Environment lighting for the GLSL mode

Environment lighting (aka ambient) is a key component of any renderer.
It's implemented like the Environment lighting of BI render for Approximate Gather mode. It support "Sky Color" and "White" Environment lighting modes.

It would be great if the user could see actual lighting conditions right in the Blender viewport instead of waiting for the renderer to complete the final image, exporting for external renderer or for a game engine.

Before:
{F113921}

After:
{F113922}

Example file: {F319013}

Original author: valentin_b4w

Alexander (Blend4Web Team)

Reviewers: valentin_b4w, campbellbarton, merwin, brecht

Reviewed By: brecht

Subscribers: panzergame, youle, duarteframos, AlexKowel, yurikovelenov, dingto, Evgeny_Rodygin

Projects: #rendering, #opengl_gfx

Differential Revision: https://developer.blender.org/D810

3 files changed, 41 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index a79334df8ce..0d92d22a173 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -337,6 +337,7 @@ void GPU_mist_update_enable(short enable);
 void GPU_mist_update_values(int type, float start, float dist, float inten, float color[3]);
 void GPU_horizon_update_color(float color[3]);
 void GPU_ambient_update_color(float color[3]);
+void GPU_zenith_update_color(float color[3]);
 
 struct GPUParticleInfo
 {
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index f14b2e6e170..095a5b1b66a 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -88,6 +88,7 @@ static struct GPUWorld {
 	float mistcol[4];
 	float horicol[3];
 	float ambcol[4];
+	float zencol[3];
 } GPUWorld;
 
 struct GPUMaterial {
@@ -1673,6 +1674,11 @@ void GPU_ambient_update_color(float color[3])
 	GPUWorld.ambcol[3] = 1.0f;
 }
 
+void GPU_zenith_update_color(float color[3])
+{
+	copy_v3_v3(GPUWorld.zencol, color);
+}
+
 void GPU_shaderesult_set(GPUShadeInput *shi, GPUShadeResult *shr)
 {
 	GPUMaterial *mat = shi->gpumat;
@@ -1729,6 +1735,33 @@ void GPU_shaderesult_set(GPUShadeInput *shi, GPUShadeResult *shr)
 					ulinfac, ulogfac, &shr->spec);
 			}
 
+			/* environment lighting */
+			if (!(mat->scene->gm.flag & GAME_GLSL_NO_ENV_LIGHTING) && (world->mode & WO_ENV_LIGHT) && (mat->scene->r.mode & R_SHADOW) &&
+				!BKE_scene_use_new_shading_nodes(mat->scene))
+			{
+				if ((world->ao_env_energy != 0.0f) && (GPU_link_changed(shi->amb) || ma->amb != 0.0f) &&
+					(GPU_link_changed(shi->refl) || ma->ref != 0.0f))
+				{
+					if (world->aocolor != WO_AOPLAIN) {
+						if (!(is_zero_v3(&world->horr) & is_zero_v3(&world->zenr)))
+						{
+							GPUNodeLink *fcol, *f;
+							GPU_link(mat, "math_multiply", shi->amb, shi->refl, &f);
+							GPU_link(mat, "math_multiply", f, GPU_uniform(&world->ao_env_energy), &f);
+							GPU_link(mat, "shade_mul_value", f, shi->rgb, &fcol);
+							GPU_link(mat, "env_apply", shr->combined, GPU_dynamic_uniform(GPUWorld.horicol, GPU_DYNAMIC_HORIZON_COLOR, NULL),
+									GPU_dynamic_uniform(GPUWorld.zencol, GPU_DYNAMIC_ZENITH_COLOR, NULL), fcol, GPU_builtin(GPU_VIEW_MATRIX), shi->vn, &shr->combined);
+						}
+					}
+					else {
+						GPUNodeLink *f;
+						GPU_link(mat, "math_multiply", shi->amb, shi->refl, &f);
+						GPU_link(mat, "math_multiply", f, GPU_uniform(&world->ao_env_energy), &f);
+						GPU_link(mat, "shade_maddf", shr->combined, f, shi->rgb, &shr->combined);
+					}
+				}
+			}
+
 			/* ambient color */
 			if (GPU_link_changed(shi->amb) || ma->amb != 0.0f) {
 				GPU_link(mat, "shade_maddf", shr->combined, GPU_uniform(&ma->amb),
diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 9914c4bb362..02e9ba1c8c3 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -2182,6 +2182,13 @@ void shade_madd_clamped(vec4 col, vec4 col1, vec4 col2, out vec4 outcol)
 	outcol = col + max(col1 * col2, vec4(0.0, 0.0, 0.0, 0.0));
 }
 
+void env_apply(vec4 col, vec4 hor, vec4 zen, vec4 f, mat4 vm, vec3 vn, out vec4 outcol)
+{
+	vec3 vv = normalize(vm[2].xyz);
+	float skyfac = 0.5 * (1.0 + dot(vn, -vv));
+	outcol = col + f * mix(hor, zen, skyfac);
+}
+
 void shade_maddf(vec4 col, float f, vec4 col1, out vec4 outcol)
 {
 	outcol = col + f * col1;