BLADERUNNER: Fixed fog rendering

Fogs were not animated.
Clean up of the fog calculation routines.

1 files changed, 145 insertions, 214 deletions

diff --git a/engines/bladerunner/fog.cpp b/engines/bladerunner/fog.cpp
index cb8235ba64..dac7f29679 100644
--- a/engines/bladerunner/fog.cpp
+++ b/engines/bladerunner/fog.cpp
@@ -43,9 +43,6 @@ Fog::Fog() {
 	_m32ptr             = nullptr;
 	_m33ptr             = nullptr;
 	_m34ptr             = nullptr;
-	_parameter1         = 0.0f;
-	_parameter2         = 0.0f;
-	_parameter3         = 0.0f;
 	_next               = nullptr;
 }
 
@@ -74,14 +71,14 @@ void Fog::readAnimationData(Common::ReadStream *stream, int size) {
 	}
 
 	_m11ptr = _animationData;
-	_m12ptr = _m11ptr + (_animatedParameters & 0x1 ? _frameCount : 1);
-	_m13ptr = _m12ptr + (_animatedParameters & 0x2 ? _frameCount : 1);
-	_m14ptr = _m13ptr + (_animatedParameters & 0x4 ? _frameCount : 1);
-	_m21ptr = _m14ptr + (_animatedParameters & 0x08 ? _frameCount : 1);
-	_m22ptr = _m21ptr + (_animatedParameters & 0x10 ? _frameCount : 1);
-	_m23ptr = _m22ptr + (_animatedParameters & 0x20 ? _frameCount : 1);
-	_m24ptr = _m23ptr + (_animatedParameters & 0x40 ? _frameCount : 1);
-	_m31ptr = _m24ptr + (_animatedParameters & 0x80 ? _frameCount : 1);
+	_m12ptr = _m11ptr + (_animatedParameters &   0x1 ? _frameCount : 1);
+	_m13ptr = _m12ptr + (_animatedParameters &   0x2 ? _frameCount : 1);
+	_m14ptr = _m13ptr + (_animatedParameters &   0x4 ? _frameCount : 1);
+	_m21ptr = _m14ptr + (_animatedParameters &   0x8 ? _frameCount : 1);
+	_m22ptr = _m21ptr + (_animatedParameters &  0x10 ? _frameCount : 1);
+	_m23ptr = _m22ptr + (_animatedParameters &  0x20 ? _frameCount : 1);
+	_m24ptr = _m23ptr + (_animatedParameters &  0x40 ? _frameCount : 1);
+	_m31ptr = _m24ptr + (_animatedParameters &  0x80 ? _frameCount : 1);
 	_m32ptr = _m31ptr + (_animatedParameters & 0x100 ? _frameCount : 1);
 	_m33ptr = _m32ptr + (_animatedParameters & 0x200 ? _frameCount : 1);
 	_m34ptr = _m33ptr + (_animatedParameters & 0x400 ? _frameCount : 1);
@@ -94,14 +91,14 @@ void Fog::reset() {
 
 void Fog::setupFrame(int frame) {
 	int offset = frame % _frameCount;
-	_matrix._m[0][0] = (_animatedParameters & 0x1 ? _m11ptr[offset] : *_m11ptr);
-	_matrix._m[0][1] = (_animatedParameters & 0x2 ? _m12ptr[offset] : *_m12ptr);
-	_matrix._m[0][2] = (_animatedParameters & 0x4 ? _m13ptr[offset] : *_m13ptr);
-	_matrix._m[0][3] = (_animatedParameters & 0x8 ? _m14ptr[offset] : *_m14ptr);
-	_matrix._m[1][0] = (_animatedParameters & 0x10 ? _m21ptr[offset] : *_m21ptr);
-	_matrix._m[1][1] = (_animatedParameters & 0x20 ? _m22ptr[offset] : *_m22ptr);
-	_matrix._m[1][2] = (_animatedParameters & 0x40 ? _m23ptr[offset] : *_m23ptr);
-	_matrix._m[1][3] = (_animatedParameters & 0x80 ? _m24ptr[offset] : *_m24ptr);
+	_matrix._m[0][0] = (_animatedParameters &   0x1 ? _m11ptr[offset] : *_m11ptr);
+	_matrix._m[0][1] = (_animatedParameters &   0x2 ? _m12ptr[offset] : *_m12ptr);
+	_matrix._m[0][2] = (_animatedParameters &   0x4 ? _m13ptr[offset] : *_m13ptr);
+	_matrix._m[0][3] = (_animatedParameters &   0x8 ? _m14ptr[offset] : *_m14ptr);
+	_matrix._m[1][0] = (_animatedParameters &  0x10 ? _m21ptr[offset] : *_m21ptr);
+	_matrix._m[1][1] = (_animatedParameters &  0x20 ? _m22ptr[offset] : *_m22ptr);
+	_matrix._m[1][2] = (_animatedParameters &  0x40 ? _m23ptr[offset] : *_m23ptr);
+	_matrix._m[1][3] = (_animatedParameters &  0x80 ? _m24ptr[offset] : *_m24ptr);
 	_matrix._m[2][0] = (_animatedParameters & 0x100 ? _m31ptr[offset] : *_m31ptr);
 	_matrix._m[2][1] = (_animatedParameters & 0x200 ? _m32ptr[offset] : *_m32ptr);
 	_matrix._m[2][2] = (_animatedParameters & 0x400 ? _m33ptr[offset] : *_m33ptr);
@@ -109,175 +106,119 @@ void Fog::setupFrame(int frame) {
 	_inverted = invertMatrix(_matrix);
 }
 
-void FogCone::read(Common::ReadStream *stream, int frameCount) {
+void FogSphere::read(Common::ReadStream *stream, int frameCount) {
 	_frameCount = frameCount;
 	int size = readCommon(stream);
-	_parameter1 = stream->readFloatLE();
+	_radius = stream->readFloatLE();
 	readAnimationData(stream, size - 52);
 }
 
-void FogCone::calculateCoeficient(Vector3 position, Vector3 viewPosition, float *coeficient) {
+void FogSphere::calculateCoeficient(Vector3 position, Vector3 viewPosition, float *coeficient) {
 	*coeficient = 0.0f;
 
-	Vector3 positionT = _matrix * position;
-	Vector3 viewPositionT = _matrix * viewPosition;
-
-	Vector3 vectorT = (viewPositionT - positionT).normalize();
-
-	float v67 = - positionT.x * vectorT.x - positionT.y * vectorT.y - positionT.z * vectorT.z;
-	float v66 = - (positionT.z * positionT.z) - (positionT.y * positionT.y) - (positionT.x * positionT.x) + (v67 * v67) + (_parameter1 * _parameter1);
+	// ray - sphere intersection, where sphere center is always at 0, 0, 0 as everything else tranformed by the fog matrix
+	Vector3 rayOrigin = _matrix * position;
+	Vector3 rayDestination = _matrix * viewPosition;
+	Vector3 rayDirection = (rayDestination - rayOrigin).normalize();
 
-	if (v66 >= 0.0f) {
-		float v24 = sqrt(v66);
+	float b = Vector3::dot(rayDirection, rayOrigin);
+	float c = Vector3::dot(rayOrigin, rayOrigin) - (_radius * _radius);
+	float t = b * b - c;
 
-		Vector3 v29 = positionT + (v67 - v24) * vectorT;
-		Vector3 v36 = positionT + (v67 + v24) * vectorT;
+	if (t >= 0.0f) { // there is an interstection between ray and the sphere
+		Vector3 intersection1 = rayOrigin + (-b - sqrt(t)) * rayDirection;
+		Vector3 intersection2 = rayOrigin + (-b + sqrt(t)) * rayDirection;
 
-		Vector3 v39 = _inverted * v29;
-		Vector3 v42 = _inverted * v36;
+		Vector3 intersection1World = _inverted * intersection1;
+		Vector3 intersection2World = _inverted * intersection2;
 
-		float v74 = (v39 - position).length();
-		float v76 = (v42 - position).length();
+		float intersection1Distance = (intersection1World - position).length();
+		float intersection2Distance = (intersection2World - position).length();
 
-		Vector3 vector = viewPosition - position;
+		float distance = (viewPosition - position).length();
 
-		float vectorLength = vector.length();
-
-		if (v74 < 0.0f) {
-			v74 = 0.0f;
+		if (intersection1Distance < 0.0f) {
+			intersection1Distance = 0.0f;
 		}
-		if (v76 > vectorLength) {
-			v76 = vectorLength;
+		if (intersection2Distance > distance) {
+			intersection2Distance = distance;
 		}
-		if (v76 >= v74) {
-			*coeficient = v76 - v74;
+		if (intersection2Distance >= intersection1Distance) {
+			*coeficient = intersection2Distance - intersection1Distance;
 		}
 	}
 }
 
-void FogSphere::read(Common::ReadStream *stream, int frameCount) {
+void FogCone::read(Common::ReadStream *stream, int frameCount) {
 	_frameCount = frameCount;
 	int size = readCommon(stream);
-	_parameter1 = stream->readFloatLE();
+	_coneAngle = stream->readFloatLE();
 	readAnimationData(stream, size - 52);
 }
 
-void FogSphere::calculateCoeficient(Vector3 position, Vector3 viewPosition, float *coeficient) {
+void FogCone::calculateCoeficient(Vector3 position, Vector3 viewPosition, float *coeficient) {
 	*coeficient = 0.0f;
 
+	// ray - cone intersection, cone vertex V lies at (0,0,0) and direction v = (0,0,-1)
+	// The algorithm looks like from book Alan W. Paeth (1995), Graphics Gems V (p. 228-230)
+
 	Vector3 positionT = _matrix * position;
 	Vector3 viewPositionT = _matrix * viewPosition;
 
-	Vector3 v158 = Vector3::cross(positionT, viewPositionT);
-
-	if (v158.x != 0.0f || v158.y != 0.0f || v158.z != 0.0f) {
-		Vector3 v167 = v158.normalize();
-		if (v167.z < 0.0f) {
-			v167 = -1.0f * v167;
-		}
+	Vector3 v(0.0f, 0.0f, -1.0f);
 
-		float v173 = sqrt(1.0f - v167.z * v167.z);
-		if (v173 > cos(_parameter1)) {
-			Vector3 v37 = Vector3(v167.y, -v167.x, 0.0f).normalize();
+	Vector3 planeNormal = Vector3::cross(positionT, viewPositionT).normalize();
 
-			float v41 = 1.0f / v173 / v173 - 1.0f;
-			float v42 = sqrt(v41);
-			float v43 = tan(_parameter1);
-			float v44 = sqrt(v43 * v43 - v41);
+	if (planeNormal.x != 0.0f || planeNormal.y != 0.0f || planeNormal.z != 0.0f) {
 
-			Vector3 v45 = v44 * v37;
+		if (planeNormal.z < 0.0f) {
+			planeNormal = -1.0f * planeNormal;
+		}
 
-			Vector3 v48 = Vector3(
-				-v37.y * v42,
-				v37.x * v42,
-				0.0f * v42);
+		float cosTheta = sqrt(1.0f - Vector3::dot(planeNormal, v) * Vector3::dot(planeNormal, v));
 
-			Vector3 v51 = v48 + Vector3(0.0f, 0.0f, -1.0f);
+		if (cosTheta > cos(_coneAngle)) {
+			Vector3 u = Vector3::cross(v, planeNormal).normalize();
+			Vector3 w = Vector3::cross(u, v).normalize();
 
-			Vector3 v186 = v51 - v45;
-			Vector3 v183 = v51 + v45;
+			float tanTheta = sqrt(1.0f - cosTheta * cosTheta) / cosTheta;
 
-			Vector3 vector = viewPositionT - positionT;
+			Vector3 temp1 = tanTheta * w;
+			Vector3 temp2 = sqrt(tan(_coneAngle) * tan(_coneAngle) - tanTheta * tanTheta) * u;
 
-			Vector3 v177 = -1.0f * positionT;
-			Vector3 v174 = Vector3::cross(v186, vector);
+			Vector3 delta1 = v + temp1 - temp2;
+			Vector3 delta2 = v + temp1 + temp2;
 
-			float v189, v191;
-			if (fabs(v174.x) <= fabs(v174.y)) {
-				if (fabs(v174.y) <= fabs(v174.z)) {
-					v191 = v177.x * v186.y - v177.y * v186.x;
-					v189 = v186.y * vector.x - v186.x * vector.y;
-				} else {
-					v191 = v177.z * v186.x - v186.z * v177.x;
-					v189 = v186.x * vector.z - v186.z * vector.x;
-				}
-			} else {
-				if (fabs(v174.x) <= fabs(v174.z)) {
-					v191 = v177.x * v186.y - v177.y * v186.x;
-					v189 = v186.y * vector.x - v186.x * vector.y;
-				} else {
-					v191 = v186.z * v177.y - v186.y * v177.z;
-					v189 = v186.z * vector.y - v186.y * vector.z;
-				}
-			}
+			Vector3 d = viewPositionT - positionT;
+			Vector3 vecVD = -1.0f * positionT;
 
-			float v88;
-			if (v189 == 0.0f) {
-				v88 = 0.0f;
-			} else {
-				v88 = v191 / v189;
-			}
+			Vector3 crossddelta1 = Vector3::cross(d, delta1);
+			Vector3 crossddelta2 = Vector3::cross(d, delta2);
 
-			Vector3 v196 = -1.0f * positionT;
-			Vector3 v193 = Vector3::cross(v183, vector);
-
-			float v190, v192;
-			if (fabs(v193.x) <= fabs(v193.y)) {
-				if (fabs(v193.y) <= fabs(v193.z)) {
-					v192 = v196.x * v183.y - v196.y * v183.x;
-					v190 = v183.y * vector.x - v183.x * vector.y;
-				} else {
-					v192 = v196.z * v183.x - v183.z * v196.x;
-					v190 = v183.x * vector.z - v183.z * vector.x;
-				}
-			} else {
-				if (fabs(v193.x) <= fabs(v193.z)) {
-					v192 = v196.x * v183.y - v196.y * v183.x;
-					v190 = v183.y * vector.x - v183.x * vector.y;
-				} else {
-					v192 = v183.z * v196.y - v183.y * v196.z;
-					v190 = v183.z * vector.y - v183.y * vector.z;
-				}
-			}
+			float r1 = Vector3::dot(Vector3::cross(vecVD, delta1), crossddelta1) / Vector3::dot(crossddelta1, crossddelta1);
+			float r2 = Vector3::dot(Vector3::cross(vecVD, delta2), crossddelta2) / Vector3::dot(crossddelta2, crossddelta2);
 
-			float v114;
-			if (v190 == 0.0f) {
-				v114 = 0.0f;
-			} else {
-				v114 = v192 / v190;
+			if (r2 < r1) {
+				float temp = r1;
+				r1 = r2;
+				r2 = temp;
 			}
 
-			if (v114 < v88) {
-				float temp = v88;
-				v88 = v114;
-				v114 = temp;
-			}
-
-			if (v88 <= 1.0f && v114 >= 0.0f) {
-				if (v88 < 0.0f) {
-					v88 = 0.0;
+			if (r1 <= 1.0f && r2 >= 0.0f) {
+				if (r1 < 0.0f) {
+					r1 = 0.0;
 				}
-				if (v114 > 1.0f) {
-					v114 = 1.0;
+				if (r2 > 1.0f) {
+					r2 = 1.0;
 				}
 
-				Vector3 v139 = positionT + (v88 * vector);
-				Vector3 v142 = _inverted * v139;
+				Vector3 intersection1 = positionT + (r1 * d);
+				Vector3 intersection1World = _inverted * intersection1;
 
-				Vector3 v148 = positionT + (v114 * vector);
-				Vector3 v151 = _inverted * v148;
+				Vector3 intersection2 = positionT + (r2 * d);
+				Vector3 intersection2World = _inverted * intersection2;
 
-				*coeficient = (v151 - v142).length();
+				*coeficient = (intersection2World - intersection1World).length();
 			}
 		}
 	}
@@ -286,111 +227,101 @@ void FogSphere::calculateCoeficient(Vector3 position, Vector3 viewPosition, floa
 void FogBox::read(Common::ReadStream *stream, int frameCount) {
 	_frameCount = frameCount;
 	int size = readCommon(stream);
-	_parameter1 = stream->readFloatLE();
-	_parameter2 = stream->readFloatLE();
-	_parameter3 = stream->readFloatLE();
+	_size.x = stream->readFloatLE();
+	_size.y = stream->readFloatLE();
+	_size.z = stream->readFloatLE();
 	readAnimationData(stream, size - 60);
 }
 
 void FogBox::calculateCoeficient(Vector3 position, Vector3 viewPosition, float *coeficient) {
-	Vector3 positionT = _matrix * position;
-	Vector3 viewPositionT = _matrix * viewPosition;
+	*coeficient = 0.0f;
+
+	// line - box intersection, where everything is rotated to box orientation by the fog matrix
+
+	Vector3 point1 = _matrix * position;
+	Vector3 point2 = _matrix * viewPosition;
 
-	Vector3 positionTadj = positionT;
-	Vector3 viewPositionTadj = viewPositionT;
+	Vector3 intersection1 = point1;
+	Vector3 intersection2 = point2;
 
-	Vector3 direction = viewPositionT - positionT;
+	Vector3 direction = point2 - point1;
 
-	float parameter1half = _parameter1 * 0.5f;
-	if (positionT.x < -parameter1half) {
-		if (viewPositionT.x < -parameter1half) {
-			*coeficient = 0.0f;
+	// clip X
+	float minX = -(_size.x * 0.5f);
+	if (point1.x < minX) {
+		if (point2.x < minX) {
 			return;
 		}
-		float v28 = (-positionT.x - parameter1half) / direction.x;
-		Vector3 v29 = v28 * direction;
-		positionTadj = positionT + v29;
-	} else if (viewPositionT.x < -parameter1half) {
-		float v19 = (-viewPositionT.x - parameter1half) / direction.x;
-		Vector3 v20 = v19 * direction;
-		viewPositionTadj = viewPositionT + v20;
+		float scale = (minX - point1.x) / direction.x;
+		intersection1 = point1 + scale * direction;
+	} else if (point2.x < minX) {
+		float scale = (minX - point2.x) / direction.x;
+		intersection2 = point2 + scale * direction;
 	}
 
-	if (parameter1half < positionTadj.x) {
-		if (parameter1half < viewPositionTadj.x) {
-			*coeficient = 0.0f;
+	float maxX = _size.x * 0.5f;
+	if (intersection1.x > maxX ) {
+		if (intersection2.x > maxX) {
 			return;
 		}
-		float v48 = (parameter1half - positionTadj.x) / direction.x;
-		Vector3 v49 = v48 * direction;
-		positionTadj = positionTadj + v49;
-	} else if (parameter1half < viewPositionTadj.x) {
-		float v40 = (parameter1half - viewPositionTadj.x) / direction.x;
-		Vector3 v41 = v40 * direction;
-		viewPositionTadj = viewPositionTadj + v41;
+		float scale = (maxX - intersection1.x) / direction.x;
+		intersection1 = intersection1 + scale * direction;
+	} else if (intersection2.x > maxX) {
+		float scale = (maxX - intersection2.x) / direction.x;
+		intersection2 = intersection2 + scale * direction;
 	}
 
-	float parameter2half = _parameter2 * 0.5f;
-	if (positionTadj.y < -parameter2half) {
-		if (viewPositionTadj.y < -parameter2half) {
-			*coeficient = 0.0f;
+	// clip Y
+	float minY = -(_size.y * 0.5f);
+	if (intersection1.y < minY) {
+		if (intersection2.y < minY) {
 			return;
 		}
-		float v71 = (-positionTadj.y - parameter2half) / direction.y;
-		Vector3 v72 = v71 * direction;
-		positionTadj = positionTadj + v72;
-	} else if (viewPositionTadj.y < -parameter2half) {
-		float v62 = (-viewPositionTadj.y - parameter2half) / direction.y;
-		Vector3 v63 = v62 * direction;
-		viewPositionTadj = viewPositionTadj + v63;
+		float scale = (minY - intersection1.y) / direction.y;
+		intersection1 = intersection1 + scale * direction;
+	} else if (intersection2.y < minY) {
+		float scale = (minY - intersection2.y) / direction.y;
+		intersection2 = intersection2 + scale * direction;
 	}
 
-	if (parameter2half < positionTadj.y) {
-		if (parameter2half < viewPositionTadj.y) {
-			*coeficient = 0.0f;
+	float maxY = _size.y * 0.5f;
+	if (intersection1.y > maxY) {
+		if (intersection2.y > maxY) {
 			return;
 		}
-		float v91 = (parameter2half - positionTadj.y) / direction.y;
-		Vector3 v92 = v91 * direction;
-		positionTadj = positionTadj + v92;
-	} else if (parameter2half < viewPositionTadj.y) {
-		float v83 = (parameter2half - viewPositionTadj.y) / direction.y;
-		Vector3 v84 = v83 * direction;
-		viewPositionTadj = viewPositionTadj + v84;
+		float scale = (maxY - intersection1.y) / direction.y;
+		intersection1 = intersection1 + scale * direction;
+	} else if (intersection2.y > maxY) {
+		float scale = (maxY - intersection2.y) / direction.y;
+		intersection2 = intersection2 + scale * direction;
 	}
 
-	if (0.0f > positionTadj.z) {
-		if (0.0f > viewPositionTadj.z) {
-			*coeficient = 0.0f;
+	// clip Z
+	if (intersection1.z < 0.0f) {
+		if (intersection2.z < 0.0f) {
 			return;
 		}
-		float v111 = -positionTadj.z / direction.z;
-		Vector3 v112 = v111 * direction;
-		positionTadj = positionTadj + v112;
-	} else if (0.0f > viewPositionTadj.z) {
-		float v103 = -viewPositionTadj.z / direction.z;
-		Vector3 v104 = v103 * direction;
-		viewPositionTadj = viewPositionTadj + v104;
+		float scale = -intersection1.z / direction.z;
+		intersection1 = intersection1 + scale * direction;
+	} else if (intersection2.z < 0.0f) {
+		float scale = -intersection2.z / direction.z;
+		intersection2 = intersection2 + scale * direction;
 	}
 
-	if (positionTadj.z > _parameter3) {
-		if (viewPositionTadj.z > _parameter3) {
-			*coeficient = 0.0f;
+	if (intersection1.z > _size.z) {
+		if (intersection2.z > _size.z) {
 			return;
 		}
-		float v132 = (_parameter3 - positionTadj.z) / direction.z;
-		Vector3 v133 = v132 * direction;
-		positionTadj = positionTadj + v133;
-	} else if (viewPositionTadj.z > _parameter3) {
-		float v124 = (_parameter3 - viewPositionTadj.z) / direction.z;
-		Vector3 v125 = v124 * direction;
-		viewPositionTadj = viewPositionTadj + v125;
+		float scale = (_size.z - intersection1.z) / direction.z;
+		intersection1 = intersection1 + scale * direction;
+	} else if (intersection2.z > _size.z) {
+		float scale = (_size.z - intersection2.z) / direction.z;
+		intersection2 = intersection2 + scale * direction;
 	}
 
-	Vector3 v137 = _inverted * positionTadj;
-	Vector3 v140 = _inverted * viewPositionTadj;
-	Vector3 v143 = v140 - v137;
+	Vector3 intersection1World = _inverted * intersection1;
+	Vector3 intersection2World = _inverted * intersection2;
 
-	*coeficient = v143.length();
+	*coeficient = (intersection2World - intersection1World).length();
 }
 } // End of namespace BladeRunner