wined3d: Handle degenerate viewport Z ranges.

dlls/wined3d/device.c

@@ -3565,6 +3565,7 @@ static HRESULT process_vertices_strided(const struct wined3d_device *device, DWO
     struct lights_settings ls;
     unsigned int vertex_size;
     BOOL do_clip, lighting;
+    float min_z, max_z;
     unsigned int i;
     BYTE *dest_ptr;
     HRESULT hr;
@@ -3648,6 +3649,8 @@ static HRESULT process_vertices_strided(const struct wined3d_device *device, DWO
     init_transformed_lights(&ls, state, device->adapter->d3d_info.wined3d_creation_flags
             & WINED3D_LEGACY_FFP_LIGHTING, lighting);
 
+    wined3d_viewport_get_z_range(&vp, &min_z, &max_z);
+
     for (i = 0; i < dwCount; ++i)
     {
         const struct wined3d_stream_info_element *position_element = &stream_info->elements[WINED3D_FFP_POSITION];
@@ -3720,11 +3723,11 @@ static HRESULT process_vertices_strided(const struct wined3d_device *device, DWO
 
                 x *= vp.width / 2;
                 y *= vp.height / 2;
-                z *= vp.max_z - vp.min_z;
+                z *= max_z - min_z;
 
                 x += vp.width / 2 + vp.x;
                 y += vp.height / 2 + vp.y;
-                z += vp.min_z;
+                z += min_z;
 
                 rhw = 1 / rhw;
             } else {

dlls/wined3d/state.c

@@ -4037,6 +4037,7 @@ static void viewport_miscpart(struct wined3d_context *context, const struct wine
 {
     const struct wined3d_gl_info *gl_info = wined3d_context_gl(context)->gl_info;
     struct wined3d_viewport vp[WINED3D_MAX_VIEWPORTS];
+    float min_z, max_z;
 
     if (gl_info->supported[ARB_VIEWPORT_ARRAY])
     {
@@ -4048,8 +4049,9 @@ static void viewport_miscpart(struct wined3d_context *context, const struct wine
         get_viewports(context, state, state->viewport_count, vp);
         for (i = 0; i < state->viewport_count; ++i)
         {
-            depth_ranges[i * 2]     = vp[i].min_z;
-            depth_ranges[i * 2 + 1] = vp[i].max_z;
+            wined3d_viewport_get_z_range(&vp[i], &min_z, &max_z);
+            depth_ranges[i * 2] = min_z;
+            depth_ranges[i * 2 + 1] = max_z;
 
             viewports[i * 4]     = vp[i].x;
             viewports[i * 4 + 1] = vp[i].y;
@@ -4073,7 +4075,8 @@ static void viewport_miscpart(struct wined3d_context *context, const struct wine
     else
     {
         get_viewports(context, state, 1, vp);
-        gl_info->gl_ops.gl.p_glDepthRange(vp[0].min_z, vp[0].max_z);
+        wined3d_viewport_get_z_range(&vp[0], &min_z, &max_z);
+        gl_info->gl_ops.gl.p_glDepthRange(min_z, max_z);
         gl_info->gl_ops.gl.p_glViewport(vp[0].x, vp[0].y, vp[0].width, vp[0].height);
     }
     checkGLcall("setting clip space and viewport");
@@ -4090,6 +4093,7 @@ static void viewport_miscpart_cc(struct wined3d_context *context,
     GLdouble depth_ranges[2 * WINED3D_MAX_VIEWPORTS];
     GLfloat viewports[4 * WINED3D_MAX_VIEWPORTS];
     unsigned int i, reset_count = 0;
+    float min_z, max_z;
 
     get_viewports(context, state, state->viewport_count, vp);
 
@@ -4097,8 +4101,9 @@ static void viewport_miscpart_cc(struct wined3d_context *context,
 
     for (i = 0; i < state->viewport_count; ++i)
     {
-        depth_ranges[i * 2]     = vp[i].min_z;
-        depth_ranges[i * 2 + 1] = vp[i].max_z;
+        wined3d_viewport_get_z_range(&vp[i], &min_z, &max_z);
+        depth_ranges[i * 2] = min_z;
+        depth_ranges[i * 2 + 1] = max_z;
 
         viewports[i * 4] = vp[i].x + pixel_center_offset;
         viewports[i * 4 + 1] = vp[i].y + pixel_center_offset;

dlls/wined3d/wined3d_private.h

@@ -5319,6 +5319,14 @@ static inline BOOL wined3d_resource_check_fbo_attached(const struct wined3d_stat
     return FALSE;
 }
 
+static inline void wined3d_viewport_get_z_range(const struct wined3d_viewport *vp, float *min_z, float *max_z)
+{
+    *min_z = vp->min_z;
+
+    /* The magic constant is derived from tests. */
+    *max_z = max(vp->max_z, vp->min_z + 0.001f);
+}
+
 /* The WNDCLASS-Name for the fake window which we use to retrieve the GL capabilities */
 #define WINED3D_OPENGL_WINDOW_CLASS_NAME "WineD3D_OpenGL"