From 1bb794dd39987ee26fd08cb104a3539013ac8a0c Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <mclaughc@outlook.com>
Date: Sun, 15 Sep 2019 01:18:58 +1000
Subject: [PATCH] GPU: Use max vertex count based on buffer size

---
 src/pse/gpu_hw.cpp        |  4 +++-
 src/pse/gpu_hw.h          |  5 +++--
 src/pse/gpu_hw_opengl.cpp | 12 ++++--------
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/pse/gpu_hw.cpp b/src/pse/gpu_hw.cpp
index 60f1e8145..1cc25c35e 100644
--- a/src/pse/gpu_hw.cpp
+++ b/src/pse/gpu_hw.cpp
@@ -379,7 +379,9 @@ void GPU_HW::DispatchRenderCommand(RenderCommand rc, u32 num_vertices)
   // flush when the command changes
   if (!m_batch_vertices.empty())
   {
-    if (m_batch_vertices.size() >= MAX_BATCH_VERTEX_COUNT || m_batch_command.bits != rc.bits)
+    // including the degenerate triangles for strips
+    const u32 max_added_vertices = num_vertices + 2;
+    if ((m_batch_vertices.size() + max_added_vertices) >= MAX_BATCH_VERTEX_COUNT || m_batch_command.bits != rc.bits)
       FlushRender();
   }
 
diff --git a/src/pse/gpu_hw.h b/src/pse/gpu_hw.h
index a84c3a99e..1d8708d23 100644
--- a/src/pse/gpu_hw.h
+++ b/src/pse/gpu_hw.h
@@ -11,8 +11,6 @@ public:
   virtual ~GPU_HW();
 
 protected:
-  static constexpr u32 MAX_BATCH_VERTEX_COUNT = 1024;
-
   struct HWVertex
   {
     s32 x;
@@ -28,6 +26,9 @@ protected:
     static constexpr u16 EncodeTexcoord(u8 x, u8 y) { return ZeroExtend16(x) | (ZeroExtend16(y) << 8); }
   };
 
+  static constexpr u32 VERTEX_BUFFER_SIZE = 1 * 1024 * 1024;
+  static constexpr u32 MAX_BATCH_VERTEX_COUNT = VERTEX_BUFFER_SIZE / sizeof(HWVertex);
+
   static constexpr std::tuple<float, float, float, float> RGBA8ToFloat(u32 rgba)
   {
     return std::make_tuple(static_cast<float>(rgba & UINT32_C(0xFF)) * (1.0f / 255.0f),
diff --git a/src/pse/gpu_hw_opengl.cpp b/src/pse/gpu_hw_opengl.cpp
index 7bfbaa958..0b14b5cd3 100644
--- a/src/pse/gpu_hw_opengl.cpp
+++ b/src/pse/gpu_hw_opengl.cpp
@@ -81,7 +81,7 @@ void GPU_HW_OpenGL::CreateVertexBuffer()
 {
   glGenBuffers(1, &m_vertex_buffer);
   glBindBuffer(GL_ARRAY_BUFFER, m_vertex_buffer);
-  glBufferData(GL_ARRAY_BUFFER, 128, nullptr, GL_STREAM_DRAW);
+  glBufferData(GL_ARRAY_BUFFER, VERTEX_BUFFER_SIZE, nullptr, GL_STREAM_DRAW);
 
   glGenVertexArrays(1, &m_vao_id);
   glBindVertexArray(m_vao_id);
@@ -339,14 +339,10 @@ void GPU_HW_OpenGL::FlushRender()
   glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer_fbo_id);
   glBindVertexArray(m_vao_id);
 
+  Assert((m_batch_vertices.size() * sizeof(HWVertex)) <= VERTEX_BUFFER_SIZE);
   glBindBuffer(GL_ARRAY_BUFFER, m_vertex_buffer);
-  glBufferData(GL_ARRAY_BUFFER, static_cast<GLsizei>(sizeof(HWVertex) * m_batch_vertices.size()),
-               m_batch_vertices.data(), GL_STREAM_DRAW);
-  glVertexAttribIPointer(0, 2, GL_INT, sizeof(HWVertex), reinterpret_cast<void*>(offsetof(HWVertex, x)));
-  glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
-                        reinterpret_cast<void*>(offsetof(HWVertex, color)));
-  glVertexAttribPointer(2, 2, GL_UNSIGNED_BYTE, true, sizeof(HWVertex),
-                        reinterpret_cast<void*>(offsetof(HWVertex, texcoord)));
+  glBufferSubData(GL_ARRAY_BUFFER, 0, static_cast<GLsizei>(sizeof(HWVertex) * m_batch_vertices.size()),
+                  m_batch_vertices.data());
 
   const bool is_strip = ((m_batch_command.primitive == Primitive::Polygon && m_batch_command.quad_polygon) ||
                          m_batch_command.primitive == Primitive::Rectangle);