gl_state: Implement PROGRAM_POINT_SIZE

For gl_PointSize to have effect we have to activate
GL_PROGRAM_POINT_SIZE.

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -1272,6 +1272,7 @@ void RasterizerOpenGL::SyncPointState() {
     const auto& regs = system.GPU().Maxwell3D().regs;
     // Limit the point size to 1 since nouveau sometimes sets a point size of 0 (and that's invalid
     // in OpenGL).
+    state.point.program_control = regs.vp_point_size.enable ? GL_TRUE : GL_FALSE;
     state.point.size = std::max(1.0f, regs.point_size);
 }
 

src/video_core/renderer_opengl/gl_state.cpp

@@ -127,6 +127,7 @@ void OpenGLState::ApplyClipDistances() {
 }
 
 void OpenGLState::ApplyPointSize() {
+    Enable(GL_PROGRAM_POINT_SIZE, cur_state.point.program_control, point.program_control);
     if (UpdateValue(cur_state.point.size, point.size)) {
         glPointSize(point.size);
     }

src/video_core/renderer_opengl/gl_state.h

@@ -131,7 +131,8 @@ public:
     std::array<Viewport, Tegra::Engines::Maxwell3D::Regs::NumViewports> viewports;
 
     struct {
-        float size = 1.0f; // GL_POINT_SIZE
+        GLboolean program_control = GL_FALSE; // GL_PROGRAM_POINT_SIZE
+        GLfloat size = 1.0f;                  // GL_POINT_SIZE
     } point;
 
     struct {