Route paint render state through GL backend

src/hmd.cpp

@@ -1,8 +1,34 @@
 #include "pch.h"
 #include "hmd.h"
 #include "log.h"
+#include "renderer_gl/opengl_capabilities.h"
 #include <array>
 
+namespace {
+
+void set_opengl_viewport(std::int32_t x, std::int32_t y, std::int32_t width, std::int32_t height) noexcept
+{
+    glViewport(static_cast<GLint>(x), static_cast<GLint>(y), static_cast<GLsizei>(width), static_cast<GLsizei>(height));
+}
+
+void apply_hmd_viewport(std::int32_t x, std::int32_t y, std::int32_t width, std::int32_t height)
+{
+    const auto status = pp::renderer::gl::apply_opengl_viewport(
+        pp::renderer::gl::OpenGlViewportRect {
+            .x = x,
+            .y = y,
+            .width = width,
+            .height = height,
+        },
+        pp::renderer::gl::OpenGlViewportDispatch {
+            .viewport = set_opengl_viewport,
+        });
+    if (!status.ok())
+        LOG("HMD viewport dispatch failed because: %s", status.message);
+}
+
+}
+
 std::map<ViveController::kButton, ViveController::kButtonMask> ViveController::m_mask {
     { ViveController::kButton::Trigger, ViveController::kButtonMask::TriggerBit },
     { ViveController::kButton::Pad, ViveController::kButtonMask::PadBit },
@@ -181,7 +207,7 @@ void Vive::Draw()
     {
         m_eyes[eye].bindFramebuffer();
         m_eyes[eye].clear();
-        glViewport(0, 0, m_eyes[eye].getWidth(), m_eyes[eye].getHeight());
+        apply_hmd_viewport(0, 0, m_eyes[eye].getWidth(), m_eyes[eye].getHeight());
 
         if (on_draw)
             on_draw(m_proj[eye], m_view[eye], m_pose);