER_TYPE_PIXEL]->reg_maps.shader_version.minor <= 3)
             context->shader_update_mask |= 1 << WINED3D_SHADER_TYPE_PIXEL;
     }
-
-    if (transformed != wasrhw && !isStateDirty(context, STATE_RENDER(WINED3D_RS_ZENABLE)))
-        state_zenable(context, state, STATE_RENDER(WINED3D_RS_ZENABLE));
 }
 
 static void viewport_miscpart(struct wined3d_context *context, const struct wined3d_state *state, DWORD state_id)
diff --git a/dlls/wined3d/wined3d_gl.h b/dlls/wined3d/wined3d_gl.h
index cbb99e5..3f06601 100644
--- a/dlls/wined3d/wined3d_gl.h
+++ b/dlls/wined3d/wined3d_gl.h
@@ -48,7 +48,6 @@ enum wined3d_gl_extension
     ARB_COLOR_BUFFER_FLOAT,
     ARB_DEBUG_OUTPUT,
     ARB_DEPTH_BUFFER_FLOAT,
-    ARB_DEPTH_CLAMP,
     ARB_DEPTH_TEXTURE,
     ARB_DRAW_BUFFERS,
     ARB_DRAW_ELEMENTS_BASE_VERTEX,
@@ -137,7 +136,6 @@ enum wined3d_gl_extension
     EXT_TEXTURE_SRGB_DECODE,
     EXT_VERTEX_ARRAY_BGRA,
     /* NVIDIA */
-    NV_DEPTH_CLAMP,
     NV_FENCE,
     NV_FOG_DISTANCE,
     NV_FRAGMENT_PROGRAM,
-- 
2.0.5