Workbench: Fix incident vector calculation.

This fixes specular in perspective view.

5 files changed, 25 insertions, 22 deletions

diff --git a/source/blender/draw/engines/workbench/shaders/workbench_common_lib.glsl b/source/blender/draw/engines/workbench/shaders/workbench_common_lib.glsl
index 39c6863e71c..9a0ec7703c8 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_common_lib.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_common_lib.glsl
@@ -71,3 +71,11 @@ vec4 calculate_transparent_accum(vec4 premultiplied) {
 	float w = clamp(a * a * a * 1e8 * b * b * b, 1e-2, 3e2);
 	return premultiplied * w;
 }
+
+vec3 view_vector_from_screen_uv(vec2 uv, vec4 viewvecs[3], mat4 proj_mat)
+{
+	return (proj_mat[3][3] == 0.0)
+	             ? normalize(viewvecs[0].xyz + vec3(uv, 0.0) * viewvecs[1].xyz)
+	             : vec3(0.0, 0.0, 1.0);
+}
+
diff --git a/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl b/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
index e5ee272e7fd..4ae62352e16 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
@@ -1,5 +1,7 @@
 out vec4 fragColor;
 
+uniform mat4 ProjectionMatrix;
+
 uniform usampler2D objectId;
 uniform sampler2D colorBuffer;
 uniform sampler2D specularBuffer;
@@ -8,6 +10,7 @@ uniform sampler2D normalBuffer;
 uniform sampler2D cavityBuffer;
 
 uniform vec2 invertedViewportSize;
+uniform vec4 viewvecs[3];
 uniform float shadowMultiplier;
 uniform float lightMultiplier;
 uniform float shadowShift = 0.1;
@@ -61,6 +64,8 @@ void main()
 #  endif /* WORKBENCH_ENCODE_NORMALS */
 #endif
 
+	vec3 I_vs = view_vector_from_screen_uv(uv_viewport, viewvecs, ProjectionMatrix);
+
 #ifdef STUDIOLIGHT_ORIENTATION_VIEWNORMAL
 	vec2 matcap_uv = normal_viewport.xy / 2.0 + 0.5;
 	if (world_data.matcap_orientation != 0) {
@@ -70,8 +75,6 @@ void main()
 #endif
 
 #ifdef V3D_SHADING_SPECULAR_HIGHLIGHT
-	/* XXX Should calculate the correct VS Incoming direction */
-	vec3 I_vs = vec3(0.0, 0.0, 1.0);
 	vec4 specular_data = texelFetch(specularBuffer, texel, 0);
 	vec3 specular_color = get_world_specular_lights(world_data, specular_data, normal_viewport, I_vs);
 #else
diff --git a/source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_accum_frag.glsl b/source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_accum_frag.glsl
index e04bffdeea5..b26bc396283 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_accum_frag.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_forward_transparent_accum_frag.glsl
@@ -1,8 +1,11 @@
 #ifdef OB_TEXTURE
 uniform sampler2D image;
 #endif
+uniform mat4 ProjectionMatrix;
 uniform mat3 normalWorldMatrix;
 uniform float alpha = 0.5;
+uniform vec2 invertedViewportSize;
+uniform vec4 viewvecs[3];
 
 #ifdef NORMAL_VIEWPORT_PASS_ENABLED
 in vec3 normal_viewport;
@@ -36,12 +39,15 @@ void main()
 	diffuse_color = texture(image, uv_interp);
 #endif /* OB_TEXTURE */
 
+	vec2 uv_viewport = gl_FragCoord.xy * invertedViewportSize;
+	vec3 I_vs = view_vector_from_screen_uv(uv_viewport, viewvecs, ProjectionMatrix);
+
 #ifdef V3D_LIGHTING_MATCAP
 	diffuse_light = texture(matcapImage, normal_viewport.xy / 2.0 + 0.5).rgb;
 #endif
 
 #ifdef V3D_SHADING_SPECULAR_HIGHLIGHT
-	vec3 specular_color = get_world_specular_lights(world_data, vec4(material_data.specular_color.rgb, material_data.roughness), normal_viewport, vec3(0.0, 0.0, 1.0));
+	vec3 specular_color = get_world_specular_lights(world_data, vec4(material_data.specular_color.rgb, material_data.roughness), normal_viewport, I_vs;
 #else
 	vec3 specular_color = vec3(0.0);
 #endif
diff --git a/source/blender/draw/engines/workbench/workbench_deferred.c b/source/blender/draw/engines/workbench/workbench_deferred.c
index c4fa82d39b7..e1cb8b482ab 100644
--- a/source/blender/draw/engines/workbench/workbench_deferred.c
+++ b/source/blender/draw/engines/workbench/workbench_deferred.c
@@ -439,25 +439,7 @@ static void workbench_composite_uniforms(WORKBENCH_PrivateData *wpd, DRWShadingG
 	}
 	if (SPECULAR_HIGHLIGHT_ENABLED(wpd) || MATCAP_ENABLED(wpd)) {
 		DRW_shgroup_uniform_texture_ref(grp, "specularBuffer", &e_data.specular_buffer_tx);
-
-#if 0
-		float invwinmat[4][4];
-		DRW_viewport_matrix_get(invwinmat, DRW_MAT_WININV);
-
-		copy_v4_fl4(e_data.screenvecs[0],  1.0f, -1.0f, 0.0f, 1.0f);
-		copy_v4_fl4(e_data.screenvecs[1], -1.0f,  1.0f, 0.0f, 1.0f);
-		copy_v4_fl4(e_data.screenvecs[2], -1.0f, -1.0f, 0.0f, 1.0f);
-		for (int i = 0; i < 3; i++) {
-			mul_m4_v4(invwinmat, e_data.screenvecs[i]);
-			e_data.screenvecs[i][0] /= e_data.screenvecs[i][3]; /* perspective divide */
-			e_data.screenvecs[i][1] /= e_data.screenvecs[i][3]; /* perspective divide */
-			e_data.screenvecs[i][2] /= e_data.screenvecs[i][3]; /* perspective divide */
-			e_data.screenvecs[i][3] = 1.0f;
-		}
-		sub_v3_v3(e_data.screenvecs[0], e_data.screenvecs[2]);
-		sub_v3_v3(e_data.screenvecs[1], e_data.screenvecs[2]);
-		DRW_shgroup_uniform_vec4(grp, "screenvecs[0]", e_data.screenvecs[0], 3);
-#endif
+		DRW_shgroup_uniform_vec4(grp, "viewvecs[0]", (float *)wpd->viewvecs, 3);
 	}
 	DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
 	DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
diff --git a/source/blender/draw/engines/workbench/workbench_forward.c b/source/blender/draw/engines/workbench/workbench_forward.c
index 8bd27e18da2..3bc016e139b 100644
--- a/source/blender/draw/engines/workbench/workbench_forward.c
+++ b/source/blender/draw/engines/workbench/workbench_forward.c
@@ -207,6 +207,10 @@ static WORKBENCH_MaterialData *get_or_create_material_data(
 					BKE_studiolight_ensure_flag(wpd->studio_light, STUDIOLIGHT_EQUIRECTANGULAR_RADIANCE_GPUTEXTURE);
 					DRW_shgroup_uniform_texture(grp, "matcapImage", wpd->studio_light->equirectangular_radiance_gputexture);
 				}
+				if (SPECULAR_HIGHLIGHT_ENABLED(wpd) || MATCAP_ENABLED(wpd)) {
+					DRW_shgroup_uniform_vec4(grp, "viewvecs[0]", (float *)wpd->viewvecs, 3);
+					DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
+				}
 				break;
 			}