From 953544718cc1b9034268b04b295a513710204042 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sun, 13 Dec 2020 16:11:00 +0300
Subject: [PATCH] Implement bump-mapping in deferred renderer

---
 .../include/psemek/gfx/renderer/deferred.hpp  |  1 +
 libs/gfx/source/renderer/deferred.cpp         | 28 ++++++++++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/libs/gfx/include/psemek/gfx/renderer/deferred.hpp b/libs/gfx/include/psemek/gfx/renderer/deferred.hpp
index a532c435..163584cd 100644
--- a/libs/gfx/include/psemek/gfx/renderer/deferred.hpp
+++ b/libs/gfx/include/psemek/gfx/renderer/deferred.hpp
@@ -33,6 +33,7 @@ namespace psemek::gfx
 		{
 			std::optional<color_4f> color;
 			texture_2d const * texture = nullptr;
+			texture_2d const * bump_map = nullptr;
 			bool transparent = false;
 			bool lit = true;
 			bool blooming = false;
diff --git a/libs/gfx/source/renderer/deferred.cpp b/libs/gfx/source/renderer/deferred.cpp
index 3aafdc7d..51ee5827 100644
--- a/libs/gfx/source/renderer/deferred.cpp
+++ b/libs/gfx/source/renderer/deferred.cpp
@@ -45,6 +45,7 @@ const uint O_PRE_TRANSFORM  = 1u << 5;
 const uint O_POST_TRANSFORM = 1u << 6;
 const uint O_INSTANCED      = 1u << 7;
 const uint O_BLOOMING       = 1u << 8;
+const uint O_BUMP_MAP       = 1u << 9;
 
 uniform uint u_flag_mask;
 )";
@@ -68,27 +69,34 @@ out vec4 color;
 out vec2 texcoord;
 out vec3 normal;
 
+out mat3 normal_transform;
+
 void main()
 {
 	vec4 pos = in_position;
 	vec3 n = in_normal;
 
+	mat3 nt = mat3(1.0);
+
 	if ((u_flag_mask & O_PRE_TRANSFORM) != 0u)
 	{
 		pos = vec4(u_pre_transform * pos, 1.0);
 		n = u_pre_transform * vec4(n, 0.0);
+		nt = mat3(u_pre_transform);
 	}
 
 	if ((u_flag_mask & O_INSTANCED) != 0u)
 	{
 		pos = vec4(transpose(in_instance_transform) * pos, 1.0);
 		n = transpose(in_instance_transform) * vec4(n, 0.0);
+		nt = mat3(transpose(in_instance_transform)) * nt;
 	}
 
 	if ((u_flag_mask & O_POST_TRANSFORM) != 0u)
 	{
 		pos = vec4(u_post_transform * pos, 1.0);
 		n = u_post_transform * vec4(n, 0.0);
+		nt = mat3(u_post_transform) * nt;
 	}
 
 	position = pos.xyz;
@@ -98,6 +106,7 @@ void main()
 	color = in_color;
 	texcoord = in_texcoord;
 	normal = n;
+	normal_transform = nt;
 }
 )";
 
@@ -106,6 +115,7 @@ R"(
 
 uniform vec4 u_color;
 uniform sampler2D u_texture;
+uniform sampler2D u_bump_texture;
 uniform vec2 u_material;
 uniform float u_max_intensity;
 
@@ -113,6 +123,7 @@ in vec3 position;
 in vec4 color;
 in vec2 texcoord;
 in vec3 normal;
+in mat3 normal_transform;
 
 layout (location = 0) out vec3 out0;
 layout (location = 1) out vec4 out1;
@@ -187,9 +198,15 @@ void main()
 			albedo = color;
 	}
 
+	vec3 n = normal;
+	if ((u_flag_mask & O_BUMP_MAP) != 0u)
+	{
+		n = normal_transform * (2.0 * texture(u_bump_texture, texcoord).xyz - vec3(1.0));
+	}
+
 	out0 = position;
 	out1 = vec4(albedo.rgb / u_max_intensity, (u_flag_mask & O_LIT) != 0u ? 1.f : 0.f);
-	out2 = pack_normal(normalize(normal));
+	out2 = pack_normal(normalize(n));
 	out3 = u_material;
 }
 )";
@@ -837,6 +854,7 @@ void main()
 	{
 		impl().g_buffer_pass_program.bind();
 		impl().g_buffer_pass_program["u_texture"] = 0;
+		impl().g_buffer_pass_program["u_bump_texture"] = 1;
 
 		for (std::size_t i = 0; i < 4; ++i)
 		{
@@ -946,6 +964,7 @@ void main()
 	static std::uint32_t const O_POST_TRANSFORM = 1 << 6;
 	static std::uint32_t const O_INSTANCED      = 1 << 7;
 	static std::uint32_t const O_BLOOMING       = 1 << 8;
+	static std::uint32_t const O_BUMP_MAP       = 1 << 9;
 
 	std::uint32_t mask(deferred_renderer::object const & o)
 	{
@@ -959,6 +978,7 @@ void main()
 		if (o.post_transform) m |= O_POST_TRANSFORM;
 		if (o.mesh->is_instanced()) m |= O_INSTANCED;
 		if (o.mat->blooming) m |= O_BLOOMING;
+		if (o.mat->bump_map) m |= O_BUMP_MAP;
 		return m;
 	}
 
@@ -1101,6 +1121,12 @@ void main()
 						mat->texture->bind();
 					}
 
+					if (mask & O_BUMP_MAP)
+					{
+						gl::ActiveTexture(gl::TEXTURE1);
+						mat->bump_map->bind();
+					}
+
 					program["u_material"] = geom::vector<float, 2>{mat->specular.intensity, mat->specular.shininess};
 
 					for (std::size_t i = clip_by_camera ? p.second.first_visible : 0; i < p.second.objects.size(); ++i)