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+/* Starshatter OpenSource Distribution
+ Copyright (c) 1997-2004, Destroyer Studios LLC.
+ All Rights Reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+ this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+ * Neither the name "Destroyer Studios" nor the names of its contributors
+ may be used to endorse or promote products derived from this software
+ without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGE.
+
+ SUBSYSTEM: nGenEx.lib
+ FILE: Projector.cpp
+ AUTHOR: John DiCamillo
+
+
+ OVERVIEW
+ ========
+ 3D Projection Camera class
+*/
+
+#include "MemDebug.h"
+#include "Projector.h"
+
+// +--------------------------------------------------------------------+
+
+static const float CLIP_PLANE_EPSILON = 0.0001f;
+static const double Z_NEAR = 1.0;
+
+void Print(const char* fmt, ...);
+
+// +--------------------------------------------------------------------+
+
+static Camera emergency_cam;
+
+// +--------------------------------------------------------------------+
+
+Projector::Projector(Window* window, Camera* cam)
+: camera(cam), infinite(0), depth_scale(1.0f), orthogonal(false), field_of_view(2)
+{
+ if (!camera)
+ camera = &emergency_cam;
+
+ UseWindow(window);
+}
+
+Projector::~Projector()
+{ }
+
+// +--------------------------------------------------------------------+
+
+void
+Projector::UseCamera(Camera* cam)
+{
+ if (cam)
+ camera = cam;
+ else
+ camera = &emergency_cam;
+}
+
+void
+Projector::UseWindow(Window* win)
+{
+ Rect r = win->GetRect();
+ width = r.w;
+ height = r.h;
+
+ xcenter = (width / 2.0);
+ ycenter = (height / 2.0);
+
+ xclip0 = 0.0f;
+ xclip1 = (float) width-0.5f;
+ yclip0 = 0.0f;
+ yclip1 = (float) height-0.5f;
+
+ SetFieldOfView(field_of_view);
+}
+
+void
+Projector::SetFieldOfView(double fov)
+{
+ field_of_view = fov;
+
+ xscreenscale = width / fov;
+ yscreenscale = height / fov;
+
+ maxscale = max(xscreenscale, yscreenscale);
+
+ xangle = atan(2.0/fov * maxscale/xscreenscale);
+ yangle = atan(2.0/fov * maxscale/yscreenscale);
+}
+
+double
+Projector::GetFieldOfView() const
+{
+ return field_of_view;
+}
+
+void
+Projector::SetDepthScale(float scale)
+{
+ depth_scale = scale;
+}
+
+double
+Projector::GetDepthScale() const
+{
+ return depth_scale;
+}
+
+int
+Projector::SetInfinite(int i)
+{
+ int old = infinite;
+ infinite = i;
+ return old;
+}
+
+// +--------------------------------------------------------------------+
+
+void
+Projector::StartFrame()
+{
+ SetUpFrustum();
+ SetWorldSpace();
+}
+
+// +--------------------------------------------------------------------+
+// Transform a point from worldspace to viewspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::Transform(Vec3& vec) const
+{
+ Vec3 tvert = vec;
+
+ // Translate into a viewpoint-relative coordinate
+ if (!infinite)
+ tvert -= camera->Pos();
+
+ // old method:
+ vec.x = (tvert * camera->vrt());
+ vec.y = (tvert * camera->vup());
+ vec.z = (tvert * camera->vpn());
+
+ // Rotate into the view orientation
+ // vec = tvert * camera->Orientation();
+}
+
+// +--------------------------------------------------------------------+
+// Transform a point from worldspace to viewspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::Transform(Point& point) const
+{
+ Point tvert = point;
+
+ // Translate into a viewpoint-relative coordinate
+ if (!infinite)
+ tvert -= camera->Pos();
+
+ // old method:
+ point.x = (tvert * camera->vrt());
+ point.y = (tvert * camera->vup());
+ point.z = (tvert * camera->vpn());
+
+ // Rotate into the view orientation
+ // point = tvert * camera->Orientation();
+}
+
+// +--------------------------------------------------------------------+
+// APPARENT RADIUS OF PROJECTED OBJECT
+// Project a viewspace point into screen coordinates.
+// Use projected Z to determine apparent radius of object.
+// +--------------------------------------------------------------------+
+
+float
+Projector::ProjectRadius(const Vec3& v, float radius) const
+{
+ return (float) fabs((radius * maxscale) / v.z);
+}
+
+// +--------------------------------------------------------------------+
+// IN PLACE PROJECTION OF POINT
+// Project a viewspace point into screen coordinates.
+// Note that the y axis goes up in worldspace and viewspace, but
+// goes down in screenspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::Project(Vec3& v, bool clamp) const
+{
+ double zrecip;
+
+ if (orthogonal) {
+ double scale = field_of_view/2;
+ v.x = (float) (xcenter + scale * v.x);
+ v.y = (float) (height - (ycenter + scale * v.y));
+ v.z = (float) (0.0f);
+ }
+
+ else {
+ //zrecip = 2 * (1.0e5 / (1.0e5-1)) / v.z;
+ //zrecip = 2 * 0.97 / v.z; -- what the heck was this version used for?
+
+ zrecip = 2 / v.z;
+ v.x = (float) (xcenter + maxscale * v.x * zrecip);
+ v.y = (float) (height - (ycenter + maxscale * v.y * zrecip));
+ v.z = (float) (1 - zrecip);
+ }
+
+ // clamp the point to the viewport:
+ if (clamp) {
+ if (v.x < xclip0) v.x = xclip0;
+ if (v.x > xclip1) v.x = xclip1;
+ if (v.y < yclip0) v.y = yclip0;
+ if (v.y > yclip1) v.y = yclip1;
+ }
+}
+
+// +--------------------------------------------------------------------+
+// IN PLACE PROJECTION OF POINT
+// Project a viewspace point into screen coordinates.
+// Note that the y axis goes up in worldspace and viewspace, but
+// goes down in screenspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::Project(Point& v, bool clamp) const
+{
+ double zrecip;
+
+ if (orthogonal) {
+ double scale = field_of_view/2;
+ v.x = (xcenter + scale * v.x);
+ v.y = (height - (ycenter + scale * v.y));
+ v.z = 0;
+ }
+
+ else {
+ zrecip = 1 / v.z;
+ v.x = (xcenter + 2 * maxscale * v.x * zrecip);
+ v.y = (height - (ycenter + 2 * maxscale * v.y * zrecip));
+ v.z = (1 - zrecip);
+ }
+
+ // clamp the point to the viewport:
+ if (clamp) {
+ if (v.x < xclip0) v.x = xclip0;
+ if (v.x > xclip1) v.x = xclip1;
+ if (v.y < yclip0) v.y = yclip0;
+ if (v.y > yclip1) v.y = yclip1;
+ }
+}
+
+// +--------------------------------------------------------------------+
+// IN PLACE UN-PROJECTION OF POINT
+// Convert a point in screen coordinates back to viewspace.
+// Note that the y axis goes up in worldspace and viewspace, but
+// goes down in screenspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::Unproject(Point& v) const
+{
+ double zrecip = 1 / v.z;
+
+ /***
+ * forward projection:
+v.x = (xcenter + maxscale * v.x * zrecip);
+v.y = (height - (ycenter + maxscale * v.y * zrecip));
+v.z = (1 - zrecip);
+***/
+
+ v.x = ( v.x - xcenter) / (maxscale * zrecip);
+ v.y = (height - v.y - ycenter) / (maxscale * zrecip);
+}
+
+// +--------------------------------------------------------------------+
+// IN PLACE PROJECTION OF RECTANGLE (FOR SPRITES)
+// Project a viewspace point into screen coordinates.
+// Note that the y axis goes up in worldspace and viewspace, but
+// goes down in screenspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::ProjectRect(Point& v, double& w, double& h) const
+{
+ double zrecip;
+
+ if (orthogonal) {
+ double scale = field_of_view/2;
+ v.x = (xcenter + scale * v.x);
+ v.y = (height - (ycenter + scale * v.y));
+ v.z = 0;
+ }
+
+ else {
+ zrecip = 1 / v.z;
+ v.x = (xcenter + 2 * maxscale * v.x * zrecip);
+ v.y = (height - (ycenter + 2 * maxscale * v.y * zrecip));
+ v.z = (1 - Z_NEAR*zrecip);
+
+ w *= maxscale * zrecip;
+ h *= maxscale * zrecip;
+ }
+}
+
+// +--------------------------------------------------------------------+
+// Set up a clip plane with the specified normal.
+// +--------------------------------------------------------------------+
+
+void
+Projector::SetWorldspaceClipPlane(Vec3& normal, Plane& plane)
+{
+ // Rotate the plane normal into worldspace
+ ViewToWorld(normal, plane.normal);
+ plane.distance = (float) (camera->Pos() * plane.normal + CLIP_PLANE_EPSILON);
+}
+
+// +--------------------------------------------------------------------+
+// Set up the planes of the frustum, in worldspace coordinates.
+// +--------------------------------------------------------------------+
+
+void
+Projector::SetUpFrustum()
+{
+ double angle, s, c;
+ Vec3 normal;
+
+ angle = XAngle();
+ s = sin(angle);
+ c = cos(angle);
+
+ // Left clip plane
+ normal.x = (float) s;
+ normal.y = (float) 0;
+ normal.z = (float) c;
+ view_planes[0].normal = normal;
+ view_planes[0].distance = CLIP_PLANE_EPSILON;
+ SetWorldspaceClipPlane(normal, world_planes[0]);
+
+ // Right clip plane
+ normal.x = (float) -s;
+ view_planes[1].normal = normal;
+ view_planes[1].distance = CLIP_PLANE_EPSILON;
+ SetWorldspaceClipPlane(normal, world_planes[1]);
+
+ angle = YAngle();
+ s = sin(angle);
+ c = cos(angle);
+
+ // Bottom clip plane
+ normal.x = (float) 0;
+ normal.y = (float) s;
+ normal.z = (float) c;
+ view_planes[2].normal = normal;
+ view_planes[2].distance = CLIP_PLANE_EPSILON;
+ SetWorldspaceClipPlane(normal, world_planes[2]);
+
+ // Top clip plane
+ normal.y = (float) -s;
+ view_planes[3].normal = normal;
+ view_planes[3].distance = CLIP_PLANE_EPSILON;
+ SetWorldspaceClipPlane(normal, world_planes[3]);
+}
+
+// +--------------------------------------------------------------------+
+// Clip the point against the frustum and return 1 if partially inside
+// Return 2 if completely inside
+// +--------------------------------------------------------------------+
+
+int
+Projector::IsVisible(const Vec3& v, float radius) const
+{
+ int visible = 1;
+ int complete = 1;
+
+ Plane* plane = (Plane*) frustum_planes;
+ if (infinite) {
+ complete = 0;
+
+ for (int i = 0; visible && (i < NUM_FRUSTUM_PLANES); i++) {
+ visible = ((v * plane->normal) >= CLIP_PLANE_EPSILON);
+ plane++;
+ }
+ }
+ else {
+ for (int i = 0; visible && (i < NUM_FRUSTUM_PLANES); i++) {
+ float dot = v * plane->normal;
+ visible = ((dot + radius) >= plane->distance);
+ complete = complete && ((dot - radius) >= plane->distance);
+ plane++;
+ }
+ }
+
+ return visible + complete;
+}
+
+// +--------------------------------------------------------------------+
+// Clip the bouding point against the frustum and return non zero
+// if at least partially inside. This version is not terribly
+// efficient as it checks all eight box corners rather than just
+// the minimum two.
+// +--------------------------------------------------------------------+
+
+int
+Projector::IsBoxVisible(const Point* p) const
+{
+ int i, j, outside = 0;
+
+ // if all eight corners are outside of the same
+ // frustrum plane, then the box is not visible
+ Plane* plane = (Plane*) frustum_planes;
+
+ if (infinite) {
+ for (i = 0; !outside && (i < NUM_FRUSTUM_PLANES); i++) {
+ for (j = 0; j < 8; j++)
+ outside += (p[j] * plane->normal) < CLIP_PLANE_EPSILON;
+
+ if (outside < 8)
+ outside = 0;
+
+ plane++;
+ }
+ }
+ else {
+ for (i = 0; !outside && (i < NUM_FRUSTUM_PLANES); i++) {
+ for (j = 0; j < 8; j++)
+ outside += (p[j] * plane->normal) < plane->distance;
+
+ if (outside < 8)
+ outside = 0;
+
+ plane++;
+ }
+ }
+
+ // if not outside, then the box is visible
+ return !outside;
+}
+
+// +--------------------------------------------------------------------+
+
+float
+Projector::ApparentRadius(const Vec3& v, float radius) const
+{
+ Vec3 vloc = v;
+
+ Transform(vloc); // transform in place
+ return ProjectRadius(vloc, radius);
+}
+
+
+// +--------------------------------------------------------------------+
+// Rotate a vector from viewspace to worldspace.
+// +--------------------------------------------------------------------+
+
+void
+Projector::ViewToWorld(Point& pin, Point& pout)
+{
+ // Rotate into the world orientation
+ pout.x = pin.x * camera->vrt().x + pin.y * camera->vup().x + pin.z * camera->vpn().x;
+ pout.y = pin.x * camera->vrt().y + pin.y * camera->vup().y + pin.z * camera->vpn().y;
+ pout.z = pin.x * camera->vrt().z + pin.y * camera->vup().z + pin.z * camera->vpn().z;
+}
+
+void
+Projector::ViewToWorld(Vec3& vin, Vec3& vout)
+{
+ // Rotate into the world orientation
+ vout.x = (float) (vin.x * camera->vrt().x + vin.y * camera->vup().x + vin.z * camera->vpn().x);
+ vout.y = (float) (vin.x * camera->vrt().y + vin.y * camera->vup().y + vin.z * camera->vpn().y);
+ vout.z = (float) (vin.x * camera->vrt().z + vin.y * camera->vup().z + vin.z * camera->vpn().z);
+}
+
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