quick support for w buffers

hw/xbox/nv2a.c

@@ -394,6 +394,7 @@
 #       define NV_PGRAPH_CONTROL_0_ZFUNC_GEQUAL                     6
 #       define NV_PGRAPH_CONTROL_0_ZFUNC_ALWAYS                     7
 #   define NV_PGRAPH_CONTROL_0_DITHERENABLE                     (1 << 22)
+#   define NV_PGRAPH_CONTROL_0_Z_PERSPECTIVE_ENABLE             (1 << 23)
 #   define NV_PGRAPH_CONTROL_0_ZWRITEENABLE                     (1 << 24)
 #   define NV_PGRAPH_CONTROL_0_STENCIL_WRITE_ENABLE             (1 << 25)
 #   define NV_PGRAPH_CONTROL_0_ALPHA_WRITE_ENABLE               (1 << 26)
@@ -765,6 +766,7 @@
 #   define NV097_SET_CONTROL0                                 0x00970290
 #       define NV097_SET_CONTROL0_STENCIL_WRITE_ENABLE            (1 << 0)
 #       define NV097_SET_CONTROL0_Z_FORMAT                        (1 << 12)
+#       define NV097_SET_CONTROL0_Z_PERSPECTIVE_ENABLE            (1 << 16)
 #   define NV097_SET_FOG_MODE                                 0x0097029C
 #       define NV097_SET_FOG_MODE_V_LINEAR                        0x2601
 #       define NV097_SET_FOG_MODE_V_EXP                           0x800
@@ -2943,20 +2945,20 @@ static void pgraph_bind_shaders(PGRAPHState *pg)
                                    NV_PGRAPH_CONTROL_0_ALPHAFUNC),
         },
 
+        /* fixed function stuff */
         .skinning = GET_MASK(pg->regs[NV_PGRAPH_CSV0_D],
                              NV_PGRAPH_CSV0_D_SKIN),
-
         .lighting = GET_MASK(pg->regs[NV_PGRAPH_CSV0_C],
                              NV_PGRAPH_CSV0_C_LIGHTING),
-
         .normalization = pg->regs[NV_PGRAPH_CSV0_C]
                            & NV_PGRAPH_CSV0_C_NORMALIZATION_ENABLE,
 
-        /* fixed function stuff */
         .fixed_function = fixed_function,
 
         /* vertex program stuff */
         .vertex_program = vertex_program,
+        .z_perspective = pg->regs[NV_PGRAPH_CONTROL_0]
+                            & NV_PGRAPH_CONTROL_0_Z_PERSPECTIVE_ENABLE,
 
         /* geometry shader stuff */
         .primitive_mode = pg->primitive_mode,
@@ -4297,6 +4299,12 @@ static void pgraph_method(NV2AState *d,
         uint32_t z_format = GET_MASK(parameter, NV097_SET_CONTROL0_Z_FORMAT);
         SET_MASK(pg->regs[NV_PGRAPH_SETUPRASTER],
                  NV_PGRAPH_SETUPRASTER_Z_FORMAT, z_format);
+
+        bool z_perspective =
+            parameter & NV097_SET_CONTROL0_Z_PERSPECTIVE_ENABLE;
+        SET_MASK(pg->regs[NV_PGRAPH_CONTROL_0],
+                 NV_PGRAPH_CONTROL_0_Z_PERSPECTIVE_ENABLE,
+                 z_perspective);
         break;
     }
 

hw/xbox/nv2a_shaders.c

@@ -628,6 +628,7 @@ static QString *generate_vertex_shader(const ShaderState state,
         vsh_translate(VSH_VERSION_XVS,
                       (uint32_t*)state.program_data,
                       state.program_length,
+                      state.z_perspective,
                       header, body);
     } else {
         assert(false);

hw/xbox/nv2a_shaders.h

@@ -74,6 +74,7 @@ typedef struct ShaderState {
     bool vertex_program;
     uint32_t program_data[NV2A_MAX_TRANSFORM_PROGRAM_LENGTH][VSH_TOKEN_SIZE];
     int program_length;
+    bool z_perspective;
 
     /* primitive format for geometry shader */
     enum ShaderPolygonMode polygon_front_mode;

hw/xbox/nv2a_vsh.c

@@ -690,9 +690,10 @@ static const char* vsh_header =
     "}\n";
 
 void vsh_translate(uint16_t version,
-                       const uint32_t *tokens,
+                   const uint32_t *tokens,
-                       unsigned int length,
+                   unsigned int length,
-                       QString *header, QString *body)
+                   bool z_perspective,
+                   QString *header, QString *body)
 {
 
 
@@ -732,7 +733,8 @@ void vsh_translate(uint16_t version,
         "    vtx.inv_w = 1.0;\n"
         "  } else {\n"
         "    vtx.inv_w = 1.0 / oPos.w;\n"
-        "  }\n");
+        "  }\n"
+    );
 
     qstring_append(body,
         /* the shaders leave the result in screen space, while
@@ -741,6 +743,16 @@ void vsh_translate(uint16_t version,
          */
         "  oPos.x = 2.0 * (oPos.x - surfaceSize.x * 0.5) / surfaceSize.x;\n"
         "  oPos.y = -2.0 * (oPos.y - surfaceSize.y * 0.5) / surfaceSize.y;\n"
+    );
+    if (z_perspective) {
+        qstring_append(body, "  oPos.z = oPos.w;\n");
+    }
+    qstring_append(body,
+        /* Map the clip range into clip space so z is clipped correctly.
+         * Note this makes the values in the depth buffer wrong. This should be
+         * handled with gl_ClipDistance instead, but that has performance issues
+         * on OS X.
+         */
         "  if (clipRange.y != clipRange.x) {\n"
         "    oPos.z = (oPos.z - 0.5 * (clipRange.x + clipRange.y)) / (0.5 * (clipRange.y - clipRange.x));\n"
         "  }\n"
@@ -755,7 +767,6 @@ void vsh_translate(uint16_t version,
              * can't multiply by W because it could be meaningless here */
         "    oPos.w = 1.0;\n"
         "  }\n"
-
     );
 
 }

hw/xbox/nv2a_vsh.h

@@ -134,6 +134,7 @@ uint8_t vsh_get_field(const uint32_t *shader_token, VshFieldName field_name);
 void vsh_translate(uint16_t version,
                    const uint32_t *tokens,
                    unsigned int length,
+                   bool z_perspective,
                    QString *header, QString *body);