[vulkan] Get point light shadows working

Other than the rather bad shadow acne, this is actually quake itself
working nicely. Still need to get directional lights working for
community maps, and all sorts of other little things (hide view model,
show player, fix brush backfaces, etc).

libs/video/renderer/vulkan/shader/lighting_cascade.frag

@@ -4,7 +4,7 @@
 layout (set = 3, binding = 0) uniform sampler2DArrayShadow shadow_map[32];
 
 float
-shadow (uint map_id, uint layer, uint mat_id, vec3 pos)
+shadow (uint map_id, uint layer, uint mat_id, vec3 pos, vec3 lpos)
 {
 	return 1;
 }

libs/video/renderer/vulkan/shader/lighting_cube.frag

@@ -7,11 +7,24 @@ layout (set = 0, binding = 0) buffer ShadowMatrices {
 layout (set = 3, binding = 0) uniform samplerCubeArrayShadow shadow_map[32];
 
 float
-shadow (uint map_id, uint layer, uint mat_id, vec3 pos)
+shadow (uint map_id, uint layer, uint mat_id, vec3 pos, vec3 lpos)
 {
-	vec4 p = shadow_mats[mat_id] * vec4 (pos, 1);
+	vec3 dir = pos - lpos;
-	float depth = (p / p.w).z;
+	vec3 adir = abs(dir);
-	return texture (shadow_map[map_id], vec4 (p.xyz, layer), depth);
+	adir = max (adir.yzx, adir.zxy);
+	uint ind = dir.x <= -adir.x ? 5
+			 : dir.x >=  adir.x ? 4
+			 : dir.y <= -adir.y ? 0
+			 : dir.y >=  adir.y ? 1
+			 : dir.z <= -adir.z ? 3
+			 : dir.z >=  adir.z ? 2 : 0;
+	vec4 p = shadow_mats[mat_id + ind] * vec4 (pos, 1);
+	p = p / (p.w - 0.5);	//FIXME hard-coded bias
+	float depth = p.z;
+	dir = mat3(vec3( 0, 0, 1),
+			   vec3(-1, 0, 0),
+			   vec3( 0, 1, 0)) * dir;
+	return texture (shadow_map[map_id], vec4 (dir, layer), depth);
 }
 
 #include "lighting_main.finc"

libs/video/renderer/vulkan/shader/lighting_main.finc

@@ -54,7 +54,7 @@ main (void)
 		uint        map_id = bitfieldExtract (id_data, 13, 5);
 		uint        layer = bitfieldExtract (id_data, 18, 11);
 
-		I *= shadow (map_id, layer, mat_id, p);
+		I *= shadow (map_id, layer, mat_id, p, l.position.xyz);
 
 		float       namb = dot(l.direction.xyz, l.direction.xyz);
 		I *= spot_cone (l, incoming) * diffuse (incoming, n);

libs/video/renderer/vulkan/shader/lighting_none.frag

@@ -2,7 +2,7 @@
 #extension GL_GOOGLE_include_directive : enable
 
 float
-shadow (uint mapid, uint layer, uint mat_id, vec3 pos)
+shadow (uint mapid, uint layer, uint mat_id, vec3 pos, vec3 lpos)
 {
 	return 1;
 }

libs/video/renderer/vulkan/shader/lighting_plane.frag

@@ -7,7 +7,7 @@ layout (set = 0, binding = 0) buffer ShadowMatrices {
 layout (set = 3, binding = 0) uniform sampler2DArrayShadow shadow_map[32];
 
 float
-shadow (uint map_id, uint layer, uint mat_id, vec3 pos)
+shadow (uint map_id, uint layer, uint mat_id, vec3 pos, vec3 lpos)
 {
 	vec4 p = shadow_mats[mat_id] * vec4 (pos, 1);
 	p = p / (p.w - 0.5);	//FIXME hard-coded bias

libs/video/renderer/vulkan/vulkan_lighting.c

@@ -349,7 +349,6 @@ lighting_update_lights (const exprval_t **params, exprval_t *result,
 				//.id_data = make_id(r->matrix_id, r->map_index, r->layer,
 				//r->mode),
 				.id_data = 0x80000000,	// no style
-				.style = 11,
 			};
 		}
 		dlight_offset = sizeof (qfv_light_render_t[lctx->dynamic_base]);
@@ -1157,7 +1156,7 @@ create_light_matrices (lightingctx_t *lctx)
 					mmulf (side_view, qfv_z_up, side_view);
 					mmulf (lm[j], proj, side_view);
 				}
-				r->matrix_id = r->matrix_base + BOX_FRONT;
+				r->matrix_id = r->matrix_base;
 				break;
 			case ST_CASCADE:
 				// dependent on view fustrum and cascade level
@@ -1197,6 +1196,9 @@ static uint32_t
 make_id (uint32_t matrix_index, uint32_t map_index, uint32_t layer,
 		 uint32_t type)
 {
+	if (type == ST_CUBE) {
+		layer /= 6;
+	}
 	return ((matrix_index & 0x1fff) << 0)
 		 | ((map_index & 0x1f) << 13)
 		 | ((layer & 0x7ff) << 18)