Fixups in MTL loader.

Add specular lighting.

libretro.cpp

@@ -228,22 +228,37 @@ static void init_mesh(const string& path)
       "varying vec4 vPos;\n"
 
       "uniform sampler2D sDiffuse;\n"
+      "uniform sampler2D sAmbient;\n"
 
       "uniform vec3 uLightDir;\n"
       "uniform vec3 uLightAmbient;\n"
       "uniform vec3 uMTLAmbient;\n"
       "uniform float uMTLAlphaMod;\n"
       "uniform vec3 uMTLDiffuse;\n"
+      "uniform vec3 uMTLSpecular;\n"
+      "uniform float uMTLSpecularPower;\n"
 
       "void main() {\n"
-      "  vec4 colorDiffuse = texture2D(sDiffuse, vTex);\n"
-      "  if (colorDiffuse.a < 0.5) discard;\n"
+      "  vec4 colorDiffuseFull = texture2D(sDiffuse, vTex);\n"
+      "  vec4 colorAmbientFull = texture2D(sAmbient, vTex);\n"
+
+      "  if (colorDiffuseFull.a < 0.5)\n"
+      "    discard;\n"
+
+      "  vec3 colorDiffuse = mix(uMTLDiffuse, colorDiffuseFull.rgb, vec3(colorDiffuseFull.a));\n"
+      "  vec3 colorAmbient = mix(uMTLAmbient, colorAmbientFull.rgb, vec3(colorAmbientFull.a));\n"
+
       "  vec3 normal = normalize(vNormal.xyz);\n"
       "  float directivity = dot(uLightDir, -normal);\n"
 
-      "  vec3 diffuse = colorDiffuse.rgb * (clamp(directivity, 0.0, 1.0) + uLightAmbient * uMTLAmbient);\n"
+      "  vec3 diffuse = colorDiffuse * clamp(directivity, 0.0, 1.0);\n"
+      "  vec3 ambient = colorAmbient * uLightAmbient;\n"
 
-      "  gl_FragColor = vec4(diffuse, uMTLAlphaMod * colorDiffuse.a);\n"
+      "  vec3 modelToFace = normalize(-vPos.xyz);\n"
+      "  float specularity = pow(clamp(dot(modelToFace, reflect(uLightDir, normal)), 0.0, 1.0), uMTLSpecularPower);\n"
+      "  vec3 specular = uMTLSpecular * specularity;\n"
+
+      "  gl_FragColor = vec4(diffuse + ambient + specular, uMTLAlphaMod * colorDiffuseFull.a);\n"
       "}";
 
    shared_ptr<Shader> shader(new Shader(vertex_shader, fragment_shader));

mesh.cpp

@@ -85,6 +85,7 @@ namespace GL
       shader->use();
 
       SYM(glUniform1i)(shader->uniform("sDiffuse"), 0);
+      SYM(glUniform1i)(shader->uniform("sAmbient"), 0);
 
       SYM(glUniformMatrix4fv)(shader->uniform("uModel"),
             1, GL_FALSE, value_ptr(model));
@@ -97,6 +98,8 @@ namespace GL
             1, value_ptr(material.diffuse));
       SYM(glUniform3fv)(shader->uniform("uMTLSpecular"),
             1, value_ptr(material.specular));
+      SYM(glUniform1f)(shader->uniform("uMTLSpecularPower"),
+            material.specular_power);
       SYM(glUniform1f)(shader->uniform("uMTLAlphaMod"),
             material.alpha_mod);
 

mesh.hpp

@@ -27,12 +27,14 @@ namespace GL
          ambient(1, 1, 1),
          diffuse(1, 1, 1),
          specular(0, 0, 0),
+         specular_power(60.0),
          alpha_mod(1.0f)
       {}
 
       glm::vec3 ambient;
       glm::vec3 diffuse;
       glm::vec3 specular;
+      float specular_power;
       float alpha_mod;
       std1::shared_ptr<Texture> diffuse_map;
    };

object.cpp

@@ -121,7 +121,7 @@ namespace OBJ
 
       for (string line; getline(file, line); )
       {
-         line = line.substr(0, line.find_first_of('\r'));
+         line = String::strip(line);
 
          size_t split_point = line.find_first_of(' ');
          string type = line.substr(0, split_point);
@@ -141,8 +141,12 @@ namespace OBJ
             current.diffuse = parse_line<vec3>(data);
          else if (type == "Ks")
             current.specular = parse_line<vec3>(data);
-         else if (type == "Tr" || type == "d")
+         else if (type == "Ns")
+            current.specular_power = String::stof(data);
+         else if (type == "d")
             current.alpha_mod = String::stof(data);
+         else if (type == "Tr")
+            current.alpha_mod = 1.0f - String::stof(data);
          else if (type == "map_Kd")
          {
             string diffuse_path = Path::join(Path::basedir(path), data);
@@ -176,7 +180,7 @@ namespace OBJ
 
       for (string line; getline(file, line); )
       {
-         line = line.substr(0, line.find_first_of('\r'));
+         line = String::strip(line);
 
          size_t split_point = line.find_first_of(' ');
          string type = line.substr(0, split_point);
@@ -226,7 +230,7 @@ namespace OBJ
             current_material = materials[data];
          }
          else if (type == "mtllib")
-            materials = parse_mtllib(Path::join(Path::basedir(path), data + ".mtl"));
+            materials = parse_mtllib(Path::join(Path::basedir(path), data));
       }
 
       if (vertices.size())

shader.cpp

@@ -30,7 +30,7 @@ namespace GL
             SYM(glGetProgramInfoLog)(prog, len, &out_len, &buf[0]);
 
             char err_str[256];
-            snprintf(err_str, sizeof(err_str), "Link error: %s", &buf[0]);
+            snprintf(err_str, sizeof(err_str), "Link error: %s\n", &buf[0]);
             retro_stderr(err_str);
          }
       }
@@ -58,7 +58,7 @@ namespace GL
             SYM(glGetShaderInfoLog)(shader, len, &out_len, &buf[0]);
 
             char err_str[256];
-            snprintf(err_str, sizeof(err_str), "Shader error: %s", &buf[0]);
+            snprintf(err_str, sizeof(err_str), "Shader error: %s\n", &buf[0]);
             retro_stderr(err_str);
          }
 

simple.obj

@@ -1,4 +1,4 @@
-mtllib simple
+mtllib simple.mtl
 
 v -1.0 -1.0 0.0
 v 1.0 -1.0 0.0

texture.cpp

@@ -45,7 +45,7 @@ namespace GL
       else
       {
          char err_str[256];
-         snprintf(err_str, sizeof(err_str), "Failed to load image: %s", path.c_str());
+         snprintf(err_str, sizeof(err_str), "Failed to load image: %s\n", path.c_str());
          retro_stderr(err_str);
       }
    }

util.hpp

@@ -56,6 +56,16 @@ namespace String
    {
       return static_cast<float>(std::strtod(str.c_str(), NULL));
    }
+
+   inline std::string strip(const std::string& str)
+   {
+      size_t first_non_space = str.find_first_not_of(" \t\r");
+      if (first_non_space == std::string::npos)
+         return "";
+
+      return str.substr(first_non_space,
+            str.find_last_not_of(" \t\r") - first_non_space + 1);
+   }
 }
 
 #endif