From 57d02ec977e04003aadbca8fc18ed0f4b98b3288 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 3 Dec 2023 14:22:06 +0000
Subject: Set the viewPoint uniform in shadow shaders

---
 gfx/gl/shadowMapper.cpp | 30 +++++++++++++++++++-----------
 gfx/gl/shadowMapper.h   |  8 ++++----
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/gfx/gl/shadowMapper.cpp b/gfx/gl/shadowMapper.cpp
index 07db6a1..66905df 100644
--- a/gfx/gl/shadowMapper.cpp
+++ b/gfx/gl/shadowMapper.cpp
@@ -131,12 +131,15 @@ ShadowMapper::update(const SceneProvider & scene, const Direction3D & dir, const
 	glCullFace(GL_FRONT);
 
 	const auto lightView = glm::lookAt(camera.getPosition(), camera.getPosition() + dir, up);
+	const auto lightViewDir = glm::lookAt(origin, dir, up);
+	const auto lightViewPoint = camera.getPosition();
 	const auto bandViewExtents = getBandViewExtents(camera, lightView);
 
 	Definitions out;
 	std::transform(bandViewExtents.begin(), std::prev(bandViewExtents.end()), std::next(bandViewExtents.begin()),
 			DefinitionsInserter {out},
-			[&scene, this, &lightView, bands = bandViewExtents.size() - 2, &out](const auto & near, const auto & far) {
+			[&scene, this, &lightView, bands = bandViewExtents.size() - 2, &out, &lightViewPoint, &lightViewDir](
+					const auto & near, const auto & far) {
 				const auto extents_minmax = [extents = std::span {near.begin(), far.end()}](auto && comp) {
 					const auto mm = std::minmax_element(extents.begin(), extents.end(), comp);
 					return std::make_pair(comp.get(*mm.first), comp.get(*mm.second));
@@ -146,16 +149,16 @@ ShadowMapper::update(const SceneProvider & scene, const Direction3D & dir, const
 					return glm::ortho(x.first, x.second, y.first, y.second, -z.second, -z.first);
 				}(extents_minmax(CompareBy {0}), extents_minmax(CompareBy {1}), extents_minmax(CompareBy {2}));
 
-				const auto lightViewProjection = lightProjection * lightView;
-				fixedPoint.setViewProjection(lightViewProjection);
-				dynamicPoint.setViewProjection(lightViewProjection);
-				dynamicPointInst.setViewProjection(lightViewProjection);
+				const auto lightViewDirProjection = lightProjection * lightViewDir;
+				fixedPoint.setViewProjection(lightViewPoint, lightViewDirProjection);
+				dynamicPoint.setViewProjection(lightViewPoint, lightViewDirProjection);
+				dynamicPointInst.setViewProjection(lightViewPoint, lightViewDirProjection);
 
 				const auto & viewport = viewports[bands][out.maps];
 				glViewport(size.x >> viewport.x, size.y >> viewport.y, size.x >> viewport.z, size.y >> viewport.w);
 				scene.shadows(*this);
 
-				return std::make_pair(lightViewProjection, shadowMapRegions[bands][out.maps]);
+				return std::make_pair(lightProjection * lightView, shadowMapRegions[bands][out.maps]);
 			});
 
 	glCullFace(GL_BACK);
@@ -163,13 +166,17 @@ ShadowMapper::update(const SceneProvider & scene, const Direction3D & dir, const
 	return out;
 }
 
-ShadowMapper::FixedPoint::FixedPoint(const Shader & vs) : Program {vs}, viewProjectionLoc {*this, "viewProjection"} { }
+ShadowMapper::FixedPoint::FixedPoint(const Shader & vs) :
+	Program {vs}, viewProjectionLoc {*this, "viewProjection"}, viewPointLoc {*this, "viewPoint"}
+{
+}
 
 void
-ShadowMapper::FixedPoint::setViewProjection(const glm::mat4 & viewProjection) const
+ShadowMapper::FixedPoint::setViewProjection(const GlobalPosition3D viewPoint, const glm::mat4 & viewProjection) const
 {
 	use();
 	glUniformMatrix4fv(viewProjectionLoc, 1, GL_FALSE, glm::value_ptr(viewProjection));
+	glUniform3iv(viewPointLoc, 1, glm::value_ptr(viewPoint));
 }
 
 void
@@ -179,16 +186,17 @@ ShadowMapper::FixedPoint::use() const
 }
 
 ShadowMapper::DynamicPoint::DynamicPoint() :
-	Program {shadowDynamicPoint_vs}, viewProjectionLoc {*this, "viewProjection"}, modelLoc {*this, "model"},
-	modelPosLoc {*this, "modelPos"}
+	Program {shadowDynamicPoint_vs}, viewProjectionLoc {*this, "viewProjection"}, viewPointLoc {*this, "viewPoint"},
+	modelLoc {*this, "model"}, modelPosLoc {*this, "modelPos"}
 {
 }
 
 void
-ShadowMapper::DynamicPoint::setViewProjection(const glm::mat4 & viewProjection) const
+ShadowMapper::DynamicPoint::setViewProjection(const GlobalPosition3D viewPoint, const glm::mat4 & viewProjection) const
 {
 	glUseProgram(*this);
 	glUniformMatrix4fv(viewProjectionLoc, 1, GL_FALSE, glm::value_ptr(viewProjection));
+	glUniform3iv(viewPointLoc, 1, glm::value_ptr(viewPoint));
 }
 
 void
diff --git a/gfx/gl/shadowMapper.h b/gfx/gl/shadowMapper.h
index b53a7f1..01520ca 100644
--- a/gfx/gl/shadowMapper.h
+++ b/gfx/gl/shadowMapper.h
@@ -27,22 +27,22 @@ public:
 	class FixedPoint : public Program {
 	public:
 		FixedPoint(const Shader & vs);
-		void setViewProjection(const glm::mat4 &) const;
+		void setViewProjection(const GlobalPosition3D, const glm::mat4 &) const;
 		void use() const;
 
 	private:
-		RequiredUniformLocation viewProjectionLoc;
+		RequiredUniformLocation viewProjectionLoc, viewPointLoc;
 	};
 
 	class DynamicPoint : public Program {
 	public:
 		DynamicPoint();
-		void setViewProjection(const glm::mat4 &) const;
+		void setViewProjection(const GlobalPosition3D, const glm::mat4 &) const;
 		void use(const Location &) const;
 		void setModel(const Location &) const;
 
 	private:
-		RequiredUniformLocation viewProjectionLoc;
+		RequiredUniformLocation viewProjectionLoc, viewPointLoc;
 		RequiredUniformLocation modelLoc;
 		RequiredUniformLocation modelPosLoc;
 	};
-- 
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