Fix bug to retrieve material specular map in DrawMesh function, with incorrect index (#3758)

src/rmodels.c

@@ -1352,10 +1352,10 @@ void DrawMesh(Mesh mesh, Material material, Matrix transform)
     if (material.shader.locs[SHADER_LOC_COLOR_SPECULAR] != -1)
     {
         float values[4] = {
-            (float)material.maps[SHADER_LOC_COLOR_SPECULAR].color.r/255.0f,
-            (float)material.maps[SHADER_LOC_COLOR_SPECULAR].color.g/255.0f,
-            (float)material.maps[SHADER_LOC_COLOR_SPECULAR].color.b/255.0f,
-            (float)material.maps[SHADER_LOC_COLOR_SPECULAR].color.a/255.0f
+            (float)material.maps[MATERIAL_MAP_SPECULAR].color.r/255.0f,
+            (float)material.maps[MATERIAL_MAP_SPECULAR].color.g/255.0f,
+            (float)material.maps[MATERIAL_MAP_SPECULAR].color.b/255.0f,
+            (float)material.maps[MATERIAL_MAP_SPECULAR].color.a/255.0f
         };
 
         rlSetUniform(material.shader.locs[SHADER_LOC_COLOR_SPECULAR], values, SHADER_UNIFORM_VEC4, 1);