fix bump example tangent lighting wrong

examples/06-bump/fs_bump.sc

@@ -1,4 +1,4 @@
-$input v_wpos, v_view, v_normal, v_tangent, v_bitangent, v_texcoord0 // in...
+$input v_wpos, v_view, v_normal, v_tangent, v_bitangent, v_texcoord0// in...
 
 /*
  * Copyright 2011-2018 Branimir Karadzic. All rights reserved.
@@ -15,7 +15,8 @@ uniform vec4 u_lightRgbInnerR[4];
 vec2 blinn(vec3 _lightDir, vec3 _normal, vec3 _viewDir)
 {
 	float ndotl = dot(_normal, _lightDir);
-	vec3 reflected = _lightDir - 2.0*ndotl*_normal; // reflect(_lightDir, _normal);
+	//vec3 reflected = _lightDir - 2.0*ndotl*_normal; // reflect(_lightDir, _normal);
+	vec3 reflected = 2.0*ndotl*_normal - _lightDir;
 	float rdotv = dot(reflected, _viewDir);
 	return vec2(ndotl, rdotv);
 }
@@ -45,25 +46,31 @@ vec3 calcLight(int _idx, mat3 _tbn, vec3 _wpos, vec3 _normal, vec3 _view)
 {
 	vec3 lp = u_lightPosRadius[_idx].xyz - _wpos;
 	float attn = 1.0 - smoothstep(u_lightRgbInnerR[_idx].w, 1.0, length(lp) / u_lightPosRadius[_idx].w);
-	vec3 lightDir = mul(_tbn, normalize(lp) );
+	vec3 lightDir = mul( normalize(lp), _tbn );
 	vec2 bln = blinn(lightDir, _normal, _view);
 	vec4 lc = lit(bln.x, bln.y, 1.0);
 	vec3 rgb = u_lightRgbInnerR[_idx].xyz * saturate(lc.y) * attn;
 	return rgb;
 }
 
+mat3 mtx3FromCols(vec3 c0, vec3 c1, vec3 c2)
+{
+#ifdef BGFX_SHADER_LANGUAGE_GLSL
+	return mat3(c0, c1, c2);
+#else
+	return transpose(mat3(c0, c1, c2));
+#endif
+}
+
+
 void main()
 {
-	mat3 tbn = mat3(
-				normalize(v_tangent),
-				normalize(v_bitangent),
-				normalize(v_normal)
-				);
+	mat3 tbn = mtx3FromCols(v_tangent, v_bitangent, v_normal);
 
 	vec3 normal;
 	normal.xy = texture2D(s_texNormal, v_texcoord0).xy * 2.0 - 1.0;
 	normal.z = sqrt(1.0 - dot(normal.xy, normal.xy) );
-	vec3 view = -normalize(v_view);
+	vec3 view = normalize(v_view);
 
 	vec3 lightColor;
 	lightColor =  calcLight(0, tbn, v_wpos, normal, view);

examples/06-bump/vs_bump.sc

@@ -8,30 +8,37 @@ $output v_wpos, v_view, v_normal, v_tangent, v_bitangent, v_texcoord0
 
 #include "../common/common.sh"
 
+mat3 mtx3FromCols(vec3 c0, vec3 c1, vec3 c2)
+{
+#ifdef BGFX_SHADER_LANGUAGE_GLSL
+	return mat3(c0, c1, c2);
+#else
+	return transpose(mat3(c0, c1, c2));
+#endif
+}
+
 void main()
 {
 	vec3 wpos = mul(u_model[0], vec4(a_position, 1.0) ).xyz;
+	v_wpos = wpos;
+
 	gl_Position = mul(u_viewProj, vec4(wpos, 1.0) );
 	
 	vec4 normal = a_normal * 2.0 - 1.0;
-	vec3 wnormal = mul(u_model[0], vec4(normal.xyz, 0.0) ).xyz;
-
 	vec4 tangent = a_tangent * 2.0 - 1.0;
+
+	vec3 wnormal = mul(u_model[0], vec4(normal.xyz, 0.0) ).xyz;
 	vec3 wtangent = mul(u_model[0], vec4(tangent.xyz, 0.0) ).xyz;
 
-	vec3 viewNormal = normalize(mul(u_view, vec4(wnormal, 0.0) ).xyz);
-	vec3 viewTangent = normalize(mul(u_view, vec4(wtangent, 0.0) ).xyz);
-	vec3 viewBitangent = cross(viewNormal, viewTangent) * tangent.w;
-	mat3 tbn = mat3(viewTangent, viewBitangent, viewNormal);
+	v_normal = normalize(wnormal);
+	v_tangent = normalize(wtangent);
+	v_bitangent = cross(v_normal, v_tangent) * tangent.w;
 
-	v_wpos = wpos;
-
-	vec3 view = mul(u_view, vec4(wpos, 0.0) ).xyz;
-	v_view = mul(view, tbn);
-
-	v_normal = viewNormal;
-	v_tangent = viewTangent;
-	v_bitangent = viewBitangent;
+	mat3 tbn = mtx3FromCols(v_tangent, v_bitangent, v_normal);
 
+	// eye position in world space
+	vec3 weyepos = mul(vec4(0.0, 0.0, 0.0, 1.0), u_view).xyz;	
+	// tangent space view dir
+	v_view = mul(weyepos - wpos, tbn);	
 	v_texcoord0 = a_texcoord0;
 }

examples/06-bump/vs_bump_instanced.sc

@@ -25,19 +25,16 @@ void main()
 	vec4 tangent = a_tangent * 2.0 - 1.0;
 	vec3 wtangent = instMul(model, vec4(tangent.xyz, 0.0) ).xyz;
 
-	vec3 viewNormal = normalize(mul(u_view, vec4(wnormal, 0.0) ).xyz);
-	vec3 viewTangent = normalize(mul(u_view, vec4(wtangent, 0.0) ).xyz);
-	vec3 viewBitangent = cross(viewNormal, viewTangent) * tangent.w;
-	mat3 tbn = mat3(viewTangent, viewBitangent, viewNormal);
+	v_normal = wnormal;
+	v_tangent = wtangent;
+	v_bitangent = cross(v_normal, v_tangent) * tangent.w;
+
+	mat3 tbn = mat3(v_tangent, v_bitangent, v_normal);
 
 	v_wpos = wpos;
 
-	vec3 view = mul(u_view, vec4(wpos, 0.0) ).xyz;
-	v_view = instMul(view, tbn);
-
-	v_normal = viewNormal;
-	v_tangent = viewTangent;
-	v_bitangent = viewBitangent;
+	vec3 weyepos = mul(vec4(0.0, 0.0, 0.0, 1.0), u_view).xyz;		
+	v_view = instMul(weyepos - wpos, tbn);
 
 	v_texcoord0 = a_texcoord0;
 }