From 7db40551e9197142b0b6cb7fd883b325684bb8c2 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 18 Apr 2021 10:23:04 +0300
Subject: [PATCH] Use persistent cameras in effects

This allows implementing per-camera caching of culling and sorting in
scenes, and is also required for some Vulkan-related things.
---
 source/effects/environmentmap.cpp | 33 ++++++++++++++++---------------
 source/effects/environmentmap.h   |  9 +++++++--
 source/effects/shadowmap.cpp      | 13 ++++++------
 source/effects/shadowmap.h        |  2 ++
 4 files changed, 32 insertions(+), 25 deletions(-)

diff --git a/source/effects/environmentmap.cpp b/source/effects/environmentmap.cpp
index 1448c49c..d9812c49 100644
--- a/source/effects/environmentmap.cpp
+++ b/source/effects/environmentmap.cpp
@@ -23,19 +23,22 @@ EnvironmentMap::EnvironmentMap(Resources &resources, unsigned s, Renderable &r,
 	depth_buf.storage(DEPTH_COMPONENT32F, size, size);
 	for(unsigned i=0; i<6; ++i)
 	{
-		fbo[i].attach(COLOR_ATTACHMENT0, env_tex, TextureCube::enumerate_faces(i), 0);
-		fbo[i].attach(DEPTH_ATTACHMENT, depth_buf);
-		fbo[i].require_complete();
+		TextureCubeFace face = TextureCube::enumerate_faces(i);
+		faces[i].fbo.attach(COLOR_ATTACHMENT0, env_tex, face, 0);
+		faces[i].fbo.attach(DEPTH_ATTACHMENT, depth_buf);
+		faces[i].fbo.require_complete();
+		faces[i].camera.set_look_direction(TextureCube::get_face_direction(face));
+		faces[i].camera.set_up_direction(TextureCube::get_t_direction(face));
+		faces[i].camera.set_field_of_view(Geometry::Angle<float>::right());
+		faces[i].camera.set_aspect_ratio(1);
+		faces[i].camera.set_depth_clip(0.1, 100);
 	}
-
-	camera.set_field_of_view(Geometry::Angle<float>::right());
-	camera.set_aspect_ratio(1);
-	camera.set_depth_clip(0.1, 100);
 }
 
 void EnvironmentMap::set_depth_clip(float n, float f)
 {
-	camera.set_depth_clip(n, f);
+	for(unsigned i=0; i<6; ++i)
+		faces[i].camera.set_depth_clip(n, f);
 }
 
 void EnvironmentMap::set_update_interval(unsigned i)
@@ -74,17 +77,15 @@ void EnvironmentMap::setup_frame(Renderer &renderer)
 	Renderer::Exclude exclude1(renderer, renderable);
 	Renderer::Exclude exclude2(renderer, *this);
 
-	camera.set_position(matrix->column(3).slice<3>(0));
+	Vector3 center = matrix->column(3).slice<3>(0);
 
-	BindRestore bind_fbo(fbo[0]);
+	BindRestore bind_fbo(faces[0].fbo);
 	for(unsigned i=0; i<6; ++i)
 	{
-		TextureCubeFace face = TextureCube::enumerate_faces(i);
-		fbo[i].bind();
-		fbo[i].clear();
-		camera.set_look_direction(TextureCube::get_face_direction(face));
-		camera.set_up_direction(TextureCube::get_t_direction(face));
-		renderer.set_camera(camera);
+		faces[i].camera.set_position(center);
+		faces[i].fbo.bind();
+		faces[i].fbo.clear();
+		renderer.set_camera(faces[i].camera);
 		renderer.render(environment);
 	}
 }
diff --git a/source/effects/environmentmap.h b/source/effects/environmentmap.h
index a13bea3f..56c76c45 100644
--- a/source/effects/environmentmap.h
+++ b/source/effects/environmentmap.h
@@ -27,13 +27,18 @@ environment.
 class EnvironmentMap: public Effect
 {
 private:
+	struct Face
+	{
+		Framebuffer fbo;
+		Camera camera;
+	};
+
 	unsigned size;
 	Renderable &environment;
 	TextureCube env_tex;
 	Renderbuffer depth_buf;
-	Framebuffer fbo[6];
+	Face faces[6];
 	const Sampler &sampler;
-	Camera camera;
 	mutable ProgramData shdata;
 	bool rendered;
 	unsigned update_interval;
diff --git a/source/effects/shadowmap.cpp b/source/effects/shadowmap.cpp
index 41a97f80..0af93271 100644
--- a/source/effects/shadowmap.cpp
+++ b/source/effects/shadowmap.cpp
@@ -59,15 +59,14 @@ void ShadowMap::setup_frame(Renderer &renderer)
 	rendered = true;
 	renderable.setup_frame(renderer);
 
-	Camera camera;
-	camera.set_object_matrix(*light.get_matrix());
-	camera.set_position(target);
+	shadow_camera.set_object_matrix(*light.get_matrix());
+	shadow_camera.set_position(target);
 	// TODO support point and spot lights with a frustum projection.
 	// Omnidirectional lights also need a cube shadow map.
-	camera.set_orthographic(radius*2, radius*2);
-	camera.set_depth_clip(-radius, radius);
+	shadow_camera.set_orthographic(radius*2, radius*2);
+	shadow_camera.set_depth_clip(-radius, radius);
 
-	shadow_matrix = camera.get_object_matrix();
+	shadow_matrix = shadow_camera.get_object_matrix();
 	shadow_matrix.scale(radius*2, radius*2, -radius*2);
 	shadow_matrix.translate(-0.5, -0.5, depth_bias/size-0.5);
 	shadow_matrix.invert();
@@ -77,7 +76,7 @@ void ShadowMap::setup_frame(Renderer &renderer)
 	fbo.clear(DEPTH_BUFFER_BIT);
 
 	Renderer::Push push(renderer);
-	renderer.set_camera(camera);
+	renderer.set_camera(shadow_camera);
 
 	renderer.render(renderable, "shadow");
 }
diff --git a/source/effects/shadowmap.h b/source/effects/shadowmap.h
index 9fc0f449..d7b4eef9 100644
--- a/source/effects/shadowmap.h
+++ b/source/effects/shadowmap.h
@@ -1,6 +1,7 @@
 #ifndef MSP_GL_SHADOWMAP_H_
 #define MSP_GL_SHADOWMAP_H_
 
+#include "camera.h"
 #include "effect.h"
 #include "framebuffer.h"
 #include "programdata.h"
@@ -25,6 +26,7 @@ private:
 	unsigned size;
 	const Light &light;
 	Framebuffer fbo;
+	Camera shadow_camera;
 	Matrix shadow_matrix;
 	Texture2D depth_buf;
 	const Sampler &sampler;
-- 
2.43.0