simple_renderer.cpp

    // Render meshes
    {
        glEnable(GL_CULL_FACE);
        glEnable(GL_DEPTH_TEST);

        gl->pbrShader.Use();

        glUniformMatrix4fv(gl->pbrShader.projLoc, 1, GL_FALSE, projection.e);
        glUniformMatrix4fv(gl->pbrShader.viewLoc, 1, GL_FALSE, view.e);

        mat4 viewInverse = Mat4::InverseTransformNoScale(view);

        GLMesh* lastMesh = nullptr;
        GLMaterial* lastMaterial = nullptr;
        for (GLDrawCall& drawCall : gl->drawList.drawCalls)
        {
            mat4 modelView    = view * drawCall.model;
            mat4 normalMatrix = Mat4::Transpose(drawCall.modelInverse * viewInverse);

            glUniformMatrix4fv(gl->pbrShader.modelViewLoc, 1, GL_FALSE, modelView.e);
            glUniformMatrix4fv(gl->pbrShader.normalMatrixLoc, 1, GL_FALSE, normalMatrix.e);

            if (drawCall.material != lastMaterial)
            {
                drawCall.material->BindTo(gl->pbrShader);
                lastMaterial = drawCall.material;
            }

            if (drawCall.mesh != lastMesh)
            {
                drawCall.mesh->Bind();
                lastMesh = drawCall.mesh;
            }

            drawCall.mesh->Draw();
        }
    }

    gl->skybox.Draw(projection, view);