From 3d2cdf368ad93ea5a5dbf0e9d86d8e6d11579a30 Mon Sep 17 00:00:00 2001
From: Martin Felis <martin@fysx.org>
Date: Fri, 22 Jun 2018 16:51:15 +0200
Subject: [PATCH] Enabled shadow mapping in deferred lighting

---
 data/shaders/fs_deferred_lighting.glsl | 57 +++++++++++++++++++++++++-
 src/modules/RenderModule.cc            |  9 ++--
 2 files changed, 59 insertions(+), 7 deletions(-)

diff --git a/data/shaders/fs_deferred_lighting.glsl b/data/shaders/fs_deferred_lighting.glsl
index 9b9a11e..6b6f3f7 100644
--- a/data/shaders/fs_deferred_lighting.glsl
+++ b/data/shaders/fs_deferred_lighting.glsl
@@ -17,11 +17,58 @@ uniform vec3 uViewPosition;
 
 uniform vec3 uLightDirection;
 uniform mat4 uLightSpaceMatrix;
+uniform mat4 uViewToLightSpaceMatrix;
 
 in vec2 ioFragTexCoords;
 
 out vec3 outColor;
 
+float ShadowCalculationPCF(vec4 frag_pos_light_space, vec3 frag_normal_light_space) {
+	vec3 projected_coordinates = frag_pos_light_space.xyz / frag_pos_light_space.w;
+	projected_coordinates = projected_coordinates * 0.5 + 0.5;
+
+	float current_depth = projected_coordinates.z;
+
+	float bias = 0.00;
+	bias = max(0.02 * (1.0 - dot(frag_normal_light_space, uLightDirection)), 0.003);
+
+	float shadow = 0.0;
+	vec2 texel_size = 1.0 / textureSize(uShadowMap, 0);
+	for (int x = -1; x <= 1; ++x) {
+		for (int y = -1; y <= 1; ++y) {
+#ifdef USE_SAMPLER2D_SHADOW
+			vec2 coordinate = projected_coordinates.xy + vec2(x, y) * texel_size;
+			float pcf_depth = texture(uShadowMap, vec3(coordinate, current_depth - bias));
+#else
+			float pcf_depth = texture(uShadowMap, projected_coordinates.xy).r;
+#endif
+			shadow += current_depth - bias > pcf_depth ? 1.0 : 0.0;
+		}
+	}
+
+	shadow /= 9.0;
+
+	return shadow;
+}
+
+float ShadowCalculation(vec4 frag_pos_light_space, vec3 frag_normal_light_space) {
+	vec3 projected_coordinates = frag_pos_light_space.xyz / frag_pos_light_space.w;
+	projected_coordinates = projected_coordinates * 0.5 + 0.5;
+
+	float current_depth = projected_coordinates.z;
+
+	float bias = 0.01;
+
+#ifdef USE_SAMPLER2D_SHADOW
+	float closest_depth = texture(uShadowMap, vec3(projected_coordinates.xy, current_depth - bias));
+#else
+	float closest_depth = texture(uShadowMap, projected_coordinates.xy).r;
+	bias = max(0.005 * (1.0 - dot(frag_normal_light_space, uLightDirection)), 0.003);
+#endif
+
+	return current_depth - bias > closest_depth ? 1.0 : 0.0;
+}
+
 void main() {
 	vec3 color = texture(uColor, ioFragTexCoords).rgb;
 	vec3 normal = texture (uNormal, ioFragTexCoords).xyz;
@@ -46,5 +93,13 @@ void main() {
 	vec3 specular = spec * vec3(0.5);
 
 	// shadow
-	outColor = ambient + (diffuse + specular);
+	
+	// TODO: transform to light space
+	vec4 position_light_space = uViewToLightSpaceMatrix * vec4(position, 1.0);
+	vec3 normal_light_space = normal;
+
+	float shadow = ShadowCalculationPCF(position_light_space, normal);
+	outColor = ambient + (1.0 - shadow) * (diffuse + specular);
+
+//	outColor = ambient + (diffuse + specular);
 }
diff --git a/src/modules/RenderModule.cc b/src/modules/RenderModule.cc
index 234bc77..4d12d8b 100644
--- a/src/modules/RenderModule.cc
+++ b/src/modules/RenderModule.cc
@@ -681,8 +681,10 @@ void Renderer::RenderGl() {
 
 		glActiveTexture(GL_TEXTURE3);
 		glBindTexture(GL_TEXTURE_2D, mLight.mShadowMapTarget.mDepthTexture);
-		mDeferredLighting.SetInt("uDepth", 3);
+		mDeferredLighting.SetInt("uShadowMap", 3);
 		mDeferredLighting.SetMat44("uLightSpaceMatrix", mLight.mLightSpaceMatrix);
+		Matrix44f view_to_light_matrix = mCamera.mViewMatrix.inverse() * mLight.mLightSpaceMatrix;
+		mDeferredLighting.SetMat44("uViewToLightSpaceMatrix", view_to_light_matrix);
 
 		// TODO: remove and reconstruct position from depth
 		glActiveTexture(GL_TEXTURE4);
@@ -693,11 +695,6 @@ void Renderer::RenderGl() {
 		Matrix33f view_mat_rot = mCamera.mViewMatrix.block<3,3>(0,0);
 		view_mat_rot = view_mat_rot.transpose();
 		Vector3f light_direction = view_mat_rot * mLight.mDirection.normalized();
-		
-//		gLog ("Light direction %3.4f, %3.4f, %3.4f", 
-//				light_direction[0],
-//				light_direction[1],
-//				light_direction[2]);
 
 		mDeferredLighting.SetVec3("uLightDirection", light_direction);
 		mDeferredLighting.SetVec3("uViewPosition", mCamera.mEye);