pbr: support ambient occlusion maps

AO maps modulate environment light

resources/00-taisei.pkgdir/shader/interface/pbr.glslh

@@ -10,6 +10,7 @@
 #define PBR_FEATURE_ROUGHNESS_MAP       8
 #define PBR_FEATURE_ENVIRONMENT_MAP    16
 #define PBR_FEATURE_DEPTH_MAP          32
+#define PBR_FEATURE_AO_MAP             64
 
 UNIFORM(1) int features_mask;
 
@@ -19,18 +20,19 @@ UNIFORM(4) sampler2D ambient_map;
 UNIFORM(5) sampler2D roughness_map;
 UNIFORM(6) samplerCube environment_map;
 UNIFORM(7) sampler2D depth_map;
-UNIFORM(8) sampler2D ibl_brdf_lut;
+UNIFORM(8) sampler2D ao_map;
+UNIFORM(9) sampler2D ibl_brdf_lut;
 
 // These either modulate their respective maps, or are used instead of them
-UNIFORM(9) vec4 diffuseRGB_metallicA;
-UNIFORM(10) vec4 ambientRGB_roughnessA;
-UNIFORM(11) float depth_scale;
+UNIFORM(10) vec4 diffuseRGB_metallicA;
+UNIFORM(11) vec4 ambientRGB_roughnessA;
+UNIFORM(12) float depth_scale;
 
-UNIFORM(12) mat4 inv_camera_transform;   // only used if PBR_FEATURE_ENVIRONMENT_MAP is set
+UNIFORM(13) mat4 inv_camera_transform;   // only used if PBR_FEATURE_ENVIRONMENT_MAP is set
 
-UNIFORM(13) int light_count;
-UNIFORM(14) vec3 light_positions[PBR_MAX_LIGHTS];
-UNIFORM(20) vec3 light_colors[PBR_MAX_LIGHTS]; // layout-id also depends on PBR_MAX_LIGHTS
+UNIFORM(14) int light_count;
+UNIFORM(15) vec3 light_positions[PBR_MAX_LIGHTS];
+UNIFORM(21) vec3 light_colors[PBR_MAX_LIGHTS]; // layout-id also depends on PBR_MAX_LIGHTS
 
 VARYING(3) vec3 pos;
 VARYING(4) vec3 tangent;

resources/00-taisei.pkgdir/shader/pbr.frag.glsl

@@ -14,12 +14,6 @@ void main(void) {
 	if(bool(features_mask & PBR_FEATURE_DEPTH_MAP)) {
 		vec3 vdir = normalize(transpose(tbn) * -pos);
 		uv = parallaxOcclusionMap(depth_map, depth_scale, uv, vdir);
-
-		/*
-		if(uv.x > 1.0 || uv.y > 1.0 || uv.x < 0.0 || uv.y < 0.0) {
-			discard;
-		}
-		*/
 	}
 
 	if(bool(features_mask & PBR_FEATURE_ROUGHNESS_MAP)) {
@@ -73,7 +67,13 @@ void main(void) {
 	}
 
 	if(bool(features_mask & PBR_FEATURE_ENVIRONMENT_MAP)) {
-		color += PBR_EnvironmentLight(pbr, ibl_brdf_lut, environment_map);
+		vec3 envLight = PBR_EnvironmentLight(pbr, ibl_brdf_lut, environment_map);
+
+		if(bool(features_mask & PBR_FEATURE_AO_MAP)) {
+			envLight *= texture(ao_map, uv).r;
+		}
+
+		color += envLight;
 	}
 
 	color = PBR_TonemapReinhard(color);

src/resource/material.c

@@ -45,9 +45,10 @@ struct mat_load_data {
 			char *ambient_map;
 			char *roughness_map;
 			char *depth_map;
+			char *ao_map;
 		};
 
-		char *maps[5];
+		char *maps[6];
 	};
 };
 
@@ -78,6 +79,7 @@ static void material_load_stage1(ResourceLoadState *st) {
 		{ "ambient_map",      .out_str = &ld->ambient_map },
 		{ "roughness_map",    .out_str = &ld->roughness_map },
 		{ "depth_map",        .out_str = &ld->depth_map },
+		{ "ao_map",           .out_str = &ld->ao_map },
 		{ "diffuse_color",    .callback = kvparser_vec3, .callback_data = ld->mat->diffuse_color },
 		{ "ambient_color",    .callback = kvparser_vec3, .callback_data = ld->mat->ambient_color },
 		{ "roughness",        .out_float = &ld->mat->roughness_value },
@@ -119,6 +121,7 @@ static void material_load_stage2(ResourceLoadState *st) {
 	LOADMAP(ambient);
 	LOADMAP(roughness);
 	LOADMAP(depth);
+	LOADMAP(ao);
 
 	res_load_finished(st, ld->mat);
 	free_mat_load_data(ld);

src/resource/material.h

@@ -18,6 +18,7 @@ typedef struct PBRMaterial {
 	Texture *ambient_map;
 	Texture *roughness_map;
 	Texture *depth_map;
+	Texture *ao_map;
 
 	vec3 diffuse_color;
 	vec3 ambient_color;

src/stageutils.c

@@ -172,6 +172,11 @@ void pbr_set_material_uniforms(const PBRMaterial *m, const PBREnvironment *env)
 		flags |= PBR_FEATURE_ENVIRONMENT_MAP;
 	}
 
+	if(m->ao_map) {
+		r_uniform_sampler("ao_map", m->ao_map);
+		flags |= PBR_FEATURE_AO_MAP;
+	}
+
 	vec4 diffuseRGB_metallicA;
 	glm_vec3_copy((float*)m->diffuse_color, diffuseRGB_metallicA);
 	diffuseRGB_metallicA[3] = m->metallic_value;

src/stageutils.h

@@ -55,6 +55,7 @@ typedef struct PointLight3D {
 #define PBR_FEATURE_ROUGHNESS_MAP       8
 #define PBR_FEATURE_ENVIRONMENT_MAP    16
 #define PBR_FEATURE_DEPTH_MAP          32
+#define PBR_FEATURE_AO_MAP             64
 
 typedef struct PBREnvironment {
 	mat4 cam_inverse_transform;