Fix out of bound Memory read in Material.maps (#5534)

* Fix out of bounds Memory read in Material.Maps by using the MATERIAL_MAP_SPECULAR define instead of the SHADER_LOG_SPECULAR enum

* Fix out of bounds Memory read in Material.Maps by using the MATERIAL_MAP_SPECULAR define instead of the SHADER_LOG_SPECULAR enum

src/rmodels.c

@@ -1719,10 +1719,10 @@ void DrawMeshInstanced(Mesh mesh, Material material, const Matrix *transforms, i
     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);