Blender Internal: Add "Lamp Data" shader node that allows shaders to acquire information such as light vector from specified Lamp.

For now this provides the following outputs:

- Color
- Light Vector
- Distance
- Shadow
- Visibility Factor

Note: Color output is multiplied by the lamp energy.  Multiplication of
color*max(dot(light_vector,normal_vector),0)*shadow*visibility_factor
produces the exact same result as the Lambert shader.

Many thanks to Brecht for code review and discussion!

3 files changed, 82 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index 29da72a00fe..8c4c7d47558 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -133,6 +133,7 @@ void GPU_material_bind(GPUMaterial *material, int oblay, int viewlay, double tim
 void GPU_material_bind_uniforms(GPUMaterial *material, float obmat[4][4], float obcol[4], float autobumpscale);
 void GPU_material_unbind(GPUMaterial *material);
 int GPU_material_bound(GPUMaterial *material);
+struct Scene *GPU_material_scene(GPUMaterial *material);
 
 void GPU_material_vertex_attributes(GPUMaterial *material,
 	struct GPUVertexAttribs *attrib);
@@ -244,6 +245,7 @@ void GPU_lamp_update_colors(GPULamp *lamp, float r, float g, float b, float ener
 void GPU_lamp_update_distance(GPULamp *lamp, float distance, float att1, float att2);
 void GPU_lamp_update_spot(GPULamp *lamp, float spotsize, float spotblend);
 int GPU_lamp_shadow_layer(GPULamp *lamp);
+GPUNodeLink *GPU_lamp_get_data(GPUMaterial *mat, GPULamp *lamp, GPUNodeLink **col, GPUNodeLink **lv, GPUNodeLink **dist, GPUNodeLink **shadow);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index ed7a2f4ede0..8e7194bb4a1 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -355,6 +355,11 @@ int GPU_material_bound(GPUMaterial *material)
 	return material->bound;
 }
 
+Scene *GPU_material_scene(GPUMaterial *material)
+{
+	return material->scene;
+}
+
 void GPU_material_vertex_attributes(GPUMaterial *material, GPUVertexAttribs *attribs)
 {
 	*attribs = material->attribs;
@@ -1953,6 +1958,48 @@ int GPU_lamp_shadow_layer(GPULamp *lamp)
 		return -1;
 }
 
+GPUNodeLink *GPU_lamp_get_data(GPUMaterial *mat, GPULamp *lamp, GPUNodeLink **col, GPUNodeLink **lv, GPUNodeLink **dist, GPUNodeLink **shadow)
+{
+	GPUNodeLink *visifac;
+
+	*col = GPU_dynamic_uniform(lamp->dyncol, GPU_DYNAMIC_LAMP_DYNCOL, lamp->ob);
+	visifac = lamp_get_visibility(mat, lamp, lv, dist);
+	shade_light_textures(mat, lamp, col);
+
+	if (GPU_lamp_has_shadow_buffer(lamp)) {
+		GPUNodeLink *vn, *inp;
+
+		GPU_link(mat, "shade_norm", GPU_builtin(GPU_VIEW_NORMAL), &vn);
+		GPU_link(mat, "shade_inp", vn, *lv, &inp);
+		mat->dynproperty |= DYN_LAMP_PERSMAT;
+
+		if (lamp->la->shadowmap_type == LA_SHADMAP_VARIANCE) {
+			GPU_link(mat, "shadows_only_vsm",
+				 GPU_builtin(GPU_VIEW_POSITION),
+				 GPU_dynamic_texture(lamp->tex, GPU_DYNAMIC_SAMPLER_2DSHADOW, lamp->ob),
+				 GPU_dynamic_uniform((float*)lamp->dynpersmat, GPU_DYNAMIC_LAMP_DYNPERSMAT, lamp->ob),
+				 GPU_uniform(&lamp->bias), GPU_uniform(&lamp->la->bleedbias),
+				 GPU_uniform(lamp->shadow_color), inp, shadow);
+		}
+		else {
+			GPU_link(mat, "shadows_only",
+				 GPU_builtin(GPU_VIEW_POSITION),
+				 GPU_dynamic_texture(lamp->tex, GPU_DYNAMIC_SAMPLER_2DSHADOW, lamp->ob),
+				 GPU_dynamic_uniform((float*)lamp->dynpersmat, GPU_DYNAMIC_LAMP_DYNPERSMAT, lamp->ob),
+				 GPU_uniform(&lamp->bias), GPU_uniform(lamp->shadow_color), inp, shadow);
+		}
+	}
+	else {
+		GPU_link(mat, "set_rgb_one", shadow);
+	}
+
+	/* ensure shadow buffer and lamp textures will be updated */
+	add_user_list(&mat->lamps, lamp);
+	add_user_list(&lamp->materials, mat->ma);
+
+	return visifac;
+}
+
 /* export the GLSL shader */
 
 GPUShaderExport *GPU_shader_export(struct Scene *scene, struct Material *ma)
diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 1dd33080d94..3a4aa75aa01 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -166,6 +166,15 @@ void camera(vec3 co, out vec3 outview, out float outdepth, out float outdist)
 	outview = normalize(co);
 }
 
+void lamp(vec4 col, vec3 lv, float dist, vec3 shadow, float visifac, out vec4 outcol, out vec3 outlv, out float outdist, out vec4 outshadow, out float outvisifac)
+{
+	outcol = col;
+	outlv = lv;
+	outdist = dist;
+	outshadow = vec4(shadow, 1.0);
+	outvisifac = visifac;
+}
+
 void math_add(float val1, float val2, out float outval)
 {
 	outval = val1 + val2;
@@ -1973,6 +1982,30 @@ void test_shadowbuf_vsm(vec3 rco, sampler2D shadowmap, mat4 shadowpersmat, float
 	}
 }
 
+void shadows_only(vec3 rco, sampler2DShadow shadowmap, mat4 shadowpersmat, float shadowbias, vec3 shadowcolor, float inp, out vec3 result)
+{
+	result = vec3(1.0);
+
+	if(inp > 0.0) {
+		float shadfac;
+
+		test_shadowbuf(rco, shadowmap, shadowpersmat, shadowbias, inp, shadfac);
+		result -= (1.0 - shadfac) * (vec3(1.0) - shadowcolor);
+	}
+}
+
+void shadows_only_vsm(vec3 rco, sampler2D shadowmap, mat4 shadowpersmat, float shadowbias, float bleedbias, vec3 shadowcolor, float inp, out vec3 result)
+{
+	result = vec3(1.0);
+
+	if(inp > 0.0) {
+		float shadfac;
+
+		test_shadowbuf_vsm(rco, shadowmap, shadowpersmat, shadowbias, bleedbias, inp, shadfac);
+		result -= (1.0 - shadfac) * (vec3(1.0) - shadowcolor);
+	}
+}
+
 void shade_light_texture(vec3 rco, sampler2D cookie, mat4 shadowpersmat, out vec4 result)
 {